KEY POINTS
- JCOG1208 was a prospective, multicentre, single-arm study enrolling 57 patients from 23 institutions with T1-2N0-1M0 tonsillar, base-of-tongue or soft-palate cancer according to Union for International Cancer Control seventh-edition staging.
- Patients received two-step adaptive intensity-modulated radiotherapy without concurrent chemotherapy: 46 Gy in 23 fractions to the initial and elective target volumes, followed by a 24 Gy in 12 fractions boost, for 70 Gy in 35 fractions.
- The primary endpoint was met: three-year overall survival was 93.0% (95% confidence interval, 82.4%-97.3%), exceeding the prespecified 80% threshold. Five-year overall survival, progression-free survival and locoregional progression-free survival were 87.6%, 77.0% and 78.8%, respectively.
- Nine patients developed progression, but no recurrence occurred solely within an omitted prophylactic nodal region. Most patients with progression had p16-negative or unknown disease, a smoking history, or both.
- Grade 3 or higher acute adverse events occurred in 29.8% of patients, including one fatal dehydration event. One patient experienced a grade 3 or higher late adverse event, while grade 2 or higher xerostomia declined from 30.4% at three months to 5.7% at 36 months.
CLINICAL TAKEAWAY
Definitive intensity-modulated radiotherapy alone with reduced elective nodal irradiation appears feasible for carefully selected patients with early-stage oropharyngeal cancer, with selection informed by p16 or human papillomavirus status and smoking history. The prospective and mature follow-up strengthens the signal, but the small nonrandomised cohort, older staging system, incomplete human papillomavirus data and absence of a comparator make the evidence supportive rather than practice-defining.