Updated Trial Results Support Aggressive Treatment of DCIS

NEW ORLEANS —Updated results from two clinical trials of ductal carcinoma in situ (DCIS) continue to support the use of radiation therapy and tamoxifen (Nolvadex) after lumpectomy in these patients. D. Lawrence Wickerham, MD, associate chairman of the National Surgical Adjuvant Breast and Bowel Project (NSABP), reported the findings at the American College of Surgeons 87th Clinical Congress.

NSABP B-17 and B-24

Dr. Wickerham presented the most recent follow-up on NSABP protocols B-17 and B-24, both of which evaluated treatments for DCIS. Since 1993, the diagnosis of DCIS has increased by more than 300%, thought largely due to increased use of screening mammography. The proper treatment of this condition, which is diagnosed in 20,000 to 30,000 women a year in the United States, has been a subject of debate.

NSABP B-17 began in 1985 and entered more than 800 women with DCIS. Women were randomized to either lumpectomy or lumpectomy followed by radiation therapy.

After 12 years of follow-up, the results show a 62% decrease in the subsequent development of invasive breast cancer, and a 51% decrease in the recurrence of DCIS in women receiving radiation therapy along with lumpectomy, reported Dr. Wickerham, associate professor of human oncology, Medical College of Pennsylvania/Hahnemann University, Pittsburgh.

NSABP B-24, which followed B-17, involved more than 1,800 women treated with lumpectomy and radiation therapy. Additionally, these women were randomized to receive tamoxifen or placebo for a 5-year period.

The 7-year results of B-24 show a 37% decrease in the incidence of invasive breast cancer for women receiving tamoxifen. Based on earlier findings from NSABP B-24, tamoxifen was approved as a treatment for DCIS in June 2000.

Dr. Wickerham said that prior to the current results, data were reported at the 8-year follow-up period for B-17 and the 5-year follow-up point for B-24. The updated results are very similar to the earlier data; therefore, there is no indication of a lessening treatment effect over time, he said.

The new findings reiterate that radiation therapy and tamoxifen after lumpectomy offer optimum therapy for DCIS. The 5-year survival rate for DCIS is close to 100%, he said.