Testing a theory for health-related quality of life in cancer patients: a structural equation approach.

The purpose of this study was to test a Roy Adaptation Model-based theory of health-related quality of life in patients with newly diagnosed cancer. Using a structural equation model, health-related quality of life (HRQOL) was regarded as a latent variable measured by 4 empirical indicators representing the 4 biopsychosocial response modes of the Roy Adaptation Model (RAM). The response modes are physiologic, self-concept, interdependence, and role function. These were empirically represented by physical symptoms, affective status, social support, and functional support, respectively. In this secondary analysis, 3 RAM propositions were tested in a sample of 375 newly diagnosed postsurgical cancer patients 60 years and over. These were: (a) that the 4 response modes are interrelated; (b) that environmental stimuli of gender, race, age, income, marital status, cancer treatment, and severity of illness influence the biopsychosocial response modes; and (c) that the biopsychosocial responses soon after diagnosis predict biopsychosocial responses 3 months later. The analyses did not support the proposition that all 4 response modes were interrelated. The results, however, revealed that severity of illness and adjuvant cancer treatment had the strongest association with the biopsychosocial responses and should be considered the focal environmental stimuli. The remaining environmental stimuli can be considered contextual. Also, the proposition that initial biopsychosocial responses predicted later responses was supported.