296P - Item response theory and factor analysis as mean to characterize occurrence of response shift for longitudinal quality of life study in breast cance...
|Date||01 October 2012|
|Event||ESMO Congress 2012|
|Session||Poster presentation III|
|Topics|| Breast Cancer, Early Stage
Psychosocial Aspects of Cancer
A. Anota1, C. Bascoul-Mollevi2, F. Guillemin3, T. Conroy4, M. Velten5, D. Jolly6, M. Mercier7, S. Causeret8, T.S. Dabakuyo9, F. Bonnetain9
Health-related quality of life (HRQoL) is a dynamic process which depends on the adaptation of the patient and reflected by a Response Shift (RS) effect. RS results in a recalibration, a reprioritization and a reconceptualization of key HRQoL domains. Longitudinal analyses of HRQoL have to take into account the possible occurrence of RS. However, there is no standard of statistical analysis to characterize RS. Two complementary methods are investigated to characterize RS.Methods
This work builds on data of a prospective multicenter study including all primitive breast cancer patients or suspicion. HRQoL was evaluated using the EORTC QLQ-C30 and QLQ-BR23 at baseline, after surgery, at 3 months and 6 months, according to the « then-test/post-test » design: the retrospective assessments done after surgery and at 3 months refer to baseline HRQoL; the retrospective measurement done at 6 months refers to HRQoL at 3 months. The order then-test and post-test of HRQoL questionnaires was randomized. Recalibration was explored by Multiple Correspondence Analyses (MCA) and the Linear Logistic Model with Relaxed Assumptions (LLRA) of Item Response Theory (IRT). LLRA gives trend of item easiness parameters. Reprioritization and reconceptualization were explored by Principal Component Analyses (PCA).Results
Between February 2006 and February 2008, 381 patients were included, 90% had a confirmed breast cancer. PCA show a secondary reprioritization of the QLQ-C30's dimensions. Fatigue and pain remain priority symptoms. Secondary symptoms are insomnia at baseline, diarrhea after surgery, nausea and vomiting at 3 months and 6 months. A stronger and stronger link between functional scales reflects a reconceptualization. Main recalibration's profiles reflected by MCA are from one modality to an adjacent one. A lower or upward recalibration of each dimension is reflected by the IRT model. Based on retrospective assessment at six months of HRQoL at three months, arm and breast symptoms were overestimated with trend parameters equal to -0.59 and -1.05 (p < 0.001).Conclusions
IRT models have mainly been used to validate HRQoL questionnaires. This work shows their interest to characterize occurrence of RS. Further analyses should be lead to validate their abilities to characterize all RS components.Disclosure
All authors have declared no conflicts of interest.