Perceived Quality of Life After Prostate Cancer Treatment: Response Shift
Dirksen, Shannon Ruff
Belyea, Michael J.
MetadataShow full item record
Purpose: Response shift refers to when individuals alter their internal standards in adjusting to changing circumstances such as illness. This shift can occur in persons with cancer who may perceive quality of life differently over time as their definition of health changes. Determination of whether quality of life after cancer treatment is associated with a response shift is limited. The purpose of this study was to explore the existence of a response shift among men with prostate cancer before radiation treatment and retrospectively at the end of treatment. Methods: Men receiving radiation treatment (n=83) completed the 39-item Functional Assessment of Cancer Therapy-Prostate Cancer (FACT-P) which has five subscales that measure the multiple dimensions of quality of life. The FACT-P was administered prior to treatment (T1) and at the end of treatment (T2) with directions at this second time point to rate scale items with the time frame of 'before you started treatment'. Response shift was assessed by the then-test which compares individual scores. Significant mean score differences are suggestive of a response shift. Results: Participants had a mean age of 69 years old (SD=8.2), were predominately White (84%), with Gleason scores ranging from 5 to 10 (M=7.14, SD=1.0). When retrospectively reevaluated at T2, men indicated that their physical and prostate cancer well-being were significantly lower with emotional well-being rated as significantly higher. Cohen's d (>. 5) indicated that some of these changes were clinically significant and that a true score change had also occurred. Conclusion: This study adds to our understanding of the effect of treatment for prostate cancer and how it may lead some men to adjust their internal standards by which they perceive quality of life. An accurate assessment of changes in quality of life should include determining if a response shift has occurred. Funding: NIH/NCI R21 CA13907