Ask the Veterinarian/Canine Mast Cell Tumor
My dog, Bogey, is a Chow/Sharpei mix, 60 lbs., 13 yrs and 9 months, and has always been high strung, active. Recently he was diagnosed with a stage 1, grade 3 mast cell tumor. I have gotten 2, seemingly differernt opinions on his prognosis.
My regular vet said: ""The good news is that it was stage 1, with clear margins and no lymph node involvement or metastasis. The bad news is that it is a high grade 3 and there is a 90% chance that it will return in 6-12 months.""
The second vet said: ""There is a strong possibility that it is indeed in the lymph nodes but only on the cellular level and thus not detectable as of yet."" When I told him about what the first vet said, he called the first vet's prognosis ""the best case scenario for sure"" and a ""glass half full"" prognosis.
Some added info: The MCT was only 5 days old when removed. Bogey remains extremely active and hyper. I have ruled out Kinavet and chemo due to cost and side effects. I have ruled out Prednisone due to side effects alone. He is on Benadryl (75 mg twice daily). The lab report is below. My question is: Which prognosis is more realistic? What can I expect? Thank you. Robert
Source / History: 13 year old, male castrated, chow chow canine. Growth removed and
additional skin is from the caudal side of incision. Mass is from the
right ventral thorax per anatomic diagram.
Region effacing the dermis extending into the subcutis abutting the
subjacent skeletal muscle is a nodular, unencapsulated, mildly
infiltrative round cell neoplasm. Cells are arranged in sheets and
rows supported by small to moderate amounts of fibrovascular stroma.
Cells are round with moderate to large amounts of eosinophilic
granular cytoplasm, few to small numbers of basophilic granules, and
well-defined cell borders. Nuclei are round to irregular with finely
stippled chromatin and up to 3 nucleoli. Mitoses are 50 per 10
high-powered fields (400 X) and there are occasional bizarre mitotic
figures. Anisocytosis and anisokaryosis are moderate to marked with
frequent karyomegalic and moderate numbers of binucleate neoplastic
cells. Scattered throughout the mass are rare eosinophils,
lymphocytes, plasma cells, and hemosiderin-laden macrophages.
Inflammatory cells and neoplastic cells are multifocally separated by
small to moderate amounts of edema. The overlying epidermis is
regionally ulcerated and the denuded neoplasm contains enmeshed
hemorrhage, fibrin, cellular debris, and neutrophils. The mass appears
completely excised. No neoplastic cells are identified in separate
submitted sections of skin and subcutis.
Haired skin, right ventral thorax: Mast cell tumor, grade III, high
Mitotic index: 50
Margins: Complete, 4.6 to 43 mm latera margins, 10 mm deep margin
Vascular invasion: Not observed
Comments: The mass consists of a malignant proliferation of neoplastic round
cells. Based on the cell morphology including the cytoplasmic
granularity and the presence of eosinophils admixed with the
neoplastic cells, the neoplasm is consistent with a mast cell tumor.
The surgical margins are clean; please see above description for
specific margin measurements. Based on the degree of differentiation,
hypogranulation, high mitotic index (50) and anisokaryosis, this mast
Generated by VetConnect® PLUS
September 25, 2015 4:32 PM Page 1 of 2
Greenleaf Animal Hospital Miami Beach
Patient: HONEY NEEDELMAN
cell tumor is classified as a grade III tumor based upon the Patnaik
grading system. These tumors tend to have rapid growth rates and are
aggressive malignancies that frequently recur after surgery, and have
moderate to high metastatic potential; therefore, they are associated
with a poor prognosis.
This mast cell tumor is classified as a high grade tumor based on the
newer two-tiered grading system. This grading system was proposed to
provide better prognostic information for mast cell tumors (Vet Pathol
2011, 48(1):147-155). In this newer grading scheme, the diagnosis of a
high-grade mast cell tumor is based on mitotic index, multinucleation,
bizarre nuclear features or karyomegaly. According to this grading
system, high-grade mast cell tumors were significantly associated with
shorter time to metastasis or new tumor development, and with shorter
survival time. The median survival time was less than 4 months for
PCR analysis for mutations in exon 8 and exon 11 of the c-KIT gene may
offer additional information regarding clinical behavior for this mast
cell tumor. Improved clinical response with chemotherapy containing
tyrosine kinase inhibiting compounds has been demonstrated in PCR
positive mast cell tumors. (Vet Path 2004, 41:371-377, Clin Cancer
Res. 2009, 15(11):3856-3865). PCR analysis for mutations in exon 8 and
exon 11 of the c-KIT gene on this tissue sample is available through
IDEXX for an additional charge, test code 3374 (Mast Cell Tumor
Prognostic Panel 3). Please contact customer service if you would like
to have this performed.
Discussion with an oncologist regarding prognostic benefits of the
mast cell tumor panel is recommended. Our team of oncology specialists
is always available for complimentary consultation. Please call
Mast cell tumors that are Grade I or II that can be completely removed have a good prognosis without additional treatment. Grade II tumors can recur locally.Tumors that have spread to the lymph nodes or other parts of the body have a poor prognosis. Any dog showing symptoms of mastocytosis or with a Grade III tumor has a poor prognosis. I will have to back your regular vets view in this regard.
My opinion will be to try Kinavet, thereby obtaining efficacy against the tumor and potential metastases and to protect against future recurrence. As we all know immunity can be affected by cancer fighting drugs, it will be important to protect the dog from other illness during this period, as well as sticking closely to a healthy, immune boosting diet.
regards and all the best