Management of Malignant Melanoma
BULLETIN FOR MEDICAL PRACTITIONERS
Prepared by Dr Eileen Tan, Associate Consultant
Assoc Professor Giam Yoke Chin, Senior Consultant & Deputy Medical Director
Summarized by Dr Eileen Tan
National Skin Centre
Introduction
Cutaneous malignant melanoma is a potentially lethal tumour arising from melanocytes. It is widely accepted that early diagnosis and treatment are keys to a good prognosis.
Clinico-histological Classification of Malignant Melanoma
Cutaneous malignant melanoma can be classified into different categories on the basis of clinical presentation and histopathology. They include:
- Superficial spreading melanoma
- Nodular melanoma
- Acral-lentiginous melanoma
- Lentigo maligna melanoma
- Other rarer histologic variants include desmoplastic melanoma, balloon-cell melanoma and amelanotic melanoma.
Assesment of Patient with Malignant Melanoma Should Include:
A. History and physical examination
- Record duration/ location/ appearance of lesion.
- Assess risk factors for developing melanoma; these include a personal history or family history of melanoma, light skin type, acute and intermittent sun exposure or sunburning in childhood and adolescence, one or more large or irregular atypical pigmented lesions (dysplastic moles and lentigo maligna are 2 pigmented lesions that are potential precursors of melanoma), immunosuppression, and congenital moles (for giant congenital naevi, the lifetime risk of progression to malignant melanoma is estimated at 4-8%. For small and medium congenital naevi, the risk is unknown).
- Inspect and palpate around the lesion and over lymphatic drainage area for satellite metastases.
- Palpate regional lymph nodes for clinical presence of metastases.
- Examine cutaneous surface for other melanomas, congenital and/or atypical nevi. 6. Examine pigmentation of nailfold and nail plate.
B. Investigations
Biopsy and histopathology As management and prognosis is dependent on the thickness of the primary tumour, a total excisional biopsy is advocated. If there is any difficulty, a punch or elliptical biopsy may be performed on the thickest and darkest lesions. A full histopathology report should include the diagnosis, Breslow’s thickness (thickness of the lesion in millimeters measured from the top of the granular cell layer to the deepest point of tumour invasion) and the status of the margins.
Other investigations may be indicated to evaluate the extent of spread of the tumour. They include: biochemistry and hematologic studies (e.g. full blood counts, liver function tests, serum lactic dehydrogenase), radiographic studies (e.g. chest radiographs, CT or MRI scan), open lymph node or sentinel node biopsy.
Treatment Guidelines
A. First line treatment
Surgery
Surgery is the treatment of choice for primary melanomas and for some operable metastases. The current recommended surgical margins are as follows:
Mohs microscopic surgery may be used as a tissue saving technique, especially on the face.
B. Management of patients with lymph node involvement
Lymph node dissection
Therapeutic lymph node dissection is recommended when there are clinically suspected regional lymph node enlargement. The role of elective regional lymph node dissection (ERLND) is still controversial and is not indicated for early melanoma < 1 mm thick. Sentinel lymph node biopsy may help to identify early micrometastasis.
C. Management of advanced disease
Chemotherapy
For advanced melanomas, dacarbazine is currently regarded as the most effective chemotherapeutic agent. Other cytotoxic agents have been reported to demonstrate some efficacy in disseminated melanomas include nitrosoureas, carmustine, tamoxifen, bleomycin, vindesine, and cisplatin.
Radiotherapy
Radiotherapy may be used for lentigo maligna in the elderly and for the treatment of metastases (e.g. bone metatases) or local recurrences
Follow-up Evaluation
First year: 3 monthly review which includes a through physical examination, routine blood investigations, ultrasound examination of regional lymph node bases and of the abdomen, CXR yearly, CT/MRI (for patients with findings suggestive of metastatic melanoma.
Second year: 6 monthly review. Third and subsequent years (for the rest of life): yearly reviews.
DEDICATED TO EXCELLENCE IN DERMATOLOGY
By National Skin Centre (Singapore)
Copyright (C) 1995 - National Skin Centre (Singapore)
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