Podcast
Questions and Answers
What is the primary characteristic of osteosarcoma mentioned in the content?
What is the primary characteristic of osteosarcoma mentioned in the content?
Which imaging technique is essential in the diagnosis and staging of osteosarcoma?
Which imaging technique is essential in the diagnosis and staging of osteosarcoma?
What is one of the two key reasons for opting for a fine needle aspirate (FNA) in osteosarcoma diagnosis?
What is one of the two key reasons for opting for a fine needle aspirate (FNA) in osteosarcoma diagnosis?
What complicating factor might arise from a bone biopsy?
What complicating factor might arise from a bone biopsy?
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Which histologic grade of osteosarcoma indicates the highest percent of necrosis?
Which histologic grade of osteosarcoma indicates the highest percent of necrosis?
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After chemotherapy for osteosarcoma, which area is most likely to experience treatment failure?
After chemotherapy for osteosarcoma, which area is most likely to experience treatment failure?
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What is a common method for obtaining histological samples from a tumor?
What is a common method for obtaining histological samples from a tumor?
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In the study mentioned, what was the composition of the tumor grades among the 166 dogs evaluated?
In the study mentioned, what was the composition of the tumor grades among the 166 dogs evaluated?
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What characteristic is commonly seen with soft tissue sarcomas in dogs?
What characteristic is commonly seen with soft tissue sarcomas in dogs?
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What percentage of Grade 1 soft tissue sarcomas metastasize?
What percentage of Grade 1 soft tissue sarcomas metastasize?
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Which malignancy is characterized by its origin in tenosynovial tissue?
Which malignancy is characterized by its origin in tenosynovial tissue?
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What is a key factor in determining the prognosis of soft tissue sarcomas?
What is a key factor in determining the prognosis of soft tissue sarcomas?
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What does a wide surgical excision aim to achieve?
What does a wide surgical excision aim to achieve?
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Which type of sarcoma has the highest occurrence in the provided incidence statistics?
Which type of sarcoma has the highest occurrence in the provided incidence statistics?
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What is the treatment approach for a high-grade soft tissue sarcoma?
What is the treatment approach for a high-grade soft tissue sarcoma?
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In which species is the histopathology grade expected to predict metastatic potential for sarcomas?
In which species is the histopathology grade expected to predict metastatic potential for sarcomas?
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Which factor is commonly associated with paraneoplastic syndrome in tumors?
Which factor is commonly associated with paraneoplastic syndrome in tumors?
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How are soft tissue sarcomas classified histologically?
How are soft tissue sarcomas classified histologically?
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What is the most common primary bone tumor in dogs and cats?
What is the most common primary bone tumor in dogs and cats?
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What is a significant risk factor for the development of feline injection-site sarcoma?
What is a significant risk factor for the development of feline injection-site sarcoma?
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What is the initial treatment recommendation for vaccine-site reactions that persist for more than 3 months?
What is the initial treatment recommendation for vaccine-site reactions that persist for more than 3 months?
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What percentage of vaccinated cats are expected to develop post-vaccinal reactions?
What percentage of vaccinated cats are expected to develop post-vaccinal reactions?
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What role does dysregulated p53 play in tumor development related to inflammation?
What role does dysregulated p53 play in tumor development related to inflammation?
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What is the expected median survival time for patients undergoing chemotherapy for metastatic bone disease?
What is the expected median survival time for patients undergoing chemotherapy for metastatic bone disease?
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What is a potential downside to using amputation as a treatment for limb disease?
What is a potential downside to using amputation as a treatment for limb disease?
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Which of the following palliative treatments is considered to potentially prolong the life of patients with bone tumors?
Which of the following palliative treatments is considered to potentially prolong the life of patients with bone tumors?
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What is a characteristic of patients suitable for limb spare surgery?
What is a characteristic of patients suitable for limb spare surgery?
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What is the major concern for owners regarding the decision to proceed with amputation for their pets?
What is the major concern for owners regarding the decision to proceed with amputation for their pets?
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What type of treatment is described as having excellent outcomes when applied to the ulna?
What type of treatment is described as having excellent outcomes when applied to the ulna?
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Which palliative treatment is indicated for systemic disease in bone cancer?
Which palliative treatment is indicated for systemic disease in bone cancer?
