Small Animal Oncology

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Small Animal Oncology

• Vance Kawakami
• Kristin Kender

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Cancer Statistics

• Cancer is the major cause of death in pets
  greater than 10 years old
• 45 of all dogs older than 10 years of age die of
  cancer
• 23 of all dogs die of cancer

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Feline Cancer Facts

• Lymphoma is the most frequently diagnosed tumor
  in cats
• Spaying female cats decreases the incidence of
  lymphoma by 40-50

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Canine Cancer Facts

• Skin cancers are the most frequently diagnosed
  tumors of dogs.
• Mastocytomas account for 23
• Mammary tumors are the most common tumors in
  female dogs.
• Spaying a dog prior to her first heat cycle will
  decrease the risk of developing mammary cancer by
  7-fold.

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Contributors to an IncreasingIncidence of Cancer

• Larger population of geriatric pets
• Advances in health care
• An improved recognition and diagnosis of cancer
• Increased willingness of both veterinarian and
  owner to treat cancer
• Environmental changes

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What is cancer?

• Cancer is a group of neoplastic diseases in which
  there is a transformation of normal body cells
  into malignant ones.

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PTH 551
Thank you Dr. Patterson!
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AVMAs Signs of Cancer

• Abnormal swelling that persists or cont. to grow
• Sores that do not heal
• Unexplained weight loss
• Loss of appetite
• Bleeding or discharge from any body opening
• Bad odor, especially from the mouth
• Difficulty eating or swallowing
• Reluctance to exercise or loss of stamina
• Difficulty breathing, urinating, defecating
• Change in behavior

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Diagnostic Tests and Procedures

• CBC
• Serum chemistry profile
• Urinalysis
• Radiographs
• CAT scan
• MRI
• Ultrasonography
• Biopsy
• Tumor staging

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Biopsy

• Excisional
• Complete removal of the tumor
• Feasible if mass is moveable
• Lymph nodes, small cutaneous nodules, mammary
  gland and CNS tumors, and tumors found during
  exploratory surgeries

• Nonexcisional
• Removal of only a portion of the tumor
• Cytology from a fine-needle aspirate, brush
  samples, or impression smears or effusions
• Histopathology of cutting forcep biopsies,
  cutting needle biopsies, punch biopsies, and
  incisional biopsies

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Tumor-Node-Metastasis System

• T primary tumor size or extent
• Tis preinvasive tumor (in situ)
• T0 no evidence of tumor
• T1 tumor primary site
• T2 tumor 5 cm in diameter or ruptured tumor
• T3 infiltrative tumor
• a no bone invasion
• b bone invasion
• N nodes
• N0 no evidence of lymph node enlargement
• N1 moveable ipsilateral nodes enlarged
• N2 moveable contralateral/bilateral nodes
  enlarged
• N3 fixed nodes
• M metastasis
• M0 no metastasis
• M1 metastasis detected

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Curative vs. Palliative Treatment

• Curative
• The likelihood that a given tumor type will be
  controlled for at least one year following
  treatment.

• Palliative
• Designed to reduce pain or functional
  difficulties such as swallowing, urinating, etc.
  without attempting to cure the tumor

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Methods of Treatment

• Surgery
• Radiation therapy
• Chemotherapy
• Hyperthermia
• Photodynamic therapy
• Others
• Gene therapy
• Anti-angiogenic drugs
• Immunotherapy
• Alternative therapies

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Surgery
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Surgery-Indications

• Mammary tumors (except inflammatory mammary
  cancer)
• Prostate tumors
• Oropharyngeal tumors
• Skin cancers
• GI tumors
• Lung tumors
• Bone tumors

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Surgery-Limitations and Complications

• Risks increase with age of patient
• Most mortalities resulting from surgery are
  associated with
• pulmonary emboli
• Pneumonia
• cardiovascular collapse
• primary disease
• Other complications include
• Abscesses
• wound infections
• blood loss
• incomplete wound healing

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Radiation
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Radiation-Indications

• Brain tumors
• Curative small pituitary tumors
• Longer survival time intracranial tumors and
  spinal lymphomas
• Tumors of the nasal cavity
• Thyroid tumors
• Soft tissue sarcomas
• Mast cell tumors

