NON METASTATIC BREAST-CANCER SURGERY IN T HE RHONE DEPARTMENT (FRANCE) BETWEEN 1988 AND 1994

Background : From the results obtained in the breast cancer register t his report describes the usual surgical practice of breast cancer in t he Rhone department (France). Methods : This study concerned 4028 case s of non-metastatic breast cancer diagnosed during period 1988-1994. T hree periods were determined (1988-89, 1990-92, 1993-94). Univariate a nalysis described rite relation between the type of surgical practice and the explanatory factors. Logistic regression analysis was used to search for changes in surgical practice during the three periods. Resu lts: The proportion of conservative breast surgery rose from 53% in 19 88 to 64.5% in 1994. Taking the period 1988-89 as the reference period , the adjusted odds ratio of conservative surgery during the period 19 90-92 was 1.4 [1.1-1.7]. During the period 1993-94, this adjusted odds ratio was 1.9 [1.6-2.3]. Finally we observed that conservative surger y was less frequent in patients 70 years of age or older Conclusion: C onservative breast surgery increased significantly during the defined period. This observation can be explain by two events. First there was a significant increase of small breast cancer (< 20 mm) among women a ged 50-69 who benefited from the systematic screening breast cancer si nce 1988. Secondly a significantly ''period effect'' was observed. Thi s ''period effect'' proves a modification of surgical practice after a fter adjustment for cancer characteristics.