Prevalence and risk of depressive symptoms 3-4 months post-surgery in a nationwide cohort study of Danish women treated for early stage breast-cancer

Background Elevated levels of depressive symptoms are generally found among cancer patients, but results from existing studies vary considerably with respect to prevalence and proposed risk factors. Purpose To study the prevalence of depressive symptoms and major depression 3-4 months following surgery for breast cancer, and to identify clinical risk factors while adjusting for pre-cancer sociodemographic factors, comorbidity, and psychiatric history. Patients and methods The study cohort consists of 4917 Danish women, aged 18-70 years, receiving standardized treatment for early stage invasive breast cancer during the 2 1/2 year study period. Of these, 3343 women (68%) participated in a questionnaire study 12-16 weeks following surgery. Depressive symptoms (Beck's Depression Inventory II) and health-related behaviors were assessed by questionnaire. The Danish Breast Cancer Cooperative Group (DBCG) and the surgical departments provided disease-, treatment-, and comorbidity data for the study cohort. Information concerning sociodemographics and psychiatric history were obtained from national longitudinal registries. Results The results indicated an increased prevalence of depressive symptoms and major depression (13.7%) compared to population-based samples. The pre-cancer variables: Social status, net-wealth, ethnicity, comorbidity, psychiatric history, and age were all independent risk factors for depressive symptoms. Of the clinical variables, only nodal status carried additional prognostic information. Physical functioning, smoking, alcohol use, and BMI were also independently associated with depressive symptoms. Conclusion Risk factors for depressive symptoms were primarily restricted to pre-cancer conditions rather than disease-specific conditions. Special attention should be given to socio-economically deprived women with a history of somatic- and psychiatric disease and poor health behaviors.