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J. Kirpensteijn1
1Hil’’s Pet Nutrition, GPVA, Topeka, USA
Canine Oral Malignant Melanoma Epidemiology
Materials and Methods: VSSO Symposium 2016
During the VSSO symposium in Napa, California (2016), COMM were discussed. A pre-event enquiry was sent
to the VSSO liststerve with questions pertaining to COMM and similar questions were discussed. During the VSSO discussion a maximum of 99 oncology interested veterinary surgeons, including diplomate specialists of the various colleges, were actively involved using live polling. All polling answers were recorded.
Clinical guidelines obtained from discussion
Of the various staging procedures, distant metasta-
ses was recognised as the most important factor to determine prognosis (70%) and only 13% the size of
the tumor. If there are no distant metastases, the most important factors were deemed: lymph node involvement (43%), size of tumor (29%) and the resectability of the tumor (26%).
Lymph node staging
In case of an COMM, 56% percent of the interviewed would aspirate both mandibular lymph nodes, 24% the ispilateral lymph node and 15% bilateral mandibular and retropharyngeal lymph nodes.
When asked what lymph node they would routinely remove during surgery, 45% would use advanced diagnostic imaging to determine, 6% used sentinel lymph node determination, 26% removed standard the ipsilateral lymph node, 13% bilateral mandibular and 10% bilateral mandibular and retropharyngeal.
Diagnostic imaging
If people had to choose between 3 way thoracic radiographs and CT scan of the chest, 78% would prefer a CT. Fifty percent of the active participants additionally perform diagnostic imaging of the abdomen in oral MM patients, either by ultrasound (64%) or CT (36%). CT of the head and neck is seen as the most ideal preoperative staging and preparation technique by 96% of the interviewed.
Therapy for oral MM
The preferred approach for a large oral MM was wide or radical surgical excision (89%). Radiation as a sole therapy was chosen by 11% of the audience.
Most of the audience (68%) would recut cases that had marginally excised oral mucocutaneous MM after a full diagnostic work up. Fifteen percent would only use adjunctive therapy for these cases.
When asked what the role of radiation therapy was, 77% answered when surgery was not an option and 21%
An Urban Experience
  Canine Oral Malignant Melanoma (COMM) is a neoplasm of melanocytic cells. MM account for 7% of all malignant neoplasms and between 9 to 20% of all skin tumors in dogs. The most frequently affected site is the oral cavity, making COMM the most common oral neoplasm. The site for oral melanomas is the gingiva, buccal or labial mucosa, hard or soft palate and the tongue. COMM
are rapidly growing, invasive and potentially metastatic tumors. They often recur after surgical excision and radio- or chemotherapy. COMM tend to metastasize in 70 to 90% of all cases. COMM are most often diagnosed in dogs older than 10 years with a mean age of 11.6 years.
The World Health Organization (WHO) has developed
a scheme for classifying oral melanomas, which was adapted for dogs. The classification of a tumor is based on: de anatomic site of the tumor, the tumor size and the tumor stage. These variables give an impression of the prognosis of COMM.
The tumor size and stage can be subdivided in categories:
- Category 1: tumor ≤ 2 cm diameter
- Category 2: tumor diameter 2 to 4 cm
- Category 3: tumor ≥ 4 cm diameter
- Category 4: distant metastasis. Distant metastasis has a higher grade than lymph node metastasis.
The tumor stage is subdivided in:
- Stage 1; tumor ≤ 2 centimeter in diameter, without lymph node involvement and no proven metastasis
- Stage 2; tumor 2-4 centimeter in diameter, without lymph node involvement and no proven metastasis
- Stage 3; tumor ≥ 4 centimeter in diameter, with or without lymph node involvement and has no proven metastasis or any tumor size with lymph node metastasis
- Stage 4; proven metastasis, independent of tumor size or lymph node involvement

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