Breast conservation versus mastectomy in patients with T3 breast cancers (> 5 cm): an analysis of 37,268 patients from the National Cancer Database.

Breast conservation therapy (BCT) is standard for T1-T2 tumors, but early trials excluded breast cancers > 5 cm. This study was performed to assess patterns and outcomes of BCT for T3 tumors. We reviewed the National Cancer Database (NCDB) for noninflammatory breast cancers > 5 cm, between 2004 and 2011 who underwent BCT or mastectomy (Mtx) with nodal evaluation. Patients with skin or chest wall involvement were excluded. Patients having clinical T3 tumors were analyzed to determine outcomes based upon presentation, with those having pathologic T3 tumors, subsequently assessed, irrespective of presentation. Overall survival (OS) was analyzed using multivariable Cox proportional hazards models, with adjusted survival curves estimated using inverse probability weighting. After exclusions, 37,268 patients remained. Median age and tumor size for BCT versus Mtx were 53 versus 54 years (p < 0.001) and 6.0 versus 6.7 cm (p < 0.001), respectively. Predictors of BCT included age, race, location, facility type, year of diagnosis, tumor size, grade, histology, nodes examined and positive, and administration of chemotherapy and radiotherapy. OS was similar between Mtx and BCT (p = 0.36). This held true when neoadjuvant chemotherapy patients were excluded (p = 0.39). BCT percentages declined over time (p < 0.001), while tumor sizes remained the same (p = 0.77). Median follow-up was 51.4 months. OS for patients with T3 breast cancers is similar whether patients received Mtx or BCT, confirming that tumor size should not be an absolute BCT exclusion. Declining use of BCT for tumors > 5 cm in younger patients may be accounted for by recent trends toward mastectomy.