Husband had an operation for colon cancer. Went back to surgeon today and was told that he didn't think cancer had spread to nodes but wants to send him to cancer center for 2nd opinion. What is the procedure for finding if it has spread? Confused!!!

Here is the link to the National Cancer Institute. Once there, look up your husband's specific primary diagnosis. There are several different types of colon cancer and there may be some important differences in how each type spreads/metastasizes.
http://www.nci.nih.gov/CancerInformation/

The link below is to a general article on colon cancer; it may be worth reading as on overview.
http://www.nlm.nih.gov/medlineplus/ency/article/000262.htm