By destroying only 50% to 75% of liver tumor volume, the rats' immune systems were able to clear away the rest, with no evidence of recurrence or metastases in more than 80% of animals.

"Even if we don't target the entire tumor, we can still cause the tumor to regress and also reduce the risk of future metastasis," said Zhen Xu, professor of biomedical engineering at U-M and corresponding author of the study.

Results also showed the treatment stimulated the rats' immune responses, possibly contributing to the eventual regression of the untargeted portion of the tumor and preventing further spread of the cancer.