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Radiation-Limitations and Complications

• Survival of cancer cells at the center of larger
  tumors
• Local effects to skin, lining of GI tract, and
  hair
• Long term effects
• Necrosis
• Non-healing ulcerations
• Organ dysfunction
• blindness

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Radiation Surgery

• Used prior to surgery to shrink tumor size
• Used following surgery to destroy remaining
  cancer cells that were left behind
• Limitations
• Radiation must be postponed until surgical
  incision has completely healed
• Cancer cells in the area of scar tissue are often
  more resistant to radiation

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Chemotherapy
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Chemotherapy-Indications

• As sole agent
• Systemic cancers
• hematologic malignancies
• metastatic carcinomas
• Metastatic sarcomas

• As adjunct therapy
• Given to patients with no overt evidence of
  residual cancer following surgery or radiation

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Chemotherapy-Limitations and Complications

• Toxicities are particularly against cells of the
  bone marrow, GI lining, and hair follicles and
  can result in
• Immunosuppression
• Anemia
• Nausea and vomitting
• Delayed wound healing
• Hair loss

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Chemotherapy as anAdjunctive Therapy

• Chemotherapy Radiation
• Certain drugs are radiosensitizers
• This increases the efficacy of the radiation
• Help slow down metastatic growth

• Chemotherapy Surgery
• Shrink large tumors prior to surgery
• Help eradicate microscopic cancer cells which
  remain after surgery
• Help slow down metastatic growth

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Hyperthermia
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Hyperthermia-Indications

• Most effective in the treatment of localized
  tumors in combination with radiation or
  chemotherapy
• Used to treat small (and malignant superficial tumors

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Hyperthermia-Limitations and Complications

• Equally damaging to both cancer and normal cells
• Frequency of skin burns and infarcts can be as
  high as 45

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Hyperthermia as anAdjunctive Therapy

• Hyperthermia Radiation
• In humans, combining these two therapies to treat
  cancer was found to double the number of complete
  responses
• In dogs, this combination improved the rate of
  complete response in primary tumors resulting in
  prolonged survival time
• However, many dogs later succumb to metastatic
  disease

• Hyperthermia Chemo.
• Some drugs work more efficiently above normal
  body temperatures
• Hyperthermia may offer a protective effect for
  normal tissues against drug toxicities
• Some studies have shown that combining these
  therapies actually increases toxicity

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Photodynamic Therapy (PDT)
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PDT-Indications

• Has been used limitedly in veterinary medicine
• Used in dogs with localized, superficial, and
  minimally invasive tumors such as those affecting
  skin and linings of urinary bladder and oral
  cavity

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Photodynamic Therapy-Limitations and
Complications

• Inability of light to penetrate deeply into tumor
  tissue
• Tissue retention time of photosensitizers
• Patient must remain in subdued light for 4-6
  weeks
• Not all tumors absorb photosensitizers at same
  rate and at same concentration

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Other Treatment Options

• Gene therapy
• Anti-angiogenic drugs
• Immunotherapy
• Alternative therapies
• Acupuncture
• Massage
• Herbal and botanical medicine

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Gene Therapy

• Suicide gene therapy
• Genetic immunotherapy
• Tumor suppressor gene therapy
• Drug resistance gene therapy

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Anti-Angiogenic Drugs

• Inhibit tumor growth by cutting off tumors blood
  supply
• Many of these drugs are in the early stages of
  clinical development in the treatment of both
  human and canine cancer

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Immunotherapy

• Biologic Reponse Modifiers
• Nonspecific immunomodulators
• Lymphokines/monokines
• Adoptive cellular therapy
• Antibody therapy
• Growth factors
• Indications
• Lymphoma
• Melanoma
• Mastocytoma
• Oteosarcoma
• Soft tissue sarcomas, including fibrosarcoma and
  hemangiosarcoma

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Alternative Therapies

• Acupuncture
• Palliative treatment
• Pain
• Post-op chemo-induced nausea and vomiting
• Massage
• May be contraindicated
• Herbal and Botanical Medicine
• Herbs are used in conjunction with chemotherapy
  or radiation to help strengthen the individual
  and mitigate side effects

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Nutritional Management

• Often ignored aspect of cancer treatment
• Important in treating cancer cachexia
• May control growth of certain tumors
• Decrease side effects of cancer treatments

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Assessment of Nutrition status

• Animals with cancer have alterations in
  metabolism which results in clinical alterations
• This occurs early in all cancers and decreases
  quality and quantity of life
• Broken in four phases

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Phase 1

• Clinical changes
• Preclinical, silent phase, no obvious signs.

