Breast conservation therapy in the United States following the 1990 National Institutes of Health Consensus Development Conference on the treatment of patients with early stage invasive breast carcinoma.

BACKGROUND: A National Institutes of Health (NIH) Consensus Development Conference on the treatment of patients with early stage invasive breast carcinoma, held in June 1990, recommended breast conservation therapy for the majority of women with Stage I or II breast carcinoma. The authors evaluated the national use of breast conservation therapy before and after the conference to determine whether the conference had had an impact on utilization.
METHODS: Women with Stage I or II breast carcinoma (n = 109,880), diagnosed during the years 1983-1995, were identified via 9 population-based cancer registries of the Surveillance, Epidemiology, and End Results (SEER) program of the National Cancer Institute. The likelihood of breast conservation surgery versus mastectomy and, among women who underwent breast conservation surgery, the likelihood of postoperative radiation therapy versus none, were assessed for 3 time periods (January 1983 to April 1985, May 1985 to June 1990, and July 1990 to December 1995). Associations between the use of breast conservation surgery or postoperative radiotherapy according to patient stage, age, race, and region were compared among women diagnosed before and after the NIH Consensus Development Conference.
RESULTS: From 1985 (the year that the U.S. randomized controlled trial demonstrating equivalent efficacy between breast conservation therapy and mastectomy was published) through 1989, approximately 35% of women with Stage I and 19% of women with Stage II breast carcinoma underwent breast conservation surgery; these percentages remained constant throughout this period. Beginning in 1990, the year of the NIH Consensus Development Conference, the use of breast conservation surgery increased in each subsequent year; by 1995, 60% of women with Stage I and 39% of women with Stage II breast carcinoma received such treatment. However, regional variation in use was observed (Stage I, range 41.4-71.4% for 1995) and no registry reported breast conservation therapy for the majority of women with Stage II disease (range, 23.8-48.0%). The use of postoperative radiotherapy for women who underwent breast conservation surgery was similar in the periods before and after the conference.
CONCLUSIONS: Although breast conservation therapy was performed more frequently following the NIH Consensus Development Conference, variation in use by region of the U.S. suggests the continued presence of barriers to widespread adoption of the recommendations formulated at the conference. Copyright 1999 American Cancer Society.