An unexpected obstacle for cancer therapy has been found

Corticosteroids, often prescribed to patients with non-small cell lung cancer to alleviate side effects, may interfere with immunotherapy. This conclusion was reached by scientists from the Keck School of Medicine (California). The research results were published in the journal Cancer Research Communications (CRC).

Analysis of data from 277 patients with stage II-IV lung cancer showed: those who took steroids before or during treatment with checkpoint inhibitors (CIs) had weaker tumor reduction and lower overall survival compared to patients who did not receive these drugs.

This effect persisted even when accounting for disease stage and other clinical factors. According to oncologist and immunologist Fumito Ito, the lead author of the study, steroids were the key factor weakening the effect of therapy.

The mechanism by which this occurs was also determined. Steroids suppress the maturation of T-cells - the very cells that should attack tumor cells during immunotherapy. Without mature T-cells, the immune system cannot fully respond to cancer. Additionally, corticosteroids mask biomarkers in the blood - important signals that doctors use to track treatment effectiveness and adjust tactics. Their absence complicates diagnosis and slows the response to unsuccessful therapy.

Although steroids are necessary in some cases - for example, with brain edema or severe nausea - the study emphasizes that they should be prescribed with caution. The new data will help doctors more accurately assess risks and, where possible, look for alternatives to control symptoms without interfering with the immune system.