Background: Cancer risk is impacted by a variety of factors besides age, which may lead to an elevated risk of cancer compared to the general population and have disparate impact on individuals. A targeted literature review was conducted to estimate the prevalence of, and the magnitude of risk of any cancer among, individuals with key risk factors, including chronic inflammation, immunodeficiency, genetics, recurrence, or behavioral. Methods: Data were abstracted using a structured search (2000-2022) in Embase, MEDLINE, and gray literature. The most recent/high quality publications involving adults with the specified risk factors were included (Table). For each risk factor, the prevalence and the standardized incidence ratio (SIR), which measures the heightened risk of cancer relative to the general population/individuals without the condition, were abstracted. Results: Overall, 35 studies were reviewed. Risk factors with the highest SIR of cancer included genetic predisposition (SIR=5.30-9.48 for Lynch syndrome or BRCA mutation), HIV (SIR=3.62), cirrhosis (SIR=2.00), and immunodeficiency disorders (SIR=1.99), with prevalence estimates of <3.0% in the general population (Table). The most prevalent risk factors were tobacco use (42.8%; SIR=1.24), family history of cancer (35.6%; SIR=1.23), and obesity (34.8%; SIR=1.09). The prevalence tended to be higher for individuals aged 65+ (Table). Almost all studies reported an elevated risk of more than one type of cancer. Conclusions: Among individuals with known risk factors, an elevated risk of cancer was observed. Risk factors that confer the highest risk of cancer are mostly genetic and immune-related with low prevalence, while other risk factors with a moderately elevated risk of cancer are more prevalent. These estimates could be useful when determining which individuals need to be screened earlier and/or with comprehensive cancer screening options.

^†Age not specified hx, history; IBD, inflammatory bowel disease; NR, not reported; PID/SID, primary or secondary immunodeficiency disorder; RA, rheumatoid arthritis, T1D, type 1 diabetes; T2D, type 2 diabetes.