Researchers have uncovered the answer to why some smokers develop lung cancer, but not others. Smoking does increase lung cancer risk, but a new study shows that the presence of a metabolite in urine is associated with higher risk of lung cancer. The findings could lead to early detection and treatment of lung cancer, improving outcomes.
Jian-Min Yuan, Ph.D., M.D., associate professor of public health at the University of Minnesota says, "Smoking leads to lung cancer, but there are about 60 possible carcinogens in tobacco smoke, and the more accurately we can identify the culprit, the better we will become at predicting risk. A history of smoking has always been thought of as a predictor of lung cancer, but it is actually not very accurate." Now scientists believe they could predict lung cancer by measuring a urine metabolite.
Studies have shown that the metabolite, NNAL, present in the urine of lab animals, induces lung cancer. Until now, human studies of NNAL and lung cancer had not been conducted.
The study included data from 18,244 men participating in the Shanghai Cohort Study and 63,257 men and women from the Singapore Chinese Health Study. Blood and urine samples, and one on one interviews were conducted on 50,000 patients to study the impact of NNAL, and its impact on lung cancer. The researchers focused on NNAL in the urine to find the association to lung cancer, finding that more NNAL in the urine increased the risk of lung cancer.
The study group was followed for ten years, and the researchers identified 246 smokers who later developed lung cancer and 245 smokers who did not develop lung cancer. Nicotine in the urine, combined with the NNAL metabolite was associated with eight and a half times the risk of lung cancer.
Researchers now know that the metabolite NNAL, found in the urine may predict the chances of smokers developing lung cancer. Smokers with low levels of NNAL in the urine were shown to have the lowest risk of lung cancer, explaining why some smokers remain cancer free. Testing for NNAL metabolite in the urine could lead to early detection of lung cancer through more intense screening for those at high risk.