Page 108 - Withrow and MacEwen's Small Animal Clinical Oncology, 6th Edition

CHAPTER 4 Epidemiology and the Evidence-Based Medicine Approach 87

TABLE 4.4 Commonly Diagnosed Cancers and Suspected Risk Factors
Cancers Suspected Risk Factors
VetBooks.ir Common Canine Cancers

Obesity, increasing age, high dietary fat intake, late age at spay, and some breeds (e.g., English Springer spaniel, pointer,
Mammary carcinoma
poodle, Boston terrier, Dachshund, German shepherd, Chihuahua)
Osteosarcoma High weight, high height, increasing age, early castration/spay, some breeds (e.g., Irish wolfhound, Saint Bernard, Great
Dane, Rottweiler, Irish setter, Doberman Pinscher, golden retriever, Labrador retriever, Leonberger)
Transitional cell carcinoma of Being neutered, exposure to phenoxy-acid containing herbicides, frequent flea dipping, increasing age, some breeds (e.g.,
the urinary bladder Scottish terrier, Beagle, Shetland sheepdog, Wirehaired fox terrier, West Highland white terrier)
Mast cell tumors Some breeds (e.g., Boxer, Rhodesian ridgeback, Vizsla, Boston terrier, Weimaraner, Chinese Shar-Pei, Bullmastiff, Dutch
pug, Labrador retriever, American Staffordshire terrier, golden retriever, English setter, English pointer), increasing age
Lymphoma ETS, exposure to chemicals containing 2,4-dichlorophenoxyacetic acid, increasing age, some breeds (e.g., Bullmastiff,
Boxer, Scottish terrier, Gordon setter, Irish wolfhound, Basset hound, golden retriever)
Common Feline Cancers
Lymphoma FeLV, FIV, ETS increasing age
Sarcoma Vaccine injection
Cutaneous squamous cell Solar irradiation
carcinoma
ETS, Environmental tobacco smoke; FeLV, feline leukemia virus; FIV, feline immunodeficiency virus.

TABLE 4.5 Selected Observational Studies of Canine and Feline Cancers by Type of Exposure
Exposure Main Findings Strengths/Limitations
ETS
Reif, 1998 54 Positive trend for number of packs smoked by owner and increased risk of Strengths: Evaluation of nose size as an effect modifier with
canine nasal cancer among long-nosed (dolichocephalic) dogs. biologic plausibility; collected information on potential
confounders.
Limitations: Use of controls with cancer.
Reif, 1992 55 Statistically nonsignificant positive association for living with ≥1 versus no Strengths: High participation rates among cases and
smokers and canine lung cancer risk. Association was stronger among controls.
short-nosed dogs (brachycephalic or mesocephalic). Limitations: Use of controls with cancer; limited statistical
power.
Marconato, Any ETS exposure was positively associated with canine lymphoma, Strengths: Population-based study design.
2009 43 compared with no exposure. Limitations: Use of controls with cancer; limited ETS expo-
sure information was collected.
Bertone, 2002 56 Strong, statistically significant association for any household ETS exposure Strengths: Statistical power to evaluate trends; cases con-
and malignant lymphoma in cats. Statistically significant trend reported firmed by biopsy; respectable response rate among the
for a stronger association with increasing years of ETS exposure. cases and controls (>65%); use of a detailed question-
naire to assess ETS and other environmental exposures.
Limitations: No clear biologic mechanism for the observed
association.
Bertone, 2003 57 Clinic-based case-control study had ETS exposure positively associated Strengths: Cases confirmed by biopsy; good response
with feline oral SCC. Overall, results do not support a causal relationship rates; use of a detailed questionnaire (see previous
between ETS exposure and feline SCC. entry).
Limitations: Prevalence of ETS exposure was low; limiting
the statistical power to evaluate more than two levels of
exposure.
Continued