I so sorry to hear your sad news

Did your vet tell you what sort of cancer it is?
When it comes to cancer and animals, it all comes down to quality of life and you should really have a long discussion on where to go from here.
My Ena had a tumour removed earlier in the year that sadly confirmed that she had lymphoma

At the time, my vet didn't feel a need for her to be pts as she was still eating drinking and living a normal life. We were advised to take a few days out to let the news sink in.
Sadly we didn't get that far as on the same day we found out, Ena pulled her stitches out and it was revealed that due to the lymphoma, the wound wasn't able to heal so we made the decision to let her go.
But if your piggy is happy in themselves, I would have a chat with your vet about pain relief and palative care etc and enjoy what time you have left together.
But if your piggy is showing signs of discomfort, pain and not living a happy life, may be the time to say goodbye will come sooner rather than later but I really do think you need to have a good and honest chat with your vet x