Cancer is a common problem in dogs and although all breeds of dog and crossbred dogs may be affected, it is notable that some breeds of pedigree dogs appear to be at increased risk of certain types of cancer suggesting underlying genetic predisposition to cancer susceptibility. Although the aetiology of most cancers is likely to be multifactorial, the limited genetic diversity seen in purebred dogs facilitates genetic linkage or association studies on relatively small populations as compared to humans, and by using newly developed resources, genome-wide association studies in dog breeds are proving to be a powerful tool for unravelling complex disorders. This paper will review the literature on canine breed susceptibility to histiocytic sarcoma, osteosarcoma, haemangiosarcoma, mast cell tumours, lymphoma, melanoma, and mammary tumours including the recent advances in knowledge through molecular genetic, cytogenetic, and genome wide association studies.

This paper presents the results of a prospective study to investigate the prognostic value of clinical staging, histological grading, immunophenotype, mitotic count and average numbers of argyrophilic nucleolar organiser region counts in dogs with multicentric lymphosarcoma treated with a standard chemotherapy protocol comprising vincristine, cyclophosphamide and prednisolone. Forty‐nine dogs were treated according to the study protocol. Univariate and multivariate analysis with regression modelling was used to evaluate the prognostic importance of patient and tumour variables upon tumour response and relapse‐free survival. Thirty‐seven dogs (76 per cent) achieved a complete remission, seven (14 per cent) a partial remission and five (10 per cent) failed to respond to treatment. None of the variables examined had a statistically significant effect upon tumour response. Tumour immunophenotype was the only parameter found to have a significant influence on patient survival, the hazard ratio for T‐cell versus B‐cell immunophenotype was 3–99 with 95 per cent confidence interval from 1–399 to 11–372, Pa0–035.

Objective: To evaluate response to radiotherapy in dogs with oral malignant melanomas. Design: Clinical trial. Animals: 36 dogs with histologically confirmed oral malignant melanomas. Procedure: The prescribed radiation dose was 36 Gy given in 4 fractions of 9 Gy at 7-day intervals. The primary radiation source was a linear accelerator. Results: In 25 of 36 dogs, complete remission was achieved, and in 9 dogs, partial remission was achieved. Recurrence of the primary tumor was the cause of euthanasia of 4 dogs. Twenty-one dogs were euthanatized because of metastasis. Clinical Implications: Radiotherapy was an effective palliative treatment for the primary tumor in dogs with oral malignant melanomas. However, rapid development of metastatic disease remained a major challenge, (J Am Vet Med Assoc 1996;209:98–102)