Contrary to the findings in rodent studies, a class of drugs commonly used to treat depression, selective serotonin reuptake inhibitors (SSRIs) that include drugs such as Prozac, do not appear to increase the risk of breast cancer, according to a report in the American Journal of Epidemiology.

“Physicians can feel confident that the evidence has accumulated that use of SSRIs for four to five years does not increase the risk of breast cancer,” said Dr. Patricia F. Coogan, from Boston University.

Coogan and her associates note that concern was first raised in 1992, when it was reported that (Prozac) accelerated the growth of mammary tumors in rodents at doses equivalent to those used to treat people.

The team previously conducted a hospital-based, surveillance study that suggested a 1.8-fold increased risk of breast cancer among SSRI users, based on data obtained up to 1996. The current study updates the earlier data with more subjects and follow-up through 2002.

In this extended analysis, the regular use of SSRIs was not associated with breast cancer risk after factoring in other risk factors, the investigators report.

Similarly, there was no statistically significant difference between women who recently used SSRIs and those who had stopped taking SSRIs at least a year prior to their interview, the researchers note. Moreover, no differences were seen in pre- and post-menopausal women, the results indicate.

“These findings provide assurance that use of SSRIs for durations of four to five years does not increase the risk of breast cancer,” Coogan concluded. “However, these results do not address the risk of taking these drugs continually for decades,” she added.

SOURCE: American Journal of Epidemiology, November 1, 2005.