The primary objectives of this study were to examine the relationship between factors specified in the extended Self-Regulation Model (SRM) (illness and treatment perceptions and coping strategy) and three types of QoL outcome. Secondary objectives were to examine the relationships between outcome measures (general and cancer-specific HR-QoL and the Patient Generated Index (PGI)). Cross-sectional questionnaire study. Eighty-two newly diagnosed patients with head and neck cancer (HNC) completed the Illness Perception Questionnaire--Revised (IPQ-R), the Beliefs about Medicines Questionnaire (BMQ), the Hospital Anxiety and Depression Scale (HADS), the Brief COPE and the Life Orientation Test (LOT-R). Patient outcomes were assessed using the European Organization for Research and Treatment of Cancer (EORTC) QLQ-C30, MOS Short Form Health Survey (SF-12v2) and the Patient Generated Index (PGI). These pre-treatment cross-sectional results have shown that key components of the SRM (beliefs and coping) were explanatory factors of HR-QoL outcomes. The PGI was not associated with any of the components of the SRM. The PGI was partially correlated with HR-QoL measures; in particular, Global QoL/health status (EORTC) and Mental Component Summary scores (SF-12).
Our findings suggest that the illness perceptions approach may be a useful method for eliciting and understanding patients' beliefs regarding HNC. In order to maximize outcomes, simple interventions could address particular patient beliefs and coping styles.
The relationship between the Patient Generated Index (PGI) and measures of HR-QoL following diagnosis with head and neck cancer: are illness and treatment perceptions determinants of judgment-based outcomes?