Cancer risk factors and barriers to cancer prevention services among people experiencing homelessness

While people experiencing homelessness are more exposed to cancer-associated risk factors, there is a lack of awareness and structures for targeted cancer prevention. Yet people experiencing homelessness are twice as likely to be affected by cancer as people who are resident. Against this backdrop, an international team led by Igor Grabovac and Maren Jeleff from MedUni Vienna's Center for Public Health has systematically assessed the health challenges of this population group for the first time in order to create a scientifically sound basis for the development of preventive measures. Their review article has just been published in the top journal "The Lancet Public Health".

By analyzing 40 studies on aspects of the topic, it was possible for the first time to gain a comprehensive overview of the many factors that determine access to cancer preventive services for people experiencing homelessness. "We systematically collected the findings on both the cancer risk factors and the barriers to cancer prevention among people experiencing homelessness," says study leader Igor Grabovac (Department of Social and Preventive Medicine, Center for Public Health at MedUni Vienna), summarizing the special feature of the review.

In addition to the obvious focus of people experiencing homelessness on basic needs such as food and a safe place to sleep, the deficits in cancer prevention include a lack of support from family and friends, a low level of education or a lack of infrastructure and privacy for preparing for examinations. However, studies have also shown that negative experiences with the healthcare system and staff can also be an obstacle. Sexual trauma, for example, combined with judgemental and unsympathetic treatment during the PAP test for the early detection of cervical cancer, leads to screening services not being used or no longer being used. "Conversely, sexually traumatized women experiencing homelessness were willing to have a PAP test if they had a trusting relationship with the provider and received sensitive care," says first author Maren Jeleff (Department of Social and Preventive Medicine, Center for Public Health at Medical University of Vienna), citing a not insignificant factor in cancer prevention in this group.

Considering living conditions and experiences

How many people experiencing homelessness use or are able to use the opportunities offered by screening is not recorded. As studies show, for example, in the case of breast and bowel cancer screening in the USA, less than 50 per cent of this group have access to it. As early detection is essential for the prognosis of cancer in particular, cancer mortality is also significantly higher in this group. The fact that the incidence of cancer among homeless people is twice as high as among the housed population can be explained by the higher prevalence of risk factors. Substance abuse, especially tobacco and alcohol, high-risk sexual practices and increased exposure to environmental risk factors such as sunlight or pollutants have a greater impact on this group. "The study results show that people experiencing homelessness are highly exposed to certain cancer risk factors. Accordingly, there is an urgent need for prevention measures that are tailored to the living conditions and experiences of this group," says Igor Grabovac in the run-up to further research and initiatives. The review was conducted as part of the large-scale EU project "CANCERLESS" (Cancer prevention and early detection among the homeless population in Europe: Co-adapting and implementing the Health Navigator Model), which is also led by Grabovac.