Concurrent chemoradiotherapy (CRT) is the standard of care (SoC) in locally advanced (LA) head and neck squamous cell carcinomas (HNSCC). This trial was designed to test whether dose-escalated IMRT and cisplatin could improve locoregional control without increasing complications over 3D-radiotherapy.

Patients were randomized between 70 Gy/35F in 7 weeks with 3D-RT (Arm A) versus 75 Gy/35F with IMRT (Arm B). Both arms received 50 Gy in 25 fractions followed by a sequential boost of 20 Gy/10F in Arm A and 25 Gy/10F to gross tumor volume in Arm B, as well as 3 cycles of cisplatin at 100 mg/m2 during RT. The primary endpoint was locoregional progression (LRP).

188 patients were randomized: 85% oropharynx and 73% stage IVa. P16 status was documented for 137 oropharyngeal tumors with P16+ in 53 (39%) patients; and 90% were smokers. Median follow-up was 60.5 months. Xerostomia was markedly decreased in arm B (p < 0.0001). The 1-year grade ≥2 xerostomia (RTOG criteria) was 63% vs 23% and 3-year 45% vs 11% in arms A and B, respectively. Xerostomia LENT-SOMA scale was also reduced in arm B. Dose-escalated IMRT did not reduce LRP with an adjusted HR of 1.13 [95%CI = 0.64-1.98] (p = 0.68). Survival was not different (adjusted HR: 1.19 [95%CI = 0.78-1.81], p = 0.42). No interaction between p16 and treatment effect was found.

Dose-escalated IMRT did not improve LRC in LA-HNSCC patients treated with concomitant CRT over standard 3D-RT. This trial reinforces the evidence showing IMRT reduces xerostomia in LA-HNSCC treated with radiotherapy. Clinicaltrial.gov: NCT00158678.