full free access:Prevalence of mental health conditions in cancer patients in acute care—a meta-analysis — Ann Oncol

"Further research is needed to identify reasons for the heterogeneity in prevalence rates. It may be that tumour site, stage, and treatment as well as cultural factors may play a role, but this needs further investigation. In addition, a fair amount of oncological care takes place in outpatient settings. It would therefore be worthwhile to carry out another meta-analysis of studies, investigating the prevalence of mental disorders at that stage of cancer care."