Antidepressant use linked to lower death rates in cancer patients receiving immunotherapy

October 7, 202612:59 pm

Cancer patients with solid tumors and depression or anxiety who were taking antidepressants had fewer deaths during the two years after starting immunotherapy than patients treated with sedatives, according to a new study by researchers in Taiwan.

The study analyzed medical records of adults with solid tumors who began treatment with immune checkpoint inhibitors, a type of immunotherapy that helps the immune system attack cancer cells.

Researchers compared 1,567 patients taking selective serotonin reuptake inhibitors, or SSRIs, with 1,567 patients taking benzodiazepines. The groups were matched based on 49 characteristics, including demographics, tumor features, other medical conditions, medications and laboratory results.

During the two-year follow-up period, 368 patients in the SSRI group died, compared with 539 among those taking benzodiazepines. That represented mortality rates of 23.5% and 34.4%, respectively.

An analysis that considered the timing of deaths associated SSRI use with an approximately 37% lower relative risk of death during the follow-up period. The researchers stressed that this does not mean patients lived 37% longer.

One possible explanation involves serotonin and its role beyond the brain. Researchers noted that T cells involved in fighting cancer also respond to serotonin. A previous study found that blocking the serotonin transporter targeted by SSRIs strengthened antitumor immunity in mice.

However, the researchers emphasized that the findings do not prove that antidepressants extend the lives of cancer patients. The study was observational, meaning patients were not randomly assigned to receive SSRIs or benzodiazepines.

Oncologist Cho-Hao Lee said a randomized clinical trial would be needed to determine how much of the association is causal and how much could be explained by other factors. He also cautioned patients against starting an SSRI to enhance immunotherapy or stopping a benzodiazepine without medical advice.