Families of lung cancer patients more likely to get cancers themselves

Researchers in the US have discovered that people closely related to lung cancer patients who have never smoked are at an increased risk of developing some form of cancer themselves. The findings, which were presented last week at the annual conference of the American Association for Cancer Research, suggest a strong link between genetics and the propensity to develop cancer. The researchers also found that the specific risk of developing lung cancer was greatly increased in family members of lung cancer patients who had not contracted the disease through smoking.

The research, presented by Dr Olga Gorvola of the Department of Epidemiology at the MD Anderson Cancer Centre in Houston, Texas, looked at the number of cancers among first-degree relatives - parents, children and siblings - of 316 lung cancer patients who had never smoked. They compared these to the number of cancers among relatives of 318 healthy non-smokers, matching the samples for age, gender and ethnicity. Altogether, they compared the records of 2,465 relatives in the lung cancer relatives' group and 2,441 in the control group.

The researchers discovered that relatives of the lung cancer patients had an increased risk of developing cancer of 25 per cent compared to the relatives in the control group. They found that children of the lung cancer patients had two-fold increased risk of cancer but that mothers of patients - whose average age was 61 - were more than twice as likely to develop breast cancer as mothers of members of the control group.

The researchers also found that the risk of developing cancer at a young age was higher for relatives of the lung cancer patients - and increased still further among those who were smokers. The risk of lung cancer was six times higher than that of relatives of the control group, and the risk of being diagnosed with any kind of cancer before the age of 50 was increased by 44 per cent. Relatives of the lung cancer patients also tended to be diagnosed at an earlier age with lung cancer - at an average of 60.6 years compared to 74.2 years old in the control group.

The researcher hope that their findings will be useful when counselling relatives of patients with non-smoking related lung cancer, particularly in terms of advice about giving up smoking or offering regular screening. They plan to follow up their study by looking for the exact genetic factors that contribute to the underlying increased risk of cancer and lung cancer in some families.