ORIGINAL ARTICLE Determinants of Breast Conservation Rates: Reasons for Mastectomy at a Comprehensive Cancer Center M. Catherine Lee, MD, Kendra Rogers, MBA, Kent Griffith, MPH, MS, Kathleen A. Diehl, MD, Tara M. Breslin, MD, Vincent M. Cimmino, MD, Alfred E. Chang, MD, Lisa A. Newman, MD, MPH, and Michael S. Sabel, MD Division of Surgical Oncology, The Department of Surgery and the Biostatistics Core of the University of Michigan Comprehensive Cancer Center, Ann Arbor, Michigan n Abstract: Bias in referral patterns and variations in multi-disciplinary management may impact breast conservation therapy (BCT) rates between hospitals. Retrospective studies of BCT rates are limited by their inability to differentiate indi- cated mastectomies versus those chosen by the patient. Our prospective breast cancer data base was queried for patients with invasive breast cancer who underwent surgical therapy at the University of Michigan over a 3-year period. Demograph- ics, stage and histology were recorded along with the reason mastectomy was performed, categorized as ‘‘by need’’ (con- traindication to BCT) or ‘‘by choice.’’ Multivariate analysis was used to identify factors significantly associated with mastectomy by choice. BCT was associated with tumor size, histology and nodal status, but not older age, either by choice or by need. Of the 34% of patients initially felt to be poor candidates for BCT, it was absolutely contraindicated in 44%, while 56% were thought to have a tumor-to-breast size ratio too large for successful BCT. Of this latter group, 80% under- went neo-adjuvant chemotherapy in an attempt to downstage the primary tumor and perform BCT, which was successful in over half the patients. For the patients initially thought to be good candidates for BCT, only 15% chose to undergo mastec- tomy, while 5% eventually required mastectomy due to failed attempts to achieve negative margins. Overall, the BCT rate was 63%, however without the use of neo-adjuvant chemotherapy, the BCT rate would have been only 53%. At a tertiary referral center, BCT rates are driven more by contraindications than patient choice, and may be heavily skewed towards mastectomy due to referral patterns. In addition to tumor factors such as stage and histology, BCT rate can be dramatically impacted by neo-adjuvant chemotherapy or genetic counseling. Examining BCT rates alone as a measure of quality, there- fore, is not an appropriate standard across institutions serving diverse populations. n Key Words: breast conservation rates, breast surgery, quality measure T he evolution of breast cancer surgery from radical mastectomy to modified radical mastectomy and now breast conservation therapy (BCT) has been accompanied by randomized controlled trials demon- strating the oncologic safety and therapeutic efficacy of less radical procedures. In 1990, a National Insti- tutes of Health consensus statement recommended BCT with radiation for the majority of women with stages I and II breast cancers (1). Increased screening and earlier diagnosis have increased the number of women presenting with early stage breast cancer, and with the introduction and increased use of neo-adju- vant chemotherapy to downstage primary breast cancers, even more women may ultimately avoid mastectomy. Despite these facts, many patients with breast can- cer are still being treated by mastectomy. Many stud- ies have examined patient and physician factors that might influence use of BCT versus mastectomy (2–6). There has also been discussion of using BCT rates as a measure of quality for comparing breast cancer care between hospitals (7). However, many mastectomies are performed because of absolute contraindictions to BCT. At the University of Michigan, our multi-disciplin- ary approach is heavily weighed towards promoting breast conservation, the success of which has been well documented (8–10). Despite this philosophical approach, the nature of our practice, in large part comprised of second opinions, may impact our breast conservation rate. Breast cancer patients initially offered lumpectomy might be more likely to stay with Address correspondence and reprint requests to: Michael S. Sabel, MD, 3304 Cancer Center, 1500 East Medical Center Drive, Ann Arbor, MI 48109-0932, USA, or e-mail: msabel@umich.edu. Ó 2009 Wiley Periodicals, Inc., 1075-122X/09 The Breast Journal, Volume 15 Number 1, 2009 34–40