Patients with intellectual or developmental disabilities (IDD) are more likely to die from breast, colon, and lung cancer than those without IDD, according to a new study from Ontario, Canada.
In a population-based retrospective cohort study including approximately 340,000 participants, patients with IDD were 2.28 times more likely to die from breast cancer, 2.57 times more likely to die from colorectal cancer, and 1.38 times more likely to die from lung cancer during the study period than patients without IDD.
With a few exceptions, poor survival rates persisted for people with IDD regardless of stage at diagnosis, according to lead researcher and study author Alison Mahar, PhD, of Queen’s University in Kingston, Ontario, Canada, and her colleagues.
Allison Maher
A previous literature review by the research team on cancer outcomes for adults with IDD found “very little research” on delayed cancer diagnosis and its consequences (e.g., late-stage disease) or survival after a cancer diagnosis, Mahar told Medscape Medical News. “Our research team thought that a lack of information was a major barrier to equitable access to cancer care that needed to be addressed.”
The current study was published February 5 in the Canadian Journal of Public Health.
Reduced survival rate
Researchers examined data from adults in Ontario who were diagnosed with breast cancer (women), colorectal cancer, or lung cancer between 2007 and 2019. Patients’ IDD status prior to cancer was determined using an established algorithm. Diagnoses of interest included intellectual disability, fetal alcohol syndrome, autism, and Down syndrome.
123,695 breast cancer patients, 98,809 colorectal cancer patients, and 116,232 lung cancer patients were followed from the date of cancer diagnosis to the earlier of death or December 31, 2021. Primary outcomes were all-cause mortality and cancer-related mortality.
The prevalence of IDD was 0.39% in breast cancer patients, 0.51% in colorectal cancer patients, and 0.33% in lung cancer patients.
Patients with IDD had significantly poorer survival than those without IDD across cancer cohorts: 5-year survival rates were 61.5% and 81.7% for breast cancer patients and those without IDD, 34.2% and 56.6% for colorectal cancer patients, and 11.9% and 19.7% for lung cancer patients.
The adjusted hazard ratios for all-cause mortality in patients with breast, colorectal, and lung cancer with IDD were 2.74, 2.42, and 1.49 times higher than in patients without IDD.
Subsequent analyses revealed that the cumulative incidence of cancer-specific deaths differed significantly by IDD status in the breast and colorectal cancer cohorts, but not in the lung cancer cohort: after adjustment, patients with IDD were 2.28 times more likely to die from breast cancer, 2.57 times more likely to die from colorectal cancer, and 1.38 times more likely to die from lung cancer than patients without IDD.
“With some exceptions, individuals with IDD continue to have poor survival regardless of stage at diagnosis,” the authors write. “It is essential to identify and intervene in the factors and structures that contribute to survival disparities.”
This study had several limitations. For example, the prevalence of IDD in this study was lower than the overall Canadian estimates. The algorithm to identify individuals with IDD was not validated, meaning misclassification was likely in young adults. Also, the definition of IDD grouped together multiple diagnoses and severity of the disorder.
Useful for doctor training
Mahar said physician training could help make care for people with IDD more equitable, citing the Canadian Academy of Family Physicians’ Developmental Disabilities Members Interest Group, which offers webinars and other training to help doctors address the health of people with IDD safely and comprehensively.
Additionally, Canada has guidelines for primary care physicians who work with patients with IDD, and the Canadian Association on Disability and Oral Health includes an educational component for professionals who provide oral care to patients with disabilities. However, no cancer-specific guidelines or organizations exist yet, Mahar noted.
“Clinicians can help by asking people with IDD, their families and caregivers what they need to have the options to live long and healthy lives with cancer,” she said, “and also reflect on how their own implicit and explicit biases and knowledge gaps impact the care they provide to adults with IDD.”
“Taking a broader perspective, we can consider how ableism in health care and nursing contributes to inequitable outcomes,” she added. “Seeking training and resources to better support adult patients with intellectual disabilities, and taking the lead in integrating formal education into curricula for medical, nursing and other allied health professionals, is a way to specifically increase the capacity of individual clinicians to provide cancer care to adult patients with intellectual disabilities.”
take time
Nancy Chang, MD, director of breast cancer clinical research and co-chair of the protocol review and monitoring committee at New York University Langone Perlmutter Cancer Center in New York City, works with several patients with cognitive and physical disabilities. She told Medscape Medical News that one of her new patients, who has cerebral palsy, transferred from another center. The patient, who is wheelchair-bound but cognitively intact, said that whenever she saw her previous doctor, “the team didn’t talk to her, they kept talking to her healthcare assistant, because they assumed from her appearance that she wasn’t doing well. But she was doing well. She just spoke slowly, so it took a long time to talk to her.”
Nancy Chan, MD
Chan said working with people with IDD usually means spending more time and extending visits when possible. Having social services on-site at the facility also helps. “Not all facilities have social services, but it’s important for our patients to have another person they can reach out to and check in on, not just medically but support-wise.”
“These patients often have comorbidities,” Chan added. “So good communication between doctors from different disciplines is also important, and that also takes time. I would say we’re doing our best, and I think the more vigilant we are, the more likely we are to put in the extra effort because we know we can make a difference.”
This research was supported by the Canadian Institutes of Health Research. Mahar and Chan report no relevant financial conflicts of interest.