Hemangiosarcoma in dogs: treatment, prognosis and clinical trials

Dogs · USA & Canada

Understanding hemangiosarcoma

Hemangiosarcoma is a cancer of blood-vessel-forming cells. In dogs it often develops in the spleen, heart or liver, where it can rupture and cause sudden internal bleeding, although skin forms can behave very differently. Even when scans look clear, internal hemangiosarcoma carries a significant risk of microscopic spread.

What does the prognosis look like?

The outlook depends first on where the tumor started. A tumor limited to the surface of the skin may sometimes be cured with complete removal. In one retrospective study of visceral hemangiosarcoma, the typical survival time was about 2 months in the surgery-only group and about 9 months in the surgery-plus-doxorubicin group. Some dogs lived less and some lived longer. Surgery did not start the cancer clock: the dogs reached treatment at different points in the disease. These group results mainly show why removing the bleeding mass may not control hidden disease and why an oncology discussion should not be delayed.

What matters next

First determine whether there is active or recent internal bleeding and whether the disease is confined to one site or already visible elsewhere. Collapse, marked weakness, pale gums or a swollen abdomen can be an emergency. After stabilization or surgery, pathology and staging guide the systemic-treatment discussion.

Where are you now?

A splenic or abdominal mass is bleeding or may have ruptured

Pale gums, collapse, marked weakness, a distended abdomen, or breathing trouble can be urgent. Stabilization and control of bleeding come before a long-term cancer plan, and a suspected splenic mass is not yet a confirmed hemangiosarcoma until pathology establishes it.

The spleen or primary tumor was already removed

Confirm the pathology diagnosis and stage, and note whether rupture or abdominal bleeding occurred. Those details help frame the discussion about adjuvant chemotherapy and expected risk.

A right-atrial or cardiac mass is suspected

Echocardiography helps define the mass and whether pericardial fluid is present. Collapse or breathing difficulty with fluid around the heart can require urgent treatment; cardiac hemangiosarcoma is a different local problem from splenic disease.

Metastases are already visible

Systemic treatment and symptom control become central. Ask what treatment is realistically expected to accomplish and which disease site is most likely to cause the next clinical problem.

If you are waiting for oncology

Visceral hemangiosarcoma is different from many cancers because bleeding can become urgent. Collapse, pale gums, abdominal distension or breathing difficulty should not wait for a routine oncology visit. If surgery has already occurred, gather pathology, rupture/bleeding history and staging before the oncology discussion.

Questions to ask your oncologist

Was there rupture or internal bleeding, and what stage is the disease now?
Is there any evidence of cardiac involvement or distant metastasis?
What benefit is realistically expected from chemotherapy or a trial in this stage?

How the diagnosis may appear in the record

A splenic mass seen on imaging is not yet a confirmed hemangiosarcoma; benign hematoma and other tumors can look similar. Surgical pathology establishes the diagnosis. The record should also distinguish superficial cutaneous, subcutaneous, splenic, cardiac, hepatic, or other visceral disease because these forms do not share one prognosis.

Changes to watch for at home

Collapse, pale gums, sudden weakness, a swollen abdomen, rapid breathing, or breathing distress can indicate internal bleeding or fluid around the heart and is urgent. After surgery, report new weakness or pallor promptly. A superficial skin lesion does not carry the same immediate bleeding risk as visceral disease.

How it is usually treated

When a visceral tumor can be removed safely, surgery treats the primary bleeding mass and provides tissue for diagnosis. Because microscopic spread is a major concern, systemic chemotherapy is often discussed after surgery. Skin hemangiosarcoma may need only local treatment when it is superficial and completely removed.

What can affect treatment choices

A superficial skin tumor and a ruptured splenic or cardiac tumor are very different diseases in practice. Primary site, bleeding, stage, metastasis and recovery from surgery drive the next choice.

Tests that may matter

CBC and chemistry help assess blood loss and organ function. Chest and abdominal imaging are commonly used for staging, and echocardiography is useful when a heart-base or right-atrial lesion is suspected. Additional tumor assays should have a clear purpose before they are ordered.

Treatment options available now

9 options currently in our catalog.

