The long answer is:
If a pet has a type of cancer that arises from the immune system I recommend that vaccinations be limited as stimulating the immune system MAY cause the cancer to progress or potentially come out of remission. Examples of a few common cancers that arise from the immune system include: Lymphoma, Mast cell tumors, and Plasma cell tumors. Many other types of cancer do not arise from the immune system and so there is less concern for the above.
Now, this in no way means that every pet with cancer should be exempt from vaccinations. Vaccinations are very important and serve to benefit your pet by protecting them from numerous infectious diseases (some of which have very serious consequences even including death, such as with the Rabies virus).
The best approach to determine which vaccines your pet with cancer should receive is to partner with your pet's general health care veterinarian and with us at the VCC. Instead of a blanket recommendation for every pet I emphasize the importance of looking at a pet's individual risk and benefit profile regarding each vaccination. Here is an example to help clarify: a pet that lives in an area that has a high prevalence of Lyme disease and who hunts all day in the woods would benefit from the Lyme vaccine due to that pet's personal high risk of contracting Lyme disease. In contrast, for a pet with an immune system cancer living in a geographic area that sees very little Lyme disease I would not recommend this vaccine as the risk of the vaccine would outweigh the benefit in this pet.
A titer can also be run on some vaccinations. A titer is a blood test that is used to determine if the immunity imparted from a particular vaccine is still high in your pet. If a titer is run and it shows that a pet still has strong immunity to a particular disease it may not be necessary to re-vaccinate for that disease. An example of a vaccine for which a titer can be performed is the distemper vaccine.
There are also some legal implications to consider when deciding whether to vaccinate a pet with cancer. Certain vaccines are mandated by state law for the protection of the individual pet as well as the protection of other animals and of people. The best example of this is the Rabies vaccine which is required by state law in CT. In some cases an exemption letter can be written to allow an individual pet exemption from the vaccine, however, this decision needs to be made very cautiously.
So unfortunately there is no short and easy answer to the question put forth above. It is imperative that you partner with your pet’s general health care veterinarian and with us at the VCC to make the best decisions for your individual pet based on his or her risk/benefit profile. Utilizing a team approach with input from your pet’s general health care veterinarian, your pet’s oncologist, and you (the pet’s parent) will allow for development of the optimal vaccination plan for your pet.