{"product_id":"can-exercise-protect-memory-and-daily-functioning-after-colorectal-cancer-surgery-results-from-the-physsurg-c-trial","title":"Can Exercise Protect Memory and Daily Functioning After Colorectal Cancer Surgery? Results From the PHYSSURG-C Trial","description":"\u003cp\u003eThis exploratory secondary analysis of the PHYSSURG-C randomised controlled trial examined whether a short-term, unsupervised exercise programme could protect memory and daily functioning in 631 patients undergoing surgery for colorectal cancer. The exercise programme involved moderately intense aerobic activity for 30 minutes a day, starting two weeks before surgery and continuing for four weeks after. At four weeks after surgery, the exercise group was more likely to report a greater ability to shop for food or other necessities (OR 1.53, 95% CI 1.07 to 2.20). At twelve months, the exercise group was less likely to report being told they had poor memory (OR 0.61, 95% CI 0.38 to 0.98). No other significant differences appeared between the groups. The authors concluded that an exercise programme of this duration and intensity may be insufficient to substantially improve memory or daily activities compared with standard care.\u003c\/p\u003e\n\n\u003ch1\u003eCan Exercise Protect Memory and Daily Functioning After Colorectal Cancer Surgery? Results From the PHYSSURG-C Trial\u003c\/h1\u003e\n\n\u003ch2\u003eTable of Contents\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\u003ca href=\"#ddn-key-points\"\u003eKey Points\u003c\/a\u003e\u003c\/li\u003e\n\n  \u003cli\u003e\u003ca href=\"#background\"\u003eBackground: Why This Research Matters\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#study-methods\"\u003eHow the Study Was Conducted\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#participants\"\u003eWho Took Part in the Study\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#intervention\"\u003eWhat the Exercise Programme Involved\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#outcomes\"\u003eWhat the Researchers Measured\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#statistical-analysis\"\u003eHow the Data Were Analysed\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#key-findings\"\u003eKey Findings: Memory Function\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#daily-activities\"\u003eKey Findings: Daily Activities\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#time-effects\"\u003eChanges Over Time in the Whole Group\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#discussion\"\u003eWhat These Results Mean\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#limitations\"\u003eLimitations: What the Study Could Not Prove\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#recommendations\"\u003eRecommendations for Patients\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#ddn-faq\"\u003eFrequently Asked Questions\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"#source\"\u003eSource Information\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003c!-- ddn:keypoints:start --\u003e\n\u003ch2 id=\"ddn-key-points\"\u003eKey Points\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eIn 631 patients having colorectal cancer surgery, a short unsupervised exercise programme did not substantially improve self-reported memory or daily activities compared with standard care.\u003c\/li\u003e\n\u003cli\u003eAt four weeks, the exercise group was more likely to report a greater ability to shop for food or other necessities (odds ratio 1.53).\u003c\/li\u003e\n\u003cli\u003eAt twelve months, the exercise group was less likely to report being told they had poor memory (odds ratio 0.61); no other memory differences appeared.\u003c\/li\u003e\n\u003cli\u003eIn the whole group, daily activities declined at four weeks after surgery and recovered by twelve months; memory declined at twelve months.\u003c\/li\u003e\n\u003cli\u003eThe trial was not designed for these outcomes, may have been underpowered, and used self-reported questions not validated against other instruments.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- ddn:keypoints:end --\u003e\n\n\n\u003ch2 id=\"background\"\u003eBackground: Why This Research Matters\u003c\/h2\u003e\n\n\u003cp\u003eCognitive function (the brain's ability to think, remember, and process information) can decline in patients after treatment for colorectal cancer. Colorectal cancer is the third most common cancer worldwide. This makes the question of how to protect brain function during and after cancer treatment an important one for many patients.\u003c\/p\u003e\n\n\u003cp\u003eThe causes of cancer-related cognitive difficulties are multifactorial. This means that many different factors contribute to the problem. The cancer itself can cause cognitive changes. Cancer treatments, including chemotherapy and radiation, can also cause cognitive decline. Even surgery itself can contribute to cognitive difficulties.\u003c\/p\u003e\n\n\u003cp\u003ePostoperative cognitive decline (a drop in thinking and memory abilities after surgery) is often temporary. However, some patients may experience persistent symptoms. This is especially true for elderly patients. The cognitive problems that patients with cancer most commonly report concern memory and executive function.