Oncology: Thoracic tumors, OSA, urogenital, sarcomas, and MCTs (E2) Flashcards
What is most commonly the presenting complaint with chest wall tumors? What is the typical signalment?
Owners notice a firm and fixed thoracic wall mass
Middle aged large dogs
What is the most common chest wall tumor? 2nd most common?
OSA
CSA
How do you work up and stage a chest wall tumor?
- Rads
- Cytology to diagnose it as a sarcoma
-
Open (wedge) biopsy for subtype of sarcoma *SUPER IMPORTANT*
Large biospy from center of field, minimize hemorrhage - CT for surgical planning
What form of chest wall tumor is often misdiagnosed as a chondrosarcoma and why is this misdiagnosis particularly problematic?
Chondroblastic OSA
Very very aggressvie tumor
How do you treat chest wall tumors? How many ribs can you remove, at most? When would you perform a diaphragmatic advancement? What can you use to help close large defects following ressection?
En bloc exision w/chest wall reconstruction
Max 6 ribs
If the mass is located in the caudal thorax
Prosthetic mesh augementation
For what type of chest wall tumor is adjuctive chemo recommended?
OSA
(not with CSA)
While a 3cm skin margin is not required for chest wall tumors, where is it important to get margins?
Around biopsy tract
What must you place before completing reconstruction after removing a chest wall tumor?
Place a thoracic tube
Is the MST longer for chest wall OSA or CSA?
CSA
(299-1080d vs 129-249d (depending on if doing chemo for OSA or not)
What unique comorbidity occurs in cats with lung tumors?
Lung-Digit Syndrome (mets to weight-bearing digits and 3rd phalanx) - Lameness
What is the most common lung tumor in dogs and cats and how are these tumors classified? Which subtype is more common in dogs? Cats?
Carcinomas (ACA)
By location
Dogs: Bronchoalceolar
Cats: Bronchial (larger airways)
What staging method for lung tumors should be done with US guidance and under sedation? What is an essential tool for staging and why?
Transthoacic FNA/cytology
CT = essential because if metastasis to LN has occured the prognosis is poor
Why should you never amputate a cats digits without first taking chest rads?
Because the tumors on the digits are mets from a primary lung tumor, removing the toes will not prolong survival nor will removing any lung because this presentation indicates advanced disease
What are the 5 prognostic variable for lung tumors in dogs?
Tumor size (smaller=better)
Location (more peripheral=better)
Presence of CS (coughing=worse)
Clinical change (mets=worse)
Histologic score (vascular/lymphatic invasion=worse)**POST-OP DETERMINATION*
What is the diference in MST in a cat with a poorly differentiated vs a well differentiated lung tumor? The presence of what is also a negative factor?
Poorly=2.5 mo
Well=23 mo
Pleural effusion
What breeds are predisposed to histocytic sarcoma?
Bernese mountain dogs
Flat-coated retreiver
A 10 year old cat presents with a mediastinal tumor as well as edema around the head, neck and forelimbs. What does this cat have and what caused it?
Caval syndrome
Tumor invasion into the cranial vena cava
What are the 2 most common cranial mediastinal tumors?
LSA
Thymoma
A dog that has a cranial mediastinal mass and megaesophagus probably has a ______.
Thymoma
What will a cytology of a thymoma reveal? What can be done to differentiate thymic lymphocytes from lymphoma?
Neoplastic epithelial cells with large numbers of small mature lymphocytes as well as intermittent mast cells
Flow cytometry
How are thymomas classified? Which is more common in cats? What is the treatment (include any meds)?
As invasive or non-invasive
Cats: Non-invasive (50-100%)
Surgery= Gold standard treatment
Cats should always get steroids
Is the prognosis better for dogs or cats with thymoma?
Cats (MST 1825d vs 790d)
What are the 3 poor prognostic factors for dogs with thymoma?
Young age
Megaesophagus
Histologic subtype (Lymphocyte rich variant better)
What is the most common primary bone tumor in dogs and cats? Which species is affected more commonly and where do they tend to form?
OSA
Dogs
Appendicular skeleton
What is the typical signalment for OSA in dogs?
Neutered male large to giant breed (Rottweiler, Great dane, Scottish deerhounds) either 1-2yrs old or 7-9yrs old.
What are your top differentials for primary bone tumors in dogs?
OSA
CSA
FSA
HSA
If a dog presents with systemic illness and a mass that looks a lot like an OSA, what else could it be (other than a tumor)?
