Objective: The variability in the conceptualization and categorization of social support has resulted in mixed findings regarding its role in cancer progression. This systematic review identifies and summarizes the evidence for the significance of two important indices of social support in progression of different cancers.
Method: We used systematic and replicable methods to search, select, and evaluate findings.
Results: Thirty-one longitudinal prospective findings (in 26 papers) which were selected for inclusion categorized social support into structural and functional support. The types of cancer included in these studies fell into three major categories: breast cancer (16), other cancer (10), and mixed cancers (5). Results suggest that the evidence for the relationship between social support and cancer progression is sufficiently strong for breast cancer as shown by five out of seven methodologically sound studies but consistently unconvincing for other types of cancer or in studies which combined different types of cancer. Structural support indices were found to be more frequently associated with disease progression than the indices of functional support in breast cancer. Disease-related variables such as severity, treatment, nodal status, and site of metastasis were found to be significant predictors of cancer progression, and it is suggested that these variables must be considered when conducting studies on the role of psychosocial factors in cancer-related outcomes including progression.
Conclusion: Methodological limitations of the studies and counterintuitive findings are discussed, and further conclusive research, particularly randomized controlled trials of social support interventions, is warranted to support the findings of this systematic review.