\u003c\/p\u003e\n\n\u003cp\u003eExecutive function refers to a set of mental skills that include planning ahead, making decisions, following conversations, and resuming activities after an interruption. A decline in executive function can require increased effort to perform these everyday tasks.\u003c\/p\u003e\n\n\u003cp\u003eBoth memory and executive function are linked to the ability to perform daily activities. This is especially true for instrumental activities of daily living (the tasks needed to live independently), such as household chores and shopping. A reduced ability to perform daily activities can itself be a sign of cognitive decline.\u003c\/p\u003e\n\n\u003cp\u003eHabitual physical activity has a modest protective effect on cognitive decline. Physical exercise has been suggested as a possible intervention to reduce cancer-related cognitive impairment and postoperative cognitive decline. However, recent reviews have found that the evidence regarding the effects of physical activity on cancer-related cognitive difficulties is inconclusive. This is true for both short-term and long-term effects.\u003c\/p\u003e\n\n\u003cp\u003eStudies of long-term effects were underrepresented in the existing research. Most assessments of cognitive function occurred at the end of the intervention period. Also, few studies on the effect of physical activity on cognition after cancer treatment have included patients with colorectal cancer. Among those that did, the randomised trials were small or focused on effects after neoadjuvant or adjuvant treatment (treatment given before or after the main treatment).\u003c\/p\u003e\n\n\u003cp\u003ePHYSSURG-C was a large multicentre randomised controlled trial of an unsupervised, short-term physical activity intervention. The trial enrolled patients who were scheduled for elective surgery for colorectal cancer. The trial was primarily designed to investigate recovery after surgery. This exploratory study used data from PHYSSURG-C. The study explored the effect of the physical activity intervention, compared with usual care, on self-reported memory function and the ability to perform daily activities. The study looked at these outcomes at 4 weeks and 12 months after surgery.\u003c\/p\u003e\n\n\u003ch2 id=\"study-methods\"\u003eHow the Study Was Conducted\u003c\/h2\u003e\n\n\u003cp\u003ePHYSSURG-C was an open-label randomised controlled superiority trial. \"Open-label\" means that both participants and care providers knew which treatment group each participant was in. \"Randomised\" means that participants were assigned to groups by chance. \"Superiority trial\" means the trial was designed to test whether one treatment was better than another.\u003c\/p\u003e\n\n\u003cp\u003eThe trial recruited patients from five regional hospitals and one university hospital in Sweden. The recruitment period ran from 2015 to 2020. The trial was registered at ClinicalTrials.gov (NCT02299596) on 17 November 2014. The study protocol has been published. Results for the primary endpoints at 4 weeks and 12 months after surgery have also been published.\u003c\/p\u003e\n\n\u003cp\u003eThe intervention involved two parts. First, participants performed preoperative inspiratory muscle training (breathing exercises to strengthen the muscles used for breathing) during approximately two weeks before surgery. Second, participants increased their physical activity beginning about two weeks before surgery and continuing for four weeks after discharge from hospital.\u003c\/p\u003e\n\n\u003cp\u003ePatients and the public were not involved in the design, conduct, or reporting of this trial.\u003c\/p\u003e\n\n\u003ch2 id=\"participants\"\u003eWho Took Part in the Study\u003c\/h2\u003e\n\n\u003cp\u003ePatients aged 20 years or older with colorectal cancer who were scheduled to undergo elective surgery with curative intent were eligible for inclusion. \"Curative intent\" means the surgery was intended to cure the cancer. \"Elective\" means the surgery was planned in advance, not an emergency.\u003c\/p\u003e\n\n\u003cp\u003eThe exclusion criteria were:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eEmergency surgery\u003c\/li\u003e\n  \u003cli\u003eLocal excision (removal of only the tumour and a small amount of surrounding tissue)\u003c\/li\u003e\n  \u003cli\u003eCytoreductive surgery with hyperthermic intraperitoneal chemotherapy (a specialised procedure that combines surgery with heated chemotherapy delivered directly into the abdominal cavity)\u003c\/li\u003e\n  \u003cli\u003eInability to perform the intervention or to understand instructions and questionnaires (for example, due to a language barrier)\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003ePatients were included at the time of diagnosis by hospital staff at the Departments of Surgery in the participating hospitals.