Two important studies being published today challenge conventional thoughts about treating and avoiding breast cancer.
One suggests that doctors may eventually be able to identify women who do not need chemotherapy. The other says that women who have had hysterectomies can take estrogen to relieve symptoms of menopause without increasing their risk of breast cancer.
The first study, published in the Journal of the American Medical Association, indicates that many of the 70 percent of women whose cancers are fed by estrogen get so much benefit from estrogen-blocking hormonal therapy that chemotherapy provides few if any additional advantages.
The caveat, though, is that there is as yet no reliable way to identify the women who may not need chemotherapy from those who would be helped by it.
Currently, guidelines call for women to get chemotherapy if their tumors are of a certain size.
Dr. Eric P. Winer, an author of the paper and director of the Breast Oncology Center at the Dana-Farber Cancer Institute in Boston, explained: “Virtually every woman with a tumor larger than a centimeter should get chemotherapy.”
But, he said, over the past couple of years, “that question has been reopened in a major way.”
The new study, he added, is part of the re-examination.
The study involved an analysis of data from three large clinical trials that tested different chemotherapy regimens.
The conclusion was that even though the studies involved very different chemotherapy regimens, one variable always stood out – whether a woman’s cancer was estrogen-receptor- positive, meaning it was fed by estrogen, or estrogen-receptor- negative, meaning it was impervious to estrogen’s effects.
“All the benefits were in the estrogen-receptor-negatives,” Berry said.
The second paper, also in JAMA, involved a federal study of more than 10,700 healthy women whose uteruses had been removed. The question was: What are the health consequences of taking estrogen for the relief of menopausal symptoms? The study found that estrogen did not increase the women’s risk of breast cancer. But they did have more abnormal mammograms results, usually requiring that the test be repeated, and more breast biopsies. The question of estrogen’s effects on breast cancer risk had been uncertain until now, when the women had been followed for seven years.