Hi!
I am very sorry. It is the kind of diagnosis that we all have nightmares about.
Surgery may come off, but quite likely it may not; it is the sort that will tax even a small animal specialist. I call these kind of situations 'between a rock and a hard place' choices. In the end it boils down to whether you want to take the risk to give your beloved pet a chance that may quite easily not come off or whether you prefer to concentrate on providing quality of life in the time that your girl has left to live.
Which way you want to go depends on your bond, the age/health of the piggy involved, the operation prognosis/confidence of your vet and how well you can afford a risky and likely very expensive operation. There is no clear rule we can give you, as it all depends on your own situation and the factors involved, some of which won't be known until your vet opens up the piggy and can assess the full situation.
It all depends on the nature of the mass, how badly it is wrapped around any organs and whether it has already started to penetrate. The duration of the operation also plays a role when it comes to recovery chances; it is not likely going to be a quick or straight forward operation, so you have to brace yourself that you will have to syringe feed a guinea pig off their food and water round the clock for a number of days more likely than not. Your vet wants to be ideally practised in small pet operations in order to be able to speed up the time your piggy is under GA, but he can't hurry or cut corners as any mistake could be fatal.
Over the years I have had several make or break operations with piggies of mine. Some of them have come off, in others the guinea pigs have died during the operation or in the days/weeks after, never recovering properly. With others I decided not to operate and concentrate on allowing them to live out their lives in peace, without the pain and stress of an operation/longer term post-op care and with palliative support for as long as they had to live.
Neither way is the easier one, as the one brings you heart-break for sure but the comfort that you have done your best to give your piggy a happy and stress-free life for as long as possible and the other comes with a lot of anxiety, stress and the quite high potential of failure and, yes, a good likelihood of heart-break, too, but also the comfort that you have given your girl every chance within your power to have a great and happy future.
The problem is that you have to always make your decision blind without knowing all factors in play and without knowing the outcome - which is of course what you crave most at that stage! There are never any guarantees; you have to take a leap of faith.
Which way you decide to go, please listen to your heart and opt for what you yourself can live with best in the long term so you can be at peace eventually, whatever happens.
I wish I had better news and lots of reassurance, but I don't. Pet keeping can sometimes force you to make very tough choices, and this is one of the toughest you will be ever asked to make.
. I need to think about the issue and will look at the aspects you have highlighted.
