Breast cancer that spreads often infiltrates bone, causing fractures and intense pain. In such cases, chemotherapy is ineffective because the environment of the bone protects the tumor, even as the drug has toxic side effects elsewhere in the body.
Now, scientists at Washington University School of Medicine in St. Louis have developed a nanoparticle that can deliver chemotherapy directly to tumor cells that have spread to bone. In mice implanted with human breast cancer and exposed to circulating cancer cells likely to take up residence in bone, the researchers showed the treatment kills tumor cells and reduces bone destruction while sparing healthy cells from side effects.