The Silent Killer: Hemangiosarcomas, a Ruptured, Bleeding Spleen in Dogs
Among the many medical maladies affecting dogs, a ruptured, bleeding tumor on the spleen is sure quite devastating. This article is not to scare pet owners, but rather to spread awareness of a malignant form of cancer known as "hemangiosarcoma." The first time I was made aware of this condition was when an owner dropped off a dead dog at the veterinary hospital I worked for. As I filed the chart with the acronym DOA, "dead on arrival," the owner told me as she sobbed that one moment her dog was in the yard, the next she called him back inside to no reply. As she went outside to see whether he was busy chasing squirrels again, she found his body on the ground. To gain closure with a possible explanation, the owner had brought in the body and requested a necropsy. The vets performed it and the missing piece of the puzzle was found: the dog had a ruptured, bleeding spleen, the result of a silent form of cancer that went by the name of hemangiosarcoma.
On another occasion, with a less devastating outcome, an owner brought in a dog, who, minutes earlier (at home), got an itch, scratched his ears and all of a sudden his back legs splayed, and he appeared frightened and started shaking. This was an emergency appointment because the owner thought the dog had a seizure. The dog had chest x-rays, which revealed a suspicious enlargement, and then later, the dog was sent to get an ultrasound which revealed a ruptured spleen, and a splenectomy (removal of the spleen) was performed. The spleen was then sent off to IDEXX for evaluation by a pathologist. In this fortunate case, the histopathology report revealed it was a non-cancerous case of tissue overgrowth (hyperplasia). Not all masses of the spleen are necessarily cancerous, hemangiomas, hematomas, and hyperplasias are the benign versions of spleen masses.
What Does the Spleen Do?
The spleen is one of those organs that you hardly hear about, until there is some sort of trouble going on there. This vascular organ, which sits in the left forward part of the abdomen, just under the stomach to which it's attached by the gastrosplenic ligament, acts as a blood filter, removing old blood cells and working along with the immune system in defending the dog's body from disease.
The spleen also acts as a reservoir for red blood cells. Humans and dogs can virtually live without this dark-red organ that is supplied with numerous blood vessels, and their lives wouldn't be jeopardized by its absence.
If you think this is a rare type of cancer think again. The Golden Retriever Club of America National Health Survey, found that among golden retrievers, the chances for developing hemangiosarcoma in a lifetime was 1 in 5. This is the most common cancer affecting this breed, but it also affects many other breeds such as the German shepherd, Rottweiler, Portuguese Water Dog, Bernese Mountain Dog, great dane, Flat Coated Retriever, English setter, pointer, Boxer, doberman and Skye Terrier.
It's estimated that this cancer, accounts for 5 to 7% of all tumors seen in dogs. It preferably affects mostly dogs in their senior years, generally between the ages of 6 and 13, but can also be seen occasionally in younger dogs. Being aware of this cancer is important, as there are steps to reduce its incidence, and in some cases, there may be slight warning signs that may raise a flag. In the next paragraphs, we will get a closer look at this type of cancer affecting canines.
Knowledge Is Power: Introducing Canine Hemangiosarcoma
First of all, let's get to know this type of cancer better. We are talking about a very invasive form of cancer, known to affect almost exclusively dogs, and to a much smaller extent cats. It's a cancer involving the cells that line the blood vessels (endothelial cells) and can be found under the form of a tumor on the spleen, right heart base, or liver or even the skin. In this article, we will be mostly tackling hemangiosarcoma of the spleen which is the most common, and also the most common cause for bleeding within the abdomen.
Because hemangiosarcomas are fed by blood vessels, and thus very vascular, they tend to fill up with blood and eventually rupture causing life threatening hemorrhages. This cancer is highly invasive, meaning that it spreads rapidly to other organs. From the spleen, the cancer may therefore spread to the liver or the lungs or even to the brain and the heart. As mentioned, this condition doesn't typically cause pain and there may be no particularly evident clinical signs. As it happened to the owner who stepped in our clinic with a dead dog, it can happen that owners do not not realize their dog is affected until the dog collapses and drops dead.
Symptoms Suggesting Hemangiosarcoma in Dogs
Dogs affected by this condition may therefore never show signs of being affected by a devastating, life-threatening disease that causes blood vessel abnormalities. Initially, though the dog may have slight bleeding within the abdomen that may go unobserved, even by the most attentive owners.
Tumors of the spleen tend to bleed chronically, slowly and generally in small amounts before rupturing and causing a large bleed with obvious symptoms. Some dogs may therefore appear slightly lethargic and weak but this symptom is rather transient and the dog may soon recover (even within 14 hours) as new blood cells are made.
Other symptoms may include loss of appetite, enlarged abdomen (also known as ascites, which occurs when a large amount of blood is lost and the abdominal wall stretches to accommodate it), weakness in the back legs, mild anemia and a slight increase in liver enzymes.
However, despite these symptoms, as mentioned, eventually the large growing tumor will rupture causing severe bleeding, distended abdomen, pale colored tongue and gums, panting, weakness, rapid heart rate, weak pulse, followed by collapse, shock and death.
