Rat tumour

Question
My rat has what I think to be a mammary tumour by the base of her tail. Do you know how long or how big it can get before she needs to be euthanized (before she can't live with it)? Since it is near her genitals I am not sure how that would affect her.... she has had a mammary tumour before by her armpit, and had it removed- that was at the beginning of July. This new one I noticed about a week ago, and it seems to have gotten larger and harder since then. Any advice? Thank-you.
By the way, she is nearly 2 years old.

Answer
As you know, You can have it removed before it becomes too vascular. Its easy to do it any time, of course, but the sooner the better.

If you opt not to remove it, which I support your decision either way since this is the second tumor she has had not that long ago, it will still take many months before it starts to cause problems with her body.  These tumors are usually benign, but that doesnt mean they are not deadly. What they do is once they are vascular, the rat will lose weight because the tumor is tapped into the blood supply, robbing her body of nutrients needed to sustain vital organ function. Rats die from organ failure from these tumors in most cases. Due to the fact its on her lower abdomen, it will rub on the floor of the cage and become irritated from friction. You can avoid this by removing all litter from the cage and keeping it only in a little litter pan or even a shoe box with a door cut out.  Most rats prefer to use litter to go to the bathroom in, and this is one way I tell people to litter train their rats anyhow, it always seems  to work for the most part.  Anyhow, you can lay down fleece on the bottom of the cage to protect the tumor from being dragged through litter.  It will get to the point it may interfere with her walking and she may drag around. This still doesnt mean she needs put down as long as she is eating and seems happy. These nasty tumors bother us more than it  does them.  You can have the vet put her on steroids which tend to slow down the growth of  some tumors, but she needs antibiotics for a back up since steroids can weaken the immune system.

Its hard to say how long it will take before it finally takes its toll on her but from experience, I would say you have at least another 4 months, maybe 6.  Feed her high calorie foods once she starts losing weight. In fact give her whatever she wants, no need to worry about protein levels or fats and sugars if she is terminal.

I cant tell you to do the surgery since chances are once this heals another will surface. If you had one removed in July and another is growing already chances are there are others already growing that have not made it to the surface yet.

I always suggest to people to spay all female rats before the age of 6 months to prevent the growth of these nasty tumors by a qualified vet ONLY.   I refuse to own females now because so many of them had tumors and spaying is just not an option for me when I keep usually 4 females at a time.  My vet charges $300 for a spay so we are talking $1200 for four spays not including whatever else may come their way in the future.    Males can still get mammary tumors but chances are once it is removed they usually dont keep sprouting new ones.

To read more about tumors and why our rats are so prone to them plus to see photos and read stories about other rats having surgery, sometimes up to 3 or 4 surgeries, check my website here:

http://www.sandyscrittercity.com/allabouttumors.htm

Let me know what you think, and again, I support your decision no matter what.