Cancer research offers hope for Aussies
By C.A. Sharp
First published in Double Helix Network News, Fall 2008, Rev. April 2013
In the fall of 2007 the Australian Shepherd Health & Genetics Institute, Inc. (ASHGI) published the results of the cancer survey it had planned almost from the moment the organization was formed. Two general health surveys in the 1990s and a geneticist’s study of canine longevity had indicated that cancer might be an issue in the breed. The survey confirmed that suspicion. It also made it clear that two specific cancers occur significantly more often than any other types.
The survey gathered reports on 534 Aussies with cancer. More than 40% had either hemangiosarcoma (HSA) or lymphoma. HSA is a cancer of vascular tissue; lymphoma attacks the lymph glands. Both cancers occurred multiple times in related groups of dogs. Both were seen in the same families. This not only indicates some degree of inherited risk for these cancers, but the possibility that the two share cancer-causing genes and that these genes can be passed from one generation to the next.
The Deadly Duo
26.4% of the dogs surveyed had HSA. However, the actual percentage may be higher, possibly a lot higher. Some people didn’t know precisely what type of cancer their dogs had. They tended to describe the disease by where it was found. 11.3% of the dogs were reported to have liver cancer and 5.3% to have lung cancer. Both locations are common sites for HSA and primary lung cancer is rare in dogs. In addition, HSA can arise in mammary tissue. Mammary cancer is common in dogs and was the third most common reported in the survey at 5.7%. While most mammary cancers probably were not HSA, some of them may have been. Based on the probability of some cases of HSA being misidentified in the survey, it is probable that a third, and possibly more, of the dogs in the survey suffered from HSA.
Survivorship for this cancer is poor. 80% of the HSA dogs were reported as deceased at time of survey. It is likely that most of those who were living at the time have died since; HSA dogs typically don’t live more than a few weeks to months after diagnosis. The prognosis for the skin form of HSA is somewhat better, though still far from good: Affected dogs can live 6 months after diagnosis. HSA can be rapid in onset and the first sign of a sick dog may be a dead one. An apparently healthy dog that drops dead for no obvious reason may have had HSA. Ideally, such dogs should be necropsied to determine cause of death and the veterinarian doing the necropsy should be asked to look for signs of HSA.
HSA does not occur in puppies or young dogs. The survey data indicated that average age of onset was 9½ years. The youngest case reported was 4 years old and the oldest 14. The disease has several different forms, classed by where the first tumors develop. Most common are the spleen and liver; the cancer can spread so rapidly it may be difficult to determine which of these organs it began in. 65.7% of the HSA dogs in the survey indicated that the disease started in the spleen. The heart (12.7%) is another common point of origin. 5.8% were reported to have tumors in both spleen and heart at the time of diagnosis. Least common (and the type with the best survivorship after tumor removal and chemotherapy) is the skin form. 4.9% of the dogs in the survey had this form.
The survey data indicated 63.7% suffered metastasis (spreading) of the cancer and 17.8% experienced periods of remission, which implies that some of the cases were controlled for a period of time. Clinical evidence shows that these periods of remission are almost always brief.
Lymphoma, reported in 16.8% of the survey dogs, also has poor survivorship, though with chemotherapy dogs with the B-cell type often experience several months or more of remission, as indicated by the 13.3% of the lymphoma dogs reported to have had remissions in the survey. Unfortunately, T-cell lymphoma, the type most frequently diagnosed in Aussies, is not very responsive to treatment. With either type, if there is remission the cancer almost always returns. 43% experienced metastasis and 77.4% had already died at the time of the survey.
Lymphoma was reported as striking younger dogs than HSA. The average age of diagnosis among the survey dogs was 7.7 years with the oldest diagnosed at 14. Lymphoma can strike the very young: The youngest reported was only one year old.
The survey asked about a wide range of possible environmental factors. The only such issue reported at significant frequency was exposure to chemical spraying programs (urban or rural.) 18.5% of the lymphoma dogs had been so exposed.
Recognizing that cancer is a critical breed health concern, ASHGI is continuing to collect data on all types of cancer. If you have had a dog with cancer, download and submit our cancer questionnaire. We also provide researchers with logistical support and money. Since 2008 ASHGI has provided thousands of dollars to sponsor cancer research grants.
Initially ASHGI focused on cancer genomics studies, which seek to determine the genetic causes of cancer. The organization will continue to support this kind of study, but will also provide funding for studies aimed at improving diagnosis and treatment for Aussies with HSA or lymphoma. In order to do this most effectively, ASHGI has teamed with the AKC Canine Health Foundation and Morris Animal Foundation, the two largest granting agencies for canine health research. CHF and MAF have the professional staff and expertise to review, approve and administer grants, something beyond the scope of a small all-volunteer group like ASHGI. If you would like to help us support these studies, click HERE.
What YOU Can Do
If we are to make progress against cancer, it is vital that individual dog owners and breeders, as well as the breed community as a whole, recognize the signs and symptoms of what appear to be our most predominant cancers and participate in fundraisers as well as surveys and sampling studies.
The outpouring of donations for cancer research thus far has been generous and timely, but we must continue to support raise funds to continue the fight to develop improved diagnosis and treatment protocols for Aussies with cancer.
Money helps, but whenever possible we also need to provide tissue and blood samples for the researchers to work on. Information about current studies accepting samples can be found on our Current Research page. We can also save for the future by utilizing the Canine Health Information Center’s DNA Repository. This all-breed “DNA bank” maintains a large repository of canine DNA samples available to researchers around the world. The more Aussie samples they have, the better for our breed and the more likely our dogs can be part of a grant like this. The CHIC repository has the potential to make DNA available from dogs that may be key to a particular line of research even if they’ve been dead for many years.
If you have questions about cancer or cancer research, contact our cancer liaison, who can provide information, forms, and assistance with blood and tissue submissions. In cases of financial hardship assistance is available from ASHGI’s Thor Fund, named in memory of board member Kim Monti’s SAR Aussie who succumbed to HSA,
Cancer is a difficult disease and too often it leads to loss of our beloved dogs. But we don’t have to lose all the time. By working together to support cancer research in any way we can, we’ll ultimately have more and more happy endings.