Risk of breast cancer in association with exposure to two different groups of tricyclic antidepressants.

OBJECTIVE

In 2002, we reported an epidemiological study in which we found that some tricyclic antidepressants (identified as genotoxic in Drosophila Melanogaster) were associated with an increased risk of breast cancer, when exposure took place 11-15 years before the date of diagnosis. The implications of the results found lead us to carry out a separate case-control study, using the same source population, to validate the conclusions drawn from our previous study.

METHODS

We accrued 7330 breast cancer cases, diagnosed between 1981 and 2000, and 29 320 controls matched on age and time.

RESULTS

The association between exposure to genotoxic TCAs 11-15 years before diagnosis and the risk of breast cancer development was much weaker, as compared to what was reported in our previous study. The relative risk of breast cancer in women exposed to high doses of genotoxic TCAs 11-15 years before diagnosis was 1.17 (95%CI: 0.79-1.74), while in women exposed to high levels of non-genotoxic TCAs during the same period it was 0.95 (95%CI: 0.61-1.48).

CONCLUSIONS

In conclusion, we did not find supporting evidence for an increased risk of breast cancer among women exposed to TCAs up to 20 years in the past.