Abstract

Background and objective
Intellectual disability (ID) is increasingly recognised as a hidden driver of cancer mortality. However, evidence on prostate cancer (PC) care in this population is limited.

Methods
The study population comprised 29 554 men with an ID and 518 739 comparators from the Clinical Practice Research Datalink Aurum database, which is linked to hospital, mortality, and cancer registry data. Poisson and Cox regression analyses were used to estimate incidence rate ratios (IRRs), risk ratios (RRs), and hazard ratios (HRs) with 95% confidence intervals (CIs) for outcomes related to PC presentation, diagnosis, treatment, and survival.

Key findings and limitations
The ID group presented more frequently with symptoms suggestive of PC (IRR 1.35, 95% CI 1.28–1.43) but were less likely to have a prostate-specific antigen (PSA) test within 90 d (RR 0.66, 95% CI 0.63–0.70). Following detection of elevated PSA, the ID group had fewer referrals (RR 0.83, 95% CI 0.72–0.96), biopsies (RR 0.54, 95% CI 0.41–0.71), and PC diagnoses (RR 0.51, 95% CI 0.41–0.65). The ID group were also more likely to be diagnosed on the date of death (RR 5.96, 95% CI 2.70–11.77), have missing Gleason scores (RR 1.61, 95% CI 1.27–2.01), and present with de novo metastatic PC (RR 1.79, 95% CI 1.15–2.77). Among those with Gleason scores, the rate of clinically significant PC (Gleason ≥7) was comparable between the ID and control groups, while receipt of radical treatment for nonmetastatic PC was slightly lower in the ID group (RR 0.73, 95% CI 0.51–1.00). Men with an ID had twofold higher risk of death from PC following diagnosis (HR 2.11, 95% CI 1.64–2.73).

Conclusions and clinical implications
Men with an ID face disparities across the PC care pathway from investigation of relevant symptoms to survival after diagnosis. Targeted interventions are needed to address these inequities.