Metaplastic breast cancer: Disease characteristics and outcome in Arab women.

Abstract

e12534 Background: Metaplastic breast cancer (MPBC) accounts for less than 1% of all breast cancer subtypes. Methods: Patients diagnosed with MPBC between 2001 are 2018 were reviewed. Disease characteristics, progression-free survival (PFS), and overall survival (OS) were estimated by the Kaplan-Meier method and compared by log-rank test. Results: Fifty-five MPBC patients were analyzed. The median was 46 years (IQR 40–55). 14.5% had a positive family history of cancer. The majority (98.2%) presented with a lump, and two patients presented with bilateral disease. The median BMI was 31 (IQR 24.5–37.5). The majority had stage III (56.4%), and stage IV was (7.3%). Most patients (90.9%) had triple-negative disease. The tumor grade (G) was available for 63.6% of patients (G2 11.4% and G3 88.6%). Nineteen patients (34.5%) received neoadjuvant chemotherapy (NAC) [anthracycline-based (15,78.9%), and platinum-taxane (11, 57.8%)]. The majority (92.7%) underwent surgery, 56.4% MRM, 12.7% BCT, 12.7% simple mastectomy, 7.3% palliative mastectomy. 54.5% underwent ALND and 20% SLNB. One patient had pCR. Adjuvant radiation was given for (33, 60%) and (37, 67.3%) received adjuvant radiation therapy. The median follow-up duration is 44 months (IQR 21–69). For nonmetastatic disease, 3-years DFS was 67.5%. There was no difference in DFS with using NAC (p-0.96) or being obese (p = 0.50). The 3-years OS was 72.9%, and the Log-rank test revealed prolonged survival with radiation therapy 87.1% vs. 56.6% ( p = 0.02) and earlier stage at diagnosis. 3-years OS for stage II was 92.9%, stage III was 71%, and no survival in stage IV (p < 0.001). There was a clinical difference in 3 years OS between obese vs. nonobese 61.3% vs. 85.9%, with no statistical significance (p = 0.15). Conclusions: The majority of patients diagnosed with MPBC had large tumor size, nodal disease, and more triple-negative disease, locally advanced and nonmetastatic. The DFS and OS were comparable to reported survival. There is a significant correlation between survival and stage and adjuvant radiation therapy.