Patient and spouse illness beliefs and quality of life in prostate cancer patients

Objective: Among married prostate cancer (PC) patients, the spouse is often the primary provider of emotional support and personal care. However, few studies have investigated spouses' illness beliefs (i.e. about disease duration and treatment control) and their impact on patients' quality of life (QOL). Spouses' beliefs about disease duration (timeline) were hypothesised to mediate relationships between spouses' treatment control beliefs and patients' QOL six months later. Methods: Fifty-three patients who underwent localised treatment for PC, and their spouses, completed an illness beliefs measure (the revised Illness Perception Questionnaire). Patients completed a QOL measure (the Functional Assessment of Cancer Therapy - General) six months later. Results: Spouse timeline beliefs mediated the association between spouse treatment control beliefs and patient QOL six months later (total indirect effect=-0.71, 95% CI 0.02-2.03). That is, spouse beliefs that the treatment would control their loved one's illness led to beliefs that the disease would be of shorter duration, which in turn led to improved patient QOL six months later. This relationship did not occur with patients' beliefs. Conclusion: Results highlight the important influence of spouse illness beliefs over time on patient QOL with implications for clinical care and dyadic research.