This is a cancer of the bone, cartilage, fat, muscle, blood vessels, connective or supportive tissue that affects many Bernese Mountain Dogs (and also Golden Retrievers, Flat Coated Retrievers and Rottweilers). There is more than one gene involved so careful breeding is essential to try and reduce the incidence of this illness.
There are different types of Sarcoma for owners and breeders to be aware of:-
The most common benign cancer, Histiocytoma is caused when overproduction of histiocytes (white blood cells) can cause organ damage and tumour formation. They are found in connective tissue and dermis, which is the middle and thickest layer of the skin. These stay on the skin and develop as single wart-like growths on the skin surface and usually disappear by themselves within a few weeks. Any dog that has had a benign tumour should always be monitored, as they have a higher chance of developing a malignant cancer.
Another benign cancer, with single or multiple skin growths, again a dog with this type of cancer should be monitored.
This starts on the skin, usually on the head or extremities but then spreads to other organs – liver, spleen, bone marrow, lungs and mimics malignant tumours in symptoms. It is most often found in males from four years old onwards.
This is the most serious and aggressive tumour, it usually starts on the spleen and spreads rapidly to other organs and can destroy red blood cells. Often liver and spleen tumours form and spread rapidly through the blood system to the lungs, heart, brain and all major organs. Signs of liver and spleen tumours are weight loss, weakness, lameness, intermittent collapse, partial loss of movement, seizures, dementia, rapid heartbeat, abdominal mass, blood loss and abdominal fluid. Age of onset is typically 7 years and older.
**_Signs to watch out for,_** **_in general,_** **_are:_**
Anaemia, anorexia and sudden weight loss, trouble breathing, wheezing, lack of energy and appetite. Any growths on the skin, particularly a large amount of them or ones that grow in size quickly. If a joint is effected limping or lameness is often the first sign of the disease.
**_How is the disease diagnosed?_**
If a dog presents with any of the above symptoms it is essential to visit your veterinary practice as soon as possible, they will remove some tissue and send it off for diagnosis. Early detection will greatly improve the chances of survival as this is a cancer that can spread within a matter of weeks if it is malignant, and dogs can deteriorate rapidly.
**_How is this cancer treated?_**
If your dog has localised Histiocytic Sarcoma, surgery or radiation therapy may be recommended as part of the treatment protocol. If the cancer is in the joint tissue of a limb, amputation or radiation therapy may be recommended. Chemotherapy can be recommended to prevent the further spread of the disease if it is detected early. If the disease has spread to many organs it is unlikely that any treatment will be effective.
Longer survival times have been seen in dogs that have microscopic disease or have localised tumours that have been surgically removed. Histiocytosis is an aggressive disease that generally has a poor response to therapy. There are individual animals that can, however, do well.
For over eight years, the Canine Genetics team of the CNRS in Rennes (France) and their international collaborators have been conducting genetic studies on Histiocytic Sarcoma in the Bernese Mountain Dog. These studies allowed them to locate regions of the genome implicated in this disease. There is an article on how to take part in this genetic pre-test on our website. This is mainly geared towards breeders and should be an important question for potential owners to ask if the dog and bitch have been tested for this illness before they commit to buying a Berner.
A report by CNRS on this disease showed that 70% of affected dogs in their study had diagnosed relatives and 64% had other significant diseases beforehand, generally skin related.