Oral Tumors

Question 1

Which IHC markers were used to confirm amelanotic melanoma in cats?
(Saverino, Vet Pathol, 2021)

Answer 1

Melan-A, PNL-2 and S-100

TRP-1, TRP-2 are not specific in amelonotic melanomas in dogs, therefore they were not used
MST was poor for all cats-82 days

Question 2

In a study of novel malignant head and neck tumors preoperative scintigraphy with intraoperative blue dye was examined for the detection of SLN in accordance with RLN.
What was the correspondance between RLN and SLN using this techniqe?
What was the sensitivity and specifity of this method?
(Chiti, VCO, 2021)

Answer 2

52%- in 4 dogs were the SLN different then RLN (mostly parotid LNs)

sens 88%, spec. 100% (not ideal for ruling out mets)

Question 3

What are the characheristics of malignant oral tumors on CT imaging?
Is it possible to differentiate benign and malignant tumors?
(Lee, Vet Radiol Ultras, 2021)

Answer 3

• larger tumors, heterogenous contrast enhancement, teeth loss, bone lysis, invasion in the nasal cavity and orbita, ipsilateral lymphadenopathy
• there is a considerable overlap

Question 4

According to a recent paper next to SCC what are the most common tonsillar tumors in the dog?
(Mickelson, VCO, 2020)

Answer 4

Lymphoma, Melanoma, Plasma cell tumor, metastatic disease from melanoma, HSA, carcinoma most commly.

Question 5

What is the most likely patomechanism of metastasis to the tonsils in dogs?
Mickelson, VCO, 2021

Answer 5

Most likely hematogenous spread as no afferent lymphatic drainige to the palatine tonsils could be identified via indirect computed tomography lymphography.

Question 6

Is there a relationship between KIT expression and c-kit mutation in oral melanocytic malenomas? Is KIT expression useful to determine c-kit mutation.
(Smedley, Vet pathol, 2021)

Answer 6

There is no apperent relationship between KIT expession and c-kit mutation.
Most mlanomas expressed KIT regardlessly of mutational status.
9 deleterious mutations were detected of c-kit (exon 11), but these mutations where most likely not driver mutations, they occured later and play a role in the differentiation of the tumor. They could be aquiring a more aggressive phenotype.

Question 7

Would you recommend TKI in canine melanocytic tumors according to KIT expression or c-kit mutation?
(Smedley, Vet Pathol, 2021)

Answer 7

Until now there is no evidence for their use. However their benefit cannot be completly excluded due to other possible receptors, which have not been investigated.

Question 8

What are the characteristics of well diffrentiated oral/lip melanocytic neoplasms?

Answer 8

< 2 cm in diameter, rarely ulcerated, heavily pigmented, lack cellular atypia, < 4 mitoses/10 hpf (2.37 m3), <19.5% Ki67

Question 9

Which SLN mapping method identified the most SLNs in head and neck tumors?
CT lymphography vs. indocyanine green near infrared fluorescence intraoperatively vs. methylen blue intraoperatively?
What was the SLN identification rate when all methods were combined?
(Wan, VCO, 2021)

Answer 9

With indocyanine green near infrared fluorescence.

100% with the combination

Question 10

Is radiotherapy with a definitive protocol adequate as a monotherapy in canine papillary SCC?
What was the median progression free survival and median survival time?
(van der Steen, VCO, 2021)

Answer 10

canine papillary SCC appears to be sensitive and RT as monotherapy is an option instead of extensive surgery
The median PFS and MST were not reached (mean 1203 days)
9 CR and 1 PR

Question 11

Is postoperative RT benefitial in oral incompletley excised SCC and FSA?
What were de MSTs with and without RT?
(Riggs, JAVMA, 2018)

Answer 11

SCC benefitial, FSA not
SCC MST 2051 vs. 180 days
FSA MST 299 vs. 694 days
-tumors with RT were located more caudally in the maxilla

Question 12

What was the MST for dogs with multilobular osteochondrosarcoma treated with SRT?
Was there a clinical response?
(Sweet, VCO, 2019)

Answer 12

The MST was 329 days (less then with surgery ca. 2 years–> depends on grade, complete excision and location)
in ca. 50% of the patients a clinical response was noted (20-80%)

Question 13

Which mutation occures in canine acantomathous ameloblastomas?
(Peralta, VCO, 2019)

Answer 13

HRAS (94% of cases)

Question 14

Is the infection with a feline papillomavirus (Feline catus papillomavirus type 2) definitive cause for feline SCC?
(Altamura, VCO, 2020)

Answer 14

No, the findings are only suggestive, because the viral DNA was found in non-neoplastic ulcerative oral lesions as well.