\u003c\/p\u003e\n\n\u003cp\u003eRandomisation was centralised and computerised. Participants were allocated in a 1:1 ratio to the intervention group or the control group. The allocation used a block size of 4 and parallel groups. Stratification was made by surgical technique (laparoscopic or open surgery), by tumour site, and by whether the patient received neoadjuvant radiotherapy. Stratification means that these factors were balanced between the two groups.\u003c\/p\u003e\n\n\u003cp\u003eNeither participants nor care providers were blinded. This means that everyone knew which group each participant was in.\u003c\/p\u003e\n\n\u003cp\u003eOf the 761 randomised participants, a total of 631 completed the study. Of these, 296 were in the intervention group and 335 were in the control group. The lowest return rate for the questionnaire was 80% at the 12-month follow-up in the control group.\u003c\/p\u003e\n\n\u003cp\u003eThe study population had a median age of 70 years. Thirty-nine percent were women, and 61% were men. The two groups were balanced regarding demographic variables.\u003c\/p\u003e\n\n\u003cp\u003eTable 1 in the original article provides detailed demographic information:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eAge:\u003c\/strong\u003e Median 70 years in both groups (intervention group Q1–Q3: 62–76; control group Q1–Q3: 62–77)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSex:\u003c\/strong\u003e Intervention group 116 women (39%) and 180 men (61%); control group 132 women (39%) and 203 men (61%)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eBody Mass Index (BMI):\u003c\/strong\u003e Median 25.5 in the intervention group and 25.3 in the control group\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eBorn in Sweden:\u003c\/strong\u003e 243 (86%) in the intervention group and 273 (87%) in the control group\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eEducation level:\u003c\/strong\u003e Compulsory school only — 54 (19%) intervention vs 69 (22%) control; upper secondary — 120 (43%) intervention vs 139 (44%) control; university — 105 (38%) intervention vs 107 (34%) control\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMarital status:\u003c\/strong\u003e Married or cohabiting — 205 (72%) intervention vs 240 (76%) control; single or living alone — 78 (28%) intervention vs 76 (24%) control\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCurrent regular smoker:\u003c\/strong\u003e 8 (2.8%) in the intervention group and 8 (2.5%) in the control group\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eASA classification (a measure of overall health before surgery):\u003c\/strong\u003e ASA 1 — 50 (19%) intervention vs 53 (18%) control; ASA 2 — 159 (61%) intervention vs 177 (61%) control; ASA 3 — 47 (18%) intervention vs 62 (21%) control; ASA 4 — 3 (1.2%) intervention vs 0 (0%) control\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eTumour site:\u003c\/strong\u003e Colon — 151 (51%) intervention vs 165 (49%) control; rectum — 145 (49%) intervention vs 170 (51%) control\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eNeoadjuvant therapy:\u003c\/strong\u003e No radio- or chemotherapy — 191 (65%) intervention vs 215 (64%) control; long chemo(radio)therapy — 35 (12%) intervention vs 39 (12%) control; short-term radiotherapy — 70 (24%) intervention vs 81 (24%) control\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSurgical technique:\u003c\/strong\u003e Laparoscopic — 188 (68%) intervention vs 201 (64%) control; open — 88 (32%) intervention vs 111 (36%) control\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003epTNM stage (a system for describing how far cancer has spread):\u003c\/strong\u003e Stage 0 — 1 (0.4%) intervention vs 1 (0.3%) control; Stage I — 78 (29%) intervention vs 86 (28%) control; Stage II — 66 (24%) intervention vs 91 (30%) control; Stage III — 109 (40%) intervention vs 103 (34%) control; Stage IV — 16 (5.9%) intervention vs 26 (8.5%) control\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePostoperative confusion:\u003c\/strong\u003e 6 (2.0%) in the intervention group and 16 (4.8%) in the control group\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eReceived adjuvant treatment:\u003c\/strong\u003e 113 (38%) in the intervention group and 115 (34%) in the control group\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eThe high-risk subgroup included 252 participants. Of these, 93 were in the intervention group. In the intervention group, 197 participants complied with the intervention as per-protocol. This means they performed at least eight preoperative days of exercise.\u003c\/p\u003e\n\n\u003ch2 id=\"intervention\"\u003eWhat the Exercise Programme Involved\u003c\/h2\u003e\n\n\u003cp\u003eAll participants received general information about the aim of the study. All participants also followed local routines for pre- and postoperative care.\u003c\/p\u003e\n\n\u003cp\u003eParticipants in the intervention group met individually with a physiotherapist. During this meeting, they discussed suitable activities to achieve a moderately intense level of exercise. The physiotherapist instructed them to perform inspiratory muscle training. The physiotherapist also instructed them to add 30 minutes of aerobic activity of their own choice daily to their normal routine. This was to begin 14 days (with a margin of 4 days) before surgery.