Résumé
Breast-conserving treatment (BCT) has been validated for breast cancer patients receiving adjuvant chemotherapy. Our objective was to evaluate the difference in loco-regional recurrence (LRR) rates between BCT and mastectomy in patients receiving radiation therapy after neo-adjuvant chemotherapy (NCT). A retrospective data base was used to identify all patients with breast cancer undergoing NCT from 2002 to 2007. Patients with initial metastatic disease were excluded from this analysis. LRR was compared between those undergoing BCT and mastectomy. Individual variables associated with LRR were evaluated. Two hundred eighty-four patients were included, 111 (39%) underwent BCT and 173 (61%) mastectomy. Almost all patients (99%) in both groups received postoperative radiation. Pathologic complete response was seen in 37 patients, of which 28 underwent BCT (p < 0.001). Patients receiving mastectomy had more invasive lobular carcinoma (p = 0.007) and a higher American Joint Committee on Cancer (AJCC) stage (p < 0.001) at diagnosis than those with BCT. At a median follow-up of 6.3 years, the loco-regional control rate was 91% (95% CI: 86-94%). The 10-year LRR rate was similar in the BCT group (9.2% [95% CI: 4.9-16.7%]) and in the mastectomy group (10.7% [95% CI: 5.9-15.2%]; p = 0.8). Ten-year overall survival (OS) rates (63% [95% CI: 46-79%] in the BCT group; 60% [95% CI: 47-73%] in the mastectomy group, p = 0.8) were not statistically different between the two patient populations. Multivariate analysis showed that AJCC stage ≥ III (HR: 2.6; 95% CI: 1.2-5.8; p = 0.02), negative PR (HR: 6; 95% CI: 1.2-30.6, p = 0.03), and number of positive lymph nodes ≥3 (HR: 2.5; 95% CI: 1.1-5.9; p = 0.03) were independent predictors of LRR. Ten-year OS was similar in the BCT and in the mastectomy group (p = 0.1). The rate of LRR was low and did not significantly differ between the BCT and the mastectomy group after NCT. Randomized trials assessing whether mastectomy can be safely omitted in selected breast cancer patients (nonstage III tumors or those which do not require adjuvant hormone suppression) which respond to NCT are required.