Dr. Mark Socinski, University of Pittsburgh Medical Center, defines the three compartments in stage III (locally advanced) NSCLC, each of which must be treated.
When I see a patient with stage III disease, I am thinking about how I’m going to potentially cure these patients, because I believe, in a good performance status patient, the long term goal should be a cure of the disease. Now, having said that, there are three major compartments that I am concerned about in this patient population.
As I say to my patients, we have to first devise a strategy that’s going to control and eradicate the disease in the chest — obviously, in stage III disease you typically have a lung primary with mediastinal involvement — and what’s the best strategy to eradicate the disease that you can see in the chest?
The second issue is, almost all patients with stage III disease have what we refer to as micrometastatic disease. You have to think about controlling the systemic micrometastatic disease, and that really falls under the responsibility of systemic chemotherapy, in this particular setting.
So, local/regional control and distant systemic control are the first two issues. A third issue in this patient population is the central nervous system. We know that if we control the first two compartments effectively and seemingly, potentially cure a patient, that up to a third of patients may relapse in the brain itself. Some of those patients with limited relapse and aggressive brain treatment can be salvaged at this point, but it is a huge challenge.
There is some evidence that whole brain radiotherapy, prophylactically, can reduce that risk. However, it’s not clear that it leads to an overall survival advantage, so it’s not considered part of the standard of care, and there are many issues about how to adequately follow patients: how often should you go looking for recurrence in the brain with MRI screening and that sort of thing. So, there are no agreed upon guidelines for this, however, I think each individual physician kind of has their own guidelines in terms of how often they would check an MRI to see if they can diagnose CNS disease early, and perhaps eradicate it with the usual treatments we have for that condition. Of course, that would render the patient stage IV at that time, which really is a whole other set of circumstances that we deal with.