Treatment related outcomes in high-risk endometrial carcinoma: Canadian high risk endometrial cancer consortium (CHREC)

Objective: The lack of randomized clinical data pertaining to optimal surgery and adjuvant treatment in women with high-risk histotypes of endometrial cancer has resulted in selective management based on institutional policies. The objective of this study was to assess differences in treatment strategies and their outcomes among various institutions.

Method: High-risk endometrial cancer cases (2000-2012) with corresponding clinicopathologic data were collected from 7 academic cancer centers. Histotypes included grade 3 endometrioid (EC3), serous (ESC), clear cell (CCC) and carcinosarcoma (CS). Associations with overall survival were performed using Cox proportional hazard regression.

Results: 1260 patients treated between 2000 and 2012 were included in the study: 398 EC3, 449 ESC, 91 CCC, 236 CS and 83 'other'. The use of adjuvant chemotherapy, adjuvant radiation, and extent of surgical staging were statistically different among the 7 centers (P<0.001). Histotype was independently associated with overall survival (OS) in patients with stage 1 and 2 disease who underwent surgical staging (P=0.0324). Adjuvant radiation was associated with improved OS for EC3 and CCC and adjuvant chemotherapy was associated with improved OS for ESC and CS. There was a high rate of recurrence (17.8% and 21.4%) in completely staged, stage 1A patients with ESC and CS respectively.

Conclusion: There exists a wide variation in practice and outcomes for high-risk histotypes of endometrial cancer. The relative impact of adjuvant therapy appears to be histotype dependent and prospective studies examining adjuvant treatment in high-risk histotypes should use caution combining them together.