Breast cancer recurrence in relation to antidepressant use.

PURPOSE: Women with breast cancer frequently use antidepressants; however, questions about the effect of these medications on breast cancer recurrence remain.
METHODS: We identified 4,216 women ≥18 years with an incident stage I or II breast cancer diagnosed between 1990 and 2008 in a mixed-model healthcare delivery system linked to a cancer registry. Recurrences were ascertained from chart review. Medication exposures were extracted from electronic pharmacy records. We used multivariable Cox proportional hazards models to estimate hazard ratios (HR) and 95 % confidence intervals (CI) to assess the association between antidepressant use and breast cancer recurrence and mortality. We also conducted analyses restricted to tamoxifen users.
RESULTS: Antidepressants overall, tricyclic antidepressants, and selective serotonin reuptake inhibitors were not associated with risk of breast cancer recurrence or mortality. Women taking paroxetine only (adjusted HR: 1.66; 95 % CI 1.02, 2.71) and trazodone only (adjusted HR: 1.76; 95 % CI 1.06, 2.92), but not fluoxetine only (adjusted HR: 0.92; 95 % CI 0.55, 1.53), had higher recurrence risks than antidepressant nonusers. There was some suggestion of an increased recurrence risk with concurrent paroxetine and tamoxifen use compared with users of tamoxifen only (adjusted HR: 1.49; 95 % CI 0.79, 2.83).
CONCLUSIONS: In general, antidepressants did not appear increase risk of breast cancer recurrence, though there were some suggested increases in risk that warrant further investigation in other datasets. Our results combined systematically and quantitatively with results from other studies may be useful for patients and providers making decisions about antidepressant use after breast cancer diagnosis.