Cancer Care in Pets(Veterinary Oncology)

Orna Kristal, DVMDip. American College of Vet Internal Medicine

(oncology)Chavat Daat, Beit Berl

Veterinary Specialty Training Requirements: DVM degree and internship Began in the US Today in Europe as well 3 yrs of working under supervision of

specialists in different fields Tumor biology studies Publication, presentations Specialty examination

Specialty in Veterinary Medicine

Large Animals (horses, ruminants) Internal medicine, Surgery, reproduction

Small Animals Internal Medicine, oncology, cardiology,

neurology Surgery Imaging Emergency medicine Ophthalmology, Dermatology, anesthesia Exotic animals (birds, reptiles, ferrets,

rodents) Pathology – clinical and histopathology

Cancer in dogs and cats No accurate incidence rates (IR) Dorn et al. 1968 – new cancer cases a

yr in 2 counties in CA Dogs – 382/100,000 Cats – 156/100,000 IR today probably much higher

Estimated lifetime risk of cancer Dogs – 50% Cats – 30%

Comparative aspects

Humans Dogs CatsBreast/prostate

Breast* Lymphoid

Lung Skin (non-melanoma)

Skin (non-melanoma)

Colorectal Sarcoma Breast*

Testicular (intact)

Sarcoma

Lymphoid, oral tumors

Genetic factors Golden Retriever

1 in 5 – Hemangiosarcoma 1 in 8 - Lymphoma

Boxer Lymphoma (T-cell)

Bernese Mountain Dogs Histiocytic Sarcoma

Scottish Terriers Transitional Cell Carcinoma

Sharpei High grade Mast Cell Tumors

Hormonal factors

Ovariohysterectomy Before 2.5 yrs of age in dogs and 1 yr

in cats is protective of mammary tumors

Castration Reduces risk of testicular cancer

Esp. in cryptorchids Increases risk of prostate cancer (still

uncommon)

Environmental factors - Dogs Exposure may be higher in indoor pets Exposure to passive smoke

risk for lung cancer – short and medium length nose (weak)

risk for nasal cancer – long-nosed breeds

Insecticides in shampoos or dips risk of TCC, esp. if obese But not spot-ons like Frontline or Advantage

Herbicides and insecticides on lawns risk of TCC in Scottish terriers

Environmental factors - Cats

Oral Squamous Cell CA (SCC) risk with:

High intake of canned food (RR – 3.6) and canned tuna fish (RR – 4.7)

Flea collar use (RR – 5.3) risk with flea shampoo use

Lymphoma risk with exposure to passive smoking

Why treat pets with cancer? Cancer is perceived by many to be a serious

and often fatal disease Treatment in people is commonly associated

with side effects leading to poor QOL Therefore treating pets with similar treatment is

perceived as cruel and selfish This perception represents total

misunderstanding of the treatment of cancer in animals

The main goal of treating animals with cancer is to extend a good quality of life for the patient (and family) for as long as possible.

What is QOL in animals? Life without pain & daily normal

activity Happy when owners come home, plays Wants to eat and drink Has control of eliminations

Quality is more important than quantity Life without QOL means prolonging

unnecessary suffering of the animal

How do we maintain QOL? We try to prevent treatment’s side

effects

Before treatment is begun risk vs. benefit is considered

Often animals treated for cancer live longer and better than animals treated for other chronic disease (i.e - diabetes, chronic renal or heart disease)

Maintaining QOL If the animal develops significant

treatment toxicity We can lower drug dosages Use other drugs Consider stopping treatment

Treatment can be with a curative intent or palliative

Know when to quit

Treatment modalities

Treatment options depend on Tumor type Location in body Tumor stage (TNM) Comorbidities

Treatment modalities Surgery Radiation therapy (not in Israel) Chemotherapy Small molecule

inhibitors (TKI’s) Cancer Vaccines

Melanoma Multimodality Tx Symptomatic Tx

Choosing the treatment Owners ultimately choose the

treatment after hearing Different options Prognosis for each option Possible side effects Cost

Should they choose not to treat, they are making an educated decision

Common signs of cancer in small animals

Abnormal swellings that persist or continue to grow

Sores that do not heal Weight loss Loss of appetite Bleeding or discharge from an opening

סימנים שכיחים של סרטן בחיות קטנות

Offensive odor Loss of energy, tire easily Persistent lameness Difficulty breathing, chewing, urinating,

defecating

Aural SCC

Baaci 7 yr old spayed female Golden Retriever

Baaci Presented with enlarged lymph nodes, fever,

unwell and diagnosed with lymphoma on cytology

Baaci With no treatment median survival is 4-6

weeks and QOL is poor most of this time. With CHOP based chemotherapy median

survival is extended to 12 months and about 25% are alive @ 2 yrs.

Drug dosages is lower than in humans. Only 20% develop grade 3-4 toxicity.

Baaci’s owner chose to treat with chemo.

Baaci

Achieved complete remission

Treatment continued for one yr

One episode of vomiting & diarrhea

requiring supportive care.

Still alive and happy today > 4 yrs from

diagnosis.

Chaos

4 yr old female Great Dane Diagnosed with osteosarcoma

(OSA)

Osteosarcoma Many similarities to human OSA

Affects large to giant breed dogs Metaphyses of long bones most affected Most stage negative at presentation 90% are high grade Common hematogenous lung metastases

Two main differences 10 times more prevalent in dogs Mean age

Dog – 7rs human – 14 yrs

Osteosarcoma Dogs

Are an outbred species Have innate immune system Their cancer progresses more rapidly

Combined with similarities in tumor behavior they can serve as an excellent model for research of this disease

Dr. Steve Withrow - pioneer in the field Clinical trials in dogs serve a dual

purpose

Chaos

Had forequarter amputation To control primary tumor and relieve pain

Post-operatively entered into a clinical trial 5 treatments with doxorubicin Followed by the oral trial drug vs. placebo

No side effects at all

Enjoyed an excellent QOL for 18 months after treatment

Median survival with amputation and chemo is 10 months

Slim, 7 yr old male Whippet Presented with unilateral nose bleed

from the left nostril (Sept 2008) CT and biopsy – left nasal

adenocarcinoma

Slim Treated with Radiation

12 X 4 Gy, 3 days a week Tumor shrunk by 30%, was stable for 2 yrs

then started growing very slowly Receives low dose prednisone permanently for

nasal congestion

Canine Mast Cell Tumors Common skin cancer Can be benign to malignant May swell up and shrink due to surges

of histamine release

Mast cell tumors Fairly easy to diagnose by cytology Biologic behavior highly correlated with

histologic grade Treatment depends on tumor grade and

stage

Targeted therapy for canine MCTTargeted therapy for canine MCT

Toceranib Phosphate(Palladia™)

KITPDGFRβVEGFR2Flt3

Masitinib Mesylate(Masivet®)

KITPDGFRFGFR3FAK (focal adhesion kinase)

33% of MCT express mutation in c-kit

In summary The main goal in treating animals with

cancer is good QOL for as long as possible

Every case should be evaluated individually

Owners should be given all options

The decision is theirs to make after weighing risk vs. benefit and cost