Dimensions of quality of life in prostate cancer

Purpose: Quality of life research in prostate cancer involves the use of many questionnaires and specific items that may be partly redundant. We examine dimensions of quality of life in prostate cancer in the hope of somewhat simplifying communication of basic information. Materials and Methods: We analyzed cross-sectional survey data on quality of life in patients with prostate cancer belonging to a Southern California HMO. Quality of life was assessed with the University of California, Los Angeles prostate cancer index. Scree plot and parallel analysis were used to identify factors for extraction and orthogonal (varimax) rotation to examine scale loadings. Results: Four extracted factors explained a cumulative variance of 86%. The 8 physical and emotional scales loaded on 1 general factor explained 41% of the cumulative variance. Urinary function and bother, sexual function and bother, and bowel function and bother scales loaded on factors explained 16, 15 and 14% of the cumulative variance, respectively. Conclusions: The observation of only 1 general quality of life factor diverges from consistent previous observations of distinct physical and emotional factors in other types of patients, and the tight interaction of emotional and physical scales supports the vulnerability hypothesis, "with age the increasing interactions across dimensions of health leave a patient vulnerable in all when any is affected." The tight interaction of physical and emotional scales in these but not other patients opens the door theoretically to better evaluation of and targeting of health services for patients with prostate cancer.