Adding Immunotherapy to Radiotherapy Increases Survival in Patients with Brain Metastases

The addition of immunotherapy to radiotherapy to treat patients with cancer who had brain metastases was associated with an improved overall survival for patients, compared to radiotherapy alone, according to data published in JAMA Network Open.

Researchers have seen the positive results of adding immunotherapy to the treatment of patients with melanoma who developed brain metastases from their cancer, however, the association of adding immunotherapy to other treatments for patients who developed brain metastases from other cancers was not determined.

In this study of 3,112 adult patients from the National Cancer Database (NCD) researchers looked at patients with non-small cell lung cancer, breast cancer, melanoma, colorectal cancer or kidney cancer and brain metastases at the time of diagnosis and received surgery for the primary tumor site. What they found was patients treated with immunotherapy alone had an improved overall survival (OS) compared to those treated without immunotherapy. However, it was the combination of immunotherapy and radiotherapy (RT) that stood out to researchers with the combination showing a significant OS improvement over those patients treated with RT alone.

“Median OS was longer in patients who received RT plus immunotherapy compared with patients who only received RT alone,” the authors wrote. “Most importantly, we found that immunotherapy improved the OS of patients with brain metastases by 7.5 months regardless of what other treatments they received. Immunotherapy combined with RT improved OS by 10 months compared with those who only received RT.”

These results are in line with previous studies of the combination of immunotherapy and RT for patients with melanoma, but according to the researchers, this is the first to look at other cancers with patients who develop a brain metastasis who have had definitive surgery for their primary tumor.

According to the researchers, immunotherapy may enhance these results after surgery because of its response to tumor-associated antigens, moreover, RT aids immunotherapy by promoting the presence of neoantigens (antigens from altered tumor proteins due to tumor mutations) in the tumor environment increasing their immunogenicity. Meaning, the ability of the tumor to have an immune response provoked increases making immunotherapy more favorable.

“The findings warrant future clinical trials investigating the association of chemotherapy, RT, and chemoradiation combined with immunotherapy with the survival of patients who receive definitive surgery of the primary tumor,” the authors concluded.