Abstract PO5-21-07: Mitomycin: its developmental role in the treatment of patients with BRCA - associated triple-negative early and locally advanced breast cancer

Abstract

Abstract Rationale. BRCA-associated triple-negative breast cancer (TNBC) is one of the most aggressive subtypes of breast cancer with high sensitivity to chemotherapy, which leads to increased interest in the development of new strategies for neoadjuvant treatment of patients with a triple-negative tumor phenotype. The aim of the study is to determine the role of adding platinum to standard neoadjuvant systemic therapy in patients with primary BRCA-associated TNBC, to evaluate the effect of platinum preparations on relapse-free survival in patients of this category, to determine the role of adding mitomycin to platinum in patients with primary BRCA-associated TNBC. Materials and methods. The study included 80 patients diagnosed with primary BRCA - associated TNBC, divided into 3 groups according to the treatment. Each group was subdivided depending on the final pathomorphological result and the presence of relapses. Results. 80 patients with primary BRCA-associated TNBC were divided into 3 groups depending on the ongoing neoadjuvant chemotherapy (NACT). Group I included 48 (60%) patients who received the AC-T regimen, in group II — NAC according to the AC-TCarb regimen, 27 (33.75%) patients, in group III — NAC with mitomycin in combination with cisplatin, 5 (6.25%) of patients. A comparative analysis of the results of the frequency of achieving complete pathomorphological regression (pCR), depending on the addition of a platinum drug to standard NAC, showed the advantage of group II compared to group I (73.7% vs. 41.2%, respectively, p = 0.0433). Taking into account the ongoing NAC regimens, with a median follow-up of 20.7 months, patients of group I had a slightly higher risk of relapse compared to patients of group II (p = 0.099). Patients of group III demonstrated the achievement of pCR in 66.6% of cases (2/3) during the full course of NAC, 2 patients of group III did not complete the planned course of NAC for medical reasons, due to the development of a pronounced nephrotoxic effect. During the observation period of group III, no cases of relapse were recorded. Conclusions.The addition of platinum drugs to the standard anthracycline/taxane NAPCT regimen in patients with primary BRCA-associated TNBC, results in a higher pCR rate, which entails a reduced risk of disease recurrence.The use of the new NAC regimen with mitomycin in combination with platinum compounds has promising results in patients with this oncopathology, which deserves a more detailed clinical evaluation.Performinga full course of planned NAC has a positive tendency in achieving pCR in patients of this category. Keywords: BRCA1/2 mutation; triple negative breast cancer; platinum preparations; mitomycin; neoadjuvant chemotherapy. Citation Format: Petr Krivorotko, Evgeniy Imyanitov, Diana Enaldieva, Elena Zhiltsova, Roman Donskih, Anna Sokolenko, Laysan Shaikhelislamova, Larisa Gigolaeva, Tengiz Tabagua, Alexander Komyakhov, Kirill Nikolaev, Konstantin Zernov, Sergey Yerechshenko, Roman Pesotsky, Nikolay Amirov, Alexander Emelyanov, Viktoria Mortada, Yana Bondarchuk, Vladislav Semiglazov. Mitomycin: its developmental role in the treatment of patients with BRCA - associated triple-negative early and locally advanced breast cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-21-07.