\u003c\/p\u003e\n\n\u003cp\u003eParticipants were also instructed to resume the same level of physical activity as the preoperative phase after discharge from hospital. They were asked to maintain this level for 4 weeks.\u003c\/p\u003e\n\n\u003cp\u003eAll participants recorded the nature of the performed exercise, the duration, and the type of activity in a diary. All participants received a phone call from a research nurse. The nurse enquired about any adverse events, provided reminders to increase resistance during inspiratory muscle training, and motivated participation. The procedure has previously been described in detail in a separate publication.\u003c\/p\u003e\n\n\u003ch2 id=\"outcomes\"\u003eWhat the Researchers Measured\u003c\/h2\u003e\n\n\u003cp\u003eBaseline data were collected by electronic and paper case report forms. Data regarding tumour classification and the surgical procedure were retrieved from the Swedish ColoRectal Cancer Registry. Data on complications, neoadjuvant treatments, and adjuvant treatments were extracted from medical charts.\u003c\/p\u003e\n\n\u003cp\u003eParticipants received questionnaires preoperatively at inclusion and at 4 weeks and 12 months after surgery. The questionnaires and exercise diaries were returned to the central study secretariat.\u003c\/p\u003e\n\n\u003cp\u003eOutcome data were obtained from questionnaires administered at the 4-week and 12-month follow-ups in the original trial. The questions were originally developed by the research group to be used in cohort studies on quality of life in patients with cancer. The questions were constructed after content analysis of semi-structured patient interviews. They then underwent expert and patient face validation. The questions on memory function and daily activities were framed to cover the duration of the past month.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eMemory function\u003c\/strong\u003e was measured with three questions:\u003c\/p\u003e\n\u003col\u003e\n  \u003cli\u003eOne general question about whether anyone had told or suggested to the participant that they had poor memory\u003c\/li\u003e\n  \u003cli\u003eOne question on subjective memory difficulties recalling factual information\u003c\/li\u003e\n  \u003cli\u003eOne question on subjective memory difficulties remembering names\u003c\/li\u003e\n\u003c\/ol\u003e\n\n\u003cp\u003eThe questions had the same seven response categories based on frequency, ranging from never to all the time. In the analysis, three of the categories corresponding to daily frequency were combined into one, representing daily occurrence.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eDaily activities\u003c\/strong\u003e were measured with four questions:\u003c\/p\u003e\n\u003col\u003e\n  \u003cli\u003eOne question on the proportion of daily activities performed, with five response categories ranging from none to all\u003c\/li\u003e\n  \u003cli\u003eThree questions on the ability to perform specific activities (household tasks, shopping, and socialising), with four response categories ranging from no ability to great ability\u003c\/li\u003e\n\u003c\/ol\u003e\n\n\u003cp\u003eParticipants who selected the response category \"not applicable\" for the specific activity questions were excluded from those analyses.\u003c\/p\u003e\n\n\u003ch2 id=\"statistical-analysis\"\u003eHow the Data Were Analysed\u003c\/h2\u003e\n\n\u003cp\u003eA power analysis was performed for the primary outcome of the PHYSSURG-C trial (physical recovery) in a preplanned interim analysis. No posterior power analysis was performed for the outcomes examined in this study (memory function and daily activities). Statistical analyses were performed according to a predefined statistical analysis plan for these outcomes.\u003c\/p\u003e\n\n\u003cp\u003eThis study evaluated secondary outcomes of the PHYSSURG-C trial. These analyses were regarded as exploratory without the intention of making confirmatory claims. Therefore, no correction for multiple testing was applied.\u003c\/p\u003e\n\n\u003cp\u003eThe primary analysis included the intention-to-treat population, as randomised. Intention-to-treat means that all participants were analysed in the group they were originally assigned to, regardless of whether they completed the intervention.\u003c\/p\u003e\n\n\u003cp\u003eProportional odds logistic regression models were fitted to estimate the effect of treatment (intervention vs control) on ordinal outcomes assessed at 4 weeks and 12 months. Ordinal outcomes are outcomes with categories that have a natural order, such as \"never, sometimes, often, always.\" The proportional odds model was used to maintain multiple response levels. The proportional odds model also maintained the order of these response levels within the model.\u003c\/p\u003e\n\n\u003cp\u003eThe proportional odds assumption was evaluated using the Brant test and held across models. Analyses were adjusted for stratification factors used in the trial (surgical method, tumour location, and neoadjuvant therapy) and preoperative values of the corresponding outcome variables. Missing data were handled using listwise deletion; no imputation was performed. Listwise deletion means that participants with missing data for a particular analysis were excluded from that analysis.