Cocker Spaniel Breed Council

Research into Anal Sac Cancer in Cocker Spaniels

Are English Cocker Spaniels at particular risk of anal sac tumours?

Unfortunately it would appear that English Cocker Spaniels (and to a lesser extent Springer and Cavalier King Charles Spaniels) are at higher risk of developing anal sac tumours than other dogs. This conclusion is based upon the analysis of large numbers of cases of anal sac tumours using data from veterinary pathology laboratories and breed registration data from The British Kennel Club.

This raises the concern that perhaps there is a degree of inherited risk. However, there is more than one possible explanation. Other possibilities include what we would term environmental challenges; by this we mean that there might be lifestyle factors that are specific to the way in which spaniels live that somehow predispose them to anal sac tumour development.

In the field of cancer therapy, things would be so much better if we could gain some advance warning of cancer problems. Without doubt, the outcome for cancer patients is so much better if the tumour can be identified at the earliest possible stage and if suitable therapy can be instituted then rather than later. This often also means that the therapy is much less involved. Therefore one of the aims of cancer practitioners is to gain deeper insight into the development of tumours so that a better understanding of the way in which the cancer develops can be obtained.

Certain dog families can carry higher risks of tumour development. Knowledge of individual patients’ pedigrees allows us to perform some fairly complicated analyses to tell us whether the risks are inherited and how much risk is found in specific families.

A joint project is currently being undertaken by Gerry Polton of North Downs Specialist Referrals, Guards Avenue, Caterham, Surrey, CR3 5ZD (Tel 01883 343770) and David Sargan of Cambridge University Veterinary School, UK. The aim of this project is to establish whether there is an inherited risk of the development of anal sac tumours in English Cocker Spaniels. We are looking to collect samples containg DNA from Cocker Spaniels affected with anal sac gland carcinoma and from other spaniel breeds.  We would welcome your dog's participation in this research. 

We need DNA samples from Cocker Spaniels (and other spaniel types) that have been diagnosed with the specific cancer anal sac gland carcinoma by your veterinarian (not other cancers please), and also from elderly dogs (>9 years old) that are healthy and have never suffered from cancer. Where available we would also like to know the Kennel Club registration number of the dog.  Forms explaining the research to your vet and how to submit samples containing DNA are available from Dr Sargan ( and are also available to download below. Note that we can only accept blood samples that are excess remaining from samples drawn for clinical purposes by your vet.

Information sheet for your vet (pdf file)

Blood Sample Submission form (pdf file)

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