Question 15

When is RT indicated in feline salivary gland carcinomas?

Blackwood, JMFS, 2020

Answer 15

The use is unclear in the postoperative setting vs surgery alone, but it might be most benefitiary in high-risk tumors (large and invasive tumors, close or incomplete resection, high histo garde, neural or vascular invasion, positive lymphnode).

Question 16

What was the complication rate after mandibulectomy and maxillectomy in dogs? What was the overall severity?
(Cray, JAVMA, 2021)

Answer 16

The complication rate was 37 %, mostly minor complications.

Question 17

What increased the occurrence of >1 complication after mandibulectomy/maxillectomy?
What increased the rate of dehiscence and fistula formation?
(Cray, JAVMA, 2021)

Answer 17

Longer surgical time inceased the occurrence of postoperaive complications. (erach additional hour per 36%)
Preoperative chemo or RT and maxillectomy increased the rate of dehiscence and fistula formation.

Question 18

What are the advantages of a ventral mandibulectomy approch in dogs?
(de Mello Souza, VCO, 2019)

Answer 18

• The identification of important anatomical structures such as inferior alveolar artery and temporo-mandibular joint.
• Osteotomy of the zygomatic arch is not necessary
• Dissection of mand. and retropharyngeal lns is easily achieved

(Complications cervical swelling and self-limiting sublingual swelling)

Question 19

How was maxillectomy tolerated? What were the most common postoperative complications after feline maxillectomy?
What were the local recurrence and metastatic rates?
(Liptak, VCO, 2020)

Answer 19

Maxillectomy was much better tolerated in cats than mandibulectomy, where 95% of cats developed postoperative complications (hyporexia being the most common with 72%, and 12% of cats never eating again). In contrast 20% developed hyporexia and 20% incisional dehiscence, which were the most common complications.
The local recurrence was 18,3% and 4,9% of mets occured.

Question 20

What were the 1- and 2-year survival times for malignant tumors for cats with maxillectomy? What about SCC, FSA and OSA?
(Liptak, VCO, 2021)

Answer 20

1- and 2-year ST: 89 and 89%
FSA: 94% and 94%
SCC: 83% and 83% (!!!)
OSA: 80% and 80%

median PFS and MST were not reached

Question 21

What were the negative prognostic factors in cats undergoing maxillectomy?
(Liptak, VCO, 2021)

Answer 21

MI for PFI
adjuvant chemo for PFI and ST
local recurrence for ST

-addition of chemo was probably biast, e.g. in incompletley excised (due to low met rate and low response to chemo, probably other methods such as additional surgery or RT are more indicated)

Question 22

Which indirect CT lymphography identified more SLN in head and neck tumors? Direct or 4 quadrant peritumoral injection of contrast?
Which is the most reliable method? indirect CT lymphography, intraoperative methylene blue dye or lymphoscintigraphy?
(Randall, VCO, 2020)

Answer 22

Peritumoral injection is more precise.

Lymphoscyntigraphy is the most reliable method.

Question 23

What was the response rate and toxicity profile of dogs with oral SCC to electrochemotherapy? What was the recurrence rate?
Which dogs would benefit the most from electrochemotherapy?
(Simcic, VCO, 2019)

Answer 23

The response rate was one 90.9 % (9 CR, 1 PR/11 dogs)
The recurrence rate was high 27.3% in comparison to surgery (8-18%)
Dogs with tumors smaller than 1-2 cm could benefit the most from ECT.

Question 24

What is “vascular lock” in ECT?

Answer 24

Reduced blood flow and subsequent retention of chemotherapeutics within the tumor.

Question 25

What kind of cell death is expected in ECT?

Answer 25

Apopotsis, Necrosis and subsequent immunogenic death (due to release of neoantigens/DAMPS and activation of the innate immune system)
The 3 most important DAMPS are: calreticulin, ATP and HMGB1 (high mobility group box 1) protein

Question 26

Which chemoterapeutics can be utilized in ECT?

Answer 26

Hydrophilic chemotherapy, like bleomycin and cisplatin.

Doxo and Mito has also been used.

Question 27

What is the mechanism of electroporation?

Answer 27

Electroporation is the increase of cell membrane permeability through the application of short high-voltage electrical pulses, which allows the passage of water soluble ions and molecules into the cell.
It can be permanent (low voltage, longer duration pulses) causing direct death or reversible with the delivery of chemotherapy or genes (plasmids).