Clinicopathological Characteristics, NeoadjuvantTreatment Patterns and survival in Non-MetastaticTriple-Negative Breast Cancer: A Real-WorldExperience from a Peruvian Oncology Center

Abstract

In Peru, there is limited real world evidence regarding the clinical-pathological characteristics and neoadjuvant treatment patterns of non-metastatic triple negative breast cancer (NMTNBC), especially prior to the incorporation of immunotherapy. Objectives: Describe the clinical-pathological characteristics, neoadjuvant treatment patterns and the reasons for the use of carboplatin in a Peruvian cohort with NMTNBC. Materials and methods: Retrospective, descriptive and non-consecutive series, based on clinical records available of adult patients with non-metastatic TNBC treated between 2019 and 2023 in a Peruvian oncological institution.
Characteristics according to the use of carboplatin were compared using the chi square test. The overall survival (OS) was explored through/with Kaplan-Meier and log-rank, being interpreted in a descriptive nature due to the unadjusted nature of the analysis. Results: 199 patients were included. The median age was 48 years old (IQR 42-56) and 57% debuted at clinical stage III. The median time between the end of neoadjuvant therapy and surgery was 54 days. A mastectomy was performed in 73% of the cases and a pathologic complete response (pCR) was reached in 14.6% of patients. Carboplatin was used in 28% of cases, mainly due to a lack of response or progression during neoadjuvant therapy (69.5%). Its use was concentrated among patients with a higher tumor burden and residual disease (tumor ≥ 30 mm, ypT3-4, ypN (+), pathological stage III and RCB-III; p<0.05). Amongst the 178 female patients evaluable for OS, 21 deaths were documented, with a follow-up mean of 28.5 months. The OS rate at 60 months was 65%. In the multivariate analysis, only lymphovascular invasion was associated with an increased risk of death (HR: 5.4, p-value= 0.04). Conclusions: In this Peruvian cohort, NMTNBC was presented with a high anatomical burden upon diagnosis, high frequency of mastectomy and low pCR. The
use of carboplatin reflected an intensification strategy in patients with worse initial response; hence, its association with survival outcomes must be interpreted carefully and not as a causal effect.