Metastases on Mouse Lungs (image) The Ottawa Hospital Share Print E-Mail Caption Surgery is very effective in removing solid tumors, but researchers now know that it also changes the immune system in a way that allows tiny cancers (metastases) to grow and spread. Credit Rebecca Auer, Lisa MacKenzie Usage Restrictions Only for use in stories about this research. Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.