Infectious fungal disease: Valley Fever (Coccidiodes immitis), Blastomyces dermatitis
What is the most common location for an OSA to form? 2nd most common?
Distal radius
Proximal humurus
Away from the elbow, toward the knee
What are the 3 basic types of OSA? Which is most common?
Endosteal (most common)
Periosteal
Parosteal
What diagnostics should you perform for OSA?
CBC/Chem - Increased ALP is bad
Thoracic met check or CT met check
Localized imaging
Nuclear scintigraphy (gold standard) or full body rads
What is the typical radiographic appearance of OSA?
A mix of lytic and blastic pattern
Loss of cortical bone
Periosteal proliferation
Palisading coritical bone (sunburst effect)
Codman’s triangle (periosteal lifting caused by subperiosteal hemorrhage)
Loss of fine trabecular pattern in metaphyseal bone
Pathologic fractures with metaphyseal collapse
Why does OSA not cross joints?
Cartilage provides a barrier due to collagenase inhibitors (may inhibit tumor cell invasion or neoangiogenesis)
How can OSA be diagnosed?
FNA/cytology (into medullary cavity) *PREFERRED*
Bone biopsy- Jam Shedi (small diameter, gold standard) or Michele trephine (large core, more risk)
What is the gold standard for locally controling primary bone tumors? What do you need to do if you have a proximal femoral lesion?
Limb amputation
(Thoracic- Forequarter technique
Pelvic - Coxofemoral disarticulation)
Must be more aggressive w/surgery and do en-bloc acetabulectomy or subtotal hemipelvectomy
What is the most common reason for performing limb-sparing procedures for bone tumors?
Owner reluctance
What are the contraindications for limb salvage procedures with bone tumors?
Large lesion (>50% diaphysis involved)
Extensive soft tissue involvement
Pathologic fracture
Poor owner compliance
Advanced disease
Inappropriate location of tumor
At what sites is limb salvage surgery the primary mode of therapy? What are common complications and what’s the silver-lining for one of these ?
Distal radius
Distal ulna (gold standard in this location)
Digit or metacarpus/tarsus
Scapula
Complications: Implant failure, infection (silver lining is tat those that get infections survive longer than those who do not)
What is the minimum aount of radiation a bone tumor needs to get when doing SRS?
35 Gy
What is the best site for SRS based on low post-op fracture rates?
Proximal humerus
T/F: Adjunctive chemo is recommended in all cases of canine OSA.
True
What is the go to choice for adjunctive chemo for OSA in dogs?
Carboplatin
What are aminobisphosphonates? Why are they used? Name 2 drugs in this class.
Palliative therapeutic option for OSA that ingibits osteoclastic bone resorption
Zoledronate (IV)
Pamidronate (IV)
Is radiation a good palliative therapeutic option for a dog with OSA? Why or why not?
Yes, reduces local inflammation, minimizes pain, slowes progression of mets and improves QOL.
What is the prognosis for a dog with OSA with palliative therapy alone? Surgery alone? Surgery or SRS with chemo?
P: 1-3 mo (‘P’ rhymes with ‘one to three’)
S: 4-6 mo
S+C: 8-12 mo (double S alone)
What are prognostic indicators for dogs with OSA?
Body weight (smaller/lighter=better)
Age (older=better)
Site (prox humerus= worse)
Volume (larger-worse)
Histologic grade
Alkaline phosphate (every 100 I/L increase = 25% increase in risk of death)
What are the prediliction sites for feline OSA? Is it more or less aggressive than in dogs? What is the standard of care and the MST?
Distal femur
Proximal tibia
Proximal humerus
(Elbow, Shoulder, Knee)
Less aggressive in cats
Amputation without chemo - MST 24-49mo
What is the most common canine bladdeer tumor? What is the most common non-neoplastic DDx?
TCC
Polypoid cystitis (non-neoplastic)
What has been implicated in the etiology of bladder neoplasia in dogs?
Topical insecticides and heribicide exposure
Environmental pollution (city life)
Obesity (pesticides accumulate in fat)
Female gender (pee less)
Cyclophosphamide administration
Breed
What breed is the most predisposed to developing bladder neoplasia? What other breeds are predisposed. How can the risk be minimized?
Most common: Scottish Terriers
Also: WHWT, Beagle, Sheltie, Fox Terrier
Minimize risk by feeding vegetables (E.g. carrots) at least 3x per week, limit exposure to lawn chemicals and older flea/tick products
Where is the most common location for TCC development?
Trigone of bladder (urethral and prostate involvement common)