Quality improvement in surgical breast cancer care: a decrease in positive surgical margins after first breast conserving surgery

Abstract

Background: In recent years there has been a growing awareness of the quality of breast cancer care. In the Netherlands the completeness of breast conserving surgery (BCS) was introduced as a quality parameter, and hospitals are obliged to report on the proportion of patients with positive margins after first BCS since 2007. Increasing national mastectomy rates during the last decade for the treatment of early breast cancer have recently been published from the US. This study describes trends in BCS over time in relation to positive margin rates after BCS. Materials and Methods: All breast cancer patients T1–2, any N, M0 diagnosed between July 1, 2008, and December 31, 2012 who underwent surgical resection were selected from the Netherlands Cancer Registry. Type of first surgery was coded as BCS or mastectomy. Margin status was coded as clear, focally positive margins (tumor in a limited area of the inked surface, i.e. one or two foci of tumor, with a maximum of 4 mm), more than focally positive margins (MFP) or unknown. BCS rates were available in the NCR for the period 1995–2012. Results: The percentage of BCS as first surgery increased over time (48% and 64% in 1995 and 2012 respectively; χ2-test: p = 0.000), with a temporary decline in the period 2008–2009. Of the 49,570 included patients over the period 2008–2012, 62% (30,790 patients) received BCS in 89 hospitals in the Netherlands. The percentage of MFP-margins significantly decreased since the introduction of the indicator; 9.7% in 2008 versus 5.4% in 2012 (Table 1; χ2-test: p = 0.000). After case mix correction for age, tumor size, grade, lobular subtype, multifocality, hormone receptor status and HER2 status, hospital variance was substantial: corrected MFP-margin rates varied from 0% to 19%. Thirty-seven hospitals (42%) had margin rates significantly lower than 10%, while 3% showed significantly higher rates. Conclusions: The percentage of patients with positive surgical margins after first BCS for breast cancer decreased between 2008 and 2012. This decrease in positive margins was accompanied by a increase in the national BCS rates in the Netherlands during this period