Researchers have created an implant that soaks up metastatic cancer cells like a sponge, which they think could be used as an early warning system to detect the spread of cancer in a patient’s body. 

The hope is for women at high-risk of breast cancer, such as those who’ve had a tumour removed, could be monitored for the presence of cancer cells. Not only would this tip off doctors that a patient may have a recurrence of cancer but they could analyse the cells to find the best course of treatment. The implant, made of a biomaterial used in medical devices, is inserted into abdominal fat or under the skin. A signalling molecule called CCL22 in the implant attracts immune cells, which then attract cancer cells to it.

Researchers tested the implants in mice that had breast cancer, finding it attracted circulating cancer cells within about two weeks. While they trapped cancer cells before they migrated to other parts of the body, researchers said the implants are most likely best for detecting the presence of cancer rather than as an anti-cancer treatment. 

Experiments with some mice showed that a scanning system optical coherence tomography, or OCT, would allow cells in the implant to be detected without removing it. There are companies working on smartphone apps that would allow OCT to be done with a smartphone, according to New Scientist. The study was recently published in Nature Communications.