Scientists create implant to capture cancer cells spreading in body

Scientists in the US say they had created a tiny implant, which, in mice for now, captured cancer cells spreading through the body.

Cells moving from the original cancer site to infect other organs in a stealthy process called metastasis were detected too late to save a patient's life.

The early detection of circulating tumour cells, or CTCs, in the bloodstream could speed up diagnosis and life-saving treatment.

The wandering cancer cells however travel in very small numbers, often for long periods of time, before settling in a new site, and are therefore, very hard to spot.

According to the study, published in the journal Nature Communication, capturing CTCs would prevent their spread and help halt disease progression.

"Animals receiving an implant had a significantly reduced burden of disease in their lungs relative to animals that did not have an implant," study co-author Lonnie Shea at Northwestern University in Illinois told AFP.

In their experiments Shea and his team built biodegradable discs about half-a-centimetre (0.2 inches) wide, and implanted two per mouse.

The implant used immune cells as bait and also contained a scanner to detect the presence of trapped cells.

"The combined systems can enable the early detection of metastatic disease," Shea said by email.

"The initial benefit is detection -- catching the metastasis before it spreads widely throughout the body," he explained.

Cancers do not just metastasise anywhere, but flow in the blood to specific environments that they are comfortable in.

Researchers, had in the past, found that immune cells played an important role in creating these microenvironments, and that the metastasising cells tended to follow the immune cells.

In the study, researchers used sponges just a fifth of an inch in diameter made from a biocompatible plastic called PLGA on mice with breast cancer.

These were implanted in the abdomens of the mice where cancer is not known to spread usually. When the sponges were removed 28 days later, the researchers found that they contained cancer cells, though none were found in the same tissues without the sponge.

According to the researchers, when the immune cells flocked to the site of the implanted sponge, the metastatic cancer cells followed, then stayed there when trapped by the sponge. Metastatic cancer cells could thus be detected earlier to allow timely intervention.

Cancer is a disease of cell growth, but most tumours only become lethal once they metastasize or spread from their first location to sites throughout the body. (See: Lynchpin molecule for the spread of cancer found).