Did the addition of concurrent chemotherapy to conventional radiotherapy improve survival for patients with HPV+ve and HPV−ve Oropharynx cancer? A population-based study

BACKGROUND: In the absence of clear evidence on the efficacy of concurrent chemoradiotherapy (CRT) over conventional radiotherapy (RT) for HPV+ve and for HPV−ve oropharyngeal cancer (OPC), this study compares the treatments and outcomes from pre-CRT years to post-CRT years. METHODS: A population-based retrospective treatment-effectiveness study based on all patients with OPC treated in Ontario Canada in 1998, 1999, 2003 and 2004. Charts were reviewed, tissue samples were requested and tissue was tested for p16 or in situ hybridisation. Overall survival (OS) and disease-specific survival (DSS) were compared by treatment era and by treatment type for all 1028 patients, for 865 treated for cure and for 610 with HPV status. RESULTS: There was no improvement in OS comparing pre-CRT to post-CRT eras for the HPV+ve patients (P=0.147) or for the HPV−ve patients (P=0.362). There was no difference in OS comparing CRT to RT for the HPV+ve cohort (HR=0.948 (0.642–1.400)) or for the HPV–ve patients (HR=1.083 (0.68–1.727)). CONCLUSIONS: In these ‘real-world’ patients what appeared to be improvements in OS with CRT in clinical trials were confounded by HPV status in Ontario. CRT did not improve outcomes for HPV+ve or for HPV−ve patients.