Traps and lures could stop cancer from spreading (Image: Jimmy Turrell)

Some surgery to treat cancer can actually make it spread. But traps to mop up tumour cells as they infiltrate the body can boost chances of survival

IT IS the medical symptom that many of us fear the most: a lump. If it turns out to be cancer, we face, at best, a painful and debilitating course of treatment, and at worst, well… the worst.

And yet, paradoxically, this lump is not what kills most people. As long as it is somewhere accessible, a single, discrete tumour can usually be cut out.

It is only once cells escape from this primary tumour and settle elsewhere in the body – like the brain, liver, lungs or bones – that cancer typically becomes deadly. At this stage, there may be so many secondary tumours that repeated surgery becomes a losing battle.

This spreading process, called metastasis, is what kills 9 out of 10 people who die from cancer. “Metastasis is one of the most important problems in the treatment of cancer,” says Chris Marshall, who studies the phenomenon at the Institute of Cancer Research in London.

Despite its importance, the way cancers spread has for a long time remained opaque. But things are changing. New techniques to study metastasis have led to the alarming finding that standard medical procedures to investigate and treat cancer can sometimes help it spread.

Armed with this knowledge of how cancer disperses, however, researchers are devising ways to trap and snare cancer cells as they head off on this journey. As a result a whole new front is …