[Gpdd] Health: Spaying for Uterine Tumor?

[pat schuett]

Hello friends,
I am just back from a visit to the vet's office and wanted to consult your collective wisdom on a decision I am facing.
My piggie Primrose has been a bit off her food the past week or so (not much, just not finishing off everything as she usually does) so today I took in a urine sample to the vet's for analysis.  We are having a mini-blizzard today and I wanted to avoid taking Primrose in if it wasn't necessary, but the urine came back negative for infection, so Primrose and I set off in the wind and snow (we were viewing the weather from inside the car, of course).
The vet thought she could feel something in Primsie's abdomen, so she did ultrasound and x-ray to get more information.  The "something" appears to be a tumor in her uterus.  We also did ultrasound and x-ray on her last July to check for a possible bladder stone (which was not there), and this mass was not there at that time, so it appears to be fairly fast-growing.
So now I need to decide whether or not to have surgery done to remove the mass (basically this would be a spay).  Primrose is about five years old and has no other serious health concerns, aside from getting gas if she eats too many greens.  She had a head injury as a baby (before I adopted her), and still bobs her head rapidly when she gets excited but this does not affect her health.
I live in a small Western Canadian city and there is no local vet who has ever done a guinea pig spay.  There is a vet college three hours north of here where they do more frequent small animal surgery, but that's not really an option in the winter when the highways are often closed because of bad weather.  My vet here is prepared to attempt it and I trust her.  She did two bladder stone surgeries on a previous piggy of mine; the first went really well and he recovered quite quickly but a new stone formed within months and he died hours after the second surgery.
I did have another previous piggy, Olivia, who had a uterine tumor.  In that case, I decided to just let her live out her life for as long as she was comfortable.  She survived for about six months after the initial diagnosis with very good quality of life: she only appeared to be in pain for the last two days before we helped her to the Bridge.
It would really help me to hear your experiences, both good and bad, with this; I know some of you have also faced this same awful choice.  
I do love all my piggies, but Primrose has always had a special place in my heart.  She is one of those small but mighty pigs who takes no guff and refuses to accept that a mere human should get to push her around.
Thanks in advance for your help ---
Pat and the Prairie Pigs (Primrose, Faith, Edvard Munch, Guinness and Bonnie)