The genetic mutation known as BRCA1 increases a woman’s chances of developing ovarian cancer by about 40%; in women with a related gene, called BRCA2, the risk is increased by 25%. Unlike the success of screening in breast cancer, the authors note that ovarian cancer screening has not yet been shown to be effective in reducing ovarian cancer mortality, and it is uncertain whether preventative removal of the ovaries reduces the risk of ovarian cancer. Still, some women choose to have an oophorectomy — surgery to remove their ovaries — to reduce their risk of ovarian cancer.

Research also indicates that long-term oral contraceptive use lowers the risk of ovarian cancer in the general population. However, there is concern that the hormones in these pills might further elevate the breast cancer risk for women with the BRCA1 or BRCA2 mutation.

Previous studies of women whose genetic history was unknown have suggested that tubal ligation can reduce the risk of ovarian cancer by up to 67%. In the Lancet study, Steven Narod, MD, and his colleagues in the Hereditary Ovarian Cancer Clinical Study Group compared the records of 233 women with invasive ovarian cancer who had the BRCA1 or BRCA2 genes, to a matched group of women with a similar background who had no clinical evidence of cancer and had intact ovaries. There were 30 women in the BRCA1 group and 60 in the matched group who had their tubes tied.

The researchers found a 60% reduction in the risk of ovarian cancer for women who had this surgery and who also had the BRCA1 gene — but no decrease was found for the women with BRCA2. Further analysis also showed that the risk was even lower for women with BRCA1 who had their tubes tied and were also long-term users of oral contraceptives. Their risk of ovarian cancer was reduced by 72%.

"I’d like to get the tubal ligation [option] on the table," says Steven Narod, MD, the lead author of the study and a professor at the Sunnybrook and Women’s College Hospital in Toronto. "If you have BRCA1, your risk of ovarian cancer is 40% and you are going to be looking for something to do to reduce that. You could (have) a tubal ligation and your risk is reduced by 60%. It would take five years or more to achieve the same result with oral contraceptives [alone]."

"I think this is a ‘good news’ study," says Robert Young, MD, president-elect of the American Cancer Society and president of Fox Chase Cancer Center in Philadelphia. "This offers another potential avenue for reducing the risk of ovarian cancer."

"I would have said [for patients with BRCA1] to consider tubal ligation anyway on the basis that a protective effect does exist for the general population, which we’ve seen in previous studies," says Young. "But prior to this study I would have had to put a proviso on it, that there was no concrete evidence that it worked in a high-risk population. Now we have data to suggest that it would," he says.

He cautions that, as a "case-control" study, the new research does not absolutely prove that tubal ligations cause the cancer risk reduction. Instead, it provides a strong association between the two and suggests there may be some real benefit, Young says.

Women with BRCA1 who are considering taking some action to reduce their risk need to weigh several factors, says Narod: how easy the action is to accomplish, how big a reduction can be expected and what the side effects might be. Tubal ligation comes out ahead of the other options, such as ovary removal and birth control pills, says Narod, because it is easy to undergo, appears to produce a substantial reduction in risk, and has minimal side effects. It also doesn’t raise the concern about increasing the risk of breast cancer in these women who are already at very high risk of developing the disease because of the defective gene, he says.

No one knows for certain why tubal ligation appears to have this benefit. But Narod says he does not view tubal ligation as an alternative to oophorectomy; in fact, he often recommends, based on the age of the woman, that she do all three: tubal ligation followed by ovary removal and the use of birth control pills. He also finds it remarkable that women today have several options to try in the fight against ovarian cancer. "Five years ago we had nothing to offer women at all," he says.