The findings suggest that lower rates of participation in screening may be one of the reasons why people with severe mental illness are more likely to die from cancer
“Increasing early diagnosis, through screening, could help save lives from cancer, and reduce inequalities in cancer outcomes. We now need to learn more about why participation rates are lower for these individuals, so that medical professionals can tailor support and make it easier for people with severe mental conditions to attend.” Dr Robert Kerrison, co-lead of the cancer care group at the University of Surrey
People who have severe mental illness such as schizophrenia are less likely to attend cancer screening than others, according to a joint study by the University of Surrey and the Office for Health Improvement and Disparities (OHID).
The research, published in the British Journal of Cancer, looked at Clinical Practice Research Datalink (CPRD) data from 1987 to 2020. CPRD is a database of medical records from patients registered at more than 1,000 General Practices in England. As of 2017, CPRD included 13% of England’s population, and is broadly representative of the population as a whole.
The researchers assessed the records of 1.71m adults for associations between severe mental illness and bowel cancer screening, 1.34m for breast cancer screening and 2.5m for cervical cancer screening.
In all cases, it found that participation in screening was lower in adults with severe mental illness. In the case of bowel cancer, 42% of adults with severe mental illness took part in screening, compared with 59% for other adults. The comparable figures for breast cancer screening were 48% and 60%, and for cervical cancer screening they were 64% and 70%.
The analysis also found that attendance among those with severe mental illness was particularly low among those living in more deprived parts of the country, where the prevalence of severe mental illness is also higher. The widest regional inequalities in cancer screening participation, between people with and without severe mental illness, were observed in the South West for bowel cancer screening, and the North East for breast and cervical screening.
Participation for all three screening programmes was lowest in London, both for people with and without severe mental illness.
In England, people with severe mental illness are known to more likely to die prematurely from cancer. Lower participation in screening is a possible contributing factor, the researchers said.
The most pronounced disparities were for people with a diagnosis of schizophrenia, followed by those diagnosed with other psychoses and bipolar disorder.
Dr Robert Kerrison, lead author of the study and co-lead of the cancer care group at the University of Surrey, said: “People with severe mental illness are two-and-a-half times more likely to die prematurely from cancer than their peers. Their cancer is often diagnosed at an advanced stage, which limits the treatment options available to them.
“Increasing early diagnosis, through screening, could help save lives from cancer, and reduce inequalities in cancer outcomes. We now need to learn more about why participation rates are lower for these individuals, so that medical professionals can tailor support and make it easier for people with severe mental conditions to attend.”
The researchers also found that, among adults with severe mental illness, people from some ethnic minority backgrounds were less likely to attend cancer screening appointments.
The data showed that participation in bowel cancer screening was lower among Black adults with severe mental illness, compared with white adults (35% v 44% ), and that the same was true for Black adults without severe mental illness, compared to White adults (48% v 62%).
Cancer Research UK’s executive director of policy and information, Dr Ian Walker, said:
“This research not only exposes concerning barriers to participating in cancer screening faced by people with severe mental illness, it also crucially shows where these disparities persist across ethnic minority groups and in more deprived areas.
“We need to delve further into this area of research to properly understand why these gaps exist. It’s vital that we work with individuals and communities to build targeted interventions that ensure everyone benefits equally from programmes that diagnose cancer early and, ultimately, save lives.”
This large-scale study provides good evidence that people with severe mental illness are less likely to attend screening for cancer. The researchers’ hypothesis that lower participation in screening may be a contributory factor in the higher number of cancer deaths amongst people who are severely mentally ill sounds plausible. The next steps now should be to carry out more research to explore the reasons for lower participation, and for policy-makers to target this population to encourage take-up of screening.