Retrospective analysis of factors impacting efficacy of patients with later stage breast cancer receiving neoadjuvant therapy.

e12624 Background: Neoadjuvant treatment is the current standard of care for patients with early breast cancer (EBC), especially for patients with later stage breast cancer (LBC). We conducted this retrospective study to summarize the correlation between pathologic complete response (pCR), disease-free survival (DFS), overall survival (OS) and clinical impacting factors of patients with later stage received neoadjuvant treatment. Methods: We retrospectively analyzed the clinical data of patients receiving neoadjuvant treatment at the Department of Breast Oncology, Peking University Cancer Hospital from Jan. 2013 to Feb. 2022. Statistical analyses were carried out using IBM SPSS Statistics. We calculated pCR rate, DFS and OS. Pearson’s χ2 or Fisher’s exact tests were used for comparison of categorical variables. DFS and OS were estimated using the Kaplan-Meier method and compared using the log-rank test. Cox regression was used to identify factors impacting on survival. All p values were two sided and p<0.05 was considered to denote statistical significance. Results: Of 198 patients, most of them were in stage II (115/198, 58.1%), followed by stage III (79/198, 39.9%) and stage I (4/198, 2.0%), The pCR rates for different molecular subtypes were 31.6% TNBC, 29.7% for HR-Her2+ BC, 26.1% for HR+Her2+ BC and 1.3% for HR+Her2- BC, respectively (p=0.000). The median DFS of patients with or without pCR was 59.63 months (95%CI: NA-NA) and 29.83 months (95%CI: 21.31-38.35), respectively (p=0.012). DFS of patients who were cT1 59.63 months (95%CI: 37.95-81.31) or cT2 39.56 months (95%CI: 24.19-54.93) was significantly longer than that of patients who were cT3-4 25.76 months (95%CI: 14.11-37.41), p=0.041. Miller Payne (M-P) grade and ypTNM stage were also significantly associated with DFS in univariate analysis and in the multivariate cox regression model after adjusting for molecular subtypes. The 5-year OS were 87.0% for patients who reached pCR and 52.0% for patients who didn’t (p=0.009). Conclusions: The pCR was significantly associated with molecular subtypes. HR negativity and overexpression of Her2 were significantly associated with higher pCR rate. Patients reached pCR had longer DFS and OS. DFS was significantly associated with cT stage (T1 vs T2 vs T 3-4), ypTNM stage and M-P grade.