Abstract P3-20-09: Surgery vs radiation therapy as the first stage treatment in patients with locally advanced breast cancer with incomplete clinical response

Abstract

Abstract Objective: The management of patients with locally advanced breast cancer (LABC) with skin involvement continues to be one of the most controversial topics in mammology. Systemic therapy (chemotherapy and/or hormone therapy and biological agents) followed by local therapy (surgery and/or radiation therapy) are usually recommended. There are no generally accepted definitions of tumor resectability following systemic therapy (skin edema/erythema/thickening), and thus there are no specific guidelines for the priority of local treatment. Systematic well-conducted randomized trials of these patients are still rare. So the purpose of our analysis is to assess the long-term outcome in patients with incomplete clinical response to neoadjuvant systemic therapy followed by different priority of local treatment types.Materials and methods: We performed a retrospective analysis of 182 consecutive patients with N4bN0-3 non-metastatic breast cancer treated between 2010 and 2018 in N.N. Blokhin National Cancer Research Center. All patients were treated with neoadjuvant hormone- or chemotherapy and were considered as borderline for surgical resection because of partial skin edema. Ninety one (50%) received radiotherapy (RT) with (50 women, total dose 50 Gy) or without (41 women, total dose 62Gy) consecutive surgery after systemic treatment (first group) and 91 (50%) received surgery with consecutive radiotherapy (second group). The median age of the first and second group were 58,76±1,29 and 57,64±1,29 years, respectively (р = 0,539). Median follow-up time was 7,5 years. Results: The 3- and 5-​year disease-free survival (DFS) of the first group were 47% and 33,3%, of the second group were 61,4% and 54,1% respectively. DFS differed significantly between the two groups (р = 0,008). There was no difference in DFS regardless of the surgery in the first group (p = 0,931). Also, the risk of a local-regional recurrence was lower at the second group (the 3- and 5-year LRR-free survival rates were 87,7% and 85,6% vs 77,3% and 65,9%, р = 0,027). The 3- and 5-year overall survival (OS) of the first group were 75.2% and 57.9%, the 3- and 5-year overall survival (OS) of the second group were 77.1% and 57,9%, respectively. There wasn`t a statistically significant difference between the two groups (p=0,768 and p=0,619, respectively). A separate analysis, dividing the patients of the first group on with and without surgery, did not substantially alter the results of OS (p = 0,088 and p = 0,411). Mortality rate was 48,4% (CI: 38,8% - 58,0%) in the first group and 41,8% in the second group (CI:32,5% - 51,5%), р=0,228.Conclusion: Our study showed that local control and DFS in LABC patients with skin involvement after systemic treatment were better if surgery was performed as the first stage of the local treatment. Therefore, prospective randomized trials are needed to improve patient selection and optimization of the local treatment. Citation Format: Alexander Petrovsky, Victory Amosova, Oxana Trofimova, Mona Frolova. Surgery vs radiation therapy as the first stage treatment in patients with locally advanced breast cancer with incomplete clinical response [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P3-20-09.