Hemangiosarcoma in Dogs: A Veterinary Lecture (PDF)

Hemangiosarcoma Travis Laver, VMD PhD DACVIM (oncology) Assistant Professor of Oncology UGA College of Vet Med insidescientific.com Objectives After this lecture, you should be able to: List the anatomic forms of canine hemangio...

Hemangiosarcoma Travis Laver, VMD PhD DACVIM (oncology) Assistant Professor of Oncology UGA College of Vet Med insidescientific.com Objectives After this lecture, you should be able to: List the anatomic forms of canine hemangiosarcoma Discuss the biological behavior of canine hemangiosarcoma Discuss the differential diagnoses for a ruptured splenic mass (in a dog) in an emergent setting (i.e. double 2/3s rule) Formulate a diagnostic and staging plan for a patient diagnosed with hemangiosarcoma Discuss general prognosis for cutaneous, splenic and cardiac hemangiosarcoma Etiology and Tumor Biology Cell of origin: endothelial cells Etiology incompletely understood Dermal HSA – strong link to UV exposure Biology: ~50% have mutations in PTEN (a tumor suppressor) High expression of VEGF (a pro-angiogenic peptide) Anatomic Sites Spleen – common Skin – less common Right atrium/auricle – less common Miller’s Anatomy of the Dog 4th ed Liver – less common Bone – rare Retroperitoneal - rare Webmd.com Vectorstock.com myfreephotoshop.com Biological Behavior Highly locally invasive Highly metastatic Exception: Stage 1 cutaneous HSA (more later) Target organs: lungs, liver, regional lymph nodes, omentum, mesentery Most common secondary (metastatic) brain tumor in dogs Rapid growth purrduedvm.blogspot.com Signalment Older dogs Breeds: German Shepherds Goldens Labradors Cutaneous: lightly haired, lightly pigmented dogs that like to sunbathe History Physical Exam Vary from mild lethargy/inappatence Can be normal to collapse and hypovolemic shock Cranial organomegaly +/- palpable +/-intermittent periods (over days to mass possible weeks) of lethargy or collapse w/ Acute to chronic blood loss: pale recovery mucous membranes, weak to bounding pulses, tachycardia, low Cutaneous HSA often red, ulcerated body temp and may bleed frequently Muffled heart sounds secondary to pericardial effusion Cutaneous/SQ mass (see history) Hemoabdomen/Splenic Mass Stabilize the patient! Bloodwork Abdominocentesis or pericardiocentesis Imaging Diagnosis Stabilize the patient! Bloodwork: CBC Thrombocytopenia Anemia (regenerative v. non-regenerative) Schistocytes possible Chem Liver value elevations Poor perfusion v. metastatic disease Clotting profile PT/PTT often prolonged ~50% have findings consistent with DIC Abdominocentesis or pericardiocentesis Imaging Diagnosis Stabilize the patient! Bloodwork Abdominocentesis or pericardiocentesis Ultrasound guided Abdominocentesis can be done blind Non-clotting hemorrhagic effusion PCV fluid = PCV peripheral blood Fluid cytology usually not helpful (hemodilution) Imaging Diagnosis Stabilize the patient! Bloodwork Diagnostic abdominocentesis or pericardiocentesis Imaging (site dependent) Radiographs AXR: peritoneal effusion, cranial abdominal mass effect CXR: globoid heart, less likely to help with dx Important for staging (r/o metastasis) Abdominal ultrasound Echocardiography Cross-sectional imaging (CT/MRI) Rajagopalan et al JVIM 2013;27:1092-96 Right Atrial Hemangiosarcoma Splenic Mass Differential Diagnosis Differential dx: Benign (hematoma, hemangioma) Malignant (HSA) Ruptured splenic mass: Double 2/3s rule is ok estimate Step 1: 2/3 malignant, 1/3 benign Step 2: 2/3 of malignancies are HSA May be as high as 65-70% of all are HSA Incidentally noted splenic nodules: 70% benign Only way to know for sure: histopathology Bigger masses may