There are multiple pieces of info on the misuse of the term "cancer"; here's one which combines the marvelous post of a veterinary pathologist who is a highly respected ferret expert (Dr. Bruce Williams) and some dictionary definitions from veterinary/ medical dictionaries. For example, message 6510 (There ARE others with more info): At 8:59 AM +0000 8/20/01, Dr. Bruce Williams wrote: BEGIN QUOTE The thread on this is pretty good, and both Sukie and Stephanie have very valid points. The terminology of neoplasms can be confusing, and I'm sure even vets can be confused from time to time. The proper term for what you are talking about is neoplasm (or literally "new growth). For one reason or another, a clone of cells begins to grow uninhibited by normal substances or mechanisms. The word "tumor" may be technically correct, but it is actually non- specific - tumor is Latin for a swelling, but it could also be an abscess, or anything else that causes swelling - so I try to stay away from it. Now this neoplasm may be benign - without the ability for cells to detach into the bloodstream or lymph, move to another tissue, and set up shop - or malignant (where they can do this.) The process of a microscopic piece of a tumor moving to another organ is called metastasis. Metastasis is the hallmark of malignancy. The worst tumors have the propensity to go anywhere and start growing (like lymphoma). However, we can recognize malignant tumors even before they metastasize, often by characteristic features seen under the microscope. Adrenal carcinomas (malignant adrenal tumors) are interesting neoplasms. Although they possess the ability to metastasize, only a small number do, and usually only late in the course of disease. It is likely that they do metastasize a lot, but have trouble gaining a foothold in distant tissues, so it takes a long time and many attempts if they ever truly metastasize. Insulinomas are generally not malignant tumors as they only very rarely metastasize. The presence of multiple tumors in the same organ over time is not metastasis. We do not understand the mechanism behind the generation of these tumors, and when we do surgery to remove them, we really are only treating the end point of this process, without addressing the cause. Thus it is really no surprise that the rate of recurrence is about 40% within 10 months. With kindest regards, Bruce Williams, DVM END QUOTE Treat this as a supporting document to Bruce William's excellent post above taken from FHL digest 348. I especially liked his providing the direct translation of "tumor" as "swelling", and his explanation that not all growths which can metastasize do so readily. These definitions are combined ones from medical, veterinary, and biology dictionaries, but emphases are mine and i am willing to be corrected if I blew it... (New note in 2005 -- in the 4 years that this has run no one has disagreed with the medical dictionary definitions and it has been read by vets, physicians, and other experts in that time.) Important Note: some more recent dictionaries don't even include the term cancer as a valid health term any longer, and I have heard vets who won't use it due to the widespread confusion out there, and even some vets who won't use "tumor' due to too many assuming that any tumor is malignant. [Posted in FML issue 4930]