Non-Small Cell Lung Cancer
Lung cancer is smoking-related. This is a totally preventable disease if patients do not smoke. And all of what we talked about wouldn’t be necessary if not for cigarettes. So it is the second most common malignancy in both sexes. Head and neck cancer was 40,000, this is 172,000 cases per year and it’s the most common cause of death in either sex. Meaning that in males it is a more common cause of death than prostate cancer, and in females more common a cause of death than breast cancer. Eighty percent of cases at least attributed to smoking. There may be some other risk factors and a genetic predisposition – largely, we think, because there is no familial clustering outside of smoking – in terms of how individual patients metabolize or otherwise handle the carcinogens contained in the smoking.
Let’s look at some of the incidence figures. These are incidence, cancer rates. This is prostate cancer shooting up when PSA becomes available then down. This is lung cancer in terms of incidence, slightly going down in males for the last 20 years or so. This is incidence rates for females and you see it’s still rising, as far as lung cancer is concerned. This is breast cancer – more common. Now let’s look at the death rates. These are the death rates in males. This is lung cancer. Exceeding everything else by far with somewhat of a reverse trend in the last few years. And this is the same in women, exceeding everything else with what still appears to be a rising incidence of lung cancer deaths in women. So that is where smoking prevention is more important than anything we can talk about in this kind of lecture. This is way too late and conceptually of course, not in an epidemiological sense, the primary thing to do.
Now what about the histologic types? Seventy-five percent are non-small cell, that’s what we will cover here. The others are small cell and non-small cell, divided up into these cancers: in the United States now adenocarcinoma is the most common, squamous carcinoma is next. This used to be different 20 years ago but now adenocarcinomas are the common ones and we are not sure why that is. Then this is stage-specific survival. Stage I is a confined disease. These patients are treated with curative intent by resection. Stage II is very similar, with at most, hilar lymphadenopathy. Many patients can be cured although you are down now to about 30%. Stage III, we will talk about a bit more in detail, includes regionally advanced disease. So that is disease in the chest involving large primaries or lymph nodes, mediastinal lymph nodes or supraclavicular lymph nodes, but no distant metastases. Then stage IV is distant metastases. We can also look at this is a sense of how far along can we use surgery. For metastatic disease we wouldn’t, and for stage I or II we would. Because these patients can be cured surgically, at least in some cases. Then stage III is split. Where usually IIIa is, at least in theory, resectable whereas IIIb is considered un-resectable. So that is the split from a surgical point of view.