\u003c\/p\u003e\n\n\u003cp\u003eResults are presented using odds ratios (OR) for the intervention versus the control group, with 95% confidence intervals (CI) and p values. An odds ratio compares the odds of an outcome in one group to the odds in another group. A 95% confidence interval is a range of values that is likely to contain the true effect. A p value indicates the probability that the result occurred by chance.\u003c\/p\u003e\n\n\u003cp\u003eA per-protocol analysis was also performed. This analysis included only participants in the intervention group who reported aerobic exercise or inspiratory muscle training on at least 8 days between inclusion and surgery. This represents no less than 80% of the minimum available days (14 minus 4 days). The remaining participants in the intervention arm were excluded, while all participants in the control arm were included in this analysis.\u003c\/p\u003e\n\n\u003cp\u003eAn intervention with pre- and postoperative physical activity is likely to have the largest effect in patients who have a high risk of prolonged recovery. The largest effect is also likely in patients who are habitually relatively physically inactive. Therefore, a supporting per-protocol subgroup analysis was performed for high-risk inactive patients. The subgroup was defined by fulfilling two conditions:\u003c\/p\u003e\n\u003col\u003e\n  \u003cli\u003eAge over 70 years, or ASA classification of 3 or higher, or long neoadjuvant therapy\u003c\/li\u003e\n  \u003cli\u003eLow physical activity, defined as a score of 2 or less on the Saltin-Grimby physical activity level scale\u003c\/li\u003e\n\u003c\/ol\u003e\n\n\u003cp\u003eFurther, a post hoc time-effect analysis with an unadjusted proportional odds logistic regression model was carried out for descriptive purposes. This was done to examine if there were any detectable changes in the outcomes over time. The researchers reasoned that if there were no changes over time, it would be unlikely that the intervention could have shown any effect. As this was a post hoc analysis intended to evaluate the measurement and not compare groups, the whole cohort was pooled in the analysis. The compared timepoints were preoperatively to 4 weeks, preoperatively to 12 months, and 4 weeks to 12 months.\u003c\/p\u003e\n\n\u003cp\u003eAll statistical analyses were performed in R, version 4.3.2.\u003c\/p\u003e\n\n\u003ch2 id=\"key-findings\"\u003eKey Findings: Memory Function\u003c\/h2\u003e\n\n\u003cp\u003eThere were no differences between the intervention and control groups at 4 weeks regarding any of the memory outcomes.\u003c\/p\u003e\n\n\u003cp\u003eAt 12 months, a difference between the groups was observed regarding whether the participant was told or suggested they had poor memory. The odds ratio was 0.61 (95% CI 0.38 to 0.98), favouring the intervention group. An odds ratio below 1 indicates a higher likelihood that the intervention group reported memory difficulties occurring less often than the control group. In plain language, participants in the exercise group were less likely to report being told they had poor memory at 12 months.\u003c\/p\u003e\n\n\u003cp\u003eThe results of the analyses for the high-risk subgroup and the per-protocol population showed no significant effects on memory function.\u003c\/p\u003e\n\n\u003cp\u003eThe time-effect analyses for the whole cohort did not show increased memory difficulties at 4 weeks compared with preoperative levels. In contrast, difficulties remembering names were less pronounced at 4 weeks compared with preoperative levels (OR 0.67, 95% CI 0.51 to 0.87). At 12 months, there was a decline in memory function compared with levels both preoperatively and at 4 weeks for all questions.\u003c\/p\u003e\n\n\u003ch2 id=\"daily-activities\"\u003eKey Findings: Daily Activities\u003c\/h2\u003e\n\n\u003cp\u003eThe proportion of daily activities performed did not differ between the groups at 4 weeks (OR 0.96, 95% CI 0.69 to 1.33).\u003c\/p\u003e\n\n\u003cp\u003eRegarding specific tasks, the intervention group had a higher ability to shop for food or other necessities at 4 weeks. The odds ratio was 1.53 (95% CI 1.07 to 2.20). An odds ratio above 1 indicates a higher likelihood that the intervention group reported having a greater ability than the control group.\u003c\/p\u003e\n\n\u003cp\u003eThere was no statistically significant difference between the groups at 12 months for any daily activity outcome.\u003c\/p\u003e\n\n\u003cp\u003eThe per-protocol analysis showed the same pattern as the primary analysis. There was a difference at 4 weeks in the ability to shop for food or other necessities. There was no difference between the groups in the high-risk subgroup analysis.\u003c\/p\u003e\n\n\u003cp\u003eThe time-effect analysis for the whole cohort showed that the ability to perform daily activities had declined 4 weeks after surgery compared with preoperatively. The ability then recovered from 4 weeks to 12 months.