Radiotherapy-induced malignancies in breast cancer patients with TP53 pathogenic germline variants (Li –Fraumeni syndrome)

AbstractThe risk of radiotherapy-induced malignancies (RIMs) is a concern when treating Li –Fraumeni syndrome (LFS) or Li–Fraumeni Like (LFL) patients. However, the type ofTP53 pathogenic germline variant may possibly influence this risk.TP53 p.R337H mutation is particularly prevalent in Brazil. We aimed to evaluate the outcomes of patients with pathogenicTP53 variants treated for localized breast cancer in a Brazilian cohort. We evaluated retrospectively a cohort of patients with germlineTP53 pathogenic variants treated for localized breast cancer between December 1999 and October 2017. All patients were followed by the Hereditary Cancer Group of an academic cancer center. Our primary objective was to evaluate the occurrence of RIMs after adjuvant radiotherapy. Sixteen patients were evaluated; 10 (62.5%) had a germlineTP53 p.R337H pathogenic variant. Median age was 39.8  years. Thirteen patients had invasive ductal carcinoma: 8 (61.5%) were hormone receptor-positive; 6 (46.1%), human epithelial growth factor receptor 2 (HER2)-amplified. Three patients had ductal carcinoma in situ. Most patients (N = 12/16, 75%) received adjuvant radiotherapy. After a median fo llow-up of 52.5 months, 2 patients (2/12, 16.6%) had RIMs. One had a fibrosarcoma and the other, a low-grade leiomyosarcoma. In the group treated with radiotherapy, one distant recurrence was diagnosed (1/12), and no loco-regional recurrence occurred. Among 4 patients who did not receive radiothera py, 2 pres...
Source: Familial Cancer - Category: Cancer & Oncology Source Type: research