Cancer experts hail new ‘seek and destroy’ tumour weapon

ARADICAL new treatment that equips the immune system to launch a ‘search and destroy’ mission for tumours in the body is set to transform how cancer is tackled, say scientists.

The technique, which uses conventional radiotherapy but with the power turned down, enables cells in the immune system to recognise the genetic fingerprint of cancer cells and seek them out.

In one patient whose lungs, liver and bones were riddled with cancer, the treatment reversed the disease so spectacularly that his tumours disappeared altogether within six months. Five years later, there are still no tumours visible on his scans, according to radiologist Dr Silvia Formenti of the Weill Cornell School of Medicine in New York. Normally, doctors would expect such a patient to be dead in months.

The technique has also proved remarkably successful at halting the spread of a notoriously aggressive form of breast cancer which tends to affect younger women, called triple negative breast cancer (TNBC).

Dr Formenti said she believed the treatment ‘holds the potential to eradicate entire disease in people with several different types of cancer’ – including those of the breast, liver and lung. Dr Formenti said: ‘Everyone thought the only benefit from radiotherapy was shrinking the tumour.’ But targeting a tumour with a lower dose ‘can alter the tumour cells, jumpstarting the immune system’.

Her view was backed by leading London breast cancer surgeon Professor Kefah Mokbel, who thought it could work ‘in all types of solid tumour cancer’.

Explaining the process, Prof Mokbel, of the London Breast Institute, said: ‘The radiation kills cancer cells and as it does so, cancer DNA is released. That stimulates immune cells to respond to what they see as a foreign body.’

Recognising the cancer DNA as foreign, the immune cells, called T-cells, then become programmed to search and destroy cells bearing that genetic fingerprint elsewhere in the body – in the blood and in fully fledged tumours.

The challenge is getting the dose of radiation right: too high and the cancer DNA is destroyed, too low and the cancer cells remain intact.

This novel type of radiotherapy is combined with immune-system boosting drugs called checkpoint inhibitors, helping the immune system to recognise, disarm and finally destroy cancer cells.

Prof Formenti described the approach as turning a tumour

RESULTS SO FAR OF TRIALS ARE VERY VERY PROMISING

into ‘an in-situ vaccine’, as the therapy helped the immune system recognise and respond to a threat, as a jab does.

‘Most exciting’, she added, was that not only did tumours targeted with radiotherapy shrink and disappear, ‘but the ones that receive no radiation disappear too’.

In a trial of 36 women with ‘locally advanced’ TNBC – meaning tumours had started to spread within the breast, but not to other organs – 34 remained free of tumours elsewhere in the body four years later. Results were presented in December at the San Antonio Breast Cancer Symposium in Texas.

Prof Mokbel cautioned it was very early days and that the success of the method could not be proven by a study in just a few dozen patients.

But he said the results so far were ‘very, very promising’.