# Incidental Prostate Cancer Is an Uncommon but Clinically Non-negligible Cause of Death in Selected Long-term Survivors of Urothelial Carcinoma—Oncological Outcomes and a Proposed Follow-up Strategy from a Tertiary Referral Center

## TL;DR

Incidental prostate cancer found during bladder cancer surgery is usually low-risk but can cause late mortality in some long-term survivors, suggesting the need for targeted follow-up.

## Contribution

The study proposes a follow-up strategy for long-term bladder cancer survivors with higher-risk incidental prostate cancer pathology.

## Key findings

- Incidental prostate cancer was diagnosed in 41% of men undergoing radical cystoprostatectomy.
- Seven patients died of prostate cancer at a median of 72 months post-surgery.
- Higher-risk prostate cancer pathology was associated with recurrence and late mortality.

## Abstract

Incidental prostate cancer is detected frequently in men undergoing radical cystoprostatectomy for bladder cancer and is usually of low risk. While short-term outcomes are dominated by urothelial carcinoma, advanced prostate cancer features contribute to late mortality. Selective prostate-specific antigen surveillance should be considered in long-term survivors with higher-risk prostate cancer pathology.

Incidental prostate cancer is frequently identified in men undergoing radical cystoprostatectomy for urothelial carcinoma of the bladder. While usually clinically insignificant, its long natural history raises questions about long-term impact as systemic therapies prolong bladder cancer survival. The aim of this study is to describe the natural history, recurrence patterns, and survival outcomes of prostate cancer detected incidentally following radical cystoprostatectomy in a prospective cohort, and to provide a follow-up protocol for these patients.

A retrospective cohort study with prospective follow-up of consecutive men undergoing radical cystoprostatectomy with urinary diversion for urothelial carcinoma at a tertiary referral center (1999–2020) was conducted. Follow-up included serial prostate-specific antigen (PSA) testing, imaging, and cause-specific survival. Associations with recurrence and survival were assessed using Cox regression.

Incidental prostate cancer was diagnosed in 384 of 940 men (41%). Prostate cancer recurrence was reported in 23 men (6%) at a median of 25 mo, most often in bone and lymph nodes. Seven patients died of prostate cancer at a median of 72 mo after surgery. Risk factors for recurrence included higher International Society of Urological Pathology grade (hazard ratio [HR] 2.9, 95% confidence interval [CI] 2.2–3.9; p < 0.001), locally advanced stage (HR 6.8, 95% CI 4.1–11.2; p < 0.001), preoperative PSA (HR 2.3, 95% CI 1.4–3.8; p = 0.002), and nodal metastasis (HR 29.3, 95% CI 10.8–79.3; p < 0.001), although HR effect estimates were exploratory and based on a limited number of events. Overall survival was determined by bladder cancer stage, comorbidity, and age; prostate cancer features were prognostic only beyond 3 yr.

Incidental prostate cancer after radical cystoprostatectomy is usually organ confined and of low grade, with a low short-term risk. In long-term survivors with adverse pathological features, incidental prostate cancer represents a clinically non-negligible contributor to cause-specific mortality, despite a low absolute risk at the population level. Selective risk-adapted PSA surveillance should be considered in patients with higher-risk pathology and favorable bladder cancer outcomes following a protocol.

We studied men with prostate cancer diagnosed incidentally during bladder cancer surgery. While most cases of prostate cancer were at a low risk and rarely caused early problems, some patients with higher-risk prostate cancer developed metastases or died from the disease later. Careful follow-up for prostate cancer may benefit selected long-term bladder cancer survivors.