Using magnetic particles for a prostate cancer treatment that would help the body's own cells kill tumors is being developed by researchers at the University of Sheffield.
They say it would be particularly effective for the most advanced forms of the disease for which there are few drugs available.
Unlike chemotherapy and radiotherapy, the treatment can kill cancerous cells without harming healthy tissue - which is what causes side effects such as extreme tiredness, nausea and hair loss.
When prostate cancer develops some of the white blood cells, called macrophages, flock to tumours to try to fight them.
However, because these tumours grow and spread so rapidly the blood cells are unable to keep pace. To speed up their action, the researchers have injected the cells with magnetically charged nanoparticles, each one 1/50th the width of a human hair.
This magnetic force enables the cells to move much more quickly around the body targeting tumours.
Under the treatment, the cells would also be injected with a gene therapy known to kill tumours - making them even more effective.
Early tests in the lab, presented at the National Cancer Research Institute Conference in Liverpool, have shown these white blood cells can reduce numbers of cancerous cells.
"We know that when prostate cancer develops, a type of white blood cells called macrophages flock to the scene," the Daily Mail quoted Dr Jay Richardson, lead author of the study as saying.
"Previous research has allowed us to harness these cells to deliver cancer fighting therapies directly into the cancer cells. Now, with some magnetic assistance, we are able to refine this method so the macrophages deliver the therapy to prostate cancer cells only, leaving healthy cells unharmed," he added.