ANTI-INFLAMMATORIES & FIBROSARCOMA
Dr. Dennis Macy, DVM, is a noted veterinary oncologist affiliated with the University of Colorado and a member of the Feline VAS Task Force. There are excerpts from several different posts from a member of the VAS Support Group whose cat he was treating. They may be of value to anyone who has a cat with active fibrosarcoma or a similar VAS cancer.
Posted on December 24, 2003:
"Dr. Macy told me that fibrosarcoma produces so much inflammation and cytokines and that the inflammation actually drives and worsens the cancer. He said that he feels any cat diagnosed with fibrosarcoma should go on a serious anti-inflammatory right away, regardless of what other treatment may or may not be pursued."
Posted on January 21, 2003:
Subject: Anti-inflammatories for VAS kitties -- oncologist says YES, ALL sarcoma cats!
Some of you had asked if when he'd said that cats with active fibrosarcoma should be on an anti-inflammatory, if that meant ALL or just those where it was notably growing or inflamed or producing sera, or, or ? He clarified and said ALL. He said even if it was down to microscopic size, or if it was just diagnosed, that he thinks they ALL benefit from anti-inflammatories both in terms of slowing the cancer, but also quite importantly in terms of quality of life. He said that the sarcoma produces cytokines that make the cat feel terrible.
Posted on March 30, 2004:
I asked about which anti-inflammatory he preferred, and Dr. Macy said that if there's no evidence of renal problems, and the cat isn't having problems with being too skinny or throwing up a lot or anything like that, then he goes for piroxicam first. Its a cox-2 inhibitor and some of these tumors are driven by cox-2. All apparently are also driven just by inflammation, so he says that he ALWAYS puts them on an anti-inflammatory regardless of how big or fast it seems to be growing, because he believes the anti-inflammatories help slow the growth.
If the cat has any problems that make it too risky to use piroxicam, or starts having any problems while taking it, then he won't use it and will use prednisone instead. For my cat, since his was not only growing fast, but was also draining sera (about 35 to 40 cc's a day, like 1/3 of a cup or more), he started him on 5 mg prednisone per day. Then he went down to 2.5 mg every other day.
Posted on June 3, 2004:
They (Dr. Macy & his colleague Dr. Biller also Colorado State Univ.) also say that the cat, as soon as diagnosed with VAS, should be put on either piroxicam or prednisone. For some cats that can drastically reduce the amount of drainage. For piroxicam, the preferred of the two, the cat must otherwise be healthy, no existing renal problems, no problems with being too thin or throwing up or anything that way. You do need to periodically check their renal values on it to be sure its not causing any problems that way. If peroxicam isn't possible, then prednisone should be used (or prednisolone, especially if there is any liver issues since the liver converts prednisone into the active form prednisolone). My cat already had chronic renal failure, so he couldn't use peroxicam, but they put him on 5 mg/day prednisone, then after awhile the dose was slowly minimized so now he gets 2.5 mg every other day. Inflammation from the cancer actually drives the cancer and speeds its growth, plus it produces cytokines that make the cat feel sick, so putting them on an anti-inflammatory may help both slow the cancer's growth and also help keep the cat feeling as well as possible for as long as possible. Peroxicam is a cox-2 inhibitor (basically just like celebrex, etc. for humans) -- SOME fibrosarcoma really expresses cox-2, so that's why peroxicam is the preferred of the two if the cat is otherwise heathy, because if your cat happens to be the type fibrosarcoma that over-expresses cox-2 the peroxicam can actually help kill the tumor a little bit. I wouldn't expect to see any visual improvement or shrinkage from it, but as noted, it may really reduce the amount of drainage and help slow the cancer significantly.
Posted on June 3, 2004:
A good article related to this issue:
Note all the information about inflammation both in the development, the damage to DNA, etc. That's why they strongly recommend the peroxicam or prednisone.
Posted on June 11, 2004:
Dr. Macy prefers Feldene/Peroxicam over prednisone - but my impression was not because of any concern for immune suppression so much as because many fibrosarcoma overexpress cox-2, so a cox-2 inhibitor not only helps reduce inflammation but may work directly against the tumor also. He won't risk it in cats that have any renal insufficiency, or any problems already with weight loss or vomiting, etc., those he puts straight on the prednisone.