Breast cancer patients prescribed SSRIs (selective serotonin reuptake inhibitors, such as citalopram, escitalopram, fluoxetine, paroxetine or sertraline) to help with anxiety and depression after diagnosis need not fear that this will increase the risk of their cancer spreading (metastasis).
Reporting at Breast Cancer Trials’ recent Annual Scientific Meeting in Brisbane, researchers from Taiwan and Queensland presented data from 128,902 breast cancer patients who had a high risk of their cancer spreading. They compared outcomes (metastasis or mortality) for 7,672 patients who were given SSRIs within six months of their diagnosis with those for 101,708 patients who had not received SSRIs. They also looked at patients who had already been taking these medicines before their diagnosis and compared their outcomes with those of patients who never took SSRIs.
After five years there were no significant differences between the SSRI-takers and non-SSRI-takers in the numbers whose cancer had metastasised to the brain, lung, liver, bone or other site, and no differences in the numbers who had died from their cancer.
A similar comparison for patients who had been using SSRIs before their breast cancer diagnosis also showed no impact on the risk of metastasis or mortality.
The researchers concluded that SSRIs can safely be used to support mental health in high-risk breast cancer patients without compromising cancer outcomes and that further research to explore duration-, dose-, and drug-specific effects across different breast cancer subtypes is warranted.
Reference: Wang J, Kulasegaran T, Tsai K-W, McCart Reed AE and Beecher Matthews K. SSRI prescription following breast cancer diagnosis is not associated with altered early metastasis risk: A target trial emulation. Poster presented at Breast Cancer Trials Annual Scientific Meeting, 29-31 July 2026, Brisbane, Australia.
20 August 2026
