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.
Pneumonia is an infectious/inflammatory disorder of the lung parenchyma. Tiny bronchi fill the lungs; each one ends in smaller sacs known as alveoli which contain tiny blood vessels. Oxygen is added to the blood and carbon dioxide removed via the alveoli. Pneumonia causes these alveoli to fill with pus and fluids which affect the lung’s ability to exchange gases. There are several causes including infection (viral, fungal, bacterial, parasitic), aspiration of gastric contents or medications.
Allergy medicine wouldn’t help here, it may be a case that the beef tendon is causing pain or an obstruction for Kingston which may explain his posture of sitting and his increased respiratory rate. I would keep an eye on him, but if there is no improvement within a few hours I would recommend taking him into your Veterinarian for an examination; I wouldn’t induce vomiting since if there is an obstruction this may cause more pain and distress for him. Regards Dr Callum Turner DVM
Heavy rapid breathing in cats can be caused by stress and anxiety or can be linked to more serious cat diseases. If your cat cannot breathe properly, make sure to take it to the vet IMMEDIATELY as its life could be at risk. For more about rapid breathing in cats, labored breathing in cats or cat breathing difficulties, keep reading here at AnimalWised.
Big Cat Rescue is a 501(c)(3) nonprofit organization, FEID 59-3330495. Florida law requires that all charities soliciting donations disclose their registration number and the percentage of your donation that goes to the cause and the amount that goes to the solicitor. We do not utilize professional solicitors, so 0% of your donation goes to a professional solicitor, 100% goes to Big Cat Rescue. Non-program expenses are funded from tour income, so 100% of your donations go to supporting the cats and stopping the abuse. A COPY OF THE OFFICIAL REGISTRATION AND FINANCIAL INFORMATION FOR BIG CAT RESCUE, A FL-BASED NONPROFIT CORPORATION (REGISTRATION NO. CH 11409), MAY BE OBTAINED FROM THE DIVISION OF CONSUMER SERVICES BY CALLING TOLL-FREE 1-800-435-7352 WITHIN THE STATE OR BY VISITING www.800helpfla.com. REGISTRATION DOES NOT IMPLY ENDORSEMENT, APPROVAL, OR RECOMMENDATION BY THE STATE.  
This is a well-behaved cat that is easy to train. Or, rather, it easily trains its people. It enjoys a good game of fetch and will keep the game going longer than you may have time for, and you will make time because the Russian Blue is known for actually appearing hurt when it has been ignored. Elegant, and reserved, this cat is also very playful, and loves to chase after toys or sunbeams.
The Russian Blue made his first appearance on the world stage of the cat fancy at an exhibit of cats held at London’s Crystal Palace in 1875. Labeled an Archangel Cat, because he was said to be from the Russian island of Archangel, he competed against other blue cats of varying types. A newspaper report of the show described the Russian Blue as “very handsome” and “particularly furry,” adding “They resemble mostly the common wild grey rabbit.” Other early names by which the breed was known were Maltese and Foreign Blue.
The litter box should always be clean at all times and placed in an optimal location. Scoop out the waste daily and change the litter box twice a week or more if you have the time. Place the litter box in a low foot traffic area and not anywhere near where you feed him. If you’re not too fond on litter boxes you can train your Foreign Blue to use a spare toilet, which is as good as any litter box in the market.

Little is known about the origin of the Russian Blue breed, though stories are legendary. Many believe the Russian Blue is a natural breed originating from the Archangel Isles in northern Russia, where the long winters developed a cat with a dense, plush coat. Rumors also abound that the Russian Blue breed descended from the cats kept by the Russian Czars. Assuming the Russian Blue did migrate from northern Russia, it was likely via ship to England and northern Europe in the mid 1860s.
Smooth, medium wedge, neither long and tapering nor short and massive. Muzzle is blunt, and part of the total wedge, without exaggerated pinch or whisker break. Top of skull long and flat in profile, gently descending to slightly above the eyes, and continuing at a slight downward angle in a straight line to the tip of the nose. Medium in length. Length of top-head should be greater than length of nose. The face is broad across the eyes due to wide eyeset and thick fur. Muzzle smooth, flowing wedge without prominent whisker pads or whisker pinches. Neck long and slender, but appearing short due to thick fur and high placement of shoulder blades.
Big cats spawn on grass blocks at light levels of 9 or more in groups of up to 4. Some cats only spawn in certain biomes: leopards spawn in jungles, forests and forest variants; lions, panthers and tigers spawn in plains and forests; and snow leopards spawn in cold biomes. Lions and tigers also spawn more frequently than panthers. There is a 1/20 chance for a white lion, white lioness or white tiger to spawn.
Rapid breathing (tachypnea) is a respiratory disorder characterised by abnormal breathing that is rapid and shallow.  It is caused by a reduced level of oxygen, mechanical disorders (where the lungs aren’t able to expand as they should, usually due to a build-up of fluid in or around the lungs), and physiological disorders in which the cat’s respiratory centre in the brain is over stimulated.