ABSTRACT
BACKGROUND: Most studies of men undergoing treatment for prostate cancer examine physical symptoms as predictors of Quality of Life (QOL). However, symptoms vary by treatment modality in this population, and psychosocial variables, shown to be important to QOL, have rarely been examined. Litwin noted a need for analysis of QOL data in men treated for prostate cancer with different modes of therapy, as studies focusing on specific treatments will increase the homogeneity of research findings. METHODS: This cross-sectional study explored physical and psychosocial predictors of QOL in men receiving one of two types of radiation treatment for prostate cancer: Intensity Modulated Radiation Therapy (IMRT) + High Dose Rate (HDR) Brachytherapy or IMRT + seed implantation. Subjects completed a biographic questionnaire; quality of life measures, which were the eight subscales of the Medical Outcome Study Short Form Health Survey (SF-36); measures of physical symptoms including the Radiation Therapy Oncology Group and the European Organization for Research and Treatment of Cancer (RTOG/EORTC) and the Prostate Symptom Self-Report (PSSR); and measures of psychological factors, the Ways of Coping Scale (WOC), Perceived Stress Scale, the Anxiety Subscale of the SCL-90, and Strategies Used by Patients to Promote Health (SUPPH). Eight regression models including both physical and psychosocial variables were used to predict quality of life. RESULTS: Sixty-three subjects with complete data on all variables were studied. Treatment effect sizes were medium to large in predicting each of the quality of life subscales of the SF-36. Psychosocial variables were related to physical function, role function, bodily pain, general health, social function, emotional role, and mental health. Physical symptoms were related to subjects' perceived general health and mental health. DISCUSSION: The number of significant relationships among psychosocial variables and indicators of QOL exceeded the number of relationships among symptoms and QOL suggesting that psychosocial variables associate strongly with prostate cancer patients' reports of quality of life. Findings of the study may provide patients and families with knowledge that contributes to their understanding of quality of life outcomes of IMRT+ HDR and IMRT + seed implantation and their ability to make more informed treatment choices.