Intravaginal brachytherapy alone for intermediate-risk endometrial cancer
- Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY (United States)
- Department of Biostatistics, Memorial Sloan-Kettering Cancer Center, New York, NY (United States)
- Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, NY (United States)
Purpose: Despite the results of the Gynecologic Oncology Group trial No. 99 (GOG no. 99), some unanswered questions still remain about the role of adjuvant radiotherapy (RT) for intermediate-risk endometrial cancer. First, can intravaginal brachytherapy (IVRT) alone substitute for external beam RT but without added morbidity? Second, is the high-risk (HR) definition from GOG no. 99 a useful tool to predict pelvic recurrence specifically? The purpose of this study was to try to answer these questions in a group of patients with Stage IB-IIB endometrial carcinoma treated with high-dose-rate (HDR) IVRT alone. Methods and Materials: Between November 1987 and December 2002, 382 patients with Stage IB-IIB endometrial carcinoma were treated with simple hysterectomy followed by HDR-IVRT alone at our institution. Comprehensive surgical staging (CSS), defined as pelvic washings and pelvic/paraaortic lymph node sampling, was performed in 20% of patients. The mean age was 60 years (range, 29-92 years). Lymphovascular invasion (LVI) was present in 14% of patients. The median HDR-IVRT dose was 21 Gy (range, 6-21 Gy), given in three fractions. Complications were assessed in terms of late Radiation Therapy Oncology Group (Grade 3 or worse) toxicity of the GI tract, genitourinary GU tract, and vagina. Results: With a median follow-up of 48 months, the 5-year vaginal/pelvic control rate was 95% (95% confidence interval [CI], 93-98%). On multivariate analysis, a poor vaginal/pelvic control rate correlated with age {>=}60 years old (relative risk [RR], 3, 95% CI, 1-12; p = 0.01), International Federation of Gynecology and Obstetrics (FIGO) Grade 3 (RR, 9, 95% CI, 2-35; p = 0.03), and LVI (RR, 4, 95% CI, 1-13; p = 0.051). The depth of myometrial invasion and CSS, however, were not significant. With regard to pelvic control specifically, the presence of GOG no. 99 HR features did not affect the pelvic control rate. The 5-year rate for HR patients was 96% (95% CI, 90-100%) vs. 96% (95% CI, 94-99%) for those without HR disease (p = 0.48). Even when the CSS effect was taken into account, the influence of HR features on pelvic control was still not significant (p = 0.51). In contrast, pelvic control was significantly influenced when patients were grouped according to CSS and stage/grade substages. For those with Stage IB Grade 3-IIB and no CSS, the 5-year pelvic control rate was 86% compared with 97% for those with Stage IB Grade 3-IIB and CSS, 97% for Stage IB, Grade 1-2 without CSS, and 100% for those with Stage IB, Grade 1-2 and CSS (p = 0.027). The 5-year disease-free survival rate was 93% (95% CI, 90-96%). On multivariate analysis, poor disease-free survival correlated with age {>=}60 years (RR, 5; 95% CI, 1-18; p = 0.002), FIGO Grade 3 (RR 5, 95% CI 2-17; p = 0.013), and LVI (RR 3, 95% CI 1-8; p 0.054). Unlike pelvic control, disease-free survival was significantly affected by GOG no. 99 HR features, with a 5-year rate of 87% (95% CI, 76-99%) vs. 94% (95% CI, 91-97%) for those without HR features (p = 0.027). The 5-year overall and disease-specific survival rate was 93% and 97%, respectively. The overall 5-year actuarial rate of Grade 3 or worse complications was 1% (95% CI, 0-2%). Conclusion: Tumor grade, depth of invasion, and the use of CSS were better predictors of pelvic control than the GOG no. 99 HR factors. IVRT alone seemed to provide adequate tumor control with very low morbidity. Therefore, it seems prudent to consider it for intermediate-risk patients because of its superior therapeutic ratio compared with that for surgery alone or pelvic RT. Additional follow-up, however, with a larger number of patients is needed, especially for those with LVI.
- OSTI ID:
- 20698416
- Journal Information:
- International Journal of Radiation Oncology, Biology and Physics, Vol. 62, Issue 1; Other Information: DOI: 10.1016/j.ijrobp.2004.09.054; PII: S0360-3016(04)02708-7; Copyright (c) 2005 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0360-3016
- Country of Publication:
- United States
- Language:
- English
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