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What is an appropriate palliative medication dosage for gabapentin?
What is an appropriate palliative medication dosage for gabapentin?
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Study Notes
Musculoskeletal Neoplasia
- Musculoskeletal neoplasia is a common and problematic disease.
- Over 99% of animals die from the disease.
- There are many treatment options available.
- A good quality of life is achievable for some patients.
Learning Objectives
- The presentation aims to cover the origins of common soft tissue sarcomas.
- Factors affecting the prognosis of these types of cancers.
- The difference between canine and feline soft tissue sarcomas.
- How bone sarcomas differ.
- Major treatment options for osteosarcoma.
Classification
- Connective tissue cancers, including bone, muscle, collagen, cartilage, blood vessels, and nerves, are classified as sarcomas (-Oma).
- Epithelial tissue tumors, such as glandular, secretory, and lining tissues, are classified as carcinomas (-Oma).
- Round cell tumors, such as immune cells and melanocytes, generally end with -Oma.
Soft Tissue Sarcomas (STS)
- Spindle cell sarcoma and mesenchymal tumors are soft tissue sarcomas (STS), arising from mesenchymal origins.
- STS can arise in different body areas, including subcutaneous, alimentary, and urinary tracts.
Clinical Appearance
- Soft tissue sarcomas often present as soft, fluctuant, and mobile subcutaneous masses in dogs.
- About 15% of canine skin and subcutaneous masses are soft tissue tumors.
Palpate LNs & Haemogenous Spread
- Lymph nodes (LNs) should be palpated to check for reactive responses.
- Three-view chest radiographs are essential, as these sarcomas commonly spread via the bloodstream (haemogenous spread).
- Tumor grade (I, II, or III) correlates with the likelihood of metastasis. (I = lowest chance of spread).
Tumour Biology
- Characterized by locally aggressive and expansive growth with a malignant halo.
- Tumor cells often form a heterogenous mass.
- Extra-compartmental spread and poorly defined margins are common.
- Distant metastasis is possible, and the grade of the tumor impacts the likelihood of distant metastasis.
Enneking Resection Classification
- This classification system describes different tumour resection approaches.
- Includes terms such as pseudocapsule, reactive zone, satellite and skip metastasis.
Onyx Myxosarcoma Grade II
- This particular presentation describes radiological findings of a low-grade myxosarcoma.
- The image shows a reactive response in the lymph nodes and vascular, mesenchymal, and inflammatory responses in the myxosarcoma tissue.
Wide Removal
- Tissue removal involves a margin of normal surrounding tissue or an anatomical mesodermal barrier (e.g., fascia, cartilage, or bone).
- The wide excision extends beyond the tumor mass.
Wide - 3cm and one fascial plane - This specific comment describes a surgical approach for wide removal that considers size and fascial plane.
Treatment Algorithm
- The treatment algorithm details surgical intervention considerations based on margin assessment, histological grade and chemotherapy.
- A biopsy is the first step.
- Clean surgical margins will usually determine the histological grade.
- The strategy and approach of the surgeon will be adjusted based on the tumor grade to determine whether chemotherapy is required.
Prognosis
- Early detection and appropriate management of grade 1 and 2 tumors, typically less than 5cm in diameter, result in better prognosis.
- One-year survival rate for these tumors is 95%.
- A two-year survival rate is 91%.
- A three-year survival rate ranges from 75%.
Fibrosarcoma
- Fibrosarcomas originate from the fibroblasts.
- It can develop in skin, subcutaneous tissues, oral, and nasal cavities and have a special form in the mouth
- Histologically, it is usually low grade but biologically high-grade (meaning faster growing and invasive)
- Has 20% metastasis rate.
Myxosarcoma
- Myxosarcomas start from fibroblasts that are modified by intercellular mucin.
- The biologic behaviour follows the tumour grade.
- Grade III is noted to be multi-recurrent.
Hemangiopericytoma/PNST
- The tumor originates from pericytes or nerve sheaths.
- Similar biologic behaviour to other neurogenic sarcomas, schwannoma, and neurofibrosarcomas.
- These tumors occur throughout the body.
PNST
- PNSTs are grouped based on their relationship to the central nervous system (CNS).
