Oncological Outcomes of Nonmuscle-Invasive Bladder Cancer in Patients Aged 45 Years and Younger: A Retrospective Matched Cohort Study.

PURPOSE: Most bladder cancers are diagnosed as nonmuscle invasive (NMIBC), with 90% after the age of 55 years. Although the incidence of several malignancies is increasing among younger adults in whom more aggressive behavior is observed, our knowledge about NMIBC in young patients remains limited. We compared oncological outcomes in patients with NMIBC aged 45 years and younger with a cohort of older patients.

MATERIALS AND

METHODS

This is a retrospective study of NMIBC diagnosed at age 45 years or younger (2005-2022) from 4 Canadian centers. End points included cancer-specific mortality, risk of metastasis, progression to muscle invasion, NMIBC progression (eg, Ta/carcinoma in situ to T1), grade progression, and recurrence. Competing risk analysis and Kaplan-Meier estimates were used. Hazard ratios were calculated using Fine and Gray regression. Propensity-score matching (3:1) was used with patients older than 45 years. Scores were estimated using a logistic regression model incorporating sex, carcinoma in situ, stage, grade, tumor size, and number and year of transurethral resection of bladder tumor.

RESULTS

Among 158 patients, the median age was 39 years (IQR 32-42) and median follow-up 6.0 years (IQR 2.9-9.8). The majority were male (66%), with solitary (78%), low-grade (64%), Ta (82%) tumors. After 3:1 matching, 124 younger patients were compared with 350 older patients (median age 76 years, IQR 69-82). Recurrence rates were higher in older patients (HR 1.53, 95% CI 1.09-2.14, P = .013). Cancer-specific mortality, grade progression, and progression to muscle invasion or metastasis were not significantly different (all P > .05) between groups.

CONCLUSIONS

NMIBC exhibits similar behavior in patients younger than 45 years compared with older patients but with a lower recurrence rate.