Oral oxycodone versus sublingual buprenorphine for postoperative pain control after pelvic exenteration (PROSPER): a...

This study aims to estimate the rate of recruitment of participants.

This is a pilot, multicentre, double-blind, placebo-controlled, randomised controlled trial of oral oxycodone and sublingual placebo vs sublingual buprenorphine and oral placebo for postoperative pain management for 7 days after pelvic exenteration.

Patients will be recruited from three metropolitan quaternary referral centres that offer advanced gastrointestinal surgery in Australia.

The inclusion criteria will be patients over the age of 18 years undergoing pelvic exenteration surgery and exclusion criteria are previous adverse events related to the study drugs, currently requiring monoamine oxidase inhibitor medications and if epidural analgesia is planned in the perioperative period.

Enrolled patients will undergo pelvic exenteration surgery and be initiated postoperatively on patient-controlled analgesia. In the postoperative period, when clinically appropriate to take oral medications, patients will be commenced on trial analgesia for 7 days. Participants will be randomised to receive either oral active oxycodone 5-10 mg up to 3 hourly as required (with sublingual placebo) or sublingual active buprenorphine 200-400 mcg 3 hourly as required (with oral placebo).

The primary outcome measure is the rate of recruitment over a 6-month period. Secondary outcomes include an assessment of missing data, protocol adherence and acceptability of the trial to participants.

The trial received ethics approval from Sydney Local Health District, Royal Prince Alfred Hospital Human Research Ethics Committee (No: X25-0128 & 2025/ETH01058). The results of the study will be disseminated by publication and presentation at local annual scientific meetings in Australia.

The study protocol is prospectively registered at the Australian New Zealand Clinical Trials Registry (ANZCTR) (www.anzctr.org.au; ACTRN12625000901404).