'It's incredible, like science fiction': How a new wave of immunotherapy is eliminating cancers

Personalised medicine is generating excitement in many disciplines, but Knudsen emphasises that it is particularly important for oncology, given the heterogeneity of the disease. "Cancer is not one disease," Knudsen says. "It's 200 different diseases, and they all arise due to different reasons and they have to be treated differently." Even two patients with the exact same type and stage of cancer may have different diseases at a cellular level.

"The field is at an inflection point," Demaria says. "We can now move toward treating not the cancer, but actually the patient."

Scientists at Memorial Sloan Kettering Cancer Center have already trialled one promising strategy, based on the finding that tumours with a particular genetic profile tend to respond well to immune checkpoint inhibitors such as dostarlimab. In two small trials from 2022 and 2024 treating rectal cancers with this profile, the treatment completely eradicated tumours. The team then expanded their research to include 117 patients with various types of tumours – including oesophageal, bladder and stomach – that carried the same genetic signature. Out of 103 people who finished the full course of treatment, 84, including Sideris, saw complete disappearance of their tumours, with only two requiring additional surgery.

Researchers from MD Anderson have reported similar results for an approach using a different checkpoint inhibitor. And other groups have shown that – even if patients do undergo surgery eventually – their operative results may be better, in at least some cases, if the tumours are first attacked with immunotherapy.

While more research is needed, such findings are promising because they open the door to a less invasive yet highly effective era of treatment, says Luis Diaz, head of solid tumour oncology at Memorial Sloan Kettering Cancer Center. "We have to move from Medieval times to modern times," he says. "To remove your rectum or your stomach or bladder – we've got to do better than that."

The caveat is that only around 5% of tumours have the genetic makeup that makes them a good fit for the surgery-free immunotherapy treatment Diaz and his colleagues studied. "The other 95% need something as good," he says.

To that end, researchers continue to look for new immunotherapy approaches and try to improve upon older ones – such as cancer vaccines.

Traditional vaccines introduce the body to parts of a pathogen, such as a virus, so it can practice mounting an immune response to the real thing. A similar concept could work in cancer, Knudsen says – except it could be used to treat the illness rather than prevent it.