Lecture 20: Nasal Tumors and Tumors of the CNS

Question 1

• Uncommon
• 1-2% of all neoplasia in dogs
• Average age: 10 years
• Clinical signs (2-3 mo)
• Ddx includes: fungal or bacterial rhinitis, idiopathic nonspecific rhinitis, rare nasal hypertension, FB and trauma

Answer 1

Intranasal Tumors
- Carcinomas (60-75% nasal cancer)
- Sarcomas
- Rare tumor

Question 2

(T/F) Intranasal Tumors metastasis is uncommon at the time of diagnosis

Answer 2

True
- Progressive local invasion is common

Question 3

(T/F) Intranasal Tumors metastasis is uncommon at the time of diagnosis

Answer 3

True
- Progressive local invasion is common

Question 4

What type of dog has a 2-2.5x risk of developing nasal cancer?

Answer 4

Dolichocephalic breeds

Question 5

Diagnosis and staging tests for Nasal Tumors:

Answer 5

Diagnosis:
- CBC / Chem / UA / Coagulation
- Chest X-rays
- Skull CT
- Mandibular LNs FNA
- Biopsy and histopathology
Clinical Staging: Adams’ Modified system
- T1: Confined to one nasal passage w/ no bony involvement
- T2: Bony involvement, without evidence of orbit, subcutaneous, or submucosal mass
- T3: Involvement of orbit, or nasopharynx, or a subcutaneous, or submucosal mass
- T4: Tumor extension into or through cribriform plate

Question 6

Treatment options for Nasal tumors:

Answer 6

• Symptomatic (palliative) care (95 days)
  
  • Addition of NSAIDs DID NOT prolong survival time
• Surgery post-RT
  
  • Difficult
  • 3-6 months
  • Small tumors can be treated with preoperative RT followed by dorsal rhinotomy
    - MST: 48 mo vs 20 mo for RT alove
• Chemotherapy
  
  • Poor perfusion into bulky nasal tumors
  • Cisplatin, Carboplatin + Doxorubicin + Piroxicam, Palladia
• Radiation therapy

Question 7

Negative Prognostic Factors of Nasal Tumors:

Answer 7

• Age >10 years
• Epistaxis at time of diagnosis
• Metastasis: LNs & lungs
• Cribriform plate destruction on images
• Tumor histological subtype
  - MST: Carcinoma < Sarcoma
  SCC < Adenocarcinoma

Question 8

Describe the biological behavior of brain tumors in dogs and cats:

Question 9

Construct the diagnostic approach to brain tumors in a dog and cat:

Question 10

Describe the imaging approach to brain tumors in a dog and cat:

Question 11

Construct a treatment option for a brain tumor in a dog and cat:

Question 12

what is the most common brain tumor in dogs?

Answer 12

Meningioma (Primary Brain Tumors) (45%)
- Age: >5 years

Question 13

What breeds are more likely to get Meningiomas & Choroid plexus tumors?

Answer 13

Large breed dogs

Question 14

What breeds are more likely to get Gliomas?

Answer 14

Brachycephalic breeds

Question 15

(T/F) Brain tumors are common in cats

Answer 15

False, Less common (2%)
- 70% are PBT, >50% meningiomas
- SBT: LSA (50%) and pituitary tumors (30%)

Question 16

For brain tumors, what must be done PRIOR to advanced diagnostics/treatments?

Answer 16

Minimum data base
- CBC, chemistry panel, urinalysis

Question 17

What is the definitive diagnosis and grading?

Answer 17

Histopathologic examination
- Excisional biopsy:
- curative-intent surgery
- Limited to patients w/ superficially located, extra-axial forebrain or cerebellar tumors

Question 18

• Arise from the meninges
• most common PBT in dogs (45%)
• Usually relatively slow growing
• More invasive into the brain parenchyma than cat meningiomas
• Most common extra-axial origin
• Broad-based skull attachment, distinct tumor margins, marked and often uniform contrast enhancement

Answer 18

Meningiomas

Question 19

• Can range in malignancy from low grade and slowly growing to high grades, poorly differentiated malignant tumors (GBM)

Answer 19

Gliomas (brachycephalic)
- Ring-enhancing pattern
- no way to differentiate b/w type and grade based on imaging
- often poorly marginated, may not contract to enhance

Question 20

Brain Tumor Therapy: Goals

Answer 20

Control secondary effects
- Seizure control if warranted
- Cerebral edema
Eradicate the tumor/reduce its size
- Surgery
- Radiation therapy
- Medical treatment (chemotherapy)

Question 21

Palliative Care

Answer 21

• Manage seizures - anticonvulsant drugs (ACD)
  
  • Phenobarbital
  • Keppra (levetiracetam)
  • Zonisamide
• Peritumoral edema – corticosteroids
• Pain control
  
  • steroids, opioids, neuropathic pain agents - gabapentin

Question 22

(T/F) RT is a relatively effective and noninvasive treatment for local control of nasal tumor

Answer 22

True
- MST of definitive RT: 1-1.5 y

Question 23

• Is a radiation delivery technique
• Allow doses of radiation delivered to tumor
• Avoid normal adjacent tissues

Answer 23

IMRT

Question 24

(T/F) Brain tumors are typically diagnosed with MRI, very rarely do we get a histologic diagnosis

Answer 24

True