Ovarian Cancer Prevention: The Trial that Almost Didn’t Happen

By Cindy Pearson

Women concerned about ovarian cancer have some good news – there’s a new prevention option, one that is safe, inexpensive, and can be used by women for whom other techniques aren’t an option. Recent research from the National Institutes of Health (NIH) has shown that reducing dietary fat and maintaining a low-fat diet for at least four years reduces a woman’s chance of developing ovarian cancer by almost 20 percent.¹ The only thing that’s upsetting about this good news is how close we came to never learning that dietary fat is linked to the development of ovarian cancer.

The good news about ovarian cancer came from results of the Women’s Health Initiative’s (WHI) Dietary Modification randomized controlled trial, which lasted from 1993 until 2005 and included 48,000 women volunteers. Two-thirds of these women were counseled about general recommendations for healthy eating; these women became the control group. The other one-third (19,000 women) were randomly chosen to receive the intervention to help women to lower their fat intake through intensive nutrition courses and regular support group meetings. Researchers hoped that the low-fat diet would lead to significantly lower rates of breast and colon cancer, as well as possibly reduced risks of ovarian and endometrial cancers. The WHI Dietary Modification trial was, by far, the largest study of cancer prevention in women.

But, it almost didn’t happen. To understand why, we have to go back almost 20 years, and look at the National Cancer Institute’s (NCI) record of support for prevention research like Dietary Modification trial. Preliminary research showed a promising association between lower dietary fat and reduced cancer rates, but the NCI repeatedly turned down requests to fund a dietary intervention trial.²  The NWHN organized letter-writing efforts in support of this research, to no avail. It took much broader campaigns that highlighted multiple examples of badly needed women’s health research before the NIH finally responded -- with the Women’s Health Initiative – in 1992. The Dietary Modification trial was a sister study to the WHI’s better-known hormone therapy trial.³  It’s safe to say that without the activism of NWHN members and colleagues, the WHI would never have been conducted. (See The Women’s Health Activist, May/June 2006, and July/August 2006 for more on the WHI.)

Now that we’ve got this good news about a low-fat diet’s role in reducing ovarian cancer, what does it mean for women? Ovarian cancer isn’t the most common women’s cancer (that distinction goes to breast cancer), but it is one of the most feared, and for good reason. There are no good screening tests for ovarian cancer, and symptoms of the disease are often vague. As result, most cases are diagnosed when the cancer has already spread, and cures are difficult to come by.

Luckily, ovarian cancer is relatively rare, and most women can go through life without worrying about it. Rare isn’t the same as non-existent, however, and 22,000 women in the U.S. are diagnosed with ovarian cancer annually, and 15,000 women die of the disease every year. With no screening test, and no easily recognizable early warning symptoms, women who are concerned about the disease have little recourse but to explore prevention. Until recently, oral contraceptives provided the only well-established way for healthy women to lower their risk of ovarian cancer short of surgically removing their ovaries – something the NWHN opposes to in all but the most extreme circumstances. But birth control pills are an option only for younger women and ovarian cancer, like almost all cancers, is most common in older women -- the average age of diagnosis is 65.

But now, older women have a prevention option -- thanks to the activism of NWHN members and other advocates who pushed for the trial that almost didn’t happen. To learn more about the low-fat eating pattern followed by women in the WHI trial, go to the WHI Participants website, and look for information under “Findings” or “FAQ”.  And, to help yourself and your practitioner better recognize symptoms of ovarian cancer, we recommend the Ovarian Cancer Symptom Consensus Statement distributed by the National Ovarian Cancer Alliance.

Cynthia Pearson is the NWHN’s Executive Director

REFERENCES

1. Prentice, RL, Thomson, CL, Caan, B, et al. “Low Fat Dietary Pattern and Cancer Incidence in the Women’s Health Initiative Dietary Modification Randomized Controlled Trial,” JNCI 2007; 99: 1534-43.

2. Pearson, C, “The Trials of the Women’s Health Trial,” The Network News. Jan/Feb 1991, page 1.

3. Pearson, C, “What Can the Women’s Health Initiative Tell us About How to Age Healthfully: Part 1,” The Women’s Health Activist, May/June 2006, page 4; and “What Can the Women’s Health Initiative Tell us About How to Age Healthfully: Part 2,” The Women’s Health Activist, July/August 2006, page 6.