Researchers have shown for the first time that women who face an increased risk of breast and ovarian cancer because of mutations in BRCA1 and BRCA2 genes can reduce their risk of these cancers if they have surgery to remove their ovaries and fallopian tubes.

Compared to intensive ovarian screening, surgery to remove the ovaries and fallopian tubes reduced the risk of subsequent breast and ovarian cancers by 75%.

"We now have prospective evidence to present to patients so that they can make informed decisions about their care," said lead investigator Kenneth Offit, MD, Chief of the Clinical Genetics Service at Memorial Sloan-Kettering Cancer Center.

The study looked at 173 women whose genetic tests found mutations in the BRCA1 and BRCA2 genes. The women were provided uniform genetic counseling regarding their options. Of those, 101 chose preventive surgery to remove their ovaries and fallopian tubes (a procedure called salpingo-oophorectomy). The other 72 opted for intensive ovarian screening (transvaginal ultrasound and a CA-125 blood test twice a year).

In addition to reducing the risk of ovarian cancer, removing the ovaries is believed to reduce breast cancer risk by decreasing estrogen, thereby halting or slowing the development of breast cancers that may depend on this hormone to spur their growth.

Among the women who chose preventive surgery, doctors were also able to detect 3 unsuspected early-stage ovarian tumors during the operation. "This highlights the limitations of current screening tests for ovarian cancer," said Dr. Richard Barakat, Chief of Gynecologic Oncology at MSKCC, and a co-author of the study.

After a two-year follow up, 3 breast and 1 peritoneal cancer were diagnosed in women who had preventive surgery, and 8 breast cancers, 4 ovarian cancers, and 1 peritoneal cancer were diagnosed in women who opted for intensive screening.

While the researchers found that the cancer risk following surgery compared to the risk while on surveillance was lower, they will continue to follow the women in the study to evaluate the long-term effects of preventive surgery on cancer rates, on other health risks, and on overall survival.

SOURCE:
Annual meeting of the American Society of Clinical Oncology, May 20, 2002, Orlando, Florida