Do psychosocial factors influence the course of breast cancer? A review of recent literature, methodological problems and future directions

The course of breast cancer is highly variable, and only part of the variability in progression rate can be predicted by clinicopathological factors. It is suggested that some of the variation may be ascribed to behavioral factors, but their importance in determining progression of breast cancer is still controversial. Several groups have found an association between progression of breast cancer and psychosocial factors including stressful life events, the expression of negative emotions—anger and anxiety—the presence of hopelessness, social support, and participating in psychosocial counselling. However, other groups failed to confirm these results. Here we review psycho-oncology research studies with breast cancer patients including those employing cross-sectional, longitudinal and experimental designs. Results of these studies, methodological problems and future directions for this line of research are discussed.