Who benefits from psychosocial interventions in oncology? A systematic review of psychological moderators of treatment outcome.

Medical and demographic characteristics and psychological morbidity of individuals with cancer prior to a psychosocial intervention can influence the efficacy of interventions. However, little is known about the moderating role of patients' psychosocial characteristics on intervention effects. This review sought to identify and synthesize the impacts of psychosocial moderators of the effect of psychosocial interventions on the psychological well-being of cancer patients. A systematic review of the published literature was conducted. Databases searched included PsycINFO, PubMed, MEDLINE, Scopus, CINAHL, Web of Science, and Psychology and Behavioural Sciences Collection. Randomized controlled studies examining a moderator effect of patients' psychosocial characteristics other than baseline depression and anxiety levels were included. Of 199 potential papers, a total of 20 studies, involving 3,340 heterogeneous cancer patients are included. Of the 17 potential psychosocial moderators examined in this review, 14 significantly moderated the effects of interventions. Moderators were categorized into personality traits, mental and physical quality of life, social environment, and self-efficacy. Patients with poorer quality of life, interpersonal relationships and sense of control benefitted more from interventions than those who already had adequate resources. Patients with low levels of optimism and neuroticism, high levels of emotional expressiveness, interpersonal sensitivity, and dispositional hypnotizability also showed greater benefits from various interventions. This review adds to the growing literature aimed at personalizing psychosocial cancer treatment by identifying who benefits from which psychosocial interventions.