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No Survival Benefit With Adjuvant Chemo or RT for Endometrial Cancer

Post-operative systemic chemotherapy and radiotherapy did not improve overall survival (OS) in high-risk women with stage I endometrial cancer, according to a study presented by Rachelle Findley, MD, University of Calgary, Alberta, at the 2021 SGO Virtual Annual Meeting on Women's Cancer.

“The aim of our study was to evaluate survival and recurrence patterns for patients with surgically treated stage I endometrial carcinoma as a whole, and then to focus in on the high risk cohort,” explained Dr Findley.

This study took place across eight cancer centers in Canada, with consecutive patients from 2000 to 2010 who had stage I endometrial cancer (defined as either stage IB grade 3 endometrioid histology or myoinvasive non-endometrioid histology) were included. 

Patient disease and treatment characteristics were summarized by descriptive statistics, while OS, disease-specific survival (DSS), and relapse-free survival (RFS) were calculated by log-rank statistics, followed by the construction of Kaplan Meier curves.

Throughout the 11 years, 2327 patients were identified as having stage I endometrial cancer, with 414 of all cases being considered high-risk. Of the high-risk patients, 99 received adjuvant chemotherapy, and 235 received radiotherapy, with 115 receiving combined therapy. 

Among those receiving adjuvant chemotherapy, there was no significant difference in OS (median, 8.52 vs 7.48 years, HR, 0.70; 95% CI, 0.46-1.14; P = 0.13). Although the curve favors those who receive chemotherapy, researchers thought this to be related to section bias. The disease-specific survival confirmed this, as it showed very little difference in survival (HR, 1.06; 95% CI, 0.61-1.85; P = 0.84). 

However, chemotherapy did improve RFS (median, 8.52 vs 6.92 years, HR, 0.61; 95% CI, 0.39-0.95; P = 0.03), whereas radiation therapy did not improve OS, RFS, or DSS.

Patients aged 55 and over or who had stage IB, a higher grade, or lymphovascular space invasion, had a higher recurrence and lower survival rates. 

“We found no associated overall survival benefit with systemic adjuvant therapy or adjuvant radiation. Recurrence-free survival from radiation did not reach statistical significance, however adjuvant chemotherapy was associated with a reduction in recurrence,” concluded Dr Findley.—Alexandra Graziano

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