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 (AIs; 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), AIs (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, AIs or trastuzumab. Psychological evaluation and support are necessarily needed in breast cancer survivors who received adjuvant therapies.
Keywords: Adjuvant treatments; Breast cancer; Depressive disorders.
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