This was the conclusion of a recently published Nature Communications study, in which researchers uncovered an immune system mechanism that helps tumors to develop resistance to radiation therapy.

The study builds on earlier work, in which the team examined what happens to cancer cells when they are exposed to radiotherapy, and in particular, how the immune system responds.

When doctors choose a cancer treatment they weigh up a number of factors, such as the type of cancer, its severity, how advanced it is, how old the patient is, and their state of health.

For many patients, the aim of cancer treatment is to cure the disease, but, in some cases, this may not be feasible and so the goal is to manage symptoms and control the disease.

Most treatments involve surgery combined with one or more therapies, including chemotherapy and radiation therapy, and perhaps even hormonal or biological therapy.

Radiation therapy shrinks tumors by directing X-rays, gamma rays, or charged particles at them. These high-energy beams — which can come from a machine outside the body or from radioactive materials implanted into the body — kill the cancer cells by destroying their DNA.

There is also a type of radiation therapy, called systemic radiotherapy, in which the radioactive material travels to the cancer cells in the bloodstream.