Chemotherapy FAQ
Chemotherapy FAQ
The word chemotherapy conjures images of people losing their hair and suffering chronic nausea. It is unfortunate that many pets (and probably people, too) do not receive chemotherapy based upon these unpleasant images that do not truly represent the current state of treatment response at least in pets. Chemotherapy simply means therapy using medication (as opposed to surgery or radiation). Decades of research has gone into patient comfort, minimizing side effects and maximizing response so it is important to keep an open mind. The following are common questions pet owners commonly have regarding chemotherapy for their dog.
The median survival time for most dogs on chemotherapy is approximately one year with 25% of dogs surviving two years. 
My dog is not acting sick in any way. Shouldn't I wait until she at least feels sick before beginning chemotherapy?
This might seem like a reasonable approach at first glance but let us assure you that it is not. One of the most important factors in determining the quality of remission (i.e., how fast we get remission and how long it lasts) is whether or not the patient is feeling sick at the time chemotherapy is started. When lymphoma patients are staged (see above under "does my pet need further tests?"), stages are subcategorized as a or b, depending on whether or not the patient is feeling ill or not. (For example, a multicentric lymphoma dog who feels well is in stage IIIa compared to a multicentric lymphoma dog who is vomiting or not eating is in stage IIIb). You will have a much better chance for long-term quality survival if lymphoma is treated while the patient is an a.
Should we see an oncologist?
Lymphoma is an area of veterinary medicine that not all veterinarians are comfortable performing. Discuss with your veterinarian whether referral to a specialist would be best for you and your pet.
Will chemotherapy make my dog sick?
Probably not. Nausea and infection are possibilities but most dogs do not experience any such complications. Only 7% of patients require hospitalization due to side effects of chemotherapy. The bottom line here is to know that animals rarely get sick from chemotherapy but that you should know what to do in case of a problem (see later).
Will chemotherapy make my dog lose his hair or go bald?
While whiskers are commonly lost, substantial hair loss is not experienced by most dogs or cats on chemotherapy for cancer. There are some notable exceptions: breeds that have synchronous hair follicle activity. Most breeds have hairs in all different stages of the growth-shed cycle at the same time. A few breeds have all hairs in the same stage of growth-shed at the same time. These are the breeds that can have a baldness issue: the Old English Sheepdog, the poodle, the Lhasa apso, the Shih Tzu.
How will I know when we have achieved remission?
A patient in remission is indistinguishable from a completely cancer-free patient. The lymph nodes will go down to normal size and if there were any signs of illness related to the cancer, these should resolve. There is approximately a 75% chance of achieving remission regardless of protocol selected.
How will I know when we have lost remission?
The most obvious sign will be that the lymph node enlargement has returned. This means that the cancer is now resistant to the drugs being used and new drugs must be chosen. (This is called a rescue.)
How long will my dog have quality life on chemotherapy?
This depends on what protocol you choose, and there are many. There are also many factors that influence how an individual will do relative to the average response. Important parameters to note when reviewing a protocol are:
- the disease-free interval (i.e., how long the patient is free from illness)
- survival time
- typical duration of remission
- expense
- scheduling.
*From the Pet Health Library, June 2011
