Reduced-Dose Radiotherapy for HPV-Positive Oropharyngeal Carcinoma
A phase II trial conducted at the University of California at Davis and at Los Angeles showed good outcomes with reduced-dose radiotherapy in patients with human papillomavirus (HPV)-positive oropharyngeal squamous cell carcinoma. These findings were reported in The Lancet Oncology by Chen et al.
Study Details
The study included 44 evaluable patients with newly diagnosed stage III or IV disease. Patients received 2 cycles of induction therapy with paclitaxel at 175 mg/m² and carboplatin at an AUC of 6 given 21 days apart, followed by intensity-modulated radiotherapy with daily image guidance plus concomitant paclitaxel at 30 mg/m²/wk. Patients with complete or partial response to induction received 54 Gy in 27 fractions, and those with less than partial or no response received 60 Gy in 30 fractions.
Outcomes
Overall, 24 patients (55%) had a complete or partial response to induction chemotherapy and received 54 Gy radiation, and 20 patients (45%) with less than partial response received 60 Gy. Median follow-up was 30 months. Locoregional tumor recurrence was observed in 3 patients (7%), and distant metastasis was observed in 1 patient (2%). The 2-year progression-free survival rate was 92%, and the 2-year locoregional tumor control rate was 95%.
Adverse Events
Grade 3 adverse events (no grade 4 events) occurred in 26 patients (59%); the most common adverse event during induction were leukopenia (39%) and neutropenia (11%), and the most common adverse event during chemoradiotherapy were dysphagia (9%) and mucositis (9%). One patient was dependent on a gastrostomy tube at 3 months after treatment; none were dependent at 6 months.
The investigators concluded: “Chemoradiotherapy with radiation doses reduced by 15%–20% [eg, from standard dose of 70 Gy] was associated with high progression-free survival and an improved toxicity profile compared with historical regimens using standard doses. Radiotherapy de-escalation has the potential to improve the therapeutic ratio and long-term function for these patients.” A phase III trial of reduced-dose radiation in HPV-positive disease is being planned.
The study was funded by the University of California.
Allen M. Chen, MD, of the Department of Radiation Oncology, University of Kansas School of Medicine, is the corresponding author of The Lancet Oncology article.
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