Surgically removing a woman's ovaries during a hysterectomy may nearly double
her risk of developing lung cancer, according to a new Canadian study that
surprised even the researchers.
The finding may help explain why only about 15% of smokers eventually develop
lung cancer, and it suggests hormones might play an important role in the
leading cancer killer of women in Canada.
Hysterectomy -- removal of the uterus -- is the second most frequently performed
surgical procedure for Canadian women, after cesarean sections. More than 36,000
women had a hysterectomy in 2007-08, according to the Canadian Institute for
Health Information, and about 30% had both ovaries removed as well.
About 90% of hysterectomies are done for benign or non-cancerous problems such
as irregular menstruation and fibroids.
"We found that women who experienced non-natural menopause are at almost twice
the risk of developing lung cancer compared to women who experienced natural
menopause," Anita Koushik, a researcher at the Universite de Montreal's
Department of Social and Preventive Medicine, said in announcing her team's
findings Tuesday.
"This increased risk of lung cancer was particularly observed among women who
had non-natural menopause by having had both their ovaries surgically removed."
It's the second study this year to associate bilateral oophorectomy -- removal
of both ovaries -- with higher odds of developing lung cancer.
A study published in April involving more than 29,000 women participating in the
U.S. Nurses' Health Study found that oophorectomy increased the risk of lung
cancer, as well as fatal and non-fatal coronary heart disease -- compared to
women whose ovaries were kept intact.
Researchers are at a loss to explain the findings.
"Many things, if not most things in medicine are found by serendipity,"said Dr.
William Parker, lead author of the American study and a faculty member at the
John Wayne Cancer Institute at St. John's Health Center in Santa Monica, Calif.
"The smart people go, OK, we don't understand it, but let's try to figure it
out. It may be true, it may not be true," Parker said. "But now that you've got
two papers within a six-month period saying the same thing, you have to pay
attention to it."
Source : Canwest News Service
