Outcomes of HPV-related oropharyngeal cancer patients treated by radiotherapy alone using altered fractionation

Abstract Purpose To report outcome of HPV-related [HPV(+)] oropharyngeal cancer (OPC) managed predominantly by altered-fractionation radiotherapy-alone (RT-alone). Methods OPCs treated with RT-alone ( n = 207) or chemoradiotherapy (CRT) ( n = 151) from 2001 to 2008 were included. Overall survival (OS), local (LC), regional (RC) and distant (DC) control were compared for HPV(+) vs. HPV-unrelated [HPV(−)], by RT-alone vs. CRT, and by smoking pack-years (⩽10 vs. >10). Multivariate analysis identified predictors. Results HPV(+) ( n = 277) had better OS (81% vs. 44%), LC (93% vs. 76%), RC (94% vs. 79%) (all p < 0.01) but similar DC (89% vs. 86%, p = 0.87) vs. HPV(−) ( n = 81). HPV(+) stage IV CRT ( n = 125) had better OS (89% vs. 70%, p < 0.01), but similar LC (93% vs. 90%, p = 0.41), RC (94% vs. 90%, p = 0.31) and DC (90% vs. 83%, p = 0.22) vs. RT-alone ( n = 96). Both HPV(+) RT-alone ( n = 37) and CRT ( n = 67) stage IV minimal smokers had favorable OS (86% vs. 88%, p = 0.45), LC (95% vs. 92%, p = 0.52), RC (97% vs. 93%, p = 0.22), and DC (92% vs. 86%, p = 0.37). RT-alone and heavy-smoking were independent predictors for lower OS but not CSS in multivariate analysis. Conclusions Overall, HPV(+) RT-alone stage IV demonstrated lower survival but comparable disease control vs. CRT, but no difference was apparent among minimal smokers.