Adjuvant treatments of breast cancer increase the risk of depressive disorders: A population-based study

Background: Previous studies have posited conflicting results regarding depressive disorders among breast cancer survivors who received adjuvant therapies including chemotherapy, radiotherapy, selective estrogen receptor modulator (e.g. tamoxifen), third-generation aromatase inhibitors (Als; e.g. anastrozole, letrozole or exemestane), and monoclonal antibody (e.g. trastuzumab). We therefore performed a population-based study with a defined breast cancer cohort to investigate the risk of depressive disorders in breast cancer patients who received adjuvant therapies. Methods: We conducted a retrospective study of a breast cancer cohort of 36,586 participants who were selected from the National Health Insurance Research Database(NHIRD) in Taiwan. Patients were observed for a maximum of 6 years to determine the incidences of newly onset depressive disorders. Kaplan-Meier and Cox regression analyses were used to identify the risk factors associated with depressive disorders in breast cancer patients who underwent adjuvant therapies Results: Of the total 36,586 patients, 1342 (3.7%) were ascertained with depressive disorders. The Cox multivariate proportional hazards analysis showed that age of 40-59 (adjusted hazard ratio (aHR) 1.327, 95% CI 1.123-1.567, p=0.001), chemotherapy (aHR 1.555, 95% CI 1.387-1.743, p < 0.001), radiotherapy (aHR 1.385 95% CI 1.220-1.571, p < 0.001), tamoxifen (aHR 1.458, 95% CI 1.110-1.914, p=0.007), Als (aHR 1.360, 95% CI 1.193-1.550, p < 0.001), and trastuzumab (aHR 1.458, 95% CI 1.110-1.914, p=0.007) were independent risk factors for developing depressive disorders. Limitations: The dosage effect of adjuvant treatments, cancer staging, genetic or environmental confounders associated with the risk of depressive disorders were not comprehensively evaluated. Conclusion: Developing depressive disorders are at higher risk in breast cancer survivors aged 40-59 who received adjuvant treatments including chemotherapy, radiotherapy, tamoxifen, Als or trastuzumab. Psychological evaluation and support are necessarily needed in breast cancer survivors who received adjuvant therapies. (C) 2015 Elsevier B.V. All rights reserved.