Geographic Differences in Treatment of Early Stage Breast Cancer.

The objective of this study was to describe recent time and geographic variations in breast cancer treatment while controlling for patient age, race, and ethnic group. Treatment data for women diagnosed with localized breast cancer from nine defined geographic areas of the United States from 1983 through 1992 were analyzed. Of 80,887 subjects, 33.9% were treated with lumpectomy from 1983 to 1992. The proportion of women treated with lumpectomy varied greatly according to geographic area, ranging from overall percentages of 19.0% in Iowa to 41.4% in Connecticut, but increased in all sites during the time period under study. Women less than 50 years and more than age 80 years and older were most likely to have lumpectomy, while Asian/Pacific islander women were significantly less likely compared to Caucasian women. Rates for African American and Hispanic women were not significantly different than those for Caucasian women. Although consensus conferences and randomized clinical trials have indicated lumpectomy is appropriate therapy for the majority of women diagnosed with early stage breast cancer, large geographic differences in rates have persisted over time. These differences were not explained by underlying differences in age or race distributions in the geographic areas included in this study.