TORONTO - Women who take oral contraceptives lower their risk of developing ovarian cancer, with the protective effect still shielding them decades later, even if they've long since stopped taking the pill, a new study concludes.
The medical journal that published the article, The Lancet, called for wider over-the-counter access to oral contraceptives, saying there are "few drugs available that confer powerful and long-lasting protection against a highly lethal malignancy after such a short exposure."
"Women deserve the choice to obtain oral contraceptives over-the-counter, removing a huge and unnecessary barrier to a potentially powerful cancer preventing agent," the influential journal said in an unsigned editorial.
The senior author of the study, Dr. Valerie Beral of Cancer Research UK epidemiology unit at Oxford University, called the ovarian cancer protection offered by oral contraceptives "a bonus."
"Young women don't take the pill because of cancer, they take it to not get pregnant. And actually many of them, I think, worry because of all the press stories and so on that maybe this is putting them at risk of cancer in later life. But in fact, the reverse is true," Beral said in an interview from Britain on Thursday.
"It is a very fatal cancer. So it's a nice bonus to have."
Ovarian cancer is one of the heartbreaking forms of the disease. It is curable if detected early, but is almost never diagnosed in the early stages, because symptoms are vague and there is no screening test at present.
The Canadian Cancer Society estimates 2,400 women were diagnosed with ovarian cancer in this country last year and 1,700 women died from it. On the list of cancer killers of Canadian women it ranks fifth, after lung, breast, colorectal and pancreatic cancer.
Beral and her co-authors - from the collaborative group on epidemiological studies of ovarian cancer - estimated 200,000 cases of ovarian cancer and 100,000 deaths from it have been avoided worldwide because women have used oral contraceptives since they were introduced in the 1960s.
With global numbers of women using oral contraceptives having risen in later decades, the authors estimate the number of ovarian cancers being prevented will rise to at least 30,000 a year in years to come.
"When you save 30,000 deaths from ovarian cancer, that's major. In cardiovascular health or any other field they would be celebrating this," said Dr. Andre Lalonde, executive vice-president of the Society of Obstetricians and Gynecologists of Canada.
The study, which will be in Saturday's issue of The Lancet, is actually a pooling of data from 45 previous studies which followed a total of over 110,000 women. About 40,000 of them had used oral contraceptives.
The longer women used oral contraceptives, the greater the reduction in their cancer risk. The reduction persisted long after women stopped using the pill - though the protection appeared to attenuate a bit as time from usage increased.
The protective effect was seen regardless of ethnicity, education level, age at which a woman's period began, family's history of breast cancer, use of hormone replacement therapy, weight, height, smoking and drinking history.
While the protective effect was not as great as that associated with never smoking or quitting smoking, it is nonetheless substantial, Beral said.
"There's nothing much you can do for 10 years that reduces your risk for the rest of your life by 30 per cent life."
Beral didn't want to comment on The Lancet's call for over-the-counter access to oral contraceptives, though she noted Britain is in the process of mounting a pilot study which will have trained pharmacists prescribing the medications in drug stores.
Lalonde said he thought it was too soon for Canada to move in this direction.
"I think that over-the-counter, we're not there yet," he said, suggesting a Quebec program allowing nurses and nurse practitioners to prescribe oral contraceptives should be watched and assessed before further moves are considered.
And Eduardo Franco, head of McGill University's division of cancer epidemiology, also cautioned against the idea.
Franco, who wrote a commentary that accompanied the Beral article, said a decision to use oral contraceptives should be discussed with a health-care provider, because it involves weighing other risks and benefits.
That kind of encounter also gives health-care providers the chance to discuss other important reproductive health issues, such as the importance of having safer sex and the need to have regular cervical cancer screening. Franco said forgoing the discussion would mean "we're missing a wonderful opportunity to provide a message."
