Page 1414 - Clinical Small Animal Internal Medicine

1352 Section 11 Oncologic Disease

surgery alone suggest that subsequent distant metastasis including surgery, radiation and/or chemotherapy has a
VetBooks.ir is common even when no metastasis is found at presen- MST of approximately 12–14 months, with most dogs
dying of distant metastatic disease, not local recurrence.
tation or digit amputation. The prognosis for dogs with
melanoma of the footpad has not been thoroughly estab-
melanoma to have median progression‐free survival
lished; this author has found this anatomic site to be Other investigators have found dogs with stage I oral
anecdotally similar in metastatic propensity and progno- times of 19 months, similar to the original MacEwen
sis to digit melanoma. Interestingly, human acral lentigi- et al. report.
nous melanoma (plantar surface of the foot, palms of the
hand and digit) has an increased propensity for metasta-
sis, suggesting further similarities between human and Box 153.1 TNM staging system
canine melanoma.
The most thorough review of prognostic factors in T = Primary tumor
canine melanocytic neoplasms was published by Smedley
et al. This review took a regimented, systematic approach T1 Tumor <2 cm in diameter
to analyze published reports to date in order to identify T2 Tumor 2–4 cm in diameter
those factors which appear to be repeatable and statisti- T3 Tumor > 4 cm in diameter
cally defendable, while also identifying areas where addi- N = Regional lymph nodes
tional work is necessary due to incomplete data.
N0 No evidence of regional node involvement
N1 Histologic/cytologic evidence of regional node
Size and Stage involvement
N2 Fixed nodes
For dogs with oral melanoma, primary tumor size has
been found to be extremely prognostic. The WHO stag- M = Metastasis
ing scheme for dogs with oral melanoma is based on size M0 No evidence of distant metastasis
and metastasis and is summarized in Box 153.1. M1 Evidence of distant metastasis
MacEwen and colleagues reported MST for dogs with Stage I T1 N0 M0
oral melanoma treated with surgery to be approximately Stage II T2 N0 M0
17–18, 5–6, and three months with stage I, II, and III dis- Stage III T2 N1 M0 or T3 N0 M0
ease, respectively. More recent reports suggest that stage Stage IV Any T, Any N and M1
I oral melanoma treated with standardized therapies

Further Reading

Grosenbaugh DA, Leard AT, Bergman PJ, et al. Safety and treated with external beam radiation. Vet Radiol
efficacy of a xenogeneic DNA vaccine encoding for Ultrasound 2003; 44(3): 352–9.
human tyrosinase as adjunctive treatment for oral Ramos‐Vara JA, Beissenherz ME, Miller MA, et al.
malignant melanoma in dogs following surgical excision Retrospective study of 338 canine oral melanomas with
of the primary tumor. Am J Vet Res 2011; 72(12): 1631–8. clinical, histologic, and immunohistochemical review of
MacEwen EG, Patnaik AK, Harvey HJ, Hayes AA, Matus R. 129 cases. Vet Pathol 2000; 37(6): 597–608.
Canine oral melanoma: comparison of surgery versus Smedley RC, Spangler WL, Esplin DG, et al. Prognostic
surgery plus Corynebacterium parvum. Cancer Invest markers for canine melanocytic neoplasms: a
1986; 4(5): 397–402. comparative review of the literature and goals for future
Proulx DR, Ruslander DM, Dodge RK, et al. A investigation. Vet Pathol 2011; 48(1): 54–72.
retrospective analysis of 140 dogs with oral melanoma