Surgery cuts ovarian cancer risk

Sterilisation reduced the cancer risk for women with mutated gene

Women at high risk of developing ovarian cancer could benefit from surgery to tie their fallopian tubes.

The claim is made by scientists who carried out a survey to assess whether the process, known as tubal ligation, protects against hereditary ovarian cancer in the case of women carrying the high risk BRCA1 or BRCA2 genes.

Mutations in BRCA1 increase the lifetime risk of ovarian cancer by 40% and women with deformities in BRCA2 have a 25% greater chance of getting the disease.

We believe that tubal ligation is associated with a reduction in risk of ovarian cancer in women who carry BRCA1 mutations

Steven Narod
researcher

Most women have about a 1% risk of developing ovarian cancer.

Tubal ligation offers an alternative for younger women to the more radical option of removing the ovaries.

Ovary removal results in the immediate onset of the menopause, and leave women requiring high doses of oestrogen replacement therapy.

With tubal ligation, usually performed for contraceptive reasons, women continue to ovulate. There is also a slim chance of reversing the procedure.

The research team found the risk of developing cancer for women carrying the BRCA1 mutated gene decreased by 60% after "tubal ligation" surgery.

For those who had surgery and had a history of oral contraceptive use, the risk was reduced by 72%.

The controlled study of 232 women in the UK, USA and Canada was devised by Steven Narod and colleagues from Sunnybrook and Women's College Hospital, Toronto, Canada.

Ovary removal

Mr Narod said: "Currently, many women choose to undergo oophorectomy (removal of an ovary) to prevent ovarian cancer.

"The age at which oophorectomy is done should take into account the woman's desire to preserve fertility, the level of protection offered against breast and ovarian cancer, and the consequences of surgical menopause.

"Few women choose to have oophorectomy before age 35 years, but offering tubal ligation as soon as childbearing is complete is reasonable, and can be followed by an oophorectomy at a later date.

The effects of the pill may be underestimated

"We believe that tubal ligation is associated with a reduction in risk of ovarian cancer in women who carry BRCA1 mutations.

"For maximum protection, tubal ligation should be considered in combination with oral contraceptives, oophorectomy, or both."

The research team is not sure how tubal ligation reduces the risk of ovarian cancer, but they suspect it could be linked to interrupting ovarian blood flow or its effect on hormones.

The researchers said they could not make specific recommendations for carriers of BRCA2, and further studies were needed for this subgroup.

Doubts

But another cancer specialist believes the research is inconclusive because it fails to take into account the effect of the combined contraceptive pill in protecting against ovarian cancer.

Dr Anne Szarewski from the Imperial Cancer Research Fund said the protective effects of the pill last for 10 years after women stop taking it.

She said: "They don't seem to have looked at the possibility of a carry over effect.

This research is interesting, but I am concerned there may be more of an effect of the pill than they thought

Dr Anne Szarewski
Imperial Cancer Research Fund

"This research is interesting, but I am concerned there may be more of an effect of the pill than they thought.

"It's more confirmation of the very high effect of the pill in protecting against ovarian cancer."

Her advice to "high risk" women considering prophylactic measures to combat the disease to choose oophorectomy over sterilisation because ovarian cancer is not possible once the ovaries have been removed.

The research is published in The Lancet medical journal.