ECOG-ACRIN E3311: TOS + Reduced-Dose RT Yields 54-mo PFS 90.6% in HPV+ Oropharyngeal Cancer

ECOG-ACRIN E3311 (phase II; NCT01898494) tested transoral surgery (TOS) with risk-based adjuvant management—observation for low-risk (arm A), IMRT 50 (arm B) vs 60 Gy (arm C) for intermediate-risk, or weekly cisplatin + 60–66 Gy for high-risk (arm D)—in resectable p16+ (HPV-initiated) oropharyngeal cancer (cT1-2 AJCC7; no matted nodes; n=359 evaluable). At 54 months, PFS was 90.6% (90% CI 87.2–93.1) and OS 95.3% (93.0–96.9); PFS by arm: A 93.2%, B 94.9%, C 90.2%, D 85.5%, with late recurrences concentrated among low-risk N1 patients without radiation. Safety was not detailed here; earlier ECOG-ACRIN E3311 reported similar disease control with better swallowing/QoL at 50 Gy vs 60 Gy, and these long-term survival rates compare favorably with cisplatin-RT in broader HPV+ cohorts (RTOG 1016 5-yr OS 84.6%, PFS 78.4%) and align with reduced-dose CRT benchmarks from HN002 (2-yr PFS 90.5%)—noting cross-trial and risk-mix differences.