Association of Age with Non-muscle-invasive Bladder Cancer: Unearthing a Biological Basis for Epidemiological Disparities?

BACKGROUND

Age disparity in patients with non-muscle-invasive bladder cancer (NMIBC) exists. Whether this is due to differences in adequate cancer care or tumour biology is unclear.

OBJECTIVE

To investigate age disparities in NMIBC using the Surveillance, Epidemiology, and End Results (SEER)-Medicare and UROMOL datasets.

DESIGN, SETTING, AND PARTICIPANTS

The SEER-Medicare data were used to identify patients with clinical stage Ta, Tis, and T1 NMIBC between 2005 and 2017 (n = 32 225). Using the UROMOL cohort (n = 834), age disparities across transcriptomic, genomic, and spatial proteomic domains were assessed.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

For the SEER-Medicare data, multivariable competing-risk regression was used to examine the association between age and recurrence, progression, and bladder cancer-specific mortality (BCSM). For the UROMOL cohort, multivariable general linear model and multinomial logistic regression were performed to evaluate the association between age and tumour biology.

RESULTS AND LIMITATIONS

An analysis of the SEER-Medicare cohort revealed 5-yr recurrence rates of 55.2%, 57.4%, and 58.9%; 5-yr progression rates of 25.6%, 29.2%, and 36.9%; and 5-yr BCSM rates of 3.9%, 5.8%, and 11.8% in patients aged 66-70, 71-80, and ≥81 yr, respectively. After multivariable adjustment, age ≥81 yr was associated with a higher risk of recurrence (hazard ratio [HR] 1.07, 95% confidence interval [CI] 1.03-1.12; p = 0.001), progression (HR 1.32, p < 0.001), and BCSM (HR 2.58, p < 0.001). UROMOL2021 transcriptomic class 2a was most frequently observed in patients with advanced age (34.0% in ≥76 yr vs 21.6% in ≤65 yr; p = 0.004), a finding confirmed on multivariable analysis (risk ratio [RR] 3.86, p = 0.002). UROMOL2021 genomic class 3 was observed more frequently in patients aged ≥76 yr (4.9% vs 24.2%; p = 0.001). Limitations include the definitions used for recurrence and progression, which may lead to under- or overestimation of true rates.

CONCLUSIONS

Among SEER-Medicare patients with NMIBC, advanced age is associated with inferior oncological outcomes. These results reflect age-related molecular biological differences observed across transcriptomic and genomic domains, providing further evidence that innate tumour biology contributes to observed disparities in NMIBC outcomes.

PATIENT SUMMARY

Older patients with non-muscle-invasive bladder cancer have worse oncological outcomes than younger patients. Some of this age disparity may be due to differences in tumour biology.

Does it matter whether a T1 high-grade tumor is molecularly classified?

A 58-yr-old male, 20 pack-year smoker, with hypertension was diagnosed with a single left-side high-grade papillary tumor with peritumoral carcinoma in situ, but no tumor was visible outside the bladder. En bloc resection was performed, and repeat transurethral resection of the bladder at 4 wk found no residual tumor. He was prescribed bacillus Calmette-Guérin (BCG) plus maintenance therapy, and cystoscopy at 9 mo found a T1b high-grade tumor, this time right sided. Is it important that the tumor should be molecularly characterized before a treatment decision is made, or is clinicopathologic characterization still the only viable option at this time? PATIENT SUMMARY: We discussed how new methods in pathology may help us find molecular structures that would help clinicians decide safely between cystectomy and conservative bladder-sparing strategies. The primary superficially infiltrative tumor and its similar recurrence 9 mo later were categorized based on standard clinical criteria, but here we discuss whether recently discovered methods for defining the molecular structure of tumors could mean that more bladder-preserving treatments might be an option.