Research

The measurement of response shift in patients with advanced prostate cancer and their partners

Jonathan Rees¹ , Michael G Clarke¹ , Dympna Waldron² , Ciaran O'Boyle³ , Paul Ewings⁴ and Ruaraidh P MacDonagh¹

¹  Department of Urology, Taunton and Somerset Hospital. Taunton, Somerset, UK

²  Department of Palliative Care Medicine, University College Hospital, Galway, Ireland

³  Department of Psychology, Royal College of Surgeons Ireland, Dublin, Ireland

⁴  Research & Development Support Unit, Taunton & Somerset Hospital, Taunton, Somerset, UK

author email corresponding author email

Health and Quality of Life Outcomes 2005, 3:21doi:10.1186/1477-7525-3-21

Published:	30 March 2005

Abstract

Background

There is increasing evidence to support the phenomenon of response shift (RS) in quality of life (QoL) studies, with many current QoL measures failing to allow for this. If significant response shift occurs amongst prostate cancer patients, it will be necessary to allow for this in the design of future clinical research and to reassess the conclusions of previous studies that have not allowed for this source of bias. This study therefore aimed to assess the presence of RS and psychosocial morbidity in patients with advanced prostate cancer and their partners.

Methods

55 consecutive advanced prostate cancer patients and their partners completed the Prostate Cancer Patient & Partner questionnaire (PPP), shortly after diagnosis and again at 3 months and 6 months. At the follow-up visits, both patients and partners also completed a then-test in order to assess RS.

Results

Partners consistently showed greater psychological morbidity than patients in relation to the prostate cancer. This was most marked on the General Cancer Distress (GCD) subscale (p < 0.001, paired t-test), and regarding worries about treatment (p = 0.01). Significant RS was identified in partners and patients by the use of the then-test technique, particularly on the GCD subscale, the concerns about treatment and the concerns about urinary symptoms items.

Conclusion

These results suggest the presence of RS in patients with advanced prostate cancer and their partners, with higher levels of psychosocial morbidity noted amongst partners. This is the first study to identify RS in partners and calls into question the interpretation of all studies assessing changes in QoL that fail to allow for this phenomenon.