Intensity-Modulated Versus Three-Dimensional Conformal Radiotherapy for Cervical Cancer: National Trend and Survival

Abstract

Definitive chemo-radiotherapy is the standard of care for locally advanced cervical cancer. Recently, a randomized trial showed pelvic intensity-modulated radiotherapy (IMRT) was associated with significantly less GI and urinary toxicities than three-dimensional radiotherapy (3DRT). The purpose of this study is to determine the trend of IMRT use in the United States and to determine if IMRT is associated with better survival compared to 3DRT. The National Cancer Database (2004-2015) was analyzed to evaluate the practice pattern and overall survival (OS) for localized cervical cancer patients treated with chemotherapy with pelvic IMRT or 3DRT. Those without treatment, treated by chemotherapy alone, RT alone or surgery, were excluded. OS was analyzed using the Kaplan-Meier method, log-rank test, Cox proportional hazards models, and propensity score-matched analyses. IMRT use increased from 32.6% to 68.1% in the United States. IMRT use was associated with later years of diagnosis, academic facility, nodal positive disease, and no brachytherapy use. At a median follow-up of 31.0 months, there was no survival difference between IMRT versus 3DRT by both univariate (HR, 0.97; P=0.57) and multivariate analysis (HR, 0.95; P=0.33). Propensity score analysis with matched baseline characteristics including brachytherapy use re-demonstrated a similar survival between IMRT and 3DRT with median survival (82.5 vs 77.0 months), 2-year OS (72.9% vs 72.4%) and 5-year OS (55.3% vs 54.9%) (HR, 0.95; P=0.41). IMRT has become the major treatment modality in the United States, preferred to 3DRT for locally advanced cervical cancer. However, there is no survival difference between IMRT and 3DRT.