Check eligibility

Vaccine study for dogs with splenic hemangiosarcoma

University of Florida · USA

Location

UF Small Animal Hospital, 2015 SW 16th Ave, Gainesville, FL 32608

Study details

Currently enrolling

What is being offered: Splenic HSA after splenectomy; treatment-naive and able to receive standard doxorubicin chemotherapy. Vaccine is added to standard care.

Who may qualify: Confirmed cancer diagnosis required; Post splenectomy; Planned doxorubicin; Splenic primary

Costs / coverage: ⚪ Owner-paid. Owners pay the oncology evaluation, surgery, histopathology, bloodwork, imaging, chemotherapy and six vaccine doses (public page estimate: approximately $1,275). The study covers only treatment of a vaccine injection-site reaction, up to $100.

Contact: UF Oncology Staff — (352) 392-2235; Study Interest Form / Oncology Referral Form on the official study page

Official study / enrollment information →

Liquid-biopsy guided treatment study for splenic hemangiosarcoma

Tufts University · USA

Location

Henry and Lois Foster Hospital for Small Animals, 200 Westboro Rd, North Grafton, MA 01536

Study details

Recruiting

What is being offered: Dogs must weigh at least 10 kg, have splenic HSA without obvious spread beyond the spleen, have no serious heart, lung, kidney or liver disease, and have received no prior HSA treatment. Recent splenectomy elsewhere may be accepted after histopathology confirmation. Protocol combines doxorubicin with mutation-guided oral small-molecule inhibitors and serial liquid-biopsy/CT monitoring.

Who may qualify: Confirmed cancer diagnosis required; No metastasis; Min weight lb: 22; Min weight kg: 10; Post splenectomy; Planned doxorubicin; Splenic primary

Costs / coverage: 🟡 Partially funded. All HSA treatment costs are covered up to $5,000; oral small-molecule inhibitors and care for treatment-related side effects are provided at no cost. A splenectomy performed at Tufts Foster Hospital qualifies for a $1,500 reimbursement only after histopathologic confirmation of HSA and confirmed trial enrollment.

Contact: Tufts Clinical Trials Office — clinicaltrials@tufts.edu

Official study / enrollment information →

Ethos-PUSH precision-medicine umbrella study for splenic hemangiosarcoma

Ethos Discovery / multicenter specialty hospitals · USA

Participating locations

Massachusetts Veterinary Referral Hospital, 20 Cabot Rd, Woburn, MA 01801
Pet Emergency and Specialty Center of Marin, 901 Francisco Blvd E, San Rafael, CA 94901
Veterinary Specialty Hospital - North County, 2055 Montiel Rd, San Marcos, CA 92069
Veterinary Specialty Hospital, 10435 Sorrento Valley Rd, San Diego, CA 92121
Veterinary Emergency + Referral Center of Hawaii, 345 N Nimitz Highway, Unit C, Honolulu, HI 96817
WVRC Grafton, 1381 Port Washington Rd, Grafton, WI 53024
WVRC Racine/Kenosha, 1123 58th Ave, Somers, WI 53144
WVRC Waukesha, W239 N1046 Pewaukee Rd, Waukesha, WI 53188
SAGE Veterinary Centers, 600 Alabama St, San Francisco, CA 94110
Summit Veterinary Referral Center, 2505 S 80th St, Tacoma, WA 98409
Colorado Animal Specialty & Emergency, 2972 Iris Ave, Boulder, CO 80301
Gulf Coast Veterinary Specialists, 8042 Katy Fwy, Houston, TX 77024
Metropolitan Veterinary Hospital, 1053 S Cleveland-Massillon Rd, Akron, OH 44321

Study details

Open / currently enrolling

What is being offered: Phase 1 splenectomy/hemoabdomen study; dogs confirmed with non-metastatic splenic HSA can continue to fully funded active-treatment Phase 2, with treatment assigned among doxorubicin, doxorubicin+rapamycin, doxorubicin+sorafenib, or oral paclitaxel regimens.

Who may qualify: No metastasis; Active tumor required; Splenic primary; Planned surgery; Pre splenectomy; Min weight kg exclusive: 5; Max weight kg exclusive: 45

Costs / coverage: 🟡 Partially funded overall. Phase 1 provides $1,000 toward splenectomy; owners remain responsible for other initial surgical/screening costs. Dogs subsequently confirmed with splenic HSA and no metastases can enter fully funded Phase 2 (> $10,000 value). Sponsor states up to $3,000 for study-related side effects.

