Table 6.2 Neoplasms in dogs.

Neo plasm Association Age a factor
Epithelial neoplasia Account for approximately 48.3% of dog tumours* Incidence increased in dogs over 5 years age †
Mesenchymal neoplasia Account for approximately 24.6% of dog tumours* Incidence increased in dogs over 7 years age †
Oropharyngeal neoplasia Account for approximately 10.3% of dog tumours*
Brachycephalic breeds
Incidence increased in dogs over 10 years age †
Skin neoplasia Most frequent tumours in dogs (24-30%) of which 20% are malignant*
Breeds at high risk: boxer, Boston terrier, Scottish terrier and others
Median age for cutaneous tumours in dogs is 10.5 years, and for cats 12 years
Mammery neoplasia A common tumour in dogs (11.4%); 50% are malignant*. Over 97% of cases occur in females hence female sex hormone-related
Entire females have 7 x risk of neutered females. Bitches neutered before first oestrus have 0.5 risk of those neutered afterwards
Prostatic neoplasia Male sex hormone-related
Perianal adenoma Male sex hormone-related
Male dogs have 7.3 x risk of females
Lipoma More frequent in females than males
Infiltrative lipoma occurred in dogs with a median age of 6 years and 87% of them weighed over 20kg body weight
More common in obese than non-obese animals
Aged dogs were labrador retrievers (Bergman et al. 1994)
Gastrointestinal tract neoplasia Account for 15.1% of tumours in dogs, of which 50% are malignant*
Haematolymphatic system neoplasia Account for 10.9% of tumours in dogs, of which 90% are malignant
German shepherd dogs increased risk for splenic haemangiosarcoma
Haemangiosarcoma was most common in dogs aged 8-13 years (Prymak et al. 1988)
Bone tumours - osteosarcoma Large and giant breeds of dogs at high risk - usually appendicular skeleton, e.g. great Dane, Irish wolfhound, rottweiler, St Bernard, German shepherd dog Common in younger animals as well as old dogs
Tonsillar carcinoma Mainly occur in urban environments.
? Air pollution a factor (Cohen et al. 1964)
Lung carcinoma Mainly occurs in urban environments.
? Air pollution a factor (Brodey 1961; Brodey & Craig 1965)
Bladder cancer ? Industrial pollution a factor (Hayes 1976)
Mast cell tumours   Mean age 10.2 yrs

(*Theilen and Madewell 1987; † Dorn et al 1968b)