Prostate cancer and quality of life: analysis of response shift using triangulation between methods

Quality of life (QoL) after prostate cancer treatment is uncertain. Patient responses to QoL questions shift for a number of reasons: measurement intervals no longer have the same psychological anchors (recalibration), the importance attributed to different QoL domains changes over time (reprioritization), and the definition of QoL differs throughout the disease continuum (reconceptualization). Therefore, the aim of this study was to describe QoL response shift in a cohort of 66 men with prostate cancer. The method involved carrying out a sequential triangulation between quantitative and qualitative methods. Patients were assessed at baseline (P1), followed by a posttest (P2) and a then-test measurement (P3). The difference between P3 and P1 was used to determine the response shift effect (recalibration). From baseline to posttest, QoL significantly decreased. The recalibration then-test confirmed a low QoL in all periods evaluated. Coping mechanisms were found to differ by age group, with older men less concerned about side effects than younger men. Health professionals should be alert to QoL changes over time and possible side effects, should coping skills fail.