Oncological outcomes of post neo adjuvant chemotherapy breast conservation surgery in patients with locally advanced breast cancer

Introduction:Breast cancer in India is phenotypically different with locally advanced breast cancers (LABCs) forming 30-50% of all cases. Use of neoadjuvant chemotherapy (NACT), among other things has contributed to surgeons using breast conservation surgery (BCS) in very selected patients with good results. Herein, we describe the oncological outcomes of BCS in LABC patients undergoing surgery post NACT.Patients and Methods:This is an ambispective observational cohort study conducted between January 1996 and December 2019 after approval by Institute Ethics Committee, to study the ipsilateral breast tumor recurrence (IBTR) in patients with LABC undergoing BCS post NACT. The secondary objectives were to ascertain the disease-free survival (DFS) and overall survival (OS) and factors associated with IBTR in these patients. Patients were staged according to the anatomic American Joint Committee on Cancer (AJCC) VIII Tumor Node Metastasis (TNM) classification and clinic-demographic, pathologic, treatment, and follow-up details were noted.Results:Out of 822 patients with LABC, 71 patients undergoing BCS post NACT were included. Average tumor size at presentation was 6.43 cm. The most common T stage was T3 (57.7%) and N stage was N1 (53.5%). The most common stage group was IIIB in 40.8%. Around 75% received anthracycline-based NACT with 28.2% having a complete clinical response. A pathological complete response was seen in 16 patients (22.5%). The mean follow-up duration was 6.14 years. A total of 25 patients had recurrences: five patients had IBTR (7%) and four had a local with regional recurrence. Two, 5, and 10 years OS were 94.0, 83.8, and 61.9%, respectively, and DFS were 87.8, 67.1, and 50.6%, respectively. A higher clinical T stage was associated with poor DFS (p = 0.01). The risk of IBTR was not found to significantly correlate with any of the standard prognostic factors.Conclusion:BCS post NACT in suitably selected patients of LABC is a safe and viable option without adversely affecting oncological outcomes.