|A Phase III Trial of Surgery with or Without Adjunctive External Pelvic Radiation Therapy in Intermediate Risk Endometrial Adenocarcinoma: a Gynecologic Oncology Group Study|
|Reviewer: Walter F. Sall, MD|
|The Abramson Cancer Center of the University of Pennsylvania|
Authors: Keys HM, Roberts JA, Brunetto VL, Zaino RJ, Spirtos NM, Bloss JD, Pearlman A, Maiman MA and Bell JG
Approximately 36,000 cases of endometrial cancer are diagnosed yearly in the USA. The majority of these are stage I. After standard hysterectomy, there is little randomized data on which to base decisions regarding the utility of post-operative radiation therapy (PORT). Creutzberg et al has previously examined the utility of PORT in a prospective randomized study in women undergoing incomplete surgical staging (no node sampling). For stage I patients, a small decrease in locoregional recurrence (LRR) was seen prompting them to recommend PORT only for their high risk sub-group: those with FIGO stage IB Grade II tumors or worse or any patient over 60 years of age. The goal of this study (GOG 99) was to investigate the utility of PORT in stage IB, IC and II (occult) patients having undergone complete surgical staging.
Materials and Methods
This is the only large, randomized study of PORT vs. NFT in a population undergoing complete surgical staging. Overall, PORT reduced LRR by 58%, primarily by greatly reducing the incidence of vaginal recurrences. The absolute risk reduction in the high intermediate risk group was 19% vs. 4% in the low intermediate risk group. There was a trend towards OS benefit in the PORT arm. However, because of the low overall recurrence rate and the impact of intercurrent disease in this elderly population this study was underpowered to detect a survival benefit. Based on unplanned sub-group analysis, the authors recommend PORT only for those stage I patients who fit their criteria for high intermediate risk.