Nearly 50 years have passed since Morales et al. first demonstrated the efficacy of intravesical Bacillus Calmette-Guerin (BCG) in the treatment of non–muscle-invasive bladder cancer (NMIBC) [1]. Although many alternative treatments have been proposed, BCG remains the first line intravesical treatment for patients with NMIBC [2]. Current guidelines from the American Urological Association (AUA), Society for Urologic Oncology (SUO), and European Association of Urology (EAU) recommend BCG for patients with intermediate and high risk NMIBC [3,4].

Though the exact mechanism by which BCG leads to tumor regression is incompletely understood, it promotes both innate and adaptive immunologic responses within the bladder leading to tumor cell death [2]. The efficacy of intravesical BCG thus relies, at least in part, on a competent immune system and any impairments of immune-competence may reduce its efficacy. It is generally accepted that immune function worsens with age, a phenomenon termed “immunosenescence,” and controversy has arisen in recent years over the impact this process might have on immunologic treatments [5,6]

It has thus been hypothesized that increasing age might lead to decreased efficacy of intravesical BCG in the treatment of NMIBC. Numerous groups have examined this question without conclusive results in regard to how age impacts cancer recurrence, disease progression, and cancer specific mortality (CSM) for patients treated with BCG [[7], [8], [9], [10]]. Partly as a result of this inconclusive evidence, current NMIBC guidelines from the AUA/SUO and EAU are in disagreement as to the role of age in patient risk stratification; AUA/SUO risk groups do not consider age a risk factor for patients with NMIBC while EAU guidelines consider patients aged > 70 at increased risk [3,4]

A recent study sought to further clarify the impact of age on oncologic outcomes in patients with NMIBC treated with BCG and found no association between age > 70 and disease progression, high grade recurrence (HGR), or CSM [11]. In the present study we sought to validate these findings and then further assess for a possible inflection point beyond which patient age negatively impacts oncologic outcomes in NMIBC patients treated with BCG.