NEW YORK, Jun 11 (Reuters Health) -- The drug tamoxifen used in combination with surgery and radiation treatment can reduce the risk of invasive breast cancer in patients with ductal carcinoma in situ, US researchers report.
The findings "suggest that mastectomy could be avoided more frequently than at present" in these patients, they conclude.
DCIS, or ductal carcinoma in situ, is a noninvasive cancer, but it is associated with an increased risk of developing invasive breast cancer, usually in the same breast. DCIS is treated by mastectomy (removal of the breast) or by lumpectomy (removal of the tumor). After lumpectomy, previous studies showed that radiation therapy could improve the results of the treatment.
Now, in a study of more than 1,800 women with DCIS, doctors show that adding tamoxifen to the lumpectomy and radiation regimen further improves treatment outcome, according to a report from the National Surgical Adjuvant Breast and Bowel Project, led by Prof. Bernard Fisher of Allegheny University of the Health Sciences in Pittsburgh, Pennsylvania.
Women who took tamoxifen experienced 43% fewer invasive breast cancers and 31% fewer noninvasive breast cancers, compared with women who took inactive (placebo) medication during the 5-year study, according to a report in the June 12th issue of The Lancet.
Throughout the study, 83.3% of women who received placebo and 87.4% of women who received tamoxifen showed no evidence of recurrent breast cancer, the study findings indicate. Overall, the survival for the two groups was the same, 97%.
Based on these results, the authors conclude that combined therapy with lumpectomy, radiation therapy, and tamoxifen could replace mastectomy for the treatment of DCIS when radiological findings indicate a noninvasive tumor.
"For every 19 women treated with tamoxifen, one (breast-cancer) event was avoided," writes Dr. Nicholas Wilcken from Westmead Hospital in Sydney, Australia, in an editorial on the study findings. "By extrapolation from the data presented," he continues, "22 mastectomies were prevented by tamoxifen, with one mastectomy avoided for every 40 women treated."
"A reasonable view of the data presented," Wilcken concludes, "should be that the benefits of tamoxifen far outweigh the risks."
SOURCE: The Lancet 1999;353:1986-1987, 1993-2000.
