Role and Timing of Radiotherapy in High-Risk Endometrial Cancer

Abstract

SUMMARYEndometrial cancer is the most common gynecological tumor in developed countries, and its incidence is increasing because of an increased prevalence of obesity and an aging population. Although most patients present with early-stage low-risk disease, a rise in the incidence is attributed to an increasing number of high-risk cases at the time of diagnosis. Despite optimal surgical treatment, the prognosis of high-risk endometrial cancer (HREC) is poor because of increased risk of local and distant recurrences and therefore, adjuvant treatment should be considered. Although the definition of high-risk patients varies between cooperative groups, the recent endometrial consensus conference defined high-risk patients as follows: (1) stage I endometrioid, grade 3, ≥50% myometrial invasion; (2) stage II disease; (3) stage III endometrioid, no residual disease; and (4) non-endometrioid histology. The optimal adjuvant treatment is controversial; however, multimodality treatment is recommended. External radiotherapy seems to be reasonable in HREC and is indicated to improve pelvic relapses. The use of adjuvant chemotherapy is also reasonable for preventing or delaying distant metastases. There is limited evidence for the benefit of vaginal cuff brachytherapy after external radiotherapy. Optimal sequence of radiation and chemotherapy is not well defined; however, concurrent chemoradiotherapy plus adjuvant chemotherapy, "sandwich" approach, and providing radiotherapy after the completion of chemotherapy may be reasonable. The role of adjuvant radiotherapy with systemic therapy for treating HREC remains an area of active investigation. Adjuvant treatment of HREC is evolving, and patients should be individually treated with respect to the stage, histology, and prognostic factors.