be higher % benign (not reliable) Higher mass to splenic volume ratio Higher splenic weight as a % of body weight lapoflove.blogspot.com Splenic hemangiosarcoma: most have a ruptured mass at initial presentation (T2) making them at least stage II Important staging distinction in cutaneous HSA: T1 vs T2 T1 isolated to dermis, not invading below basement membrane à stage 1 à good prognosis T2 invading into SQ à stage 2 à prognosis more guarded From Withrow and McEwen Small Animal Clinical Oncology 5 th ed Staging CXR/CT 3-view chest radiographs or thoracic CT AUS Echocardiography Abdominal explore + bx of abnormalities dog-health-handbook.com Staging CXR/CT AUS (or abdominal CT): Part of complete staging of HSA of any site Key organs: Spleen Liver Nodules in older dogs aren’t always metastasis! Lymph nodes Omentum and mesentery Other (kidney, retroperitoneum, etc…) Echocardiography Abdominal explore + bx of abnormalities Staging CXR/CT AUS Echocardiography Up to 24% of splenic HSA have concurrent cardiac mass Abdominal explore + bx of abnormalities Rajagopalan et al JVIM 2013;27:1092-96 Staging CXR/CT AUS Echocardiography Full abdominal explore at the time of surgery + biopsy of abnormalities Example: liver nodules Treatment - Surgery Splenic mass: splenectomy Cutaneous: STS margins 2-3 cm, 1 fascial plane deep Cardiac Very rarely right auricle masses might be resectable Pericardectomy To prevent tamponade resulting from bleeding events May prevent acute deat, but does not extend survival Treatment – Radiation Therapy Palliative protocols for cardiac HSA Impact relatively unknown Difficult to treat with high doses due to movement of heart Treatment - Chemotherapy Best outcome: surgery + chemotherapy Exception: stage I cutaneous HSA Agent of choice: doxorubicin IV q2-3 weeks X 5 Chemo alone: No benefit in splenic HSA Doxorubicin extends survival in cardia HSA Complementary and Alternative Therapies Yunan Baiyao Herbal remedy Mechanism? Enhanced surface glycoprotein expression on platelets? Might be mildly cytotoxic to HSA cells Controversies regarding manufacturing: Inclusion of pangolins in product Consistency of product Aminocaproic acid – prevents fibrinolysis Tranexamic acid – prevents fibrinolysis Any of the above might help with small bleeding events but aren’t likely to prevent/stop large bleeds Complementary and Alternative Therapies Polysaccharopeptide Bioactive component of Coriolus versicolor (“turkey tail” mushroom) Commercial product: I’m Yunity Anti-tumor activity in vitro Small (15 dogs) double-blind, randomized clinical trial (2012) Very little toxicity Delayed progression of metastases Improved survival times Interpret with caution Wikipedia.com Follow-up Splenic HSA: AUS and CXR q2-3 months Cutaneous: q3m PE and restaging (AUS/CXR) Patients w/ stage I UV-induced lesions: High risk for more lesions (regular PE very important) Low risk for metastasis (so +/- on AUS/CXR) High risk of local recurrence Others are patient/site/treatment dependent storyblocks.com Bleeding splenic mass Stage 2: Surgery alone: 1-3 months Surgery + chemotherapy: 4-6 months Stage 3: short (usually weeks) Miller’s Anatomy of the Dog 4th ed Cutaneous (completely excised): Stage 1 (not invasive into subQ): good prognosis (> 2 years) High local recurrence/new lesion rate (70% +) Stage 2 (invasive into subQ): good w/ aggressive tx (surgery + adjuvant chemo) (up to 18 months) Prognosis Cardiac Surgery (rare) + chemo: ~ 6 months Chemo alone: ~ 3-6 months RT: TBD canstockphoto.com Feline HSA Most commonly skin/sq and abdominal Skin/SQ behaves similar to other STS Spleen (and other abdominal sites) behaves similar to K9 spleen CASE BLOODWORK