\u003c\/p\u003e\n\n\u003ch2 id=\"time-effects\"\u003eChanges Over Time in the Whole Group\u003c\/h2\u003e\n\n\u003cp\u003eThe time-effect analysis examined how memory and daily activities changed over time in the entire study population, regardless of which group participants were in.\u003c\/p\u003e\n\n\u003cp\u003eFor memory function, the analysis showed that memory difficulties did not increase at 4 weeks after surgery compared with preoperative levels. In fact, difficulties remembering names were less pronounced at 4 weeks compared with preoperative levels (OR 0.67, 95% CI 0.51 to 0.87). However, at 12 months, there was a decline in memory function compared with levels both preoperatively and at 4 weeks for all questions.\u003c\/p\u003e\n\n\u003cp\u003eFor daily activities, the ability to perform daily activities declined 4 weeks after surgery compared with preoperatively. The ability then recovered from 4 weeks to 12 months.\u003c\/p\u003e\n\n\u003cp\u003eThese time-effect findings are important for interpreting the results. They show that the measurement instruments were able to detect changes over time. This makes it more likely that the lack of significant differences between the groups reflects a true lack of effect, rather than a problem with the measurement tools.\u003c\/p\u003e\n\n\u003ch2 id=\"discussion\"\u003eWhat These Results Mean\u003c\/h2\u003e\n\n\u003cp\u003eIn this exploratory study, nested in a multicentre randomised controlled trial, the researchers found no clear overall pattern in the results. The unsupervised, short-term, moderately intense aerobic pre- and postoperative exercise intervention had limited effects on memory function and the ability to perform daily activities based on self-reported outcomes.\u003c\/p\u003e\n\n\u003cp\u003eThis study contributes to the knowledge base on physical activity interventions to mitigate cancer-related cognitive decline. It does so through the analysis of data from a large randomised controlled trial with long-term follow-up and a population of patients with colorectal cancer. Previous evidence is primarily based on breast cancer cohorts and randomised trials with smaller sample sizes.\u003c\/p\u003e\n\n\u003cp\u003eBrunet and Sharma have called for better diversity and representation in studies exploring physical activity and cognition among patients with cancer. This applies both to cancer type and to participant characteristics.\u003c\/p\u003e\n\n\u003cp\u003eA major strength of this trial was the small number of exclusion criteria. This increases external validity, which means the results are more likely to apply to a broader population of patients. Patients who were screened but not randomised were comparable in age and sex to those who were included and randomised.\u003c\/p\u003e\n\n\u003cp\u003eThe compliance rate with the intervention was comparable with other studies of exercise prehabilitation among colorectal cancer surgery patients. The response rate for questionnaires was high, with over 80% at all timepoints.\u003c\/p\u003e\n\n\u003cp\u003eOf the explored outcomes, only the ability to shop for food or other necessities showed a significant difference at 4 weeks. This was seen in both the primary intention-to-treat analysis and the per-protocol analysis. Grocery shopping is a complex daily activity that demands cognitive abilities. It also requires physical exertion. The observed effect could be due to increased physical performance in the intervention group. It could also be that the exercise intervention encourages participants to spend more time outside of the home.\u003c\/p\u003e\n\n\u003cp\u003eOne memory outcome reached statistical significance in the primary analysis at 12 months. The estimated effects were in the same direction across all the memory outcomes at 12 months, although with wide confidence intervals. However, the exploratory nature of the analyses and multiple testing without correction warrant caution regarding the interpretation of the isolated significant p values observed.\u003c\/p\u003e\n\n\u003cp\u003eThe researchers had hypothesised that the intervention could be most effective in inactive individuals at a high risk of prolonged recovery. However, this was not found in the subgroup analysis. Notably, the loss of power due to the smaller sample size would have required a substantial effect to be detected in this subgroup compared with the whole study population.\u003c\/p\u003e\n\n\u003cp\u003eThe time-effect analysis showed that memory function had not declined at 4 weeks after surgery compared with preoperative values. Memory function then declined at 12 months compared both to levels at 4 weeks and preoperatively. The ability to perform daily activities declined at 4 weeks after surgery and then recovered from 4 weeks to 12 months.\u003c\/p\u003e\n\n\u003ch2 id=\"limitations\"\u003eLimitations: What the Study Could Not Prove\u003c\/h2\u003e\n\n\u003cp\u003eA limitation of this study is that the PHYSSURG-C trial was not designed to evaluate the intervention on cognitive outcomes. The sample size was not calculated for secondary outcomes. Therefore, the study could be underpowered for these exploratory analyses. \"Underpowered\" means the study may not have had enough participants to detect a true effect if one existed.