Why Does the Incidence of NMIBC Rise with Age?

The median age at diagnosis of bladder cancer is 73 and increased age is a major risk factor for progression to invasive disease. However, there is a tendency for elderly patients with non-muscle invasive bladder cancer (NMIBC) to receive less guideline-concordant care. Lobo et al. investigated factors contributing to age disparities in NMIBC care and associated tumor biology features.

The investigators used the Surveillance, Epidemiology, and End Results (SEER) database to collect data for 32,225 patients. The median age was 72 and the median follow-up duration was 5.1 years. The majority of patients were White (91.5%), male (76.1%), and had low-grade (60.7%) and stage Ta (62.4%) tumors. Older patients were more likely to be female with high-grade and T1 tumors (p < 0.001). Five-year recurrence rates were 55.2%, 57.4%, and 58.9% in patients aged 66 to 70, 71 to 80, and older than 81, respectively. The 5-year progression rates were 25.6%, 29.2%, and 36.9% across the three aforementioned age groups, respectively. In a multivariable competing-risk regression analysis, age above 81 was associated with higher risk of recurrence (HR, 1.07; 95% CI, 1.03–1.12; p = 0.001) and progression (HR, 1.32; 95% CI, 1.25–1.40; p < 0.001). Furthermore, age was significantly associated with a higher risk of dying of bladder cancer (p < 0.001).

The researchers subsequently collected data on tumor biology from the UROMOL cohort. Age was significantly associated with distinct transcriptomic signatures based on UROMOL2021 classes (p = 0.004). With respect to genomic features, patients in the 90th percentile for age (median of 85.8 years) exhibited higher ABOBEC-related mutations than patients in the tenth percentile (median of 47.7 years) (p = 0.009). Furthermore, patients who were 76 years or older exhibited higher levels of genomic alterations than patients who were 65 or younger (p < 0.001).

The findings from this study indicate that differences in outcome in older NMIBC patients may be partly attributed to differences in tumor biology including the accumulation of APOBEC-induced mutations. One limitation of the study is the lack of data accounting for non-biological age disparities. Furthermore, the estimations of recurrence or progression may be underestimated or overestimated due to a lack of data on these variables in the SEER database. Future studies will approach the research question from these additional angles.

Written by: Bishoy M. Faltas, MD, Director of Bladder Cancer Research, Englander Institute for Precision Medicine, Weill Cornell Medicine

References:

Lobo N, Duan Z, Sood A, et al. Association of Age with Non-muscle-invasive Bladder Cancer: Unearthing a Biological Basis for Epidemiological Disparities?. Eur Urol Oncol. Published online January 31, 2024. doi:10.1016/j.euo.2024.01.011

Read the Abstract

Login