Characteristics and outcomes of surgically staged multiple classifier endometrial cancer

Objective: The growing adoption of molecular and genomic characterization is changing the current landscape of treatment of endometrial cancer patients. Using the surrogate molecular classification, endometrial cancer patients can be classified in four subgroups: POLE mutated (POLEmut), MMRd/MSI-H, p53 abnormal (p53abn), and no specific mutational profile (NSMP). However, some patients can harbor two or more molecular features (defined as multiple classifier). Since the rarity of this occurrence, evidence regarding multiple classifiers is still limited. Here, we described characteristics and outcomes of multiple classifiers. Methods: This is a multi-institutional retrospective study. Data of consecutive patients having 2 or more molecular features were collected. Survival was assessed using the Kaplan-Meier and Cox proportional hazard methods. Results: Charts of 72 multiple classifiers were reviewed. Median (range) follow-up was 9.8 (1.2, 37.5) months. Overall, 31 (43%) patients had POLEmut. Patients with POLEmut-MMRd/MSI-H, POLEmut-p53abn, and POLEmut-MMRd/MSI-H-p53abn were 6 (8.3%), 20 (27.8%), and 5 (6.9%), respectively. Among those 31 patients, no recurrence occurred within a median follow-up of 10.5 months (only seven (22.6%) patients had at least 2-year follow-up). The remaining 41 (56.9%) patients were diagnosed with tumors harboring both p53 and MMRd/MSI-H. Among them, four (9.8%) recurrences occurred at a median follow-up time of 8.9 months. Adjuvant therapy (other than vaginal brachytherapy) was administered in 5/31 (16%) and 25/41 (61%) patients with and without POLEmut, respectively (p < 0.001). Conclusions: Multiple classifiers endometrial cancer with POLEmut are characterized by good prognosis even in case of presence of MMRd/MSI-H and/or p53abn. Additional studies with long-term follow-up are needed.