- Brain/spinal cord tumors are called "root" or "plexus," and peripheral tumors are classified separately from the CNS.
- Neurological changes, such as severe neuropathic pain, are possible clinical signs.
Liposarcoma
- Liposarcomas arise from new adipose tissue (de novo) but not from existing lipoma.
- Often seen in older dogs, they are locally aggressive and metastasize.
- Common in the ventral region of the body and can be subcutaneous.
- The tumor is firmer and not as easily palpated (felt by touch) compared to a lipoma.
Infiltrative Lipoma
- Non-malignant, non-metastatic.
- Locally infiltrative growth patterns, invading surrounding local muscles, fascial planes, and other structures like joints, abdominal cavity, nerves, and bone.
- Aggressive therapies, such as radiation, may be necessary.
- Radiation aims to reduce blood supply to the tumor.
Lymphangiosarcoma
- These tumors arise from lymphatic tissue.
- They are typically regional, soft, fluctuating, and edematous masses, frequently subcutaneous.
- These tumors can metastasize and are often mistaken in biopsy for a similar type of tumor, such as hemangiosarcoma.
- Lymphangiosarcoma channels do not contain red blood cells, while hemangiosarcoma channels do.
Rhabdomyosarcoma
- Originates from striated muscle tissue and often appears in younger dogs.
- Rhabdomyosarcoma is highly invasive.
- Metastasis is a significant concern, often occurring in lungs, kidneys, spleen, and adrenal glands.
- A particular type, botryoid rhabdomyosarcoma, is sometimes found in the bladder of large young dogs.
Leiomyosarcoma
- Originates from smooth muscle tissue.
- It can spread throughout the gastrointestinal tract, spleen, retroperitoneal space, genitourinary tract, and subcutaneous tissue.
- Locally aggressive and metastasizes according to grade.
- It may cause paraneoplastic syndromes, like hypoglycemia.
Synovial Cell Sarcoma
- Originates from the tenosynovial tissue.
- Early metastasis can occur to local lymph nodes.
- Most commonly affects middle-aged dogs.
- Stiffer joints like the knee are more commonly affected than the elbow.
- Histological grade may be used in the assessment to predict the metastatic potential.
- 22% of these tumors metastisize when first diagnosed, and 41% following treatment.
Feline Sarcomas
- Feline sarcomas have three main categories: viral, non-viral/non-vaccine, and injection-site sarcomas (ISS).
Non-viral non-injection sarcoma
- Commonly affect older cats.
- Often found in head and neck regions.
Injection-site sarcomas (ISS)
- A 61% increase in incidence from 1987–1991, coinciding with a shift in rabies vaccines from modified live to killed versions.
- Adjuvants may be a contributing factor.
- This type of sarcoma is associated with a range of vaccines and vaccination products.
ISS
- FeLV vaccination
- Vaccination for other feline infectious diseases
- Non-vaccine products, such as Lufenuron and Baytril
Aluminum Adjuvant
- The adjuvant aluminum can contribute to inflammation and expression of oncogenic factors.
- Increased PDGF, PGF expression, and dysregulation of p53 are possible.
- Inflammatory granulomas can be a precursor to a sarcoma formation.
Skin adjacent to tumour vs Tumour
- Different samples from a specimen show the concentration of copper and aluminum with respect to the disease and its prevalence around the affected site. This is a microscopic scale analysis.
Vaccine reactions
- 1.8% of vaccinated cats develop post-vaccination reactions, with the lesions reaching up to 6cm in diameter.
- Reactions typically resolve within 30 to 90 days.
- Lesions that persist for longer than 6 months or that exhibit significant malignant behavior need further evaluation.
Prevention and Monitoring
- Avoid over-vaccination and use single-dose vials.
- Maintain detailed vaccine records.
- Standardize and separate vaccination injections.
- Excise or biopsy any persisting reactions that are greater than 3 months old, greater than 2cm in diameter, or that increase in size after injection
- Report to USP Veterinary Practitioners.
Natural History OSA
- Osteosarcoma (OSA) is the most common primary bone cancer in dogs and cats.
- 85% of bone tumours in dogs is due to osteosarcoma
- 80% of osteosarcoma affects long bones or appendicular skeleton.
Lameness
- Lameness can range from mild to severe and from acute to chronic.