Contact: Ethos Discovery enrollment form / participating hospital; CASE: 303-545-2273

Official study / enrollment information →

Evaluation of TLR agonist Z-007 in dogs with cancer

Cummings School of Veterinary Medicine, Tufts University · USA

Location

Henry and Lois Foster Hospital for Small Animals, 200 Westboro Rd, North Grafton, MA 01536

Study details

Recruiting

What is being offered: Dog study of IV or intratumoral Z-007 for solid tumors including carcinomas, sarcomas and melanoma. Public criteria include a generally 2–7 cm repeat-biopsy-accessible tumor plus medical/laboratory requirements; no prior immunotherapy or autoimmune disease. Investigator prescreening required.

Who may qualify: Confirmed cancer diagnosis required; Min weight kg: 7; Measurable

May not qualify if: Prior immunotherapy

Costs / coverage: 🟡 Partially funded. Z-007 treatment through Day 63 and treatment of Z-007/biopsy-related side effects are covered; other owner costs should be confirmed with Tufts.

Contact: clinicaltrials@tufts.edu

Official study / enrollment information →

Experimental EGFR/HER2 tumor vaccine

Therajan / participating veterinary oncology centers · USA

Participating locations

Hope Veterinary Oncology, 1885 Knoll Drive, Ventura, CA 93003, Ventura, CA
Bridge Animal Referral Center, 8401 Main St, Edmonds, WA 98026, Edmonds, WA
WSU Veterinary Teaching Hospital, 205 Ott Rd, Pullman, WA 99164
MedVet Salt Lake City, 331 W Bearcat Dr, Salt Lake City, UT 84115
MedVet Cleveland, 20400 Emerald Pkwy, Cleveland, OH 44135
MedVet Pittsburgh, 2810 Washington Rd, McMurray, PA 15317
MedVet Cincinnati, 3964 Red Bank Rd, Cincinnati, OH 45227
IVO Integrative Veterinary Oncology, 2501 N. 32nd Street, Phoenix, AZ 85008, Phoenix, AZ
Veterinary Cancer Concierge Services, 1086 Long Ridge Road, Stamford, CT 06903, Stamford, CT

Study details

Currently enrolling at nine confirmed sites; Chicago, Richmond and Missouri are not enrolling

What is being offered: USDA-regulated EGFR/HER2 peptide-vaccine study led by Therajan. The current Canine Cancer Alliance status page identifies nine locations without a non-enrolling warning: Ventura, Edmonds, Pullman, Salt Lake City, Cleveland, Pittsburgh, Cincinnati, Phoenix and Stamford. Its same roster marks Chicago, Richmond and Columbia, Missouri as currently not enrolling. Stamford was separately confirmed on Veterinary Cancer Concierge Services' current trial page, which provides its intake pathway, eligibility materials and appointment location. Site-specific eligibility, scheduling and costs vary; MedVet restrictions apply only to its hospitals. Bridge also considers pulmonary carcinoma and high-grade mast cell tumor after records review, but those site-only indications are not mapped to the shared protocol record.

Who may qualify: Anticipated survival over 3 months; Standard of care therapy; Histology or long bone osa exception

May not qualify if: Other immunotherapy; Alternative therapy; Other clinical study

Costs / coverage: The investigational vaccine is provided at no charge; site visits, conventional treatment, administration and monitoring may be owner-paid. VCCS publishes a $695 charge for each vaccine appointment plus required testing. Confirm exact site-specific costs before enrollment.

Contact: Hope Veterinary Oncology — 805-626-6551; Bridge Animal Referral Center — 425-697-2272; Washington State University — 509-335-0711; MedVet Clinical Studies — clinicalstudies@medvet.com; MedVet Pittsburgh — oncology.pittsburgh@medvet.com; IVO — 602-841-0626; Veterinary Cancer Concierge Services — info@vetcancerconcierge.com.

