De-intensification of Radiation and Chemotherapy for Low-Risk HPV-related Oropharyngeal SCC: Follow-up Study

The proposed study is a follow-up study to NCT01530997. In NCT01530997, patients with HPV positive and/or p16 positive low-risk oropharyngeal squamous cell carcinoma (OPSCC) received de-intensified chemoradiotherapy (CRT) followed by a limited surgical evaluation. The primary endpoint of NCT01530997 was the rate of pathological complete response (pCR) after CRT. Power computations were performed for N=40 and were based on the null hypothesis (H0) that the pCR for de-intensified chemoradiotherapy is at least 87%, the historical rate. The type 1 error for this calculation was 14.2%. 43 patients enrolled and 38 were evaluable for the primary endpoint. The observed pCR rate was 89% (34/38). Since the observed pCR rate was excellent in NCT01530997 and was in concordance with the expected rate, in the proposed study we will not mandate a post-CRT surgical evaluation. Instead a PET/CT 10 to 16 weeks post-CRT will be used to determine whether a surgical evaluation is needed.