a1 Mario Negri Institute
a2 Regional Health Authority, Lombardia
The extent of variation in the use of breast-conserving surgery was analyzed using the 1990 and 1991 hospital discharge data of Lombardia, Italy. The proportion of patients undergoing breast-conserving surgery for unilateral breast cancer was estimated for each of the 10 geographic areas (9 provinces plus metropolitan Milano) in which the region is divided. Overall, the rate of use was 41% of 3,225 patients in 1990, and 45% of 3,736 patients in 1991. In both study years, patient age was strongly correlated with the likelihood of undergoing conservative surgery, with younger women more frequently treated with this approach. In each province, patients treated at centers located in the main city had a greater probability (OR, 1.54; 95% Cl, 1.37–1.69) of having conservative surgery. This procedure was also more often used in private hospitals (OR, 1.59; 95% Cl, 1.20–2.08) where care is paid at the point of consumption by patients, directly or through their private insurance. The observed variation in the use of the conservative procedure across the 10 regional areas was greater than that expected by chance alone (p <.0001), with rates ranging from 29% to 60%. This pattern persisted even after adjusting for the relevant patient and hospital characteristics. Despite the relatively large body of scientific evidence, it appears that the surgical management of breast cancer is more dependent on physicians' attitudes in each geographic area than on individual patients' characteristics.