\u003c\/p\u003e\n\n\u003cp\u003eObjective measurements, such as neurocognitive testing, are more sensitive than self-reported questionnaires. Objective measurements could have detected nuanced effects on memory function better than subjective measurements.\u003c\/p\u003e\n\n\u003cp\u003eThe outcomes are based on questions developed by the research group that have not been validated against other instruments or measurements. This limits comparability with other studies.\u003c\/p\u003e\n\n\u003cp\u003eA further limitation was that the analysis concerned one direct cognitive function (memory). The ability to perform daily activities provides only an indirect indication of cognitive functioning abilities. Thus, these results should not be generalised to all cognitive functions.\u003c\/p\u003e\n\n\u003cp\u003eThe study used no objective measures or established scoring instruments. This limits comparability with other studies.\u003c\/p\u003e\n\n\u003cp\u003eThe sample size was not calculated for secondary outcomes. This means the study may not have had enough statistical power to detect small but real differences between the groups.\u003c\/p\u003e\n\n\u003ch2 id=\"recommendations\"\u003eRecommendations for Patients\u003c\/h2\u003e\n\n\u003cp\u003eBased on the findings of this study, patients should understand the following:\u003c\/p\u003e\n\n\u003col\u003e\n  \u003cli\u003e\n\u003cstrong\u003eExercise is still beneficial for overall health.\u003c\/strong\u003e This study did not find that exercise was harmful. It simply did not find strong evidence that this particular short-term exercise programme improved memory or daily activities after colorectal cancer surgery.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMemory changes after surgery are common and often temporary.\u003c\/strong\u003e The study showed that memory function did not decline at 4 weeks after surgery compared with before surgery. However, memory did decline at 12 months. This suggests that memory changes can occur long after surgery.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eDaily activities typically recover over time.\u003c\/strong\u003e The ability to perform daily activities declined at 4 weeks after surgery but recovered by 12 months. This is a normal pattern of recovery after major surgery.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eDiscuss exercise plans with your healthcare team.\u003c\/strong\u003e The exercise programme in this study was unsupervised and short-term. A supervised programme or a longer programme might produce different results. Talk to your doctor or physiotherapist about what level of activity is right for you.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eReport memory concerns to your healthcare provider.\u003c\/strong\u003e If you notice persistent memory problems after cancer treatment, tell your doctor. These symptoms deserve attention and evaluation.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eBe patient with your recovery.\u003c\/strong\u003e Recovery after colorectal cancer surgery takes time. The study showed that daily functioning improved from 4 weeks to 12 months after surgery.\u003c\/li\u003e\n\u003c\/ol\u003e\n\n\u003cp\u003eThe authors concluded that this intervention had no substantial effect on self-reported memory function or the ability to perform daily activities after colorectal cancer surgery. The intervention was unsupervised, short-term moderately intense aerobic physical activity before and after surgery. It is possible that a physical activity intervention of this duration and intensity is insufficient to substantially improve postoperative recovery in patients with colorectal cancer compared with standard care.\u003c\/p\u003e\n\n\u003c!-- ddn:faq:start --\u003e\n\u003ch2 id=\"ddn-faq\"\u003eFrequently Asked Questions\u003c\/h2\u003e\n\u003ch3\u003eWhat was the exercise programme tested in this research?\u003c\/h3\u003e\n\u003cp\u003eParticipants in the exercise group met a physiotherapist and were asked to add 30 minutes of moderately intense aerobic activity of their own choice to their normal routine. This started about two weeks before surgery and continued for four weeks after hospital discharge. They also did breathing exercises to strengthen breathing muscles before surgery.\u003c\/p\u003e\n\u003ch3\u003eDid the exercise programme improve memory after colorectal cancer surgery?\u003c\/h3\u003e\n\u003cp\u003eAt four weeks after surgery, there were no differences between the exercise and control groups on any memory question. At twelve months, the exercise group was less likely to report being told they had poor memory (odds ratio 0.61). No other memory differences appeared. The authors concluded this short, unsupervised programme may be insufficient to substantially improve memory.\u003c\/p\u003e\n\u003ch3\u003eDid the exercise programme help with daily activities like shopping or household tasks?