For people facing aggressive brain cancer, the outlook is usually grim. Even after surgery, tumors often return, and patients typically survive just four to five months.

But a new clinical study suggests a promising combination therapy could substantially extend survival by helping the immune system do what it has long struggled to do in the brain: reach and attack cancer cells.

Researchers report that pairing a minimally invasive laser procedure with immunotherapy allowed nearly half of treated patients to still be alive 18 months later. The findings, published in Nature Communications, point to a potential new strategy for tackling one of oncology’s most difficult challenges.