Purpose: To examine the responsiveness of Functional Assessment of Cancer Therapy-Prostate (FACT-P) and Short Form-12 Health Survey version 2 (SF-12 v2) in prostate cancer patients because there is a lack of evidence to support their responsiveness in this patient population.
Methods: One hundred sixty-eight subjects with prostate cancer were surveyed at baseline and at 6 months using the SF-12 v2 and FACT-P version 4. Internal responsiveness was assessed using paired t test and generalized estimating equation. External responsiveness was evaluated using receiver operating characteristic curve analysis.
Results: The internal responsiveness of the FACT-P and SF-12 v2 to detect positive change was satisfactory. The FACT-P and SF-12 v2 could not detect negative change. The FACT-P and the SF-12 v2 performed the best in distinguishing between improved general health and worsened general health. The FACT-P performed better in distinguishing between unchanged general health and worsened general health. The SF-12 v2 performed better in distinguishing between unchanged general health and improved general health.
Conclusions: Positive change detected by these measures should be interpreted with caution as they might be too responsive to detect "noise," which is not clinically significant. The ability of the FACT-P and the SF-12 v2 to detect negative change was disappointing. The internal and external responsiveness of the social well-being of the FACT-P cannot be supported, suggesting that it is not suitable to longitudinally monitor the social component of HRQOL in prostate cancer patients. The study suggested that generic and disease-specific measures should be used together to complement each other.
Keywords: Chinese; FACT-P; Health-related quality of life; Instrument; Prostate cancer; Responsiveness; SF-12.