Effect of education level on outcome of patients treated on Radiation Therapy Oncology Group Protocol 90-03

BACKGROUND: It has been hypothesized that people in lower socioeconomic groups have worse outcomes because they present with advanced-stage cancers or receive inadequate treatment. The authors investigated this hypothesis by using education level as a proxy for socioeconomic status in patients treated on Radiation Therapy Oncology Group (RTOG) Protocol 90-03. METHODS: RTOG 90-03 was a Phase III randomized trial investigating four different radiation fractionation schedules in the treatment of locally advanced head and neck carcinomas. Overall survival and locoregional control rates were analyzed by education level as measured by patient response on the demographic form at study entry. RESULTS: A significant difference was observed in the distribution of patients by education level between the standard fractionated radiation treatment arm and the hyperfractionated radiation treatment arm. More patients in the standard fractionated treatment arm had a higher education level (P = 0.018). Patients attending college had highly and significantly better overall survival and locoregional control than the other groups combined (P = 0.0056 and P = 0.025, respectively: from Cox proportional hazards models stratified by assigned treatment with educational level, T classification, N classification, Karnofsky performance status, primary site, and race). Multivariate analysis revealed that education level was significant for predicting both overall survival and locoregional control when comparing attended college/technical school compared with all other education levels. CONCLUSIONS: Patients attending college or technical school had improved overall survival and locoregional control. These differences cannot be explained by differences in tumor stage or treatment. Poorer overall health or lack of support systems contributing to these results needs to be investigated further.