Cancer questions

Every time I search cat cancer on the internet, I'm not finding the answers to my questions.  According to everything I've read, my cat shouldn't be alive.  But she is.

When she was roughly 3, she was a stray that walked into my house, unspayed.  The vet guessed between 2-6 but most likely 3 based on her teeth.  When she was 10, she had mammary cancer.  The vet did surgery and told me she probably wouldn't live long, mammary cancers were aggressive.

The cancer came back when she was 14.  Again surgery was done, this time the vet took a lot of mammary tissue just in case.  Or at least we assume the cancer came back.  Based on my cat's medical history, the vet said that a biopsy was not really a needed expense.

She's now 16.  Is the cancer likely to come back?  Is it likely to take 4 years again, which could put her at a point where more surgery would be needless suffering?  I can't find anything about extended lifespans and extended periods between reoccurence when it comes to mammary cancer.

I don't have any answers to your question. I just wanted to say that I'm sorry you are going through this. I would think that the time frame would vary greatly from cat to cat since cancer has its own unique, devastating effects that really range.

I don't have answers either.  Just some thoughts.  

How is your kitty?  Does she act sick? Did she only have surgery or did they do chemo too?  From what I have read about breast cancer in cats, it is an 85% chance the tumor is malignant.  Maybe in your kitty, the cancer hadn't metastasized anywhere and the tumors they removed for the 1st time only had a small amount of cancer.  The 2nd time, the tumors may have been benign? That would be the only explanation I can think of.   As her age increases the ability to have surgery decreases because of the risk anesthesia poses on senior kitties.   

The only thing now is that she sleeps.  A lot.  And her grooming has gone somewhat downhill, we're dealing with mats.  But she still wanders around, moving from sleeping spot to sleeping spot, even the backs of chairs or the couch so she's jumping a little.  She never was a big jumper though.  She still demands attention on her terms, letting you know when you should be petting her and when you shouldn't be.  She can't jump onto the bed anymore, too high, we put up a stepstool to make it easier on her.  I think she has a touch of arthritis.  She's right there by her food bowl when she thinks someone might be getting out the cat food.  I feel her abdomen regularly, haven't found any more lumps.  The last one, when I found it, it was aggravating her so much she had started to chew at it, so chances are it wasn't benign according to the vet.  The vet did only surgery.  She was really surprised when the second lump occurred, she said that it was amazing it took so long to come back.