Rats with tumours - euthanise?

Question
Dear Sandra, We have two female rats, 3and a half yrs old. They have both had tumours for about 4 months. Zoe has two tumors,(golf ball size under chin, tennis ball size under rear leg) affecting her movement. Licorice has a tumour (golf ball size at under rear leg), starting to effect her movement.  They are both eating and drinking, but sleeping ALOT. When they come out for a walkabout, both are active, the one with bigger tumours gets tired fast.  My husband says to cross them over, but they are still eating etc.  We do not want them to suffer and I have read that rats are pretty tough. We have had them to the vet about 3wks ago as Licorice had breathing difficulties, which cleared up with antibiotics. Licorice has had hair loss in spots for over a year, but her coat is shiny. She thought that soon the larger tumor may lacerate just from exposure to surfaces etc and then we would have to put Zoe down.  It seems mean to wait for that to happen....Also seems mean to cross one over and not the other if she is only going to slowly waste away without her sister.  Do you have some advice please.

Answer
At first I was going to suggest removing them, but I saw their age. They are sweet grand old girls for sure.

What I did with my 3 year old rat after three surgeries when she started to grow another one is let it go, I did not want to put her through any more surgery.  However she started to get thin despite eating alot and could not walk. I felt bad so i took her to put her down. The vet felt bad, saying she had alot of life left in her so we risked it and did the surgery.  If she died under the anesthesia, I planned on putting her to sleep anyhow....but she did not die, she did fantastic, in fact, and lived close to another year longer!!!!  Now, this is not always the case, esp with an older frail rat, but its worth taking the chance.  However, if you dont want to do it, (it would have to be both of them or you would probably feel bad saving one and not the other) I would not put them down while they are still enjoying life.  After all, they are robbed of life as it is having such a short life span, so in my opinion, I feel its always best to let them decide when its time, and they let us know in their own way, despite how tough they are.  A rat that is miserable wont eat, groom, brux and boggle their eyes. Even if they cannot walk any longer, they find a way.  My Holly would propel around in her cage on her belly. She was fast too and learned to do things her own way despite the tumor. The bottom was plastic and she was litter trained so she would scoot into the box, do her thing and be done.  Because there was no real friction on her tumor other than against the smooth plastic cage bottom, there was no ulcerations to deal with.  However, another one did grow eventually that I decided not to remove and let nature take its course.  She was fine, despite her weight loss....but one day she decided it was time to go.  She was weak and very tired.  I held her for hours waiting for her to let go but she wouldnt.  She wanted me though and would not let me put her down.  I believe she had a stroke because she could not move one side of her body.  Finally after all night of holding her, I took her to put her down since of course she could not live this way, but again, she was stubborn and strong and would not even let go on her own....determined to live.  I cant take that away from y rats.  However, when they have something like respiratory  disease that causes them to become hypoxic and gasp and wheeze and nothing helps them and I know they are scared and they have panic episodes due to lack of oxygen and nothing helps, I dont wait for them to let go as I know they must be suffering, so I do have them put down by the vet.  However, this is MY opinion only.  I dont think with the tumors like this that they suffer even if they have trouble moving.  Again, rats that are in agony do not eat or drink and dont want to be bothered with anyone, you wail know when its time.  I would not put them down when they still want to live.  However, no professional even has the right to tell you to put your rat to sleep when there is no clinical findings that justify it other than the fact there is a tumor just isnt enough to warrant ending their lives that they work so hard to live. Ok so it could ulcerate, but it hasnt, and even if it does, there are things that can be done to help it such as creams and oral antibiotics to prevent infection etc.
So bottom line, my own personal opinion? Let them alone until they are unhappy, and only YOU will know when its time, nobody else.