Pelvis or involved node treatment: eradicating recurrence in prostate cancer (POINTER-PC) – study protocol paper for a phase III multicentre, open-label randomised controlled trial

Introduction Prostate cancer (PCa) is the most common cancer in men. Recurrence may occur in up to half of patients initially treated with curative intent for high-risk localised/locally advanced PCa. Pelvic nodal recurrence is common in this setting, but no clear standard of care exists for these patients, with potential therapeutic approaches including stereotactic body radiotherapy (SBRT) to the involved node(s) alone, extended nodal irradiation (ENI) to treat sites of potential micrometastatic spread in addition to involved node(s) and androgen deprivation therapy with or without additional systemic anticancer therapies. Based on observational studies, ENI is associated with promising metastasis-free survival (MFS) compared with SBRT and appears to result in low rates of severe late toxicity.

Methods and analysis Pelvis Or Involved Node Treatment: Eradicating Recurrence in Prostate Cancer is a UK multicentre, open-label, phase III randomised controlled trial, which will deliver much needed, high-quality evidence of the impact on metastatic progression from ENI compared with SBRT in patients with PCa pelvic nodal recurrence. The trial will also evaluate the long-term toxicity of 5-fraction ENI compared with a standard 20-fraction schedule. The trail will randomise 480 participants in a ratio of 2:1:1 to SBRT, 5-fraction ENI or 20-fraction ENI from 35 to 40 UK radiotherapy sites over 4 years. Coprimary endpoints are MFS at 3 years and participant-reported late bowel toxicity at 3 years. Secondary endpoints include overall survival, biochemical progression-free survival, failure-free survival, patterns of failure, participant-reported/clinician-reported toxicity and health-related quality of life. Collection of blood and tissue samples will enable future evaluation of biomarkers of disease and toxicity and support stratification of salvage therapeutic approaches.