Successful Stereotactic Body Radiation Therapy for Prostate Cancer in a Patient With Prior Total Colectomy and Ileal Pouch-Anal Anastomosis: A Case Report and Technical Considerations

<h2>Abstract</h2><h3>Background</h3> Application of stereotactic body radiation therapy (SBRT)—an emerging treatment for localized prostate cancer (PCa)—in patients with altered pelvic anatomy following total colectomy remains underreported. The proximity of the radiosensitive intestine to the prostate presents dosimetric challenges. Herein, we describe the feasibility, treatment planning approach, and clinical outcomes of SBRT in a PCa patient with prior surgery for ulcerative colitis. <h3>Case Presentation</h3> A 62-year-old man with unfavorable intermediate-risk PCa (cT2aN0M0; Gleason score 4+3=7; initial prostate-specific antigen [PSA] level, 14.46 ng/mL) and a history of total colectomy with ileal pouch-anal anastomosis was treated with SBRT. After 6 months of neoadjuvant androgen deprivation therapy, the patient underwent 35 Gy SBRT in five fractions. Two alternative treatment plans were developed to accommodate interfractional variations in the ileal pouch position, with daily pretreatment computed tomography-guided plan selection. Dose constraints for the ileal pouch were prioritized (maximum dose, 34 Gy). Within 23 months, the patient achieved a PSA nadir of 0.02 ng/mL without biochemical recurrence. Acute toxicity included grade 2 diarrhea that resolved within 8 months and grade 2 urinary frequency and urgency, which were managed conservatively without hospitalization. <h3>Conclusion</h3> SBRT is a feasible and well-tolerated treatment option for PCa patients with a history of total colectomy and ileal pouch-to-anal anastomosis, permitting curative treatment while avoiding permanent colostomies.