Lung cancer cases increasing among non-smoking females

Lung cancer cases increasing among non-smoking females

The death of Christopher Reeve's wife Dana Reeve, who was a non-smoker, due to lung cancer has brought sharp focus on the rising instances of the killer disease among those who have never lit up. And women seem especially vulnerable to the disease, with 20 per cent of all female lung cancer victims being non-smokers. Among the general population, 10 per cent of all lung cancer patients have never used tobacco.

“Now, there is a subset of a patient population that are non-smokers and that is typically a female population, 40 to 45 years of age and above, that are non-smokers, have no other risk factors and do develop lung cancer,” said Dr Susan Huntsinger, a cancer specialist from the University of Tennessee.

This small group of patients continues to baffle doctors and researchers the world over, with many blaming secondhand smoke for the phenomenon. However, the question as to why non-smoking women are more susceptible to the disease remains largely unanswered. “We need to understand why younger women are more likely to get the disease, why there are molecular differences in lung cancer between men and women, and why there are treatment differences between men and women,” said Regina Vidaver, of Women Against Lung Cancer, a research group.

In spite of all the lobbies that vehemently deny the existence of passive smoking, secondhand smoke seems to be the biggest culprit in lung cancer among non-smokers. According to various studies, at least 3,000 people develop lung cancer annually in the United States due to smoke emitted by smokers. Many states have also passed legislations banning smoking in public places.

“We know that 90 per cent of lung cancer is linked to direct smoking. The other 10 per cent is tied to occupational exposures, radon and secondhand smoke,” said American Lung Association's Pat McKone. Some aver that Dana Reeve's case might be tied to her being in pubs and nightclubs during her years as a dancer. “It was said that she had, in the course of being an entertainer, spent a lot of time in pubs, in nightclubs, in which there is a lot of cigarette smoke,” said Dr James Mulshine of Chicago's Rush University Medical Center.

While this might be the case in Reeve's death, many a times, people who don't work in smoke-filled conditions, live in smoke-free homes and are not exposed to secondhand smoke also fall victim to the dreaded disease. In such cases, air pollution due to substances like asbestos, radon, arsenic, and others might have a role to play, along with genetic predispositions that make certain individuals vulnerable to the malignancy.

“Lung cancer happens to people with no history at all of secondhand smoke. They don't work in smoky places; they don't live with a smoker. So there has to be something else at work here. Genetics, something in a person's genetic makeup that predisposes them to lung cancer, may play a role,” said Dr Jack Wei, an oncologist from the Arizona Cancer Center. Some feel that high levels of estrogen in women might contribute to the development of the disease.

According to Dr Kasra Karamlou, an oncologist from Legacy Good Samaritan Hospital and Medical Center, female non-smoking lung cancer victims usually develop tumors called adenocarcinomas. “These are less common among smokers. They tend to be clinically a bit more aggressive, they spread quicker and people don't do as well with them,” Karamlou said.

Dr Linda Garland of Arizona Cancer Center said that further studies are required to pinpoint other factors that make a person vulnerable to lung cancer. “We've come to believe there is a different biology going on in these never-smoking patients. Maybe in the future, we will have a blood test for the genetic markers that put some people at high risk for lung cancer,” she said.

The most fatal of all cancers, lung cancer claims 3 million victims worldwide every year. Only one in 10 victims lives for five years after the diagnosis, with the death rate in the first year being 60 per cent.