Background: Although endometrial cancer remains the most common gynecologic malignancy in the United States, differing approaches to adjuvant radiotherapy treatment for early disease exist within the medical community because of the lack of a national consensus.
Methods: The authors studied patterns of adjuvant care for stage I and II endometrial adenocarcinoma using a large United States population database. A retrospective analysis was conducted from the Surveillance, Epidemiology, and End Results (SEER) Program of the U.S. National Cancer Institute from 1988 to 2002, and 26,923 women with American Joint Committee on Cancer stage I and II endometrial adenocarcinoma were selected. The following prognostic factors were analyzed: age, race, stage, grade, year of diagnosis, SEER registry location, and use and type of postoperative radiotherapy (RT). Adjuvant RT was coded as none, external-beam RT (EBRT), brachytherapy (BR), or a combination of the 2 (EBRT + BR).
Results: Higher tumor grade and stage led to greater use of RT. The odds ratio (OR) for adjuvant RT was 3.4 for stage IB versus stage IA and 51.8 for stage IC/II versus stage IA. The effect of grade depended on stage: for stages IA and IB, the OR was 2.9 for grade 2 versus grade 1 and 11.7 for grade 3/4 versus grade 1; whereas, for stage IC/II, the OR was 1.5 for grade 2 versus grade 1 and 2.0 for grade 3/4 versus grade 1. Within stage I, increasing substage and grade increased the odds of EBRT with or without BR compared with BR alone. Race did not effect the choice of therapy (all P > .1). Geographic location had a significant effect on overall RT use and therapy choice.
Conclusions: To the authors' knowledge, this was the largest patterns of care analysis to date of adjuvant RT in patients with stage I and II endometrial adenocarcinoma. The current study revealed that there is significant diversity in the use of adjuvant RT across the United States, and the results reflected the absence of a national consensus on adjuvant treatment for early-stage disease.