Purpose

Synchronous presentation of clinically significant bladder urothelial carcinoma and prostate adenocarcinoma is rare. While prostate cancer identified at cystoprostatectomy is often incidental, truly synchronous high-risk disease presents challenges for patients pursuing organ preservation due to overlapping radiation fields and differing dose requirements. We report a case of muscle-invasive bladder cancer and NCCN very high-risk prostate adenocarcinoma successfully managed with bladder-preserving chemoradiation and high-dose-rate (HDR) brachytherapy boost.

Material and methods

A 70-year-old man was diagnosed with high-grade urothelial carcinoma of the bladder, initially staged as cT1 and progressing to cT2 after repeat transurethral resections and intravesical bacillus Calmette-Guérin (BCG). Concurrent prostate adenocarcinoma was identified (Gleason 5 + 4 = 9, prostate-specific antigen [PSA] 13.59 ng/ml, clinical stage IIIC). Staging with CT urogram, CT chest, PSMA PET, and prostate MRI demonstrated no metastatic disease. Following multidisciplinary discussion, the patient elected bladder preservation with definitive prostate cancer treatment. Management included androgen deprivation therapy with goserelin and abiraterone, repeat TURBT, and pelvic chemoradiation delivering 45 Gy with a sequential external beam boost of 64.8 Gy to the bladder tumor bed, with concurrent weekly cisplatin. To achieve curative prostate dosing, single-fraction HDR brachytherapy boost of 15 Gy was delivered to the prostate and proximal seminal vesicles using a transperineal, image-guided, template-based technique. Organ at risk constraints included bladder D_2cc < 10 Gy, rectum D_2cc < 8.5 Gy (α/β = 3), and urethral V₁₂₅ < 1 cc.

Results

At 24 months post-treatment, the patient remains disease-free with no grade ≥ 3 toxicities. PSA declined to < 0.01 ng/ml by 12 months and remains suppressed. Late effects included stable mild right hydronephrosis, grade 2
nocturia, and grade 1 fatigue.

Conclusions

HDR brachytherapy boost following pelvic chemoradiation is a feasible strategy for synchronous muscle-invasive bladder and very high-risk prostate cancer, enabling prostate dose escalation while respecting bladder tolerance.