Characteristics and methodological quality of 25 years of research investigating psychosocial interventions for cancer patients

The considerable amount of research examining psychosocial interventions for cancer patients makes it important to examine its scope and methodological quality. This comprehensive overview characterizes the field with as few exclusions as possible. A systematic search strategy identified 673 reports comprising 488 unique projects conducted over a 25 year time span. Although the literature on this topic has grown over time, the research was predominantly conducted in the United States (57.0%), largely with breast cancer patients (included in 70.5% of the studies). The intervention approach used most frequently was cognitive behavioral (32.4%), the treatment goal was often improving quality of life generally (69.5%), and the professionals delivering the interventions were typically nurses (29.1%) or psychologists (22.7%). Overall, there was some discrepancy between the types of interventions studied and the types of supportive services available to and sought by cancer patients. Strengths of this research include using randomized designs (62.9%), testing for baseline group equivalence (84.5%), and monitoring treatment, which rose significantly from being used in 48.1-64.4% of projects over time. However, deficiencies in such areas as examining treatment mechanisms and the adequacy of reporting of methodology, essential for useful syntheses of research on these interventions, remain to be addressed. Methodological challenges related to the complexity of this applied research, such as participants seeking treatment outside of research, contamination, and reactions to randomization, also were apparent. Future research could benefit from closer interactions between academic and voluntary sectors and expanding the diversity of participants.