Diagnosing and Managing Lung Nodules: A Guide to Solid and Sub-Solid Findings

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• Causes of Lung Nodules
• Solid Nodule Diagnosis
• Sub-Solid Nodule Management
• Role of PET CT Scans
• Patient History Importance
• When to Consult an Expert
• Conclusion and Key Takeaways

Causes of Lung Nodules

Lung nodules discovered on a CT scan can have various causes. They are not automatically indicative of lung cancer. A solitary pulmonary nodule might be a benign tumor or the result of inflammation. As Dr. Michael Lanuti, MD, explains, nodules in a non-smoker require a different consideration than those found in a patient with a significant smoking history or a prior cancer diagnosis. The initial step is to differentiate the type of nodule, as this dictates the entire diagnostic pathway.

Solid Nodule Diagnosis

The diagnostic algorithm for a solid lung nodule often begins with assessing its size. Dr. Michael Lanuti, MD, states that for a small solid nodule under 8 millimeters in a patient with no cancer history, the standard approach is surveillance with an interval CT scan in three months. The primary goal is to monitor for any growth. Solid lung nodules that grow are always suspicious and typically warrant further intervention. Dr. Michael Lanuti, MD, emphasizes that treatment is highly tailored to the individual patient, as a one-size-fits-all cookbook approach does not work.

Sub-Solid Nodule Management

Sub-solid nodules, also known as ground-glass opacity nodules, are managed very differently from solid ones. According to Dr. Michael Lanuti, MD, these nodules can be inflammatory or precursors to lung cancer. A key characteristic is their potential for extremely slow growth, sometimes taking three to seven years to change. Management primarily involves long-term surveillance imaging. If a sub-solid nodule is stable at a three-month CT scan, the next scan might be scheduled for six months, eventually moving to annual scans if it remains unchanged for years.

Dr. Michael Lanuti, MD, notes that the development of a solid component within a sub-solid nodule is a significant red flag, indicating a potential invasive cancer that likely requires surgical removal if the patient is a candidate.

Role of PET CT Scans

A PET CT scan is a valuable functional imaging tool in evaluating lung nodules. Dr. Michael Lanuti, MD, explains that lung cancer cells tend to be metabolically active and pick up the radioactive glucose used in the scan, making a PET-positive nodule highly suspicious. This result often points a surgeon toward a more aggressive approach, such as biopsy or resection. Conversely, a solid lung nodule that is PET CT negative may allow the medical team to pull back and continue with surveillance, adding another layer to the nuanced decision-making process.

Patient History Importance

Patient history is a critical factor that drastically alters the management of a lung nodule. Dr. Michael Lanuti, MD, provides a clear example: a patient with a history of colon cancer who presents with a new solid lung nodule will be managed very differently than a lifelong nonsmoker with no cancer history. For the former, the nodule is immediately more suspicious as a potential metastasis, necessitating a more urgent and invasive diagnostic workup. This underscores why the diagnostic path must be tailored specifically to the individual.

When to Consult an Expert

Given the complexity and art of managing lung nodules, consulting a specialist is often advantageous. Dr. Michael Lanuti, MD, suggests that primary care physicians and even some pulmonologists who do not focus on this area daily should seek expert opinion. This can prevent unnecessary tests, save significant costs, and ensure the patient receives the most appropriate care plan. Experts can often provide a consultation based on a review of CT scans alone, even remotely, making their input accessible. Dr. Anton Titov, MD, and Dr. Lanuti agree that this step can save a lot of trouble for patients and providers alike.

Conclusion and Key Takeaways

Effectively managing lung nodules requires a nuanced, patient-specific approach guided by expertise. Dr. Michael Lanuti, MD, concludes that solid nodules are monitored for growth, while sub-solid nodules require long-term, sometimes years-long, surveillance for any changes. The decision to move from watching to acting hinges on subtle changes seen on sequential CT scans. Ultimately, the art of diagnosis lies in integrating nodule characteristics with the patient's full clinical picture, a task for which thoracic specialists are uniquely well-suited.

Full Transcript

Dr. Anton Titov, MD: What causes nodules in the lungs? How to treat multiple lung nodules? Lung nodules in a non-smoker may be a tumor or inflammation. Solid and sub-solid lung nodules. Is it lung cancer? Can lung nodules disappear?

