PATHOS

PATHOS enrols patients with HPV-positive oropharyngeal cancer whose tumours can be removed transorally. After surgery and neck dissection, intermediate-risk patients are randomised to 50 or 60 Gy of postoperative radiotherapy, and high-risk patients (extranodal extension or positive margins) to radiotherapy alone or radiotherapy with cisplatin. The phase 2 primary endpoint is patient-reported swallowing at one year; the phase 3 endpoint is overall survival.

The design mirrors ECOG-ACRIN E3311 but goes further by dropping chemotherapy in the high-risk group, which E3311 did not test. It also collects swallowing, feeding-tube use and quality-of-life data prospectively, since function is the reason for de-escalating.

Recruitment across the United Kingdom, Ireland and other European centres continues; the phase 3 answer will decide whether reduced adjuvant treatment after transoral surgery becomes routine rather than a trial option.