 The proposed study is a follow-up study to NCT01530997. In NCT01530997, patients with HPV positive andor 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 N40 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 3438. 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 PETCT 10 to 16 weeks post-CRT will be used to determine whether a surgical evaluation is needed. 