Association between molecular classification and overall survival in patients with metastatic endometrial carcinoma: ancillary results of the UTOLA phase II GINECO trial
We aimed to describe the association between molecular sub-groups and outcomes in patients with advanced/metastatic endometrial carcinoma amenable to maintenance/active surveillance after carboplatin-based chemotherapy. Patients treated in the GINECO trial UTOLA (NCT03745950, randomly allocating patients 2:1 to olaparib/placebo after tumor control under carboplatin-based chemotherapy), with prospective centralized targeted next-generation sequencing, and mismatch repair and p53 immunostainings were included. Next-generation sequencing (667.5 kb) included POLE (exo-nuclease domain), TP53, PIK3CA, PIK3R1, PTEN, KRAS, and CTNNB1. Tumors were categorized following the 2022 European Society of Gynaecological Oncology/European Society for Radiotherapy and Oncology/European Society of Pathology guidelines as POLE-mutated, mismatch repair-deficient, p53-abnormal (immunostaining or TP53 mutation), and with no specific molecular profile. Exploratory analyses categorized non-p53-abnormal tumors based on literature (mismatch repair-deficient: mutational burden; no specificity: PIK3R1/PTEN wild-type tumors, CTNNB1/KRAS-mutated tumors, others). Among 145 patients in the intention to treat population (median follow-up 31 months), 1, 21 (15%), 76 (53%), and 45 (32%) had POLE, mismatch repair-deficient, p53-abnormal, and non-specific tumors (2 missing mismatch repair), respectively. Molecular characterization was associated with progression-free (log-rank, p = .017) and overall survival (p < .001). Patients with p53abn tumors had a hazard ratio for death of 2.43, 95% confidence interval 1.50 to 3.93 (adjusted on age, stage IV, measurable lesions after chemotherapy). Exploratory analyses showed high mutational burden mismatch repair-deficient tumors with prognostic similar to p53abn tumors, whereas tumors with lower mutational burden had better progression-free survival. PIK3R1/PTEN wild-type and CTNNB1/KRAS-mutated non-specific tumors had better outcomes than p53abn tumors. Other non-specific tumors have survival similar to p53abn tumors. Integration of molecular sub-group as a stratification parameter might be considered for randomized trials in advanced/metastatic endometrial carcinoma after carboplatin-based chemotherapy. Deeper characterization of mismatch repair-proficient tumors might enhance prognostication.