How biology makes men more of a cancer risk

biological differences rather than lifestyle choices may be why men are more at risk of cancer than women, a study suggests.

Variations between the sexes’ immune systems, genes and physical make-up appear to have a greater impact than the likes of diet, alcohol and smoking.

Developing a better understanding of these differences could lead to new ways of preventing and treating the disease and eradicate this ‘sex disparity’, experts say. The researchers assessed the risk of 21 types of cancer among 171,274 men and 122,826 women aged 50 to 71 over a 16-year period. During this

‘Environmental exposures’

time, 17,951 new cancers arose in men and 8,742 in women.

incidence was lower in men than women only for thyroid and gall bladder cancers, and risks were 1.3 to 10.8 times higher in men than women for the others.

The greatest increased risks in men were seen for oesophageal cancer (10.8 times higher), larynx (3.5 times), gastric cardia (3.5 times), and bladder cancer (3.3 times).

Men had an increased risk of most cancers, even after adjusting for a wide range of risk factors, such as diet quality, alcohol intake, smoking status, exercise levels and exposure to cancer-causing substances.

indeed, these differences only accounted for a ‘modest proportion’ of the male predominance of most cancers – ranging from 11 per cent for oesophageal cancer to 50 per cent for lung cancer. Dr Sarah Jackson, from the National cancer institute in the US, said: ‘This excess risk among men is well recognised, but it remains largely unexplained.

‘our results show that there are differences in cancer incidence that are not explained by environmental exposures alone. This suggests that there are intrinsic biological differences that affect susceptibility.’

a linked editorial published alongside the study in cancer, the journal of the american cancer Society, says: ‘Strategically including sex as a biological variable should be enforced along the whole cancer continuum – from risk prediction and primary prevention, screening and secondary prevention, to treatment and patient management.’

There are around 375,000 new cancer cases in the UK every year, of which 182,000 are in women and 193,000 in men, according to cancer Research UK.