- Evaluation of the owner's response to analgesics and whether a bone may have fractured, is critical to treatment.
Implant/Fracture Induced
- Implantation or fracture events might induce tumors.
Biopsy Options
- Cytology (fine needle aspirate, roll-prep)
- Histology (needle core (Jamshidi), Michel trephine, incisional, excisional)
Jamshidi core biopsy
- Technique for surgical tissue sampling for histology.
Tumour grade I, II, III
- Tumour grade is determined by the presence or absence of pleomorphism in cancerous cellular structures, the number of mitotic figures, and the cellularity / necrosis of the tissue.
- An assessment of grade I, II, or III affects treatment and prognosis.
- In a specific study, grade 1 and 2 tumours show only 25%, while 75% of the tumors are grade 3.
Risks of bone biopsy
- Increased lameness.
- A possible pathological fracture.
- Results sometimes are non-diagnostic.
- Possible tumour seeding.
One needle, One greyhound, & One hour later...
- This describes a complication seen in an animal subjected to a biopsy. The changes in the x-rays indicate an undesirable effect of the procedure.
You've Got a Diagnosis, Now What?...
- Treatment options for a diagnosis include palliative home care, amputation alone, palliative radiation +/− chemotherapy, amputation and chemotherapy, limb-sparing surgery (and chemotherapy), and treating a pathological fracture.
Bone Cancer
- The decision for surgical intervention, limb sparing or amputation, is heavily influenced by the extent of involvement of soft tissue, owner perspective, and costs.
- The location where the cancer originated (or if it has spread) affects the appropriate approach for treatment.
- Tumor size, location, and its growth behaviour also need to be monitored and evaluated by the surgeon for treatment.
Home-care
- NSAIDs (as needed)
- Tramadol (>5 mg/kg TID)
- Gabapentin (3-10 mg/kg TID)
- Pamidronate (1 mg/kg slow IV q4w)
- Zoledronate (0.25 mg/kg slow IV q4w).
Amputation alone
- In cases that only require amputation alone, there is reduction in bone pain, possibly with a 11% one year survival rate. It is possible to die from the effects of metastases to other organs, such as lung metastasis.
Limbspare
- The type of limb sparing will affect prognosis and outcome for the patient.
Chemotherapy
- For certain diseases, Chemotherapy can keep patients alive for a longer period.
- The median survival rate with chemotherapy for these types of diseases should be between 10-12 months.
Canine Osteosarcoma - Chemotherapy plus amputation/limb sparing
- Presentation describes the use of different chemotherapeutic drugs and their impact on survival rates, post-amputation/or amputation.
Radiation
- External beam radiation is used for various purposes.
- Intent may be curative or palliative.
- Radioactive materials are used; samarium may be systemically or regionally applied.
In summary...
- Musculoskeletal neoplasia is a significant clinical problem, where most animals eventually succumb to the disease.
- Various treatment methods are available, though outcomes are often poor.
- Quality of life and successful management are goals.
Diagnosis/Workup
- Diagnosis begins with a comprehensive clinical assessment (CBC, Chem, UA), followed by relevant radiographic images (regional radiographs).
- CT and MRI are often helpful due to the invasive nature of many of these cancers, and due to their often-difficult locations.
Staging - Distant
- A study showed that the presence of distant disease is indicative of a poor prognosis for stage 3 disease and may mean chemotherapy is ineffective .
Biopsy - Atypical location / Appearance
- Atypical locations or appearances could necessitate a biopsy.
Biopsy - 2 good reasons to try an FNA
- Thin egg-shell cortex (bone affected)
- Soft tissue extension
- FNA (fine-needle aspiration) is suggested to assess for some of the potential risks.
Biopsy Options
- Different biopsy techniques are available: cytology (fine needle aspirate, roll prep), and histology (needle core, Michel trephine, incisional/excisional).
Risks of Bone Biopsy
- Increased lameness.
- Pathological fracture.
- Non-diagnostic results.
- Tumour seeding.
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Description
Test your knowledge on osteosarcoma and soft tissue sarcomas in dogs. This quiz covers key characteristics, diagnostic techniques, histological grading, treatment outcomes, and more. Ideal for veterinary students and professionals working with canine oncology.
