Perceived stress mediates the effects of social support on health-related quality of life among men treated for localized prostate cancer

Abstract

Objective

To examine the longitudinal effect of social support on general health-related quality of life (HRQOL) in men treated for localized prostate cancer, and to evaluate the role of perceived stress as a potential mediator of that relationship, in an ethnically and demographically diverse sample.

Methods

Psychosocial assessments were administered to a sample of 175 men at baseline, and 2 years later. Hierarchical regression analyses were conducted to investigate the relationships between social support, perceived stress and HRQOL, while controlling for possible covariates that may affect HRQOL (e.g., age, time since diagnosis, medical comorbidities, etc.).

Results

Higher levels of social support at baseline predicted higher levels of HRQOL at 2-year follow-up after controlling for relevant covariates and baseline levels of HRQOL. This relationship was partially mediated by level of perceived stress at baseline. Furthermore, men perceiving high levels of social support reported significantly higher HRQOL compared with men perceiving low levels of social support.

Conclusions

Results indicate positive social relationships contribute to improved HRQOL in patients who have undergone treatment for localized prostate cancer. One pathway through which social support can benefit HRQOL is through lower perceptions of stress. Enhancing or maintaining social support and reducing perceived stress may be potential targets for future psychosocial interventions aimed at improving HRQOL.

Introduction

In 2009, approximately 192,280 US men will be diagnosed with prostate cancer (PC) [1]. Treatments such as radical prostatectomy and radiation are effective and men with localized PC have a 5-year survival rate approaching 100% [1]. However, these treatments cause decrements in urinary, sexual and/or bowel functioning that compromise health-related quality of life (HRQOL; [2], [3], [4], [5]). While the physical side effects of treatment have been well documented, the extent to which psychosocial processes may impact HRQOL needs further investigation.

Research suggests that PC survivors report greater distress when compared with matched controls [6] and that increased perceived stress (PS) is associated with poorer HRQOL [7]. For example, PC survivors experiencing urinary dysfunction report feelings of embarrassment and consequently greater PS [8]. Reductions in PS have been shown to improve HRQOL [9]. Distress over treatment-related side effects are chronic and can develop years after treatment has been completed [10].

Some have proposed that social support (SS) may buffer individuals from the negative effects of stress [11]. SS appears to have a positive effect on adjustment following treatment. Higher levels of SS have been associated with psychological benefits in PC survivors, including reduced depression and anxiety [7], [12], [13]. Furthermore, higher levels of SS are associated with less pain, and married PC survivors report better physical functioning [14].

Limited, and primarily cross-sectional work has assessed the impact of PS and SS in PC populations. Much of this past research has focused on breast cancer populations. As much of this research has focused on breast cancer populations, how SS specifically impacts PC survivors is not well understood. Furthermore, a recent review of the literature on psychosocial adjustment in PC survivors specifically identified a need to evaluate adjustment in more ethnically and demographically diverse samples [15]. To address existing gaps in this literature, this study examined the longitudinal relationships between SS, PS, and HRQOL in a diverse sample of PC survivors. The study hypotheses were, (a) higher baseline levels of SS predict greater follow-up HRQOL; (b) higher baseline levels of PS predict lower HRQOL at follow-up; and (c) PS mediates the relationship between SS and HRQOL.