Dr. Anton Titov, MD: It is common to find a single nodule in a lung on a CT scan. What to do with solitary pulmonary nodules is controversial. How do you approach solitary pulmonary nodules when you are consulted?

Dr. Anton Titov, MD: What is the general diagnostic algorithm? What people should know about pulmonary nodules?

Dr. Michael Lanuti, MD: That's a real art in the field. I think people cannot understand management of lung nodules very well. Physicians perhaps order too many diagnostic studies too fast.

Patients often present with a single nodule in the lung. We have to differentiate the type of lung nodule. There are nodules that are "solid". There are nodules that we call "sub-solid". Another term that you might see is "ground-glass" nodule, which is sub-solid.

Solid nodules have a different diagnostic algorithm than sub-solid nodules. Solid lung nodules can be several things, not necessarily cancer. It depends on where you are in the world.

Sometimes you see a single lung nodule. If it's under 8 millimeters, we generally say you need another interval scan. We have to see if that lung nodule changes. Someone who had no history of cancer.

The important thing here is that you really tailor the diagnostic path to the patient. There isn't any one cookbook way that you can say every patient has to follow this diagnostic path.

Dr. Michael Lanuti, MD: I'll give you an example. Sometimes the patient comes to me. This patient had a history of colon cancer. This patient now has a solid lung nodule.

I'm going to manage that lung nodule very differently than in someone who never had cancer and who now has a solid lung nodule. So small solid lung nodules in someone who has never had cancer are diagnosed in this way.

Let's say they are a nonsmoker. We would usually get an interval scan in three months and see what it looks like. Solid lung nodules that grow are always suspicious.

Dr. Michael Lanuti, MD: Then the surgeon has to decide.

Dr. Anton Titov, MD: Do you need a tissue biopsy? Or do you remove it?

Dr. Michael Lanuti, MD: Most of the time we say, "Things that are growing in the lung should be removed if patients are candidate for surgery." We can employ the use of a PET CT scan to look at the functionality of the lung nodule.

Lung cancer tends to pick up the radioactive glucose that's given with a PET CT scan. That would point the surgeon more towards an aggressive approach.

Sometimes a solid lung nodule is PET CT negative. Such a lung nodule tends to make you pull back a little bit. Again, you tailor diagnostic tests and therapy to the patient.

The flip side is we're seeing now many sub-solid lung nodules. Ground glass opacity nodules. Those are managed very differently.

Dr. Anton Titov, MD: What are sub-solid lung nodules?

Dr. Michael Lanuti, MD: They are either inflammatory or they can be precursors to lung cancer. Many people have sub-solid lung nodules, whether you're a smoker or not.

If you find sub-solid lung nodules, you can never stop watching them. Because sub-solid lung nodules can always over the years develop into a lung cancer.

Some sub-solid lung nodules are so slow. It takes three years for sub-solid lung nodules to start to grow. We've seen them take seven years to grow.

But sub-solid lung nodules we manage a lot of time with surveillance imaging. If sub-solid lung nodules are stable at three months, we then move the next chest CT scan to six months.

If sub-solid lung nodules are really stable for a while, we get a CT scan once a year. I will follow a ground-glass nodule for years with an annual scan whenever they start to grow.

Dr. Michael Lanuti, MD: Or if they ever start to develop a solid component, that's an indicator for an invasive cancer. That's where the treating team would say you need to do something about it.

Oftentimes we would say, "Remove it surgically," if they're a candidate.

Dr. Anton Titov, MD: So there are nuances to diagnose sub-solid lung nodules. So there is a general algorithm that you described. But also at each instance, at each branch of the algorithm, there is a very subjective decision-making step. It is based on knowledge and experience.

Dr. Michael Lanuti, MD: Agreed. I think that primary care physicians are not equipped to diagnose lung nodules. Pulmonologists know more, but if they do it all the time, usually they cannot spend too much money and manage lung nodules efficiently.

I do think that providers that are not doing it every day should probably consult with someone who is an expert.

Dr. Michael Lanuti, MD: So this is another example of the situation where consulting an expert could be very advantageous. It can save a lot of trouble and a lot of money for people.

Dr. Anton Titov, MD: Expert opinion can be based on the CT scans, even remotely.

Dr. Michael Lanuti, MD: Yes. In fact, we oftentimes are asked to review outside lung CT scans from across the world. We decide what to do with these lung nodules.

I think being the expert in the lung, we are well suited for diagnosing lung cancer in solitary lung nodules.