Breast Cancer/Anti-Depressant Link: 5 Facts

Did you catch the news in April that anti-depressants are associated with an 11% increased risk of breast and ovarian cancer?* After pouring over 61 studies of anti-depressants, lead author Lisa Cosgrove of the Harvard Center for Ethics found several other titillating facts as well. Here’s my sum-up.

  • 11% of the US takes an antidepressant, mostly women. Ouch.
  • Lisa found an important link between researchers who are affiliated or unaffiliated with pharmaceutical companies. Among “clean” researchers, with no ties to pharmaceutical companies, 43% had a positive link between antidepressant use and breast/ovarian cancer. And the affiliated researchers? 0% found a link between antidepressants and breast/ovarian cancer. You read it right: 0%. Conflict of interest? Perhaps.
  • Anti-depressants are prescribed more widely than just for depression. I was taught in my medical training to use them for hot flashes (particularly… get this, in breast cancer survivors who can’t take estrogen), headache, back pain, anxiety, eating disorders such as bulimia, fibromyalgia.
  • Women are twice as likely to be diagnosed with depression as men, and three times more likely to be diagnosed with dysthymic disorder, which is a form of low-grade depression.
  • Even short-term and/or low-dose antidepressants may increase risk, so don’t be fooled that your low dose of Zoloft is keeping you safe.

Do antidepressants directly promote tumor growth?

We don’t know and while I hate to do it, I’m going to trot out that tired line that we need more research. However, we know that antidepressants tumor growth in animals, and that Selective Serotonin Reuptake Inhibitors (SSRIs, such as Prozac and Paxil) especially inhibit or block cytochrome P450 (a system that metabolizes anticancer medications such as tamoxifen).

What about mammos?

The latest recommendations are to screen women less – to start mammographic screening at age 50. In women on antidepressants, I’d recommend the old guideline until we know more, which is annual screening in women starting at age 40.


*Antidepressants and breast and ovarian cancer risk: a review of the literature and researchers’ financial associations with industry.

Cosgrove L, Shi L, Creasey DE, Anaya-McKivergan M, Myers JA, Huybrechts KF.

PLoS One. 2011 Apr 6;6(4):e18210.