- Page: 1 | 2 | 3 | Illustration: MUC1 to the defense
An ounce of prevention
There's no need to wait for a vaccine to take preventive measures against ovarian cancer, which will be newly diagnosed in an estimated 22,220 women in the U.S. during 2005 and result in approximately 16,210 deaths. Incidence of the cancer typically peaks 15 years after ovulation stops.
"Ideally, ovarian cancer would be prevented from happening at all," says Ross Berkowitz, MD, director of Gynecologic Oncology Services at Brigham and Women's Hospital and Dana-Farber and one of the authors of the MUC1 study. "It is important to identify women at high risk and discuss precautionary measures available to them."
Ovarian cancer is not common: The average American woman's lifetime risk is only 1.5 percent. But among women who do develop the disease, about 5-10 percent have a strong genetic link as a root cause. And for those who inherited the BRCA1 or BRCA2 gene mutation, the lifetime risk jumps to 20-40 percent. Any woman who has a family history of ovarian cancer—mother, sister, daughter—should seek genetic counseling.
Until an effective screening tool is developed, the best preventive option for women at high risk is removal of the ovaries and fallopian tubes when childbearing is complete. For those with BRCA mutations, these measures reduce the risk of gynecological cancers (ovarian, fallopian tubes, and peritoneal) by more than 90 percent.
Even in women at average risk, tubal ligation lowers the risk by 30- 50 percent. "There are a couple of theories about this," explains Dr. Berkowitz. "It is possible that sealing off the perineal cavity protects the ovaries; or tissue inflammation from the surgery may lead to the production of anti-MUC1 antibodies."
Traditionally, the two strongest documented preventive factors are childbirth and birth control. Even having a single child reduces the risk by about 30 percent, and women who have had four or more children have about onethird the risk of those who have had none. Breastfeeding adds additional protection. Oral contraceptive use also decreases risk by about 7-8 percent with each year of use, even for women who carry BRCA mutations.
Prevention also means avoiding known risk factors. Susan Hankinson, ScD, an epidemiologist at Brigham and Women's Hospital and a lead investigator on the Nurses' Health Study, notes that, unlike the birth control pill, hormone replacement therapy following menopause may increase the odds of developing ovarian cancer.
Use of talc in the genital area is another risk factor. Research by Dr. Cramer shows that women who use talc on their perineum (the skin around the vagina) have about a 30 percent higher risk of developing ovarian cancer. The association has been challenged because no relation between the amount of talc use and the increase in risk has been shown. In the MUC1 study, however, investigators did observe that talc users had significantly decreased levels of anti- MUC1 antibodies.
Still under investigation are early findings showing painkillers such as aspirin, ibuprofen (found in Midol and Advil), and acetaminophen (in Tylenol) may provide a risk reduction of about 30 percent. Drs. Cramer and Hankinson are studying this area further.
"We continue to lead the way in research into what can be done to reduce risk," says Dr. Berkowitz. "There are a number of things a woman can do to meaningfully reduce her risk, and these options should be discussed with her doctor. Women need not feel they are completely helpless against this disease."
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