Analysis of risk factors for recurrence within 12 months after surgery in patients with breast cancer receiving neoadjuvant therapy at a Brazilian cancer center.

e13039 Background: Early recurrence following treatment for localized breast cancer typically occurs within 5 years, and is commonly linked to high-risk clinicopathologic factors. However, literature focusing on risk factors for earlier recurrence timeframes is scarce, particularly within the neoadjuvant treatment population. Therefore, this study aims to investigate potential predictors for recurrence within 12 months post-surgery in breast cancer patients submitted to neoadjuvant therapy. Methods: This is an observational, descriptive, retrospective study involving 310 patients with recurrent breast cancer who received neoadjuvant therapy between January 2007 and March 2022, at AC Camargo Cancer Center in São Paulo, Brazil. Patients were compared based on relapse time after surgery (<12 months or ≥12 months), and risk factors were analyzed using the Chi-Square test or Fisher’s Exact test. Results: From 310 patients analyzed, 108 relapsed within 12 months and 202 after this period. Factors predicting recurrence in less than 12 months included: Histologic grade (HG) III ( p < 0.01); nuclear grade (NG) III ( p < 0.001); mitotic counts >20/mm2 ( p = 0.02); Ki67 > 20% ( p = 0.010); triple negative breast cancer (TNBC) and HER2+/HR- subtypes ( p < 0.001); interruption of neoadjuvant therapy due to disease progression or toxicity ( p < 0.001); chemotherapy dose reduction or delay ( p = 0.001); omission of adjuvant radiotherapy ( p < 0.001) and interruption of adjuvant HER2 targeted therapy ( p < 0.001). Menopausal status, Residual Cancer Burden (RCB) index, type of surgery and clinical stage showed no significant correlation with the outcome. Conclusions: Recurrence in less than 12 months was associated with intrinsic factors, such as HG III, NG III, high mitotic counts, Ki67 > 20%, TNBC, as well as interruption or delay of neoadjuvant therapy, omission of adjuvant radiotherapy and interruption or delay of HER2 targeted therapy, pointing out potential risk factors in this population.