Feline Sarcoma Appears Suddenly
The most common site for the tumor to be located is between the shoulder blades. The tumor appears quickly, almost overnight. If you feel a large growth, take your cat to the vet for a biopsy, as this is a sign that the cancer is in the early stages.
Vaccine Benefits Far Exceed Slim Chance of Bad Reaction
Vaccine-associated feline sarcomas are far more rare than the diseases your cat's vaccine protects them from. Though you should consider vaccine sites carefully later in life to determine if your cat has developed any tumors, it's important not to abstain from any vaccines, as they can protect your pet's life, as well as your own as a result of the rabies vaccine.
Erring on the side of safety, discuss your vaccination options with your vet. Vaccinate only for the diseases that your pet could come into contact with in order to avoid unnecessary vaccinations.