Abstract
BACKGROUND: The choice between mastectomy and breast-conserving therapy (BCT) is a first step for patients with breast cancer who are confronting decisions about treatment. OBJECTIVE: To identify the most important determinants in treatment decision making by patients with breast cancer. METHODS: Between 2003 and 2013, a total of 5258 patients with breast cancer were recorded in Kaiser Permanente Northwest's cancer registry. Patients had similar clinical-pathologic profiles, education, and insurance coverage, and were managed by 1 surgical group. A total of 2604 patients with invasive breast cancer chose mastectomy or BCT as they met unambiguous criteria for equivalent outcomes with either option. We examined the influence of the patient's surgeon on patient preferences. RESULTS: Our retrospective analyses examined a study population that had similar risk profiles (age, family history of breast cancer, T category on tumor-node-metastasis staging system, tumor size, physical examination findings), surgeons consulting on similar patient types, and managed by surgeons with similar surgical performance patterns (case volumes, reexcision rates, number of reoperations, and ability to meet patient's expectations). Patients who preferred mastectomy were strongly influenced by tumor size (p < 0.001) and abnormal physical examination findings (palpable mass; p = 0.004), rather than age, family history of breast cancer, T category, or surgeon. CONCLUSION: Physical examination findings and tumor size were statistically significant determinants influencing patients to choose mastectomy. Because geographic and practice style explanations fail to explain these variations, surgeons can identify, anticipate, and consider these factors when counseling patients about mastectomy and BCT therapeutic equivalency.