Insulinoma prognosis

Question
Hello, my little Bella is nearly 6 years old and was diagnosed with insulinoma yesterday (the vet can't be 100% sure until it goes to pathology, but she has had all the symptoms off and on for around 2 months).  The pancreas tumour was 4mm in size, which sounds quite big to me considering the size of a fuzzie!  The vet also won't know if it has metastasised to the liver until surgical exploration.  I know my options are cortisone or surgery, but what I would like to know is any experiences of prognosis you have.  Bella is the older of two ferrets (the other girl is 2), so I haven't had an "old" ferret yet.  If she is operated on (and the vet thinks it is a good idea, she has been extremely healthy up until now), what kind of life expectancy am I looking at? I realise surgery is not a cure and it will grow back eventually.  I also realise she is an old ferret and will probably only last another 2 years at maximum anyway, but I would like the rest of her time here to be wonderful. If it is already in her liver, what kind of symptoms will she experience if that starts to fail?  I think I will get her the surgery, but I don't want to cause her pain if it's not really beneficial for her.
I also have a behavioural question: last night after I brought Bella home from the vet, she went straight into find Lola (the little one) and gave her a nibble and a bit of grooming.  Then, Lola started following Bella around the house, duk-dukking at her, then started to bite her.  It appears to have settled now, but I felt terrible because Bella had a yucky day at the vets and didn't want to be hassled, so I separated them for the night. Currently Bella is the dominant one, but I wonder if Lola is asserting her dominance now that Bella is weaker?
Thanks for your help.

Answer
Hello Mackenzie,

I am SO sorry to hear your little girl has insulinoma :(  No matter which method of treatment you decide to take, insulinoma is a progressive disease.  Ferrets can live up to 2 years after the initial treatment depending on if the tumor has metastasized to the liver or spleen.  Signs of liver failure are seizures, lethargy, no appetite, jaundice (yellow-looking gums/skin), and diarrhea.  Unfortunately the liver can take a lot of damage before showing symptoms.  I would consider a full panel of blood work (cbc/ghp/lytes) to see her liver levels and how her other organs are functioning.      

Her age is within reason to consider surgery.  Especially if she is otherwise healthy and there are no other complications. It is unfortunate that insulinoma is progressive, but surgery will generally buy more time.  

Ferrets, like dogs and cats, have a social hierachy.  There is a possibility that Lola is showing her dominance now that Bella is a bit weaker.  Or, perhaps Lola is just curious and confused with what is going on with her friend.  

I do have a question for you.  What sort of food do you feed your guys?  Insulinoma is thought to be diet related, although there really have not been any definite studies.  Below is a link to a previous question regarding proper nutrition and diet.  Please take a peek!

http://en.allexperts.com/q/Ferrets-2277/2008/9/Best-types-ferret-food.htm

I hope this answer is useful.  Again, my condolences to poor little Bella.

-Cindy P.