Background
Cancer is a major contributor to mortality among people with disabilities, accounting for about 20% of excess mortality in this population. Prior studies show higher mortality after cancer diagnosis among people with disabilities, but most of them have focused on specific cancer sites or disability types, leaving overall mortality patterns insufficiently explored. Quantifying mortality after cancer diagnosis remains critical as it reflects the cumulative impact of socioeconomic factors, comorbidities at diagnosis, as well as healthcare related factors, such as diagnostic delays, treatment access barriers, and quality of care received.
Objectives
To investigate differences in mortality following a cancer diagnosis between people with and without disabilities by quantifying inequalities in all-cause and cancer-specific mortality across different cancer types and disability types.
Methods
Using Swedish national registers, we identified individuals aged 18–65 with a first-time cancer diagnosis recorded in the Swedish Cancer Register between 2000 and 2020. Disability status pre-diagnosis was determined using register-based information and classified as physical, hearing, vision, psychiatric, neurodevelopmental, or unspecified. Outcomes were all-cause and cancer-specific mortality. We estimated 1- and 5-year survival using Cox proportional hazards models. Follow-up started at diagnosis and ended at death, emigration, 1 or 5 years post-diagnosis, or 31 December 2020. Model 1 adjusted for sex, age at diagnosis, and calendar year; Model 2 additionally adjusted for the Charlson Comorbidity Index; and Model 3 further adjusted for educational attainment and civil status.
Results
Among 212,867 individuals diagnosed with cancer, 15.3% had a disability at the time of diagnosis. Disability was significantly associated with higher cancer-specific mortality for most cancer types. At 1 year post-diagnosis, the largest inequalities in cancer-specific mortality were observed for malignant melanoma (HR 2.31, 95% CI 1.60–3.32), prostate cancer (HR 2.22, 95% CI 1.71–2.87), and bladder cancer (HR 2.08, 95% CI 1.71–2.54) in Model 1. Adjustment for baseline covariates attenuated the associations, but all associations that were significant in Model 1 remained significant after adjustment, except for cervical cancer. Results for 5-year cancer-specific mortality were broadly similar, with the largest inequalities observed for bladder cancer (HR 1.61, 95% CI 1.39–1.85), prostate cancer (HR 1.58, 95% CI 1.41–1.76), and breast cancer (HR 1.57, 95% CI 1.44–1.71) in Model 1. The largest inequalities were observed among individuals with neurodevelopmental and psychiatric disabilities. For example, individuals with neurodevelopmental disabilities had a 2.94-fold higher hazard of cancer-specific mortality (95% CI 2.42-3.57), while those with psychiatric disabilities had a 2.77-fold higher hazard (95%CI 2.49-3.10) compared with individuals without disabilities (Model 1). No significant differences were observed for individuals with hearing disabilities. All-cause mortality followed a similar pattern to cancer-specific mortality, although estimates were generally slightly higher.
Conclusions/Implications
People with disabilities experienced higher mortality than people without disabilities across most cancer sites, particularly for cancers with relatively good prognosis if detected early. Large mortality inequalities in these cancers suggest that early detection, access to care, treatment quality, and follow-up may play an important role in explaining these differences. Individuals with neurodevelopmental and psychiatric disabilities appear to face the greatest disadvantages.