Have you ever smoked? Or have you ever been exposed to second-hand smoke? Let's assume that you've already stopped smoking and you no longer go places where other people smoke. Your lungs are gradually healing, and your risk for lung cancer declines every day you breathe clean air. But cancer cells in general take a long time to reach critical mass and cause symptoms. Lung cancer is the most deadly cancer worldwide for men and women together. How much are you at risk?
Researchers continue to seek effective screening tests for cancer. Lung cancer is one of the most difficult to detect early. Chest x-rays and sputum cytology tests have been tried, but they are not effective in identifying cancer early enough to make a difference in mortality. Computed tomography (CT) imaging scans are somewhat more effective, but they have a false positive rate of up to 20 percent. This means that many healthy people who get CT lung scans will then get unnecessary surgery, putting them at risk of treatment complications with no treatment benefit. This is a strong motivation for a lung cancer blood test.
Early detection is the most important factor in curing cancer. According to a recent medical journal article, the 5-year survival rate for lung cancer overall is only 15 percent. For the most common (non-small cell) types, the median survival time with appropriate treatment depends on the stage at diagnosis as follows:
1. Stage 1A: 60 months
2. Stage 1B: 37 months
3. Stage 2A: 38 months
4. Stage 2B: 18 months
5. Stage 3A: 14 months
6. Stage 3B: 10 months
7. Stage 4: 6 months
For small cell lung cancers, the prognosis is even worse. Median survival time is at best 16 to 22 months.
Researchers in Germany have developed an experimental blood test based on a large group of autoantibodies to proteins characteristic of lung cancer tumors. They hope to make this test practical for screening people at risk. It is relatively easy to identify who's at risk for lung cancer: approximately 90 percent are associated with smoking. The remaining 10 percent are associated with industrial chemicals and irritants such as asbestos and radon.