Abstract
BACKGROUND: People with a learning disability (LD, also known as intellectual disability) face poorer health outcomes, yet the burden of cancer in this population is poorly understood. This study investigated cancer-related outcomes in people with a LD compared to the general population. METHODS: A matched cohort study was conducted using linked primary care, hospital, mortality, and cancer registry data from Clinical Practice Research Datalink (CPRD) Aurum. In total, 180,911 individuals with a LD were matched with 3,405,467 controls. Outcomes included urgent suspected cancer (USC) referrals, cancer diagnoses, treatment within six months, and overall survival (OS) post-diagnosis. FINDINGS: Individuals with a LD had fewer USC referrals within 28 days of possible cancer symptoms (adjusted risk ratio [aRR] 0.52, 95% confidence interval [CI] 0.49-0.55). LD was associated with several cancers, including sarcoma (adjusted hazard ratio [aHR] 1.98, 1.65-2.39), central nervous system (aHR 3.42, 2.99-3.90), testicular (aHR 2.06, 1.61-2.62), and uterine cancers (aHR 1.69, 1.40-2.05) as well as cancer before age 50 years (aHR 1.74, 1.63-1.86). Absolute incidence was lower in individuals with a LD compared to without (3396 [1.9%] vs 67,506 [2.0%]) due to increased all-cause mortality (aHR 3.19, 3.12-3.27). LD was associated with fewer diagnoses via USC referrals (aRR 0.81, 0.76-0.86), fewer treatments within six months (aRR 0.83, 0.80-0.85) and shorter OS (median 4.4 years, 95% CI 3.9-5.1 vs 9.1 years, 8.8-9.5; aHR 1.73, 1.65-1.83). Melanoma, breast, and prostate cancers were less common but had up to a fourfold increased risk of death after diagnosis in individuals with a LD. INTERPRETATION: Individuals with a LD have higher cancer risk, more diagnoses outside USC pathways, fewer treatments, and poorer prognosis. Fewer diagnoses of some cancers, alongside worse outcomes, may indicate under-investigation. As premature all-cause mortality improves, cancer burden in this population may rise disproportionately. FUNDING: NIHR Greater Manchester Patient Safety Research Collaboration (NIHR204295).