Melanoma Flashcards
What cancer is the most common oral malignancy in the dog?
melanoma
What are the most common locations of oral melanoma?
(in order of decreasing frequency)
Gingiva, lip, tongue, and hard palate
What are the most common breeds for oral melanoma?
Scottish Terrier, Golden, Chow chow, poodles, and dachshund
What are some primary factors that determine biological behaviour of oral melanoma?
site, size, location, stage, and histological parameters
What are some IHC stains for oral melanoma?
Melan-A, PNL-2, S-100, tyrosinase
small subset is also positive for c-kit
NRAS and PTEN mutations also noted
What’s the MST for digital melanoma without LN or distant metastasis?
MST approx 1 year
1y survival rate 42-57%, 2y survival rate 11-13%
What’s the % of metastasis on presentation for digital melanom?
30-40%
What’s the prognosis of foot pad melanoma compared to digital melanoma?
similiar
Define the oral melanoma staging system.
Stage 1: tumour <2cm, no mets
Stage 2: tumour between 2-4cm, no mets
Stage 3: tumour >4cm and/ or LN mets
Stage 4: any tumour size with distant mets
What’s the MST for oral melanoma based on staging?
Stage 1: 511-874 days (17-39m) - more recent studies = 12-14m
Stage 2: 160-818 days (5-27m)
Stage 3: 168-207 (5-7m)
Stage 4: 87days (3m)
What % of LN can be metastatic but still feel normal (ie not enlarged) for oral melanoma?
40%
What’s the % of LN metastasis for oral melanoma on presentation when the LN is enlarged?
70%
What are some sites of distant metastasis for melanoma?
- abdominal LN
- liver
- adrenal glands
- other intra-abdominal sites
T or F. Most canine cutaneous melanoma = benign
true
What’s ideal surgical margin for cutaneous melanoma?
minimum 1-2 cm
ideally 2-3cm and 1 fascial plane deep
What margin should be aimed for oral melanoma?
1-2cm
What’s the risk of dying for tumour related causes if the histo margin is incomplete for oral melanoma?
3.6x more likely
At what location oral location is the patient more likely to die due to tumour?
caudal to P3 - 4.3x more likely
How sensitive is melanoma to radiation?
it’s considered radio-resistant
What are the pros and cons of hypofractionated radiation therapy?
Pro:
- less acute side effects
Cons:
- lower overall biological equivalent dose
- higher risk of late side effects
Should you RT a suspect draining LN for oral melanoma even if it’s not enlarged?
Yes, still a 40% chance that it is metastatic
What’s the reported partial response rate for oral melanoma treated with RT?
25-67%
What’s the reported complete response rate for oral melanoma treated with RT?
19-69%
What’s the overall response rate of oral melanoma to RT?
82-94%