Genomic Alterations and Radioresistance in Breast Cancer: An Analysis of the Profiler Protocol

International audiencePurpose/Objective(s)Breast cancer (BC) patients with comparable prognostic features have heterogeneous outcomes, partly because of radiotherapy resistance leading to loco-regional recurrences (LRR). The ProfiLER (Profilage LYric et Région, NCT01774409) clinical trial aims at establishing a simple genetic profile of metastatic cancers in order to offer patients personalized molecular targeted therapies. In the breast cancer area, the genomic profiling of a population who ultimately became metastatic, and its correlation with the patient outcome years after LRR, provided an opportunity to identify post hoc biomarkers of the initial radiation resistance. The aim of the present study was to determine if specific tumor genetic alterations were associated with radiation resistance, defined as a LRR despite optimal surgery, radiotherapy, and systemic adjuvant therapies, in a ProfiLER series.Materials/MethodsGenetic profile of 162 BC patients’ tumors included in ProfiLER between 2013 and 2016 were analyzed using Next-Generation-Sequencing and Comparative-Genomic-Hybridization tests. Patients and tumor characteristics were analyzed for association with genomic rearrangements (mutations, amplification, homozygous deletions). Only gene alterations observed in >3% of the tumors, or included in well-known molecular pathways (PI3 Kinases pathway, MAP Kinases pathway, Tyrosine Kinase receptors family) were selected. The Cox multivariate analysis was based on (P3% of tumors. PIK3CA and ROS1 mutations were statistically correlated to the risk of LRR. A median loco-regional progression free survival (LRPFS) of 19.8 years was reported for PIK3CA mutation carriers (n = 34, 21%) versus 9.1 years for wild-type patients (HR = 0.29, 95% CI = 0.13-0.64, P = 0.002 in univariate analysis). PIK3CA mutation was identified as an independent protective factor of LRR using multivariate analysis (HR = 0.27, 95% CI = 0.09-0.82), P = 0.02). ROS1 mutated cancer patients (n = 8, 4.9%) had a median LRPFS of 4 years versus 16.1 years for wild-type patients (HR = 2.5, 95% CI = 1.74-7.05, P = 0.08 in univariate analysis), but was not identified as an independent LRR risk factor (HR = 2.45 95% CI = 0.83-7.26, P = 0.11 in multivariate analysis). Other mutations and amplifications were not associated with LRR. Among relapsing patients, the median time to LRR was nearly significantly different regarding status of the PIK3CA mutations, with 8.6 years for mutated patients versus4.7 years for non-mutated patients (P = 0.09).ConclusionPIK3CA mutation was associated with a lower risk of LRR in this BC population. ROS1 mutation was marginally associated with a higher risk of LRR, possibly because of a limited population. Results suggest PIK3CA and ROS1to be possible biomarkers of radio-sensitivity

Clinical factors associated with prolonged response and survival under olaparib as maintenance therapy in BRCA mutated ovarian cancers.

To investigate clinical factors associated with prolonged progression-free survival (PFS) and overall survival (OS) in relapsing epithelial ovarian cancer (EOC) patients with BRCA mutations and receiving olaparib as maintenance therapy in daily practice. Multicenter (8 hospitals) European retrospective study of relapsing EOC patients having germline or somatic mutations of BRCA1/BRCA2 genes and treated with olaparib as maintenance therapy after platinum-based chemotherapy. One hundred and fifteen patients were included. Median age was 54 years. There were 90 BRCA1 carriers, 24 BRCA2 carriers and one patient had germline mutation of BRCA1 and BRCA2. Six patients had somatic mutations (all BRCA1) and 109 had germline mutations. Ninety percent had serous carcinomas and were platinum-sensitive. Following ultimate platinum-based chemotherapy, 69% of the patients had normalization of CA-125 levels and 87% had RECIST objective responses, either partial (53%) or complete (34%). After a median follow-up of 21 months, median PFS was 12.7 months and median OS was 35.4 months. In multivariate analysis, factors associated with prolonged PFS under olaparib were: platinum-free interval (PFI) ≥ 12 months, RECIST complete response (CR) or partial response (PR) and normalization of CA-125 upon ultimate platinum-based chemotherapy. Factors associated with prolonged OS were PFI ≥ 12 months, CR and normalization of CA-125. Platinum-free interval ≥ 12 months, complete response and normalized CA-125 levels after ultimate platinum-based chemotherapy are associated with prolonged PFS and OS in relapsing BRCA1/BRCA2 mutated ovarian cancer patients who received olaparib as maintenance therapy