A study by UPenn and Groningen. For patients with advanced-stage oropharynx cancer treated with curative intent (PBT, n = 30; IMRT, n = 175), NTCP models were developed. The models were then applied to the PBT-treated patients to compare predicted and observed clinical outcomes. Five binary endpoints were analyzed at 6 months after treatment: dysphagia ≥ grade 2, dysphagia ≥ grade 3, xerostomia ≥ grade 2, salivary duct inflammation ≥ grade 2, and feeding tube dependence.

This study found that PBT was associated with statistically significant reductions in the mean NTCP values for each endpoint at 6 months after treatment, with the largest absolute differences in rates of ≥grade 2 dysphagia and ≥grade 2 xerostomia. This study demonstrates an NTCP model-based approach to compare predicted patient outcomes when randomized data are not available.