Interview with Heather Wakelee, MD
Dr Wakelee is Assistant Professor of Medicine in the Division of Oncology at Stanford University in Stanford, California.
Types of non-small cell lung cancer (NSCLC)
DR LOVE: Now within the so-called non-small cell, which is the majority – what about 80 percent or more I guess of all lung cancer, what types within that exist and what are the differences?
DR WAKELEE: So there are three major types, they’re the adenocarcinomas are the most common; the squamous cell carcinomas are the second most common, then we have large cell and then there’s a bunch of others and we kind of just call those non-small cell, not otherwise specified.
The adenocarcinoma is increasing in its percentage of all lung cancer. We don’t really know why. There are theories that it has to do with changes in how cigarettes were made, but that’s also the type of cancer that we see in the non-smokers. And again, non-smokers represent probably 20 percent of women who get lung cancer and maybe ten percent of men and so that’s a significant number of patients with this disease. So we don’t understand all the factors that lead to the development of lung cancer in those patients, but that’s one of the differences.
Squamous cell tends to occur in patients with a smoking history. It tends to be more centrally located. If it is removed before it has spread to lymph nodes, the cure rates are a little bit higher. The adenocarcinomas do tend to start spreading when they’re a little bit smaller, but it’s not a perfect correlation there.
And then the large cells are much less common. They tend to be a little bit more aggressive. There are also differences in how they respond to certain treatments and most of that data comes from the patients where the cancer’s already spread where it’s metastatic or advanced stage. And in those groups, some of the newer chemotherapy drugs, in particular pemetrexed seems to work best in the adenocarcinomas and the large cells. Some of the newer targeted drugs, such as the epidermal growth factor receptor drugs like erlotinib, also called Tarceva, and gefitinib, also called Iressa, those might work a little bit better in the adenocarcinoma type though they do also work in the squamous. And in the metastatic disease, some of our other “targeted drugs” might be a little bit more toxic, such as the ones targeting blood vessel formation. We don’t think that’s the same though if the cancer’s already been removed, if there’s no large tumor.