Response shift effects in the assessment of urologic cancer patients' quality of life.

OBJECTIVE: Urologic cancer patients often assess their quality of life (QoL) as being relatively good. Response shift (change in internal standards) may be one reason for that effect. The aim of this study was to test such response shift effects.

METHODS: A sample of 197 male urologic cancer patients was tested while hospitalised (t1) and three months later (t2). The participants had to assess their current health state and the health state of two anchoring vignettes. They also completed the EORTC QLQ-C30 and PHQ-4 questionnaires, including a retrospective thentest. The control sample was comprised of members of the general population.

RESULTS: The patients rated their general health as being worse than people from the general population did (effect size: d = 0.73, p < 0.001). Moreover, the patients assessed the vignette presenting physical problems as being significantly healthier than people from the general population did (d = 0.42, p < 0.001). Under the retrospective thentest condition, the patients rated their QoL and their mental burden as being significantly worse than in the pre-test condition. Both methods showed response shift effects.

CONCLUSION: Urologic cancer patients' assessments of their QoL should be handled with caution because of possible shifts in their internal standards of judgement.