\u003c\/h3\u003e\n\u003cp\u003eAt four weeks after surgery, the exercise group was more likely to report a greater ability to shop for food or other necessities (odds ratio 1.53). No other daily activity differences appeared at four weeks, and there were no differences at twelve months. The authors concluded the programme may be insufficient to substantially improve daily activities.\u003c\/p\u003e\n\u003ch3\u003eWhat does an odds ratio of 0.61 mean for the memory finding?\u003c\/h3\u003e\n\u003cp\u003eAn odds ratio below 1 means the exercise group was less likely to report the outcome than the control group. For the memory question at twelve months, an odds ratio of 0.61 means the exercise group was less likely to report being told they had poor memory. The 95% confidence interval was 0.38 to 0.98.\u003c\/p\u003e\n\u003ch3\u003eWhat are the limitations of this research?\u003c\/h3\u003e\n\u003cp\u003eThe trial was not designed to test memory or daily activities, so it may not have had enough participants to detect a true effect. Outcomes relied on self-reported questions developed by the research group that were not validated against other instruments. Only memory was directly assessed; daily activities give only an indirect indication of cognitive function.\u003c\/p\u003e\n\u003ch3\u003eWhat should patients take away about exercise and recovery after colorectal cancer surgery?\u003c\/h3\u003e\n\u003cp\u003eExercise is still beneficial for overall health, and this study did not find it harmful. Memory changes after surgery are common and often temporary, but memory declined at twelve months in the whole group. Daily activities declined at four weeks and recovered by twelve months. Discuss exercise plans and any persistent memory concerns with your healthcare team.\u003c\/p\u003e\n\u003ch3\u003eWhen should a patient recovering from colorectal cancer surgery seek a second opinion about exercise and memory or daily functioning concerns?\u003c\/h3\u003e\n\u003cp\u003eConsider a second opinion if memory problems persist or worsen after colorectal cancer surgery, since memory function declined at 12 months compared with both preoperative and 4-week levels, and if daily activities are not recovering as expected, since ability declined at 4 weeks but recovered by 12 months. A short-term, unsupervised, moderately intense aerobic programme before and after surgery had limited effects on self-reported memory and daily activities, so a supervised or longer programme might produce different results. Discuss any exercise plan and persistent memory concerns with your healthcare team. Diagnostic Detectives Network provides independent expert second opinions.\u003c\/p\u003e\n\u003c!-- ddn:faq:end --\u003e\n\n\u003ch2 id=\"source\"\u003eSource Information\u003c\/h2\u003e\n\n\u003cp\u003e\u003cstrong\u003eOriginal article title:\u003c\/strong\u003e Effect of exercise on memory function and daily activities after colorectal cancer surgery: an exploratory secondary analysis from the randomised trial PHYSSURG-C.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eAuthors:\u003c\/strong\u003e Ehrencrona C, Li Y, Afshari K, Angenete E, Buratti S, Larsson C, Onerup A, Wedin A, Haglind E.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003ePublication:\u003c\/strong\u003e BMJ Open 2026;16:e120096. doi:10.1136\/bmjopen-2026-120096\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eAuthor affiliations:\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eDepartment of Surgery, SSORG - Scandinavian Surgical Outcomes Research Group, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden\u003c\/li\u003e\n  \u003cli\u003eBiostatistics, School of Public Health and Community Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden\u003c\/li\u003e\n  \u003cli\u003eDepartment of Surgery, Sahlgrenska University Hospital, Gothenburg, Region Västra Götaland, Sweden\u003c\/li\u003e\n  \u003cli\u003eDepartment of Psychology, University of Gothenburg, Gothenburg, Sweden\u003c\/li\u003e\n  \u003cli\u003eDepartment of Pediatric Oncology, Sahlgrenska University Hospital, Gothenburg, Region Västra Götaland, Sweden\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003e\u003cstrong\u003eTrial registration number:\u003c\/strong\u003e NCT02299596\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003ePublication type:\u003c\/strong\u003e Open access Original research\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eCopyright:\u003c\/strong\u003e © Author(s) (or their employer(s)) 2026. Re-use permitted under CC BY. Published by BMJ Group.\u003c\/p\u003e\n\n\u003cp\u003e\u003cem\u003eThis patient-friendly article is based on peer-reviewed research. It is intended for educational purposes and should not replace consultation with a qualified healthcare provider. Patients should discuss their individual health concerns and treatment options with their medical team.\u003c\/em\u003e\u003c\/p\u003e","brand":"DiagnosticDetectives.Com","offers":[{"title":"Default Title","offer_id":47816847032476,"sku":null,"price":0.0,"currency_code":"KRW","in_stock":true}],"url":"https:\/\/diagnosticdetectives.kr\/products\/can-exercise-protect-memory-and-daily-functioning-after-colorectal-cancer-surgery-results-from-the-physsurg-c-trial","provider":"DiagnosticDetectives.Com","version":"1.0","type":"link"}