A major breakthrough in lung cancer treatment has emerged from an international study led by Professor Patrick Forde of Trinity St James’s Cancer Institute in Dublin. The results, published on June 2 in the New England Journal of Medicine, reveal that giving patients a combination of chemotherapy and an immunotherapy drug called nivolumab before surgery significantly increases long-term survival.

The findings were shared at a key gathering of cancer experts—the American Society of Clinical Oncology meeting held in Chicago last weekend. This study, known as the CheckMate 816 trial, followed 358 patients with early-stage non-small cell lung cancer (NSCLC), the most common type of lung cancer, over five years.

More than half of people with stage 2 or 3 lung cancer suffer a return of the disease even after surgery. The new treatment approach aims to stop that. When patients received the immunotherapy drug nivolumab along with chemotherapy before surgery—a method known as neoadjuvant therapy—they were 10% more likely to be alive five years later, compared to those who got chemotherapy alone.

Even more striking is the fact that among patients whose tumours had completely disappeared by the time of surgery (a result known as "pathologic complete response"), not a single patient died of lung cancer after five years. This suggests that early immune system activation can provide powerful long-term protection.

Immunotherapy drugs like nivolumab belong to a class called “immune checkpoint inhibitors”. They help the immune system recognise and attack cancer cells by blocking a protein called PD-1, which normally stops immune cells from attacking the body. In effect, these drugs remove the "brakes" on the immune system.

Until now, immunotherapy had mainly shown benefits in patients with advanced, or stage 4, cancer. This trial is the first to show that starting immunotherapy earlier—before surgery—can help prevent relapse and extend lives.

The treatment was also well tolerated. “Side effects did not increase significantly, and surgeries went ahead smoothly,” the researchers noted in earlier trial updates.

Prof. Forde is now leading another trial in Ireland that aims to improve survival even further. This new study adds a medicine called an antibody-drug conjugate (ADC) to the mix. ADCs are targeted treatments that attach chemotherapy directly to cancer cells, sparing healthy tissues. Early results from the trial, called NeoCOAST-2 and published in Nature Medicine, are promising.

Professor Forde, who previously worked at Johns Hopkins University in the U.S., emphasised the importance of clinical trials.

“We now have a treatment that increases the chance of cure after lung cancer surgery,” he said. “Immunotherapy combined with chemotherapy before surgery reduces the risk of cancer coming back and helps people live longer,” he said.

He added that trials also offer early access to newer and potentially better treatments, something he hopes more Irish patients can benefit from in the future.