e12658 Background: The data regarding incidence, response rates to neoadjuvant chemotherapy (NACT) and factors affecting pathological complete response (pCR) rate in locally advanced breast cancer (LABC) patients are lacking from India. Methods: This ambispective study was carried out at B.R.A., I.R.C.H, AIIMS, New Delhi, in between period of January 2013 to December 2019. We screened 1500 cases of breast cancer who presented to our institute and found 600 cases to be LABC,425 patients were started on NACT, 284 had undergone surgery and were included in our analysis. Results: The median age of diagnosis was 46 years (range 24-72years). Fifty four percent cases were postmenopausal, 54% had a left sided cancer,45 % right sided cancer,1 % had bilateral breast cancer. The median duration of symptoms was 5 months. The clinical stage according to AJCC staging system was Stage IIB – 11%(32), IIIA -21 % (58), IIIB- 60%(169) and IIIC- 8%(24) .Sixty five percent(186) cases presented with clinical skin involvement and 80% (228) patients has clinical node positivity.In our cohort 52% (148) cases were hormone positive (ER/PR positive), 42 %(119) cases were HER2/neu positive, 30%(84) were triple negative breast cancer (TNBC), 23 % (67) were positive for ER/PR and HER2/neu. Ninety percent of the cases were able to receive the planned neoadjuvant treatment before surgery. Post NACT 83% cases had a modified radical mastectomy (MRM) and 17% were able to undergo breast conserving surgery (BCS).Overall pCR was achieved in 59(21%) cases, 17% in hormone positive cases, 25% in HER2/neu positive cases (30% in cases receiving HER2/neu directed therapy vs 20% in cases who didn’t receive HER2 /neu directed therapy) and 27% in TNBC cases. During the study period 54 cases (19%) had relapsed,8 cases (3%) had a local relapse and a 46 cases (16%) had a systemic relapse. Grade ¾ toxicity occurred in 25 % cases, the most common were diarrhea, neutropenia, CINV, oral mucositis and thrombocytopenia and other rare toxicities (DVT, hand foot syndrome,myalgia). Febrile neutropenia was recorded in 2.5 % cases. There were 2 induction deaths. Stage II, absence of ER/PR expression showed statistically significant correlation with path CR rates. Conclusions: Locally advanced breast cancer constitutes around 40% cases at our institute. Post NACT pCR was achieved in 21% of cases, HER2/neu positive cases and TNBC showed higher pCR rates. The factors affecting pCR rate were absence of ER/PR expression and stage II disease.