Extended chemo eyed for early breast cancer
Shortening chemotherapy may not be a good course of treatment for some women with early-stage breast cancer, according to a study conducted by the National Surgical Adjuvant Breast and Bowel Project based at Allegheny General Hospital.
The study showed premenopausal women with early-stage breast cancer had better survival odds when they took the drugs for a longer period of time. Results appeared this week in the New England Journal of Medicine.
Doctors and patients often choose to shorten chemotherapy treatments because of the drugs' side effects or because the women are missing work and have expenses associated with the treatment, said Dr. Charles Geyer, a breast oncologist at AGH and one of the study's lead authors.
"It's telling people that maybe they need to be kept on chemotherapy longer," Geyer said. "We have clear evidence that with only four cycles (of treatment), there seemed to be a loss in terms of outcomes."
The study involved 5,351 premenopausal and postmenopausal women who had surgery and removal of lymph nodes under their arms. Those who took four cycles of doxorubicin, cyclophosphamide and docetaxel, had an eight-year overall survival of 79 percent, compared to 83 percent for women who received the drugs over longer cycles -- four cycles of doxorubicin and cyclophosphamide, followed by four cycles of docetaxel.
The study showed a link between the loss of ovarian function and survival of women with tumors whose growth did not depend on estrogen. That was a surprise to researchers aware of better outcomes among women with lost ovarian function but with tumors sensitive to estrogen. The hormone promotes the growth of most breast cancers.
The improved survival in women whose cancer didn't depend on estrogen, which rises during the menstrual cycle, suggests the ovaries may play a role beyond hormone production in promoting the cancer, Geyer said.
He said it is too early to determine if ovarian function should be inhibited in all women with early breast cancer. Instead, the finding should lead to more clinical trials for further study.