Association between antidepressant use and second breast cancer event after ductal carcinoma in situ diagnosis: a nested case–control study.

Purpose: Controversy exists regarding the potential relationship between antidepressant use and risk of breast cancer. No previous studies have evaluated the relationship between antidepressant use after diagnosis of ductal carcinoma in situ (DCIS) and risk of a subsequent breast cancer restricted to women with a history of DCIS. Methods: We conducted a population-based, nested case–control study in western Washington State. Cases included 337 women diagnosed with DCIS and a subsequent breast cancer and they were compared to 592 individually matched controls (on age, year of DCIS diagnosis, primary treatment, histology, grade, and disease-free survival time) who were diagnosed with DCIS but not a subsequent breast cancer. Information on antidepressant use after DCIS diagnosis was obtained from comprehensive medical records reviews. Antidepressant use was defined as greater or equal to 3 months of duration. Results: Antidepressant use after initial DCIS was associated with a 1.4-fold increased risk of a subsequent breast cancer event (adjusted OR 1.41, 95% CI 1.02, 1.95). Similar risks were observed when assessing individual antidepressant classes, however, there was no sufficient power across specific classes of antidepressants. Conclusions: Antidepressant use after DCIS diagnosis was associated with an increased risk of subsequent breast cancer in women. Further studies are needed to confirm the associations observed. [ABSTRACT FROM AUTHOR]