A population-based case-control study of Selective Serotonin Reuptake Inhibitors (SSRIs) and breast cancer: the impact of duration of use, cumulative dose and latency.

J E Ashbury,P A Beck,L E Lévesque,K J Aronson

doi:10.1186/1741-7015-8-90

Abstract

BackgroundSelective serotonin reuptake inhibitors (SSRIs), a popular class of antidepressants, may increase breast cancer risk by stimulating the secretion of prolactin, a potential tumour promoter. We evaluated the effects of duration of SSRI use, cumulative dose, and latency on the risk of breast cancer by conducting a population-based case-control study utilizing Saskatchewan health databases.MethodsCases included 1,701 women with primary invasive breast cancer diagnosed from 2003 to 2006, and controls consisted of 17,017 women, randomly selected from the population registry. Use of SSRIs was compiled using the Saskatchewan prescription database. Unconditional logistic regression was conducted to evaluate the impact of duration of combined SSRI use (total number of prescriptions dispensed), cumulative dose (total dosage received) and timing of use (two or more years, two to seven years and more than seven years prior to index date) on the risk of breast cancer.ResultsOverall, SSRI use was not associated with an increased risk of breast cancer regardless of our definition of cumulative use (total number of prescriptions dispensed and total dosage). In addition, our results indicate that prolonged SSRI use does not have a latent effect on breast cancer risk. Also, our findings are not suggestive of an increased risk of breast cancer with the use of individual SSRIs.ConclusionsOur study improved upon most previous studies by having a longer follow-up period, a larger sample size of long-term SSRI users and consideration of risk during specific exposure time windows that take latency into account. Given the potential health benefits of using SSRIs, our results suggest that the issue of breast cancer risk may no longer be a concern for women requiring long-term SSRIs.

Highlights

Selective serotonin reuptake inhibitors (SSRIs), a popular class of antidepressants, may increase breast cancer risk by stimulating the secretion of prolactin, a potential tumour promoter
Experimental evidence suggests that SSRIs, a popular class of antidepressants, enhance breast cell proliferation during a relatively late phase in breast cancer development, either directly through SSRI tumour-promoting mechanisms [1,2,3] or indirectly through an SSRImediated increase in prolactin, a hormone for which there is increasing evidence to suggest an association with breast cancer [4,5]
SSRI use was not associated with an increased risk of breast cancer regardless of our definition of cumulative use

Summary

Introduction

Selective serotonin reuptake inhibitors (SSRIs), a popular class of antidepressants, may increase breast cancer risk by stimulating the secretion of prolactin, a potential tumour promoter. We evaluated the effects of duration of SSRI use, cumulative dose, and latency on the risk of breast cancer by conducting a population-based case-control study utilizing Saskatchewan health databases. Few epidemiologic studies have investigated the long-term safety of SSRIs or considered a latent effect of SSRI use on breast cancer risk. Coogan [6] highlighted the ‘dearth of data’ related to long-term SSRI use and breast cancer risk and recommended further study. We evaluated the effects of duration of use, cumulative dose, and latency on breast cancer risk using a population-based case-control study Given that breast cancer is the most frequently diagnosed cancer in women [7,8] and that SSRIs have been on the market for more than 20 years and are increasingly widely prescribed in women, further investigation of the potential association between long-term SSRI use and breast cancer risk is warranted.

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Conclusion