Treatment for Canine Hemangiosarcoma
When discovered at its early stages, treatment can be initiated but this condition has an overall poor prognosis. Blood transfusions are often necessary for canine patients with severe anemia. Depending on the stage of the cancer, parts of the spleen or the entire spleen may be removed (splenectomy). According to PetMD, this could prolong the dog's life for just about 3 months, but more time can be bought if surgery is accompanied by chemotherapy.
Unfortunately, survival times, despite surgical and chemo treatment remain rather short, generally no more than 6 months..Dogs who who have a tumor of the spleen without rupture generally have a better prognosis compared to a splenic tumor that has ruptured, according to the Flat-Coated Retriever Society of America, Inc. In cases that are inoperable, it was found that chemo alone still yielded a decent response in about 40% of patients with the median survival time being 13-190 days, according toMarvista Vet.
Veterinarian Wendy C Brooks explains that at the time of the splenectomy, it may not be known yet whether the tumor is benign or malignant. According to the GRCA Health & Genetics Committee, it's estimated that approximately one-half of splenic tumors are benign. However, even if the mass is benign, it can still be quite dangerous. The spleen, being very vascular, can still easily rupture and dump a massive amount of blood that can be life threatening.
Owners should therefore discuss in advance with their vet what to do during the surgery. If upon opening your dog up the vet finds that the cancer has spread to other organs, would you elect euthanasia? Would you want the spleen removed and try chemotherapy? Would you want your dog closed up and the spleen left alone and your dog awakened? These are important decisions to make beforehand.
Despite the surgical removal of the spleen, with a splenectomy, even though the dog is probably spared from bleeding to death once the spleen is surgically removed, the dog will still have to deal with the cancer in the first place that most likely has now spread. The prognosis therefore remains poor. What happens if nothing is done? Failure to remove the spleen leads to the inevitable life-threatening hemorrhage. Owners would therefore have to keep an eye on those gums and behavior as it's a matter of when rather than if it will happen. What can owners do if symptoms suggest an ongoing hemorrhage? According to veterinarian Wendy C. Brooks, applying an ace bandage snugly around the belly and applying pressure to the bleed can be surprisingly effective—at least until you get to the vet's office. Ask your vet on how to do this for details.
Surgery may seem like the best approach but removal of this organ can still lead to complications. While dogs can live without a spleen, owners of deep chested dogs must keep in mind that once the spleen is removed, the stomach has more room and may be prone to bloat and torsion in a predisposed dog. For this reason, owners under the vet's advice often elect to get stomach tacking (preventative gastroplexy) to prevent torsion at the same the splenectomy is done.
And what about non-traditional options? Some studies by Penn Vet have revealed interesting results using from the Coriolus versicolor mushroom, commonly known as the "Yunzhi mushroom". Another pomising product known to help boost the immune system is turkey tail.
A role in preventing this devastating disease is played by breeders since it affects more some breeds and bloodlines than others, suggesting a heritable factor. For instance, 1998 studies found that 61.8 percent of American goldens die from cancers such as hemangiosarcomas, lymphosarcomas, mast-cell tumors and osteosarcoma; whereas, only 38.8 percent of goldens from English bloodlines are affected by cancer, according to a British Kennel Club (KC) study.
This seems to suggest that certain bloodlines have heritable factors that risk being passed on to future generations. Yet, we cannot ignore the fact that good health is often a combination of nature and nurture, in other words, good genes and optimal care by responsible owners through a healthy diet, good exercise regimen and protection from chemical exposure also play a role.
Breeds predisposed to hemangiosarcoma of the spleen may benefit from yearly ultrasounds of the spleen starting at age 5. Ultrasounds can show in what state the spleen is and if there are any blood-filled cavities. If a tumor is found on the spleen, it's worthy to also do an ultrasound of the heart since there are chances it may be affected as well, which seems to occur in about 25 percent of cases. If there's proof of spread to the heart, the patient will likely not be a good candidate for surgery and the prognosis is poor because of metastasis.
On top of that, the vet may palpate the abdomen for a firm mass in the area of the spleen every 6 months to check for any abnormalities, suggests veterinarianAmy Haase. Routine blood work also done every 6 months in predisposed breeds over the age of 10 may help as well. Mild anemia may be one important clue that grants further diagnostics.
Sadly, still as of today, hemangiosarcoma remains one of the most challenging, mysterious conditions encountered in modern veterinary practice. It's unfortunate that in the last 20 to 30 years no particular advances were made in the treatment of this condition. Most likely, this is due to the fact that humans don't typically get hemangiosarcoma so there's limited funding for research. However, there are opportunities for dogs to participate in research to help better understand this condition and several organizations like the AKC Canine Health Foundation are actively working to support research studies revolving around several kinds of cancer. Hopefully, things will look brighter in the next coming years.
Disclaimer: this article is fruit of my research on the topic and not be used as a substitute for professional veterinary advice. If your dog has any suspicious symptoms please consult with your vet for proper diagnosis and treatment.
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Dog Cancer Veterinarians Dr. Demian Dressler and Dr. Susan Ettinger Discuss About Hemangiosarcoma
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This article is accurate and true to the best of the author’s knowledge. It is not meant to substitute for diagnosis, prognosis, treatment, prescription, or formal and individualized advice from a veterinary medical professional. Animals exhibiting signs and symptoms of distress should be seen by a veterinarian immediately.