Work

Redefining Boundaries—Safety of Radiation Therapy in the Presence of Orthotopic Neobladder

Year: 2026

Type: article

Abstract: Introduction: Pelvic radiation therapy in patients with neobladder reconstruction following cystectomy is rare but encountered in clinical practice. Its potential impact on neobladder function remains underexplored in the current literature. Methods and Materials: We conducted a retrospective study of patients with urothelial carcinoma who underwent cystectomy with neobladder reconstruction, followed by pelvic radiation therapy. Radiation dosimetric data pertaining to the neobladder were analyzed. Medical records were reviewed for evidence of urinary or neobladder dysfunction. Results: Twenty-one patients were found to meet inclusion criteria at our institution and were subsequently analyzed. The median age at time of cystectomy and neobladder creation was 61 years. The mean equivalent dose in 2 Gy fractions (EQD2) using an α/β ratio of 10 of the prescribed total dose was 39.1 Gy. Three patients received multiple courses of pelvic radiation therapy, all other patients received a single course. Over half of the patients received hypofractionated radiation therapy; palliation was the most common indication. Among available radiation dose data, the median maximum dose (defined as D0.03 cc) in EQD2 using an α/β ratio of 10 to neobladder was 36.5 Gy (range, 5.2-98.8 Gy). The median mean dose in EQD2 using an α/β ratio of 10 to neobladder was 15.7 Gy (range, 0.5-49.6 Gy). The median maximum dose via EQD2 using an α/β ratio of 3 to neobladder (accounting for normal tissue effect) was 38.9 Gy (range, 4.6-102.9). Although 3 patients experienced acute genitourinary toxicity attributable to pelvic radiation therapy, none experienced grade 3 or worse toxicity. At median post-pelvic radiation therapy follow-up duration of 13.4 months, none of the 21 patients included on this study had neobladder dysfunction that could be attributed to radiation therapy. Conclusions: Pelvic radiation therapy following neobladder reconstruction postcystectomy appears to carry minimal risk of radiation-induced neobladder toxicity. Larger studies are warranted to further validate the safety profile of pelvic radiation therapy in patients with neobladder reconstruction.

Source: Advances in Radiation Oncology

DOI: 10.1016/j.adro.2026.102042