Page 104 - Withrow and MacEwen's Small Animal Clinical Oncology, 6th Edition

CHAPTER 4 Epidemiology and the Evidence-Based Medicine Approach 83

TABLE 4.2 Characteristics of Population-Based Companion Animal Cancer Registries and Cancer Incidence
Registry Period Cases/Population at Risk Incidence/Prevalence
VetBooks.ir California Animal Neoplasm Registry (CANR) 8,9 1963–1966 1624/80,006 dogs 381.2/100,000 dogs over 3-year
period.
448/54,786 cats
155.8/100,000 cats over the 3-year
period.
Tulsa Registry of Canine and Feline Neo- 1972–1973 899 cases/63,504 dogs; 59 cases/11,909 cats 1126 cases per 100,000 dogs; 470
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plasms (Tulsa, Oklahoma) cases per 100,000 cats
Norwegian Canine Cancer Registry 11,12 (Oslo, 1990–1998 14,401 tumors/census of dogs in Norway in Boxers: 28 and 14/1000 dogs per
Norway) 1992–93 13 year for total and malignant
tumors, respectively.
Bernese mountain dogs: 10 and
4/1000 dogs/year for total and
malignant tumors, respectively.
Genoa Registry of Animal Tumors (Genoa, 1985–2002 3303/107,981; 1,943,725 dog-years Males: 99.3/100,000 dog-years
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Italy) Females: 272.1/100,000 dog-years,
for total tumors (malignant and
benign).
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Animal Tumor Registry (Venice, Italy) 2005 2509 dogs; 494 cats/296,318 dogs; 214,683 282, 143 and 140/100,000 dogs
cats for total, malignant and benign
tumors, respectively; 77, 63,
14/100,000 cats for total,
malignant and benign tumors,
respectively.
Swiss Cancer Registry 15 1955–2008 Registered Swiss dog population 13/100,000 dogs in 1955 to
695/100,000 dogs in 2008.
Danish Veterinary Cancer Registry (DVCR) 16 2005–2008 1523 dogs/dogs registered in the Danish Dog Breeds with standardized morbidity
Registry as of August 2006 ratios ≥2: Boxer, Bernese mountain
dog, and West Highland white
terrier. Measures for all dogs were
not provided.
Piedmont Canine Cancer Registry 17 2001–2008 1175 tumors/dogs recorded in registration 804/100,000 dogs for malignant
system in Piedmont, Italy tumors; 897/100,000 dogs for
benign tumors

companion animals was the California Animal Neoplasm Regis- residents of two provinces in northern Italy over a 3-year period start-
try. 8,17 This comprehensive effort began in 1963 with the goal of ing in 2005. Earlier prevalence data for feline cancers have ranged
identifying all neoplasms diagnosed over a 3-year period among from 51.9/100,000 cat-years from the California Animal Neoplasm
animals living in the San Francisco Bay Area Counties of Alameda Registry 8,18 to 470.2/100,000 cat-years from the Tulsa Registry. 10
and Contra Costa. The denominator was estimated by conduct- In addition to population-based cancer registries, cancer occur-
ing a survey in a probability sample of households in Alameda rence data are abundantly available from veterinary teaching hos-
County to derive the age, sex, and breed distribution of pets and pital databases and insurance databases. A caution to be noted
to determine whether the household had used veterinary services. when interpreting cancer occurrence information from hospital-
Additional information on former and existing cancer registries based registries is that data may be inconsistently recorded or
for companion animals has been comprehensively reviewed. 18,19 inaccurate and the size and characteristics of the underlying popu-
lation at risk are not known 20,21 ; thus neither true incidence nor
prevalence measures can be calculated. Instead, the proportional
Prevalence morbidity ratio (PMR) is used to quantify cancer occurrence. For
Cancer prevalence information from population-based registries example, the PMR for a particular tumor type among a single
is also useful for surveillance and comparison between popula- breed is calculated as follows:
tions. Prevalence is the number of total cancer cases divided by the
number of dogs in the population at risk at one point in time. For (Number of tumor type in breed ÷
example, the prevalence of canine cancer in April 2005 was 143 number of total tumors in breed) ÷
per 100,000 dogs in an Italian population (Table 4.2). 8,9 (Number of tumor type in all other breeds ÷
number of total tumors in all other breeds).
Feline cancer prevalence has been reported from a population-
based registry in Italy as 63 per 100,000 cats (see Table 4.2). These Proportional measures are not to be interpreted as prevalence or
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data were based on a telephone survey conducted among 214,683 incidence of cancer occurrence. As an example, Craig et al presents