Grace, I was planning to post this link at some point, and this looks like the right opportunity:
http://breast-cancer-research.com/content/9/4/R40, based on your last question about node enlargement. Follow the link and then click on the provisional pdf link to see the entire article, with the formidable title, "Accuracy of computed tomography perfusion in assessing metastatic involvement of enlarged axillary lymph nodes in patients with breast cancer." (It is easier reading than it sounds!) One of the things that came up was that not all enlarged nodes were enlarged due to metastasis - some were enlarged due to inflammation.
Hopeful