KEY POINTS
- This post hoc secondary analysis compared 59 patients with T1-T2 p16-positive oropharyngeal squamous cell carcinoma treated with primary radiotherapy in the ORATOR studies: 29 received 60 Gy and 30 received 70 Gy.
- At one year, the 60 Gy cohort had a more favorable change in MD Anderson Dysphagia Inventory total score than the 70 Gy cohort: +1.9 versus -5.8 (p=0.035). Functional scores changed by +5.5 versus -3.3 (p=0.023).
- The 60 Gy cohort also reported better outcomes across several European Organisation for Research and Treatment of Cancer domains, including fatigue, pain, xerostomia, sticky saliva, appetite loss, and nausea or vomiting. Differences in swallowing scores were no longer significant at three years.
- Grade 2-3 dysphagia and mucositis were less frequent with 60 Gy (p=0.022 and p<0.001, respectively). No grade 4 or 5 toxicities occurred in either cohort, and late adverse-event rates did not differ significantly.
- Three-year overall and progression-free survival were both 100% with 60 Gy versus 96.6% with 70 Gy (p=0.22). The analysis was underpowered for survival, used different cisplatin schedules, and did not adjust for multiple comparisons.
CLINICAL TAKEAWAY
For carefully selected patients with small, resectable p16-positive oropharyngeal cancers, reducing radiotherapy from 70 Gy to 60 Gy may improve early swallowing-related quality of life and reduce acute toxicity. However, the comparison was post hoc, nonrandomized between dose groups, and confounded by different cisplatin schedules; given the broader de-escalation evidence, 60 Gy should remain investigational outside a trial.
SOURCE
International Journal of Radiation Oncology, Biology, Physics