Efficacy of prostatectomy using a Retzius-sparing approach as an additional excision in anal canal carcinoma after brachytherapy for prostate adenocarcinoma.

Introduction: Standard treatments for squamous cell carcinoma of the anal canal include chemoradiotherapy and surgical resection. We report a rare case of squamous cell carcinoma of the anal canal with prostate invasion treated with curative surgical methods using a Retzius-sparing robot-assisted approach.
Case Presentation: A 76-year-old male had undergone brachytherapy for prostate adenocarcinoma (cT2aN0M0). Nine years later, the patient was diagnosed with anal canal carcinoma (cT2N0M0) following the onset of anal pain. During a robot-assisted abdominoperineal resection, prostate invasion was suspected and a prostatectomy was performed as an additional excision of the prostate using a Retzius-sparing approach. Although an anastomotic leak was observed postoperatively, it was conservatively managed with bilateral ureteral stent placement. The patient remained recurrence-free after surgery.
Conclusion: A Retzius-sparing robot-assisted approach in radical prostatectomy may be a safe and feasible option for cases of anal canal carcinoma with suspected prostate invasion.
Competing Interests: The authors declare no conflicts of interest.
(© 2025 The Author(s). IJU Case Reports published by John Wiley & Sons Australia, Ltd on behalf of Japanese Urological Association.)