The addition of chemotherapy to radiotherapy did not reduce the rate of distant metastases in low-risk HPV-related oropharyngeal cancer in a real-world setting.

Background Distant metastases (DM) are a leading cause of death for patients with oropharyngeal cancer (OPSCC). The objective of this study was to compare the rates of DM after chemoradiotherapy (CRT) and radiotherapy alone (RT) in patients with human papillomavirus (HPV)-positive and HPV-negative OPSCC. Method In a retrospective population-based study of 525 patients across Ontario, Canada, in 1998/99/03/04, we compared treatment effectiveness using cumulative incidence function curves and cause-specific Cox regression models. Results Sixty of 525 patients developed DM. There was no difference in rates (overall 10%-15%) between HPV-positive and HPV-negative patients or between CRT- and RT-treated patients. CRT reduced the risk of DM for the 15% of all HPV-positive patients with higher risk (T4 and/or N3) and not for HPV-negative patients (hazard ratio, 1.82 [0.65-5.07]). Conclusion The addition of platin-based chemotherapy to conventional RT did not decrease the rates of DM in the majority of patients with HPV-positive or in HPV-negative OPSSC.