The day her son turned 18, Linda Medendorp was told she was going to die. After seeing a doctor about persistent problems swallowing her food, tests showed the then 51-year-old had incurable cancer that had already spread from her stomach and rectum.

“It was the biggest nightmare,” she said, but there was “one positive factor in all the bad news”. Her tumour’s characteristics meant she qualified for a Dutch trial of a checkpoint inhibitor, which removes brakes on the immune system that prevent it from attacking cancer cells. Suddenly she had a sliver of hope.

The drug she received, Bristol Myers Squibb’s Opdivo, is an immunotherapy — one of several classes of treatment to emerge in recent years that have made the outlook for cancer patients more promising than ever before.