Official study / enrollment information →

Compassionate-Use Protocol for Advanced Non-Resectable Tumors

UT Southwestern Veterinary Research and Oncology Clinic · USA

Location

Veterinary Research and Oncology Clinic, 5801 Forest Park Rd, Dallas, TX 75235

Study details

Current

What is being offered: Investigational therapy, chemotherapy, immunotherapy and combination approaches under a prospective compassionate-use protocol

Who may qualify: Confirmed cancer diagnosis required; Active tumor required; Min weight kg exclusive: 2.5; min expected survival weeks: 3 weeks; Adequate organ function

May not qualify if: Severe systemic disease

Costs / coverage: ⚪ Owner-paid. The protocol brochure states that owners fully pay for the study, although possible subsidies may be available.

Contact: Paige Neumann, Research Study Coordinator — 214-645-6221; VROC@UTSouthwestern.edu

Official study / enrollment information →

Chemotherapy with temozolomide and propranolol for canine hemangiosarcoma

UT Southwestern Veterinary Radiation Oncology Clinic (VROC) · USA

Study details

Active - Recruiting

What is being offered: Treatment study for canine hemangiosarcoma using doxorubicin/carboplatin chemotherapy with temozolomide and propranolol. Public recruitment information includes splenic, hepatic, cardiac and intramuscular hemangiosarcoma. Full eligibility requires study-team prescreening.

Who may qualify: Confirmed cancer diagnosis required; Planned chemo; min expected survival weeks: 2 weeks; Prior doxorubicin and carboplatin review

Costs / coverage: ⚪ Unfunded — AVMA lists this protocol as unfunded; confirm current owner costs with VROC.

Contact: VROC@utsouthwestern.edu

Location

Texas, USA

Official study / enrollment information →

Single-fraction SABR for progressive canine lung metastases

Tufts Cummings School of Veterinary Medicine · USA

Location

Henry and Lois Foster Hospital for Small Animals, 200 Westboro Rd, North Grafton, MA 01536

Study details

Recruiting

What is being offered: Single highly focused radiation dose for dogs with 2–10 progressive pulmonary metastatic nodules. The primary tumor, regional nodes and any non-pulmonary metastases must already be controlled; progression must be documented over 6–8 weeks, and all progressive lung lesions at least 5 mm must be safely treatable. Prior systemic therapy is allowed; cytotoxic chemotherapy pauses around SABR, while tolerated targeted therapy or immunotherapy may continue with radiation-oncologist approval. Tufts prescreening is required.

Who may qualify: Confirmed cancer diagnosis required; Active tumor required; Metastatic; Measurable lung metastases; Planned radiation

Costs / coverage: 🟡 Partially funded. The study covers SABR, the one-month follow-up, adverse-event rechecks related to lung toxicity, and up to $860 toward the 2–3-month CT visit. Owners pay pre-enrollment bloodwork, chest imaging, treatment-planning CT, and diagnostic confirmation.

Contact: Tufts Clinical Trials Office — clinicaltrials@tufts.edu; owner and referring-veterinarian prescreening questionnaires on the official page

Official study / enrollment information →

FAM-010 chemotherapy for canine splenic hemangiosarcoma — enrolling soon

University of Illinois Veterinary Teaching Hospital · USA

Location

University of Illinois Veterinary Teaching Hospital, 1008 W Hazelwood Dr, Urbana, IL 61802

Study details

Enrolling soon; study inquiries accepted through the sponsor form. Confirm the next dose-group opening with the study team.

What is being offered: Investigational albumin-linked doxorubicin (FAM-010), given by intravenous infusion every three weeks. Six treatments are planned initially; some dogs may receive up to twelve. All study dogs receive FAM-010; no placebo.

Who may qualify: Splenic primary; Planned doxorubicin; Eligible cohorts: Surgery: Yes; Prior procedure: Splenectomy; Required preferences: Surgery

May not qualify if: Prior chemo; Prior local radiation

Costs / coverage: Familiar covers study screening, FAM-010 treatment and study follow-up care. Owners pay travel to and from Urbana. Coverage of the preceding splenectomy or unrelated care is not specified.

Contact: Use Contact the study team on the official Familiar study page. The form connects eligible inquiries with the Illinois team; confirm when a dose group can start.

Official study / enrollment information →