Targeted brain radiation may offer better outcomes for patients with metastasized small cell lung cancer

Image credit Mass General Brigham Hospital

CANCER DIGEST – July 12, 2025 – Small cell lung cancer patients whose cancer has spread to the brain may have better outcomes when treated with targeted radiation of their brain tumors than when treated with standard whole brain radiation, a new clinical study shows.

The researchers at Mass General Brigham led by Ayal Aizer, MD, MHS, director of Central Nervous System Radiation Oncology at the hospital, treated 100 small cell lung cancer patients with targeted radiation aimed at as many as 10 tumors that had spread to the brain, and compared the outcomes with the historical data using whole brain radiation. The results were published in the July 11, 2025 Journal of Clinical Oncology.

“Despite being the historical standard, whole brain radiation might not be necessary for all patients,” said  Dr. Aizer in a press release, "Our findings demonstrate that targeted, brain-directed radiation may be a viable treatment for patients with limited brain metastases from small cell lung cancer and potentially spare them from the side effects of whole brain radiation.”

When small cell lung cancer spreads to the brain, current standard treatment calls for irradiating the whole brain to ensure all the cancer cells are killed. The short-term side effects of whole brain radiation, however, include fatigue, hair loss, nausea, and headaches. Long-term effects include cognitive decline, including memory loss, hearing and vision problems. While the side effects of the targeted therapy are similar, it is thought they might be milder and less extensive.

The study enrolled patients from multiple cancer centers between 2018 and 2023. In all 100 small cell lung cancer patients with one to 10 tumors that had spread to the brain were enrolled. None had previously received any radiation treatment to the brain. 

The brain tumors were treated with stereotactic radiation that narrows and aims the beam specifically to identified tumors in the brain. The median number of brain tumors treated was two, meaning half the patients had one brain tumor  and half the patients had more than two tumors. Patients were followed with imaging to monitor tumor changes.

After one year 20 of the patients had died from the brain cancer, compared to 64 patients who died from other causes. That worked out to what is called a neurological death rate of 11 percent. That compared to a historical neurological death rate of 17.5 percent. 

“These results support a shift toward more personalized, targeted treatment approaches that can help maintain quality of life while effectively managing brain metastases,” Aizer said in the press release. “By avoiding whole brain radiation in select patients, we may be able to improve quality of life and reduce cognitive side effects without compromising outcomes.”

Sources: Mass General Brigham Hospital press release and Journal of Clinical Oncology.