Cost implications of the SSO-ASTRO consensus guideline on margins for breast-conserving surgery with whole breast irradiation in stage I and II invasive breast cancer.

Over $125 billion is spent annually in the United States for cancer treatment. Among women in this country, breast cancer remains the most common nondermatologic cancer diagnosis and the second leading cause of cancerrelated death. In 2010, breast cancer treatment costs were estimated at $16.5 billion, comprising 13 % of the burden of total cancer-related costs. Health care spending varies throughout the phases of breast cancer treatment, with *23 % of total expenditures allocated during the initial episode of treatment (diagnosis and management during the first year), 41 % during continuing care, and 36 % during the last year of life. It has been estimated that surgical costs account for 25 % of breast cancer treatment expenditure among Medicare patients. An important contributor to health care costs includes deviations from the standard of care and variations in clinical practice that are not supported by evidence. Moreover, dramatic regional variations in health care spending are not associated with the quality of delivered care or with improved patient outcomes. In contrast, studies have consistently shown that adherence to clinical pathways and guidelines, and reductions in unintended practice variations are linked to improvement in clinical outcomes at lower costs. In the current treatment of early-stage breast cancer, management of surgical margins after lumpectomy is a prime example of wide variation in clinical practice. Consensus exits on the importance of removing all microscopically evident disease; however, there has historically been little agreement on what constitutes a pathologically acceptable distance from tumor cells to ink. Definitions of margin adequacy have ranged from ‘‘no tumor on ink’’ in the original NSABP B-06 trial, to the Milan trials requiring quadrantectomy with 2–3 cm of grossly normal tissue around the tumor including overlying skin and underlying fascia. Taghian et al. demonstrated this lack of consensus in defining close and negative margins in a survey of North American and European practicing radiation oncologists, with only 46 % of North American respondents considering ‘‘no tumor on ink’’ as adequately negative margins. A survey of surgeons treating breast cancer again demonstrated wide variation in defining margin adequacy, with only 3 % endorsing ‘‘no tumor on ink’’ as negative margins. The debate of what constitutes a negative margin has continued at a national level and has widespread implications for patients and cancer-related treatment costs. The meta-analysis included in this issue by Moran et al. may finally put rest to this issue. In the United States, 60–75 % of women diagnosed with early-stage breast cancer are treated with breast-conservation therapy (lumpectomy and radiotherapy) based on long-term followup and contemporary data demonstrating equivalent survival to mastectomy. The ‘‘SSO-ASTRO consensus guidelines on margins for breast-conserving surgery with whole breast irradiation in stage I–II invasive breast cancer’’ included 33 studies with 28,162 patients reviewed by an expert panel. Evidence-based consensus guidelines on Society of Surgical Oncology 2014