Long-Term Toxic Effects, Swallow Function, and Quality of Life on MC1273: A Phase 2 Study of Dose De-escalation for Adjuvant Chemoradiation in Human Papillomavirus-Positive Oropharyngeal Cancer

Purpose

Patients with human papillomavirus oropharyngeal cancer are highly curable but risk significant long-term toxic effects with standard therapy. This study investigated a de-escalation strategy of decreased adjuvant radiation therapy and chemotherapy after transoral robotic surgery, and reports on long-term functional and quality of life (QOL) outcomes.

Methods and Materials

Eligible patients had a p16-positive oropharyngeal cancer and ≤10 pack-year smoking history and underwent surgery followed by treatment with either 30 Gy delivered in 1.5-Gy fractions twice per day over 2 weeks with weekly docetaxel (15 mg/m²) if they had intermediate pathologic risk factors or 36 Gy in 1.8-Gy fractions twice per day over 2 weeks with the same chemotherapy if they had extranodal extension. Toxic effects, swallow function, and QOL were measured longitudinally.

Results

Seventy-nine patients (89.9% male) were treated and eligible for toxic effect and functional evaluation. Dry mouth was the most common grade 1 toxic effect at 1 year (55.6%), 2 years (53.3%), and 3 years (49.2%). The cumulative rates of grade 2 toxic effects at 1, 2, and 3 years were 1.4%, 6.7%, and 6.8%, respectively. There were only 2 grade 3 toxic effects at ≥1 year, including a grade 3 fatigue at 2.5 years, and a grade 3 superficial soft tissue fibrosis at 4 years. There were no grade 4 to 5 toxic effects. No patients were percutaneous endoscopic gastrostomy–dependent. Swallow function improved by 12 months posttreatment. QOL improved over time by all measurement tools and most patients returned to baseline level of function and QOL.

Conclusions

De-escalated adjuvant therapy for select patients with human papillomavirus oropharyngeal cancer resulted in low rates of long-term toxic effects, excellent swallow outcomes, and preservation of global and xerostomia-related QOL.