Pain management for cats and dogs diagnosed with cancer.

CANCER SUPPORTIVE CARE

Not all cancers will cause pain to your pet and the amount of pain will likely vary from one animal to another, even for
similar types of tumors. Human studies indicate that 20-50% of human patients experience pain upon cancer diagnosis and
up to 90% of human patients experience pain with advanced or terminal cancer. Unfortunately, cancer associated pain has
been largely overlooked by veterinary medicine but it is predicted that pets will experience cancer pain similar to their
human counterparts. In addition to pain caused by the actual tumors, pets will also experience pain associated with
treatment such as surgery, radiation therapy or chemotherapy. Untreated pain decreases quality of life in all patients, and
prolongs recovery from the illness, treatment or injury. It is, therefore, essential that veterinary teams taking care of pets
with cancer should also play a vital role in educating pet owners about recognizing and managing pain in their pets.

It is of extreme importance to make your pet's life as comfortable and painless as possible and to discuss
appropriate cancer pain management for your pet's unique condition with your veterinarian/oncologist.
Veterinarians are ethically obligated to recognize, assess, prevent and provide pain relief to all pets under
their care.

While no formal clinical studies have been conducted to evaluate the effect of specific cancers on pain, the following
tumors are most likely to cause pain.

Bone tumors
Central nervous system tumors (e.g. brain tumors)
Gastrointestinal (e.g. esophagus, stomach, colon, rectum tumors)
Inflammatory breast tumors
Genitourinary tract tumors (e.g. kidney, bladder tumors)
Prostate tumors
Oral cavity tumors
Intranasal tumors
Invasive skin tumors

Assessment of cancer pain
Because many animals may not show obvious signs of pain and also tend to hide pain as a protective mechanism,
identifying the degree of pain and the amount of suffering can be very difficult. The most likely indicators of pain are
changes in the pet's behavior, summarized below. The pet owners spend the most time with the pets and are, therefore,
the only ones who can pick up even on the slightest changes in their pet's behavior. The pet owners should bring up pain
management during veterinary visits and should ensure that their veterinarian is fulfilling his/her ethical obligation if the pet
appears to be in pain. However, even if such indicators are absent and it is known that the same type of tumor causes pain
in humans, the pets should be given the benefit of a doubt and be treated for pain as well.

Likely indicators of pain in cats and dogs

Changes in normal activity level/behavior (e.g. the pet does not play as much, does not want to go for walks as

often, avoids social interaction, hides and/or shows overall decrease in energy)

Reluctance to move (e.g. the pet is sitting or lying for prolonged periods of time, shows lameness)
Changes in appetite (e.g. the pet does not want to eat or eats substantially less)
Changes in attitude (e.g. the pet becomes more shy, dull, aggressive or growls when being touched)
Facial expression (e.g. the pet's head hangs low, sad expression, squinted eyes)
Reaction to touch (e.g. the pet cries, growls, bites, or attempts to run away when touched in an affected area)
Respiration (e.g. increased breathing)
Licking/scratching (e.g. the pet may constantly lick/scratch a specific area)
Vocalization (e.g. while rare, the pet may whine, grunt, meow, hiss)
Urinary and bowel elimination (e.g. the pets urinate and defecate in inappropriate areas)

Types of pain
Pain is divided into acute and chronic forms, each requiring its own treatment. Acute pain is generally short-lived, lasting
hours to days. Acute pain is usually a result of trauma, treatment therapies (e.g. surgery, radiation therapy), or some
underlying disease. In contrast, chronic pain persists over longer periods of time, lasting weeks or longer. It continues
beyond the expected period of healing and can be more difficult to detect compared to acute pain.

Cancer pain management
Pain management will depend on the type of pain, the species, individual pain tolerance, and the overall health status of
the pet. The best way to manage cancer pain in pets is to prevent it, a term referred to as preemptive pain management.
This strategy anticipates pain ahead of time and administers pain medication before the pet actually experiences pain,
thus ensuring the pet's maximum comfort. Sometimes the veterinarian will have to combine multiple pain therapies in order
to successfully control the pain, a term referred to as multimodal therapy. Cancer pain management is based on the
following classes of analgesics (pain killers):

Nonopioid analgesics (e.g. nonsteroidal antiinflammatory drugs)
Steroids (dexamethasone, prednisone)
Weak opioid drugs (e.g. codeine)
Strong opioid drugs (e.g. morphine)

Depending on your pet's condition, the stage of the disease, and perceived discomfort, the veterinarian will prescribe
appropriate pain relief medication(s) and doses. Pain medications vary in their strength and duration of providing pain
relief, and as the level of pain increases with progression of disease, more powerful and quick acting drugs should be
administered on a regular basis rather than on as-needed basis to maintain the pet's comfort.

To help Pet Cancer Center conduct more clinical trials across the United States in order to make more efficacious cancer
therapies along with novel pain medications available to pets, please

Additional pain management strategies
In addition to administering pain relieving medication, pain management plan should also include other strategies. Some
commonly used strategies include:

General nursing care
Comfortable bedding
Massages and physical therapy
Acupuncture
Proper nutrition and dietary supplements

Your veterinarian/oncologist should work closely with you to develop an individualized pain management plan that is best
for your animal's needs and should routinely follow up on the safety and effectiveness of that plan to ensure that your pet
is free of pain and discomfort.

Useful online resources about pain management in pets