People with intellectual disabilities are at an increased risk of cancer. This is the conclusion based on findings from a population-based cohort study of Swedish children born to mothers from the Nordic countries, The results of the study suggest that there is an unmet need for extended surveillance and early intervention in cancer among people with intellectual disabilities.

The study demonstrated that cancer risk was higher for syndromic intellectual disability. The results were presented by Qianwei Liu, MS, of the Institute of Environmental Medicine, Karolinska Institutet in Stockholm on behalf of the research team from Sweden during the proffered paper session on supportive and palliative care at ESMO Congress 2021, being held  September 16-21, 2021.

Liu explained that a large gap in knowledge about the risk of cancer in people with intellectual disabilities. Together with colleagues, Liu conducted a population-based cohort study of more than 3.5 million children of whom 27,956 (0.8%) were clinically confirmed cases of intellectual disability. The children were born between 1974 to 2013.

Qianwei Liu, MS, of the Institute of Environmental Medicine, Karolinska Institutet in Stockholm. Photo courtesy: © 2021 ESMO/Karolinska Institutet/Gunilla Sonnebring. Used with permission.

Link between intellectual disability and cancer
To examine the association between intellectual disability and cancer, the investigator’s analyzed data included in the Swedish Cancer Registry.

The study team used Cox regression models to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) as measures of cancer risk in relation to intellectual disability after detailed adjustment for potential confounding. They also analyzed the severity and type of intellectual disability and looked at siblings to investigate familial confounding.©

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The researchers found a statistically significantly increased risk for any cancer (HR 1.57, 95% CI 1.35-1.82), as well as for several cancer types, in particular oesophageal (HR 28.4, 95% CI 6.2-130.6), stomach (HR 6.1, 95% CI 1.5-24.9), small intestine (HR 12.0, 95% CI 2.9-50.1), colon (HR 2.0, 95% CI 1.0-4.1), pancreatic (HR 6.0, 95% CI 1.5-24.8), uterus (HR 11.7, 95% CI 1.5-90.7), kidney (HR 4.4, 95% CI 2.0-9.8), central nervous system (HR 2.7, 95% CI 2.0-3.7), and other or unspecified sites (HR 4.8, 95% CI 1.8-12.9), as well as acute lymphoid leukemia (HR 2.4, 95% CI 1.3-4.4) and acute myeloid leukemia (HR 3.0, 95% CI 1.4-6.4).

Excess cancer risk was not modified by severity of intellectual disability or sex, but it was higher for syndromic intellectual disability. Little support for familial confounding was shown by sibling comparison.

The authors concluded that the results of their study, supported by the European Union’s Horizon 2020 research and innovation program, the Swedish Cancer Society, the Swedish Research Council for Health, Working Life and Welfare, and the China Scholarship Council indicate a need for extended surveillance and early intervention in cancer among people with intellectual disabilities.

Reference
Liu Q, Adami H-O, Reichenberg A, et al.Cancer risk in individuals with intellectual disability. Abstract 1488O. Presented at: European Society for Medical Oncology (#ESMO21), held September 16 – 21, 2021.

Featured image: ESMO. Photo courtesy: © 2021 ESMO. Used with permission.

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