• Metabolic changes
• Hyperlactermia
• Hyperinsulinemia
• Altered blood amino profiles

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Phase 2

• Clinical changes
• Early clinical signs
• Anorexia, Lethargy
• Mild weight loss
• More susceptible to side effects from
  chemotherapy, sx, etc..

• Metabolic changes
• Similar metabolic changes

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Phase 3 (cancer cachexia)

• Clinical changes
• Cachexia
• Anorexia
• Lethargy
• More susceptible to side effects from
  chemotherapy, sx, etc..

• Metabolic changes
• Similar changes but more profound

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Phase 4 (recovery or remission)

• Clinical changes
• Recovery, Remission

• Metabolic changes
• Metabolic changes may persist
• Changes secondary to surgery, chemotherapy, or
  radiation therapy

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Nutritional management

• Specific nutritional requirements of animals with
  cancer is unknown
• Nutrients in order of importance
• water
• calories and protein
• minerals and vitamins

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Cancers effect on metabolism

• Carbohydrate metabolism
• Tumors preferentially metabolize glucose for
  energy by anaerobic glycolysis forming lactate
• buildup of lactate results in net energy loss by
  the body and net gain by the tumor (uses ATP to
  convert lactate to glucose)

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Cancers effect on metabolism

• Protein metabolism
• Good source of energy for tumor
• Can result in clinically significant deficiency
  in AA
• decreased immune function
• surgery healing
• decreased GI function
  

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Cancers effect on metabolism

• Benefits of certain AA
• Arginine- decrease tumor growth and metastatic
  rate in some rodents
• Glycine-shown to decrease cisplatin induced
  nephrotoxicity
• others as well

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Cancers effect on metabolism

• Lipid metabolism
• Some tumors cells have problems utilizing lipids
  as fuel source
• fats are usually last to be depleted
• type of lipid verses amount of lipid
• polyunsaturated n-3 fatty acids

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Other important aspects of nutrients

• Vitamins- some evidence indicate might be helpful
  in cancer patients
• Retinoids, beta carotene, Vitamin C, D, and E
• Minerals- May be helpful
• Zinc, Cu, Se, etc

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Other ingredients

• Fiber- insoluble and soluble
• Garlic- may help cancer patients
• Green/Black tea- Black tea may have soothing
  properties associated with radiation-induced oral
  mucositis.
• Shark cartilage-NO

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Food Aversion

• Food aversion- a common outcome of side effects
  of cancer and cancer treatments in humans
• Difficult to prove it occurs in animals

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Therefore..Develop a feeding plan

• What food to feed?
• How to feed the food?
• Monitor and reassess feeding plan constantly (Is
  the patient getting better)?

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What food to feed?

• Ideal diet would have
• minimal simple carbohydrates, fiber
• highly bioavailable protein with certain AA
• higher fat levels with polyunsaturated n-3 fatty
  acids
• adequate levels of antioxidants
• a great smell and taste great!
• Achieve with homemade diets or various commercial
  diets

