Abstract P4-06-06: Neoadjuvant B27 protocol in Triple-Negative Breast Cancer: Evaluation response rate, pathological complete response rates,toxicity,and the prognosis of Adolescent and Young Adult (AYA) age group compared to older population

Abstract

Background: Neoadjuvant chemotherapy (NACT) is the standard early-stage triple-negative breast cancer (TNBC) treatment. Achieving pathological complete response (pCR) is considered an essential prognostic factor with favorable long-term outcomes. Younger patients have with poorer prognosis in breast cancer. To date, few studies are comparing the prognosis of AYA and older women (≥40) with breast cancer subtypes, specifically Triple-negative breast cancer (TNBC), as AYAs had higher proportions of this subtype. Method: Retrospective review was performed on female patients who received NACT at a King Hussien Cancer Center from January 2014 to June 2020. Data were collected from patients’ electronic medical records. TNBC was histopathologically confirmed. Logistic regression analysis of predictors of pathologic complete response (pCR). Survival curves were estimated with the Kaplan-Meier method. Multivariate analysis for EFS was performed using Cox’s proportional hazards regression model, covariates included age at diagnosis (AYA vs. ≥40), tumor size, nodal status LVI and pCR Result: We analyzed 211 women with stage I-III TNBC, including 62 (29.4%) women aged 18 to 39 years (AYA) and 149 (70.6%) ≥40 years. 138 (68.3%) were node positive, and 71 (34.8%) were T3/4 disease. Median follow-up was 28.1 months, median number of ER visit during NAC is 1 (0-11), 23 (10.9 %) patients had admission during neoadjuvant chemotherapy, most commonly due to febrile neutropenia 13 (56.9%). 37 (17.5%) patients did not complete NAC, due to disease progression in 22 (10.4%), and toxicity in 15 (7.1%) patients. 195 (92.4%) patients had surgery, including 75 (35.5%) had breast-conserving surgery (BCS). 166 (76.3%) patients had objective response, and 64 (30.3%) had pCR. 170 (80.6%) received adjuvant radiotherapy, and 38 (18%) received adjuvant capecitabine. No significant differences between the AYA and the ≥40 group in terms of clinicopathological, toxicity, pCR rate, and the rate of BCS. In univariate analysis, the LVI, nodal status, pCR, and age group were significant predictors of DFS. In multivariate analysis, only PCR and age are the only independent predictor of DFS. The median DFS was worse in the AYA population 47.8 (31.21-64.39) months vs. NR in ≥40 (p-value 0.013). In patients who achieved pCR, the estimated 5-years DFS for the AYA group was 56.1% versus 86.8% for the ≥40 group, (p-value 0.71). In patients with residual disease, PFS for AYA was 34.2 (95%CI 11.5-57) months vs. 59.5 months in the ≥40 group, (p 0.009). Conclusion: Although there is no difference in pCR between the AYA age group patient treated with NACT for TNBC and the older age group, the DFS is significantly worse in the AYA than the ≥40 age group in patients with residual disease. As well, DFS is numerically worse in the AYA age vs. the ≥40 age group in patients who achieved pCR. Citation Format: Faris Tamimi, Baha’ Sharaf, Suhaib Khater, Suhaib Al-Sawajneh, Malek Horani, Khalid M. Elrabii, Anas Zayed, Hikmat Abdel-Razeq. Neoadjuvant B27 protocol in Triple-Negative Breast Cancer: Evaluation response rate, pathological complete response rates,toxicity,and the prognosis of Adolescent and Young Adult (AYA) age group compared to older population [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-06-06.