NEW ORLEANS, LA -- May 25, 2000 -- Hormonal therapy with tamoxifen, commonly used for the treatment of breast cancer, is not helpful in women who have tumors that are estrogen-receptor negative, and whose cancers have not yet spread to the lymph nodes.
The news, released here at the 36th annual meeting of the American Society of Clinical Oncology, is based on a major study of 2,008 women with estrogen receptor-negative, node-negative disease breast cancer.
The study also found that after surgical removal of the tumor, the women did equally well on either of the two most-common adjuvant chemotherapy regimens, adriamycin-cyclophosphamide (AC) or cyclophosphamide-methotrexate-fluorouracil (CMF).
Bernard Fisher, MD, of the National Surgical Adjuvant Breast and Bowel Project, in Pittsburgh, said there has been a controversy over the past decade about tamoxifen's use in these patients, due to differing trial results in Europe and North America and speculation that tamoxifen does not act strictly at the estrogen-receptor site.
He said the question about AC versus CMF was over efficacy as well as side effect profiles. Also, the AC regimen is given in a much shorter time, 63 days, versus six months for CMF.
In Dr. Fisher's study, 2,008 women received AC or CMF, with-or-without tamoxifen. The percentage of women without disease at five years was 82 percent in both treatment groups, and with-or-without tamoxifen.
"The results indicate there is no benefit from the use of tamoxifen in estrogen-receptor negative, node-negative patients, whether they receive AC or CMF," Dr. Fisher stated. "Also, there was no difference in outcome whether the women received AC or CMF."
He concluded that there is no justification for giving tamoxifen to estrogen-negative, node-negative patients, and there is no difference between the two major chemotherapy combinations.
Although there could be advantages to taking the AC regimen, due to the shorter length of treatment, Dr. Fisher advised that women who were already taking CMF chemotherapy continue with that regimen rather than being switched.