Urine could predict risk of lung cancer

Urine may be the key to why lung cancer affects some smokers and not others, a study has revealed.

Researchers found smokers with high levels of the metabolite NNAL in their urine have double the risk of lung cancer than those with low levels.

Detecting the metabolite would enable doctors to predict whether or not a patient is at greater risk of lung cancer.

The investigation found that compared with patients with low levels of NNAL in their urine, those with a mid-range level had a 43 per cent increased risk of lung cancer, while those with the highest level had a more than two-fold increased risk.

When combined with levels of nicotine in the urine, those with the highest levels of nicotine and NNAL had an 8.5-fold increased likelihood of lung cancer compared with smokers who had the lowest levels of both.

Jian-Min Yuan, one of the researchers involved with the study, said: “A history of smoking has always been thought of as a predictor of lung cancer, but it is actually not very accurate.

“Smoking absolutely increases your risk, but why it does so in some people but not others is a big question,” he concluded.