The prevalence of depression in oncological patients is 3, 4-fold compared to the general population. However, the specific risk factors for these prevalence rates are not fully understood. Methods: A systematic literature review was conducted in nine electronic databases between 2005 and 2020. The quality of the eligible studies was appraised by two persons using the adapted 11-items Downs and Black checklist. Results: Among 2010 potentially relevant articles, 40 studies were eligible, with 27 studies of high quality and 13 studies of moderate quality. A total of 156 factors associated with depression were identified which were clustered into somatic, psychological, social and sociodemographic factors. Pre-existing depression and personality factors were the most consistent associated factors with depression in cancer patients, while for most somatic and treatment-related factors only modest associations were found. Conclusions: Grouped as bio-psycho-social associated factors, somatic factors showed a modest influence, whereas social relationship (support) and previous depression are unequivocally significantly associated with depression.
