This breathing may be normal for Gracie, or may be a sign of distress and not being able to get oxygen the way that she needs to. Since I cannot assess her or her respiratory system, it would be best to have her examined by a veterinarian. They'll be able to look at her, listen to her heart and lungs, and assess her general health to see if she is having any breathing issues that need attention.
Without knowing more about Cindy, the type of cancer and location, and her history, it isn't possible for me to comment on what might be happening to her now. It would be best to call your veterinarian, as they have seen her and know her history, and let them know what is going on. They'll be able to guide you in any possible treatments for her. I hope that she is okay.
My fiance said the he saw her eat this afternoon, so that is a relief. Her gums are pink (that's one of the first things I looked at on her and I should've told you that...but... this is my BABY CAT and she has me a little panicked!.. not like dealing with humans on the ambulance... she's innocent!) I do have access to oxygen... so we can make her an oxygen tent if it's necessary. Right now, she is getting up every couple of minutes and repositioning or pacing.. her respiration rate is around 50 right now... her belly almost looks like it's spasming and her heart rate is running between 80 and 90 everytime we take it... which is low... what do you suggest??????