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 can not 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. And the important thing here is that you really tailor 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. And 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 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 have to decide. Dr. Anton Titov, MD. Do you you need tissue biopsy? Or do you remove it? 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 PET CT scan. That would point the surgeon more towards an aggressive approach. Sometimes a solid lung nodule is PET CT negative. Such lung nodule tends to make you pull back a little bit on a solid nodule. 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? They are either inflammatory or they can be precursors to lung cancer. Dr. Michael Lanuti, MD. And 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 of 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. And so 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 develop a solid component, that's an indicator for an invasive cancer. That's where the treating team would say this. 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, but nevertheless subjective decision-making step. It is based on knowledge and experience. Agreed, and so 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 can not 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. 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. And I think being the expert in the lung, I think that we are well suited for diagnosing lung cancer in solitary lung nodules.