Phase II study of de-intensified intensity-modulated radiotherapy and concurrent carboplatin/5-fluorouracil in lateralized p16-associated oropharyngeal carcinoma.

Purpose: To assess cancer control and patient-reported outcomes (PROs) after de-intensified intensity-modulated radiotherapy (IMRT) in lateralized p16-associated oropharyngeal cancer (p16-OPC).

Methods: Lateralized p16-OPC treated with radiotherapy and concurrent Carboplatin/5-fluorouracil between 2011 and 2014 were enrolled. De-intensified IMRT consisted in elective neck dose of 43.2 Gy/24 fractions and omission of contralateral retropharyngeal/level IV nodes. PROs were assessed using the EORTC QLC-C30 and QLQ-HN35 scales.

Results: Twenty-nine patients were included. Median follow-up was 44 months. As per AJCC 7th Ed, 7%, 83% and 10% of patients had stage III, IVa and IVb. 5-year locoregional control and overall survival rates were 100% and 100%, respectively. Rates of acute were 52% and 35%, respectively. At 2 years post-treatment, 50% and 14% of patients had grade 1 xerostomia and dysgueusia, respectively. Most PROs scores returned to baseline within 8 months post-treatment.

Conclusion: De-intensified IMRT was associated with excellent cancer outcomes, and rapid recovery of PROs in lateralized p16-OPC.