Phase 3 trial of de-escalated versus standard adjuvant radiotherapy for HPV-associated oropharyngeal squamous cell carcinoma

The phase 3 MC1675 trial, at two Mayo Clinics, compared toxicity of de-escalated adjuvant chemoradiotherapy (DART; 30-36 Gy plus docetaxel) versus standard chemoradiotherapy (60 Gy plus cisplatin) among patients with newly diagnosed stage III or IV HPV-associated oropharyngeal squamous cell carcinoma. The cumulative chronic grade 3 or higher toxicity rates at 3-24 months after radiotherapy were 3% in the DART group versus 11% in the standard group (p=0.044) with cumulative chronic PEG tube rate of 2% versus 8% (p=0.039). The authors conclude that among patients with newly diagnosed stage III or IV HPV-associated OPSCC, de-escalated adjuvant radiotherapy compared with standard adjuvant therapy was a more tolerable treatment in terms of chronic toxicities.