21 year old cat with cancer

Hi,
I am looking for support and any advice or kind words regarding my situation.
My cat is 21 years of age and over the past week I took her to the vet to see
what was going on with her. Turns out she has a mass in her stomach area and
it's to the point where it's pushing on her intestines. This slows the
ability of the stomach to release its contents into the intestines. The vet
suggested we just wait for the blockage to get worse and forget about trying
to treat her because of her age and other health issues. I would have to
agree with her but she has been in the family so long and I feel like I
should make every attempt at remedy. One remedy was to start her on anti-
biotics and other medicine. She wasn't handling it well. I'm wondering if
surgery to remove the mass is futile. Or perhaps some procedure to allow for
better flow from the stomach to the intestines. Perhaps I am trying to be in
denial. Thanks for your messages in advance. Bill