A Multi-institution Pooled Analysis of G-Tube Dependence in Patients With Oropharyngeal Cancer Treated With Definitive IMRT: Definitive Management of Head-and-Neck Squamous Cell Carcinoma

Abstract

To report the rate of gastrostomy tube (g-tube) dependence in a pooled multi-institutional data set of oropharyngeal cancer patients treated with definitive IMRT. Oropharyngeal cancer patients treated with definitive IMRT between 1998 and 2011 were pooled from 3 institutions. G-tube dependence was calculated from the end of RT using the Kaplan-Meier method. Patients were censored at death, last follow-up or locoregional failure. Predictors of g-tube dependence were analyzed using Cox proportional hazard models with stepwise backward elimination. A total of 2315 patients were included. The median age was 57 (range 27-91). Staging distribution was T1-3 in 85%, T4a-4b in 15%, N0-N1 in 25%, and N2a-N3 in 75%. 25% were current smokers; 75% were former or never smokers. Median RT dose was 70Gy. Cytotoxic chemotherapy and EGFR-inhibitors were administered to 62% and 12%, respectively. The median follow-up was 43.7 months (range 0.1 to 164). The 1-, 2- and 5-year rates of g-tube dependence were 7.0% (95% CI 5.8-8.2%), 4.4% (3.4-5.4%) and 3.0% (2.0-4.0%), respectively. Factors associated with longer g-tube dependence on univariate analysis included: advanced age (p<0.001), base of tongue (p=0.01) or pharyngeal wall primary (p=0.03), advanced T-category (T4a-b vs T1-3; p<0.001), advanced N-category (N2a-3 vs N0-1; p=0.01), current smoking (versus former/never; p=0.009), and administration of chemotherapy (p<0.001). EGFR inhibitor administration was not associated with g-tube dependence (p=0.89). On multivariate analysis, advanced age (p<0.001), T-category (p=0.001), N-category (p=0.02), current smoking (p=0.003) and administration of chemotherapy (p<0.001) predicted longer g-tube dependence. This multi-institution series of 2315 patients demonstrates that definitive IMRT for oropharyngeal cancer is associated with a low rate of long-term g-tube dependence, and that this quality measure can be achieved by high-volume tertiary care institutions.