Hemangiosarcoma in Dogs: New Research Offers Hope for Early Detection and Treatment

Hemangiosarcoma is one of the most devastating cancers in dogs. It is an aggressive cancer of cells associated with blood vessels and most often develops in organs such as the spleen, heart or liver. Because these tumors are highly vascular, they can bleed internally, often without warning. A dog may appear completely healthy until a tumor ruptures, causing severe internal bleeding, collapse and potentially death.

Hemangiosarcoma also can spread, or metastasize, before there are obvious signs of illness, which is one reason the prognosis is so poor. But researchers are increasingly looking at hemangiosarcoma in dogs differently. Instead of focusing only on finding better chemotherapy after diagnosis, veterinary researchers are trying to determine why the cancer develops, identify dogs at risk, detect tumors earlier, predict how aggressive they will be and develop more targeted treatments.

The non-profit Morris Animal Foundation is helping drive much of this work funding 12 studies in recent years. Its Hemangiosarcoma Initiative is a multiyear, multimillion-dollar effort supporting research into prevention, early detection, diagnosis and treatment. The Foundation says it has funded 12 studies through the initiative.

Much of that research builds on the Foundation’s Golden Retriever Lifetime Study, which has enrolled 3,044 Golden Retrievers, and researchers have access to extensive longitudinal data and biospecimens, including blood, urine and other samples providing an unusual opportunity to search for changes that occur before hemangiosarcoma becomes clinically apparent.

One motivation for super interest from Morris Animal Foundation is that anecdotally some breeds – including Goldens – are succumbing to hemangiosarcoma more often and at a younger age. Like many cancers, historically hemangiosarcoma has impacted mostly older dogs but that has perhaps changed.

Searching for an Early Warning

At Purdue University, researchers are investigating microRNAs — tiny molecules that help regulate gene activity — as potential biomarkers of hemangiosarcoma.

The hope is to identify a molecular signature that could be detected through a blood test, potentially allowing veterinarians to find hemangiosarcoma earlier and perhaps determine characteristics of a tumor.

Researchers at Virginia Tech are taking another approach, looking for evidence of hemangiosarcoma in urine. Their Morris-funded study uses Raman molecular analysis to search for a characteristic molecular “fingerprint” that could potentially help detect the disease and monitor treatment.

At the University of Pennsylvania Penn Vet School of Veterinary Medicine, researchers are even studying whether trained dogs can detect hemangiosarcoma by smell. In one study, five trained detection dogs participated in 423 blinded trials involving blood samples. The dogs aren’t intended to become a practical cancer-screening program. Instead, researchers want to identify the specific chemicals the dogs are detecting. Those compounds could potentially lead to a technology-based diagnostic test.

Can Researchers Predict What Happens Next?

Finding hemangiosarcoma earlier would be a major advance. But researchers also need to understand why some tumors behave more aggressively than others.

At the University of Minnesota College of Veterinary Medicine, scientists are investigating molecular subtypes of canine hemangiosarcoma. The work could eventually help veterinarians determine which tumors are more likely to behave aggressively and whether particular molecular characteristics are associated with response to treatment.

That raises the possibility of precision medicine for dogs — choosing treatment based on the biology of an individual tumor rather than treating every hemangiosarcoma the same way.

Genetics is another piece of the puzzle. Investigators at the University of Massachusetts are studying genetic factors associated with hemangiosarcoma in Golden and Labrador Retrievers. If researchers can identify inherited risk factors, it could eventually become possible to identify dogs at greater risk and potentially reduce the incidence of the disease through more informed breeding decisions.

Moving Beyond Traditional Chemotherapy

Researchers are also looking for ways to treat hemangiosarcoma more precisely.

At the Schwarzman Animal Medical Center and Memorial Sloan Kettering Cancer Center, researchers are investigating a protein called integrin α6β4 that appears to be more abundant on hemangiosarcoma cells. The goal is to determine whether antibodies can be designed to recognize those cancer cells and potentially deliver treatment directly to them.

Meanwhile, University of Georgia researchers are studying tumor-specific neoantigens — molecules produced by cancer cells that may provide targets for the immune system. This research could eventually contribute to development of a therapeutic cancer vaccine. And here, down the road and with other research as well) a possible application for people too.

Optimistic Future

None of these approaches is yet a proven cure for hemangiosarcoma in dogs. For dogs diagnosed today, surgery and chemotherapy remain important treatment options, but the overall prognosis for hemangiosarcoma remains poor.

However, the research is moving in an encouraging direction.

Hemangiosarcoma remains a frightening diagnosis. But with funding from organizations such as Morris Animal Foundation and research underway at veterinary schools and cancer centers around the country, scientists are steadily trying to change the outcome — from discovering hemangiosarcoma too late to detecting it earlier, understanding it better and, ultimately, treating it successfully.

However, today – which may be increasingly common – is absolutely heartbreaking as euthanasia is the most common outcome.