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Key na Information is not published by the
manufacturer. Nutrients are expressed on dry
matter basis. Values were obtained from
manufacturers' published information.
Table 25-5. Nutrient profiles of selected
commercial pet foods that can be used in cancer
patients.
Canine products Hill's Prescription Diet
Canine/Feline a/d, moist Hill's Prescription Diet
Canine n/d, moist Hill's Science Diet Feline
Maintenance Seafood Recipe lams Eukanuba
Maximum-Calorie/Canine, dry lams Eukanuba
Maximum-Calorie/Feline, dry lams Eukanuba
Maximum-Calorie/Canine Feline, moist Purina
Feline CV-Formula, moist
Products
Protein Fat
Carbohydrate n-3 fatty Arginine
45.7 38.8 45.1 40.1 44.2 43.3
28.7 32.0 25.4 29.0 29.6 41.1
16.5 20.0 20.1 22.7 19.1 7.6
2.6 7.2 0.82 0.9 0.93 0.78
2.04 2.9 2.83 na na 2.6
42.5
26.8
23.1
na
na
Feline products Hill's Prescription Diet
Canine/Feline a/d, moist Hill's Prescription Diet
Feline p/d, moist lams Eukanuba Maxim
um-Calorie/Feline, dry lams Eukanuba
Maximum-Calorie/Canine Feline, moist Purina
Feline CV-Formula, moist Select Care Feline
Development Formula, moist
45.7 48.8 44,2 43.3
28.7 31.5 29.6 41.1
16.5 11.1 19.1 7.6
2.6 0.42 0.93 0.78
2.04 2.66 na 2.6
26.8 32.2
23.1 12.1
na na
na na
42.5 48.0
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Feeding method

• Enhance palatability and aroma of the food
• whatever works
• Drug therapy- stimulate appetite
• Benzodiazepine derivatives (valium, oxazeoam)
• cyproheptadine
• Megestrol acetate

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Feeding method

• Enteral route- preferred route of nutritional
  support vs. parental administration
• safer
• less expensive
• other physiologically beneficial effects

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Enteral route

• Appropriate when
• Appetite stimulating efforts fail or if long term
  nutritional support (more than a few days) is
  needed
• Can be used proactively
• inserted during surgery
• or before radiation therapy

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Feeding method

• Parental nutrition- not covered here
• best reserved for cases in which patients are not
  able to assimilate nutrients or with intractable
  vomiting

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Monitor feeding plan

• Monitor the effects of
• Cancer on patient
• Treatment and nutritional management of tumor
• Treatment and nutritional support on the patient
• --Check body weight, and body conditioning scores
  with previous assessments
• --Assess appetite and caloric intake

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Quality of Life and Cancer

• How do you measure quality of life?
• As defined by the Veterinary oncologist at
  Animal Medical Center- five factors
• alertness/mental status
• appetite
• weight/body condition
• activity/exercise tolerance
• elimination

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Measuring QOL cont..

• Is the patient enjoying painless and carefree
  days?
• Playing with his/her favorite toys or eating
  their favorite foods?
• Add your own measurement here

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Euthanasia

• Should be discussed constantly with client
• Educate client on options
• Final human treatment

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References

• Ettinger, Stephen, and Edward Feldman. Textbook
  of Veterinary Internal Medicine. 5th edition.
  Vol. 1. Philadelphia W.B. Saunders Company,
  2000.
• Nelson, Richard, and C. Guillermo Couto. Small
  Animal Internal Medicine. 2nd edition.
  Chicago Mosby, 1998.
• Ogilvie, Gregory, and Antony Moore. Managing the
  Veterinary Cancer Patient. Trenton, NJ
  Veterinary Learning Systems, Co., Inc., 1995.
• Schwartz, Cheryl. Four Paws, Five Directions A
  Guide to Chinese Medicine for Cats and Dogs.
  Berkley, CA Celestial Arts, 1996.
• Withow, Stephen, and E. Gregory MacEwen.
  Clincial Veterinary Oncology. Philadelphia
  J.B. Lippincott Company, 1989.

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Web Sites

• Comparative Oncology Research Exchange (CORE) at
  Cornell University
• http//www.web.vet.cornell.edu/index5Finternet/ca
  ncer/index.html
• The Animal Medical Center
• http//www.amcny.org
• OncoLink at University of Pennsylvania Cancer
  Center
• http//www.oncolink.com
• Wing-n-Wave Labradors
• http//www.labbies.com/cancer3.htmsurgery
• Canine and Feline Cancer Links
• http//www.thensome.com/petcancer.htmlinks

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Thank You!
Any Questions?