Smoking twice as dangerous for women

by PETER PALLOT, Daily Mail

A woman who smokes the same number of cigarettes as a man is twice as likely to develop lung cancer, doctors have found.

Research suggests that females are highly susceptible to lung cancer even though they inhale less deeply and start smoking at a later age than men.

The key to the doubled tumour risk lies in crucial lung tissue differences from men, and the presence of the female hormone oestrogen, according to Professor Diane Stover, head of the lung unit at Sloan-Kettering Cancer Center, New York.

She described the data which revealed the threat to women as 'horrifying'.

Women are also more susceptible to the lethal lung condition chronic obstructive lung dis-ease, which is caused by smoking and is rapidly increasing in incidence.

For British women, the findings raise the prospect of a leap in lung cancer cases. Recent research suggests that the proportion of women in this country who smoke more than ten cigarettes a day has risen to one in four, bringing them in line with men for the first time.

Dr Stover said that cancer cases among women in America and Europe were significantly higher than the number of female smokers would suggest.

In Japan, a study of cancer victims among 1,000 male smokers and 700 female smokers showed that women developed the disease two years earlier than the men.

Dr Stover told an international conference, attended by 17,000 doctors and organised by the American Thoracic Society, that lung cancer was more common in non- smoking women than their male equivalents.

A mass of research showed this was true whatever the woman's circumstances - for instance whether she was exposed to passive smoking at home or at work - and under-lined the vulnerability of female smokers.

Part of the reason was the biochemical way women dealt with the 50 or more cancer-producing agents in tobacco, said Dr Stover.

'Men and women deal with these carcinogens differently,' she said.

'There are individual variations, but men tend to detoxify them and excrete them in their urine whereas in women the carcinogens take a different pathway, they are transformed into other carcinogenic substances.'

These could lead to mutations in tumour-suppressing genes or 'cell suicide', she said.

Other compelling evidence of greater female susceptibility was that a gene potentially linked to cancer, known as the GRPR, was twice as likely to trigger a tumour in women than men because it attached to the X chromosome, which was twice as common in females.

Dr Stover said: 'Another way to put this is that a cigarette smoked by a woman had double the carcinogenic effect of a cigarette smoked by a man.'

Dr Lesley Walker, director of cancer information at the Cancer Research Campaign, said: 'There are a few studies that suggest women are at higher risk than men from lung cancer caused by smoking.

'The most likely explanation is that oestrogen promotes the cancer process in some way but the underlying reasons are not clear. There are not enough studies going on in this area.

'We want both sexes to stop smoking but women may be at higher risk and this is a real concern because tobacco companies are targeting women as smokers in the developing world.'