When the conversation turns to lung cancer, smoking cannot be far behind. With over 150,000 Americans dieing annually due to primary or secondary cancers of the lungs, most people have someone in their life that they have lost to this disease. One of the primary contributing lifestyle risk factors for lung cancer is smoking.
Smoking not only contributes to lung carcinoma, it also has been documented as a significant risk factor in bladder, kidney and pancreatic cancer. In the case of lung carcinoma, changes in the structure and nature of lung cells start as soon as smoke exposure begins. The progression is somewhat predictable, resulting in abnormal cells that are more prone to turning cancerous. When people quit smoking, their lungs slowly return to normal and their risk for lung-based primary cancer drops significantly, though not to the levels of people who have never smoked.
For those that are life-long smokers, cancer incidence is highest between the ages of 55 and 65 years of age. There is some biological tipping point at which the changes in lung cells turns into lung cancer. Smoking does not ensure the appearance of lung cancers, but at least 10% of smokers die of this form of cancer. Another 5% die of other cancers linked to smoking. While not every smoker is diagnosed with small cell or non small cell carcinoma, over 90% of these patients are current or former smokers.
Cancer patients with lung carcinomas have, on average, less than a 15% five year survival rate. While there are patients who have never smoked, the vast majority have either smoked, exposure to second hand smoke, exposure to radon, or exposure to asbestos. Pollution seems to play a minor role in this cancer, mostly by aggravating other environmental risk factors such as smoking. Genetics also seem to play a role.
While the statistics are clear that many smokers are more prone to lung cancers, certain smokers appear to enjoy some strange immunity to the ill effects of the lung tissue changes. This is an unpredictable trait, but one that smokers seem to use to justify continuing to smoke despite the increased carcinoma risks.