Menopause, plus cancer: It’s a one-two punch that some women of a certain age know all too well. Just as you’re (maybe) getting a handle on all of the delightful things that come with “the change” — hot flashes and night sweats, sleep disturbances, moods swings, brain fuzziness — bang, you’re hit with the news: You’ve got breast cancer. Suddenly, a difficult situation just got a lot more challenging.
The timing can be tough for other reasons, too. “A breast cancer diagnosis is devastating, but dealing with the disease during the postmenopausal years makes it even more challenging. It’s often a time of transition, and you may be dealing with anything from divorce to children leaving home to ageism in the workplace,” says Marisa Weiss, M.D., director of breast radiation oncology and breast health outreach at Lankenau Medical Center and founder of Breastcancer.org, who notes that many of her older patients worry about having to take off time from their job for treatment.
Menopause itself doesn’t boost your breast cancer risk, but growing older does. The median age of diagnosis for women in the U.S. is 62. (Rates begin to increase after age 40 and are highest in women over age of 70.) While weakening immune systems may play a role, in older women, the biggest culprit is estrogen — or, rather, the cumulative amount of estrogen exposure a woman has had over the years. In fact, about 80 percent of breast cancers in postmenopausal women are fueled by the hormone.
“Estrogen stimulates breast tissue, and the longer your breasts are exposed to estrogen over time, the greater your breast cancer risk,” says JoAnn V. Pinkerton, M.D., executive director of the North American Menopause Society (NAMS), and professor of obstetrics and gynecology, and division director of Midlife Health at the University of Virginia Health System. “For example, women who have a late menopause, entering menopause after age 55, are at an increased risk. Likewise, starting menstruation earlier, say, before the age of 12, and then going through a late menopause, also ups your risk.”
While certain types of estrogen decrease with menopause, your body continues to produce the hormone in later years, with most of it coming from fat cells and adrenal glands. Which means that weight gain, in particular, is a risk factor for postmenopausal breast cancer, since more fat cells mean more estrogen. Studies show that women who are overweight or obese after menopause have a 20 to 60 percent higher breast cancer risk than those who are lean. In fact, extra fat — particularly around the middle — is the body’s main source of estrogen in later years. What’s more, this type of fat secretes proteins that increase inflammation throughout the body, which has been linked to a higher risk of breast cancer recurrence, particularly in postmenopausal women.
Postmenopausal hormone therapy, combining estrogen and progestin to relieve symptoms of menopause, also has been associated with an increased risk of breast cancer when used over an extended period of time. “The more years that you’re in that marinade of hormones, the higher that risk,” says Marisa Weiss, M.D., director of breast radiation oncology and breast health outreach at Lankenau Medical Center and founder of Breastcancer.org.
Dense breasts — which have a lot of fibrous or glandular tissue and not much fat — may also be a factor. Though the link between breast density and breast cancer is unclear, one possibility, says Weiss, is this: “The environment inside dense breasts is an invitation to abnormal breast cell growth. The cells that live there become overstimulated. It’s like having a party with loud music, rather than a quiet library setting.”