Change in the use of breast-conserving surgery in western Washington after the 1990 NIH Consensus Development Conference

Objective: To evaluate the use of breast-conserving surgery in western Washington before and after the National Institutes of Health Consensus Development Conference (June 18-21, 1990) during which breast-conserving surgery was recommended for most women with early invasive breast cancer. Design: Survey. Setting: Population-based cancer registry in the Seattle- Puget Sound (Washington) region. Participants: The survey included 13541 women in whom American Joint Committee on Cancer stage I or II breast cancer was diagnosed between January 1, 1983, anti December 31,1993. Main Outcome Measure: Proportion of participants who underwent breast-conserving surgery. Results: From April 1985, after results of a US randomized controlled trial showing equivalent survival in women undergoing mastectomy or breast- conserving surgery were published, to the time of the Conference, breast- conserving surgery was performed on 44.8% of women with stage I and 25.8% with stage II breast cancer. These percentages increased to 54.9% and 35.2%, respectively, during the post Conference period. While women with stage II breast cancer were less likely than women with stage I breast cancer to undergo breast-conserving surgery before and after the Conference, trends for age and education were attenuated after the Conference. Differences in the use of breast-conserving surgery observed before the Conference between counties of residence and among hospital types were also reduced after the Conference. Conclusions: These findings suggest that the Conference recommendations had an effect on the adoption of breast-conserving surgery, particularly among groups who were previously least likely to undergo such surgery. Despite progress toward the Conference recommendation that the majority of women with early invasive breast cancer undergo breast-conserving surgery, the majority of women with stage II breast cancer undergo mastectomy.