The impact of age on BCG treatment response

Bacillus Calmette-Guerin (BCG) is an immunologic treatment for patients with intermediate and high-risk Nonmuscle Invasive Bladder Cancer (NMIBC). It has been hypothesized that age related immune impairment might lead to decreased efficacy of BCG in older patients. One recent single-institution study found no association between age > 70 and worse oncologic outcomes in a cohort of 632 patients. We sought to validate these findings using a single institution database of NMIBC patients treated with BCG.

We performed a retrospective analysis of patients diagnosed with NMIBC and treated with adequate BCG between 2000 and 2023 at our institution. Patients were divided into two cohorts based on age at NMIBC diagnosis: age ≤ 70 years and age > 70 years. Fine-Gray competing risk survival analysis was performed to assess for differences in the cumulative incidence of high-grade recurrence (HGR), progression (progression to muscle invasive bladder cancer or distant metastasis) and bladder cancer specific mortality (CSM) according to patient age.

We identified 473 patients treated with adequate BCG. 232 patients (49%) were aged ≤ 70 and 241 (51%) were aged > 70. Neither cohort differed significantly in terms of race, sex, or tumor characteristics. On competing risk analysis age > 70 was not significantly associated with increased HGR (HR 0.77; 95% CI 0.59-1.02, P = 0.06), progression (HR 1.17; 95% CI 0.62-2.18, P = 0.63), or CSM (HR 1.12; 95% CI 0.42-2.95, P = 0.82).

We did not observe an association between age > 70 and increased HG recurrence, bladder cancer progression, or CSM. Our results are consistent with other recent series and suggest that BCG efficacy in NMIBC is not negatively affected by increased patient age.