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Hemangiosarcoma is a malignant tumor of blood vessel cells. With the exception of the skin form (which can often be eliminated by surgery), a diagnosis of hemangiosarcoma is bad news. This tumor is
associated with serious internal bleeding and rapid internal spread. Fortunately, it is not a completely without therapy options and, as long as expectations are realistic, temporary remissions are possible.
Hemangiosarcoma can theoretically arise from any tissue where there are blood vessels (which amounts to anywhere in the body) but there are three classical locations which account for most
presentations:
THE SKIN FORM
The skin form of hemangiosarcoma are the best types to have as they are the most easily removed surgically (and thus have the greatest potential for complete cure).
The skin forms of hemangiosarcoma are classified as either “dermal” and “subcutaneous” (also called “Hypodermal.”) The true skin form looks like a rosy red or even black growth on
the skin. This form is associated with sun exposure and thus tends to form on non-haired or sparsely haired skin (such as on the abdomen) or on areas with white fur. Dogs with short white haired fur (such as
Dalmatians and pit bull terriers) are predisposed to the development of this tumor. Approximately 1/3 of cases will spread internally in the malignant way we usually associate with cancer so it is important to
remove such growths promptly.
WHAT TO KNOW WHEN A SKIN GROWTH BIOPSY COMES BACK AS HEMANGIOSARCOMA:
- The biopsy report will indicate whether or not the growth was “completely excised.” If the tissue completely surrounding the growth is normal, this indicates that the growth has been
removed completely and that it should not grow back.
If one wants to be absolutely positive that no tumor spread has yet occurred, the following non-invasive (but not inexpensive) testing is necessary.
- Chest radiographs – hemangiosarcoma tends to spread to the lungs. Advanced tumor spread can be picked up with this simple test. (Spots of tumor spread must be 3cm in diameter to be large
enough to be visible on a radiograph.)
- Ultrasound of the belly – specifically the spleen. Even a small splenic hemangiosarcoma should be detectable with ultrasound.
- Ultrasound of the heart – even a small heart-based hemangiosarcoma should be detectable with ultrasound.
SUBCUTANEOUS OR HYPODERMAL HEMANGIOSARCOMA
The overlying skin is often totally normal on top of a subcutaneous hemangiosarcoma and often the surgeon is surprised to find a dark red blood growth under the skin when the tumor is removed.
Since up to 60% of hypodermal hemangiosarcomas spread internally the above three tests to rule out tumor spread are more important.
- If no sign of tumor spread is found after chest radiographs have been taken and ultrasound of the heart and belly are clear, prognosis is substantially better than if secondary tumor is found;
however, additional treatment with chemotherapy is recommended if cure is the goal.
- Surgery alone has been associated with a 172 day (approximately 6 months) median survival time.
HEMANGIOSARCOMA OF THE SPLEEN
The spleen is a fairly deep-seated abdominal organ which tends to go unnoticed unless it develops a growth of unusual enlargement. Splenic growths have the unfortunate
tendency to break open and bleed profusely regardless of whether they are benign or malignant. While a splenectomy (removal of the spleen certainly ends the prospect of
this type of life-threatening sudden bleed, splenic hemangiosarcoma is still a rapidly spreading malignancy.
When a splenic mass is detected, it may not be possible to tell prior to splenectomy whether or not the mass is malignant or not (though certainly basic testing is performed
in an attempt to determine this.)
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Please review the Splenectomy Page which reviews the details
of splenic mass evaluation. (Chemotherapy after removal of the
splenic hemangiosarcoma is reviewed here so be sure to click the
hemangiosarcoma link on the splenectomy page when
you are ready to return for more information.)
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- 25% of dogs with splenic Hemangiosarcoma also have a heart-based Hemangiosarcoma.
- Survival time with surgery alone is 19-65 days for splenic hemangiosarcoma.
HEART-BASED HEMANGIOSARCOMA
Like the splenic hemangiosarcoma, the heart-based hemangiosarcoma tends to exert its life-threatening effects by bleeding.
The heart is enclosed in a sac called the “pericardium.” When the hemangiosarcoma bleeds, the blood fills up the pericardium until it is so full that the heart inside is under
so much pressure that it has no room to fill with the blood it has to pump.
On chest radiographs the heart is “globoid” (spherical). In fact, the actual heart is of normal shape but all that can be seen on the radiograph is the large round heart shadow
of the pericardium filled to capacity with blood. Ultrasound is needed to truly see the effusion.
This condition, if allowed to progress, results in an emergency circulating collapse called a “pericardial tamponade” and can only be relieved by tapping the pericardium
with a needle and withdrawing the excess fluid.
- 63% of heart-based Hemangiosarcomas have evidence of tumor spread at the time of their discovery.
- Survival time for surgery alone (removing the pericardium and snipping off the heart-based hemangiosarcoma) is approximately 4 months.
Chemotherapy is necessary to create a substantial improvement in survival time. The
most current protocol involves injectable Adriamycin (Doxorubicin) every 3 weeks and oral cyclophosphamide at home for 3 days out of the week.
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Chemotherapy of Canine Hemangiosarcoma
With Doxorubicin and Cyclophosphamide
J Vet Intern Med 7[6]:370-376 Nov/Dec'93 Clinical Study 29 Refs
Karin U. Sorenmo CMV, K. Ann Jeglum VMD, and Stuart C. Helfand DVM
Dept. of Clinical Studies, VHUP, 3850 Spruce Street, Philadelphia, PA 19104.
Sixteen dogs with a histologic diagnosis of hemangiosarcoma were treated with surgery and doxorubicin/ cyclophosphamide. The patients' characteristics, ie, age, size, and
breed, were similar to those of previous studies. Historic controls for surgery alone were used to evaluate efficacy of the chemotherapy. The results show a trend of improved survival in
dogs with localized disease (Stage I) receiving combination therapy. The median survival was 250 days, with a mean of 403 days. The survival times for dogs with stage I, II, and III
disease was also improved with combination therapy, when compared to historical controls treated with surgery alone. The overall median survival was 202 days with a mean of 285 days.
Toxicities included mild to moderate neutropenia (9 of 16) and clinical signs, such as lethargy, anorexia, vomiting, diarrhea, and fever (13 of 16). Three dogs had severe neutropenia
requiring hospitalization and supportive care. One dog died from sepsis and related complications. Chemotherapy with doxorubicin and cyclophosphamide appears to improve survival with
acceptable morbidity in patients with early stage disease. (Author Abstract)
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