Kontrollüberzeugungen als Moderator der gesundheitsbezogenen Lebensqualität von Krebspatienten. Ergebnisse mit dem MHLC Form C

Abstract

From the cancer patient's view, the period of aftercare is characterized by the uncertainty of prognosis and coping with therapy-induced side-effects. It is assumed that disabilities, as ascertained with quality-of-life-questionnaires, and the patient's view of the impact of their own and other people's behaviour on the disease course are interrelated beyond the end of primary treatment. In this study, cancer patients answered questionnaires at the start of early inpatient rehabilitation. Prior to this, patients had undergone surgical treatment with potentially curative intent for early-stage breast, gastric or prostate cancer. Quality of life data were ascertained with the EORTC QLQ-C30, and disease-related control beliefs were measured with a newly-translated German version of the MHLC Form C questionnaire. MHLC Form C measures internal and external locus of control on separate scales, splitting the latter into beliefs in the control of other people, physicians, and chance. Using cluster analysis, groups of patients with similar control beliefs were formed. The clusters were confirmed by discriminant analysis. Following an earlier classification scheme for forms A and B of the MHLC-questionnaire, the clusters were labelled "believers in control" (46 cases), "pure chance externals" (89 cases), "yea [i.e. yes]-sayers" (118 cases) and, going beyond that scheme, "controllers of uncertainty" (69 cases). While earlier research reports (hypothesis) suggested the best quality of life for "believers in control" (high internal/professional-external, low social-external/chance-external locus of control), multivariate analyses of variance yielded best scores on the functio-nal scales of the QLQ-C30 for "controllers of uncertainty". This group resembles the "believers in control", but has higher chance-external locus of control scores. Multivariate analyses of variance yielded best scores on the functional scales of the QLQ-C30 for "controllers of uncertainty". However, the clusters did not differ significantly in the subjective severity of physical and mental symptoms. It may be concluded that subjective evaluation of physical and mental functioning corresponds to disease-related control beliefs. Possible explanations for this result are discussed.