Canine Melanoma and Veterinary Surgical Options
Melanoma in dogs is a common condition involving the abnormal growth of pigment-producing cells known as melanocytes. These tumors can range from benign to highly malignant and occur in various locations, including the
oral cavity,
nail beds,
skin, and
eyes. Whether a melanoma is benign or malignant influences both prognosis and treatment strategy. Fortunately, one of the primary treatment options available is
surgical excision.
Types of Canine Melanoma
- Oral Melanoma: Typically aggressive, often spreading to lymph nodes and lungs. Common locations include gums, lips, and tongue.
- Subungual (Nail Bed) Melanoma: Often aggressive and may require toe amputation. Metastasis is common at diagnosis.
- Dermal (Skin) Melanoma: These may be benign or malignant depending on their location, size, pigment levels, and cellular activity.
- Ocular Melanoma: Mostly benign but malignancy can occur, particularly in conjunctival tumors.
Veterinary Diagnosis and Assessment
Diagnosis includes:
- Clinical examination of the mass location and appearance.
- Fine needle aspiration or biopsies to identify melanin or tumor markers.
- Advanced imaging such as X-rays, CT scans, or ultrasounds to assess metastasis.
Staging follows the
World Health Organization's TNM system, evaluating Tumor size (T), Node involvement (N), and Metastasis (M).
Surgical Removal as a Primary Treatment
Surgical excision with wide margins is considered the gold standard for local control of melanoma in dogs. The approach depends on tumor location:
- Oral Melanoma: Requires partial jawbone removal (mandibulectomy or maxillectomy).
- Subungual Melanoma: Often necessitates digit amputation.
- Dermal Melanoma: Wide excision is typically curative for benign forms.
- Ocular Melanoma: May require removal of the affected eye (enucleation) if intraocular tissues are involved.
To ensure comprehensive treatment, surgeons may also remove nearby
lymph nodes for staging and control of potential spread.
When Surgery Isn’t Enough
In cases of incomplete resection or advanced disease, additional therapies may be employed:
- Radiation therapy – Highly effective, especially for oral tumors, with a response rate >80%.
- Chemotherapy – Generally has limited success and does not reliably extend survival significantly.
- Immunotherapy: The ONCEPT melanoma vaccine can extend survival when combined with surgery or radiation in stage II and III cases with adequate local control.
Prognosis Post-Surgery
Prognosis varies by:
- Tumor location – Oral and subungual melanomas are more aggressive.
- Tumor size and depth – Larger and deeply infiltrating tumors worsen prognosis.
- Histological features – High mitotic index and poor pigmentation indicate aggressive disease.
For example:
- Oral melanoma: With complete surgical removal, 80–85% still develop metastasis.
- Subungual melanoma: Survival extends to about 12 months post-amputation without metastasis.
- Dermal melanoma: Often resolved with surgery if benign.
Importance of Early Detection and Action
Early detection and surgical intervention provide the best chance for long-term control, particularly for tumors in less aggressive locations. Pet owners should watch for:
- New or changing skin or oral masses
- Lameness or toe swelling
- Oral symptoms like bad breath or difficulty eating
Routine exams and early staging with cytology or biopsy are critical. While surgical excision plays a primary role in managing melanoma in dogs, combining it with adjunctive therapies when necessary offers the most comprehensive care pathway.
Conclusion
Veterinary surgery can effectively remove melanomas in dogs, especially when tumors are detected early and are amenable to excision with wide margins. Although recurrence and metastasis remain a risk in more aggressive cases, surgical removal forms the cornerstone of treatment and can significantly improve a dog’s quality of life and survival time.