Surgery of malignant melanoma
The primary surgery for a suspect melanoma may well be performed by general practitioners. Lesions in difficult locations as the face, ear, breast, fingers, toes and foot sole should be referred for plastic surgery. Resected pigment skin lesions should routinely be sent for histopathological examination, even if there is no suspicion of malignancy.
Exsision biopsy of a suspected melanoma should be performed with an eliptical inscision 2-5 mm into normal skin with a margin of subcutaneous fat. Thereby the whole lesion can be examined with determination of the thickness of the tumor (Breslow), which will determine further surgical treatment.
For histologically verified malignant melanoma smaller extended margins have been recommended in recent years. Most surgical defects can be closed directly. The extended resection should be performed to the underlying fascia.
Sometimes it may be necessary to cover the defect with a skin graft, or a skin patch with reconstructive surgical techniques. Who should perform the resection depends on localization, the need for margins and available expertise.
|Surgical margins determined by tumor thickness (Breslow)
|Melanoma type/tumor thickness
|In situ/Lentigo maligna
|Lentigo maligna melanoma
||1 cm and 2 cm for Breslow > 2 mm
|< 1 mm
||Minimum 1 cm, max 2 cm. Back 2 cm
||Minimum 2 cm
|> 4 mm / Desmoplastic type
Nowadays examination of sentinel node is recommended in the primary diagnostics of malignant melanoma. This is particularly for tumors with thickness 1-4 mm without ulceration and for thinner ulcerated tumors. In Norway the procedure is particularly recommended for locations in the extremities. These amounts to 40% of all melanomas of the skin with 10% in the upper and 30% in the lower extremities. The sentinel node examination should ideally be performed simultaneously with the extended resection.
The lymph nodes of the axilla or groin should be examined by ultrasonography and cutology to identify patients with clinical lymph node metastases, thereby reducing the need for sentinel node examinations.
Further identification of sentinel nodes is performed with lymphoscintigraphy and injection of blue dye.
As the melanoma originate in the dermis the isotope and dye must be injected intradermally, or around the scar if the melanoma has been excised previously. The injection should not be given subcutaneously.
The recommended dose of isotope is 60-70 MBq 99m Tc-Nanocoll intradermally, in 4 injections around the melanoma/ scar, total volume 0,1 ml. The isotope examination may be performed on the day of surgery as the circulation of lymph in the skin is rapid. Bue dye is injected at the start of the operation. The sentinel node is located by inspection for blue dye in lymphatic vessels and nodes and by Geiger counter /gamma probe.
Surgical treatment of local recurrence
Local recurrence is defined as growth of tumor in or deep to the scar after the primary operation. Wide surgical excision is recommended for isolated recurrence.
In-transit metastases are metastases originating between the location of the primary tumor and the regional lymph nodes, such single metastases are widely excised. For multiple metastases the treatment will depend on the localization and extent of the metastases.
If surgery is not possible for an extremity melanoma, isolated limb infusion (ILI) or isolated limb perfusion (ILP) is the next treatment option. Oslo University Hospital is national centre for this kind of treatment.
Amputation of extremity is seldom necessary. For tumors located in the truncus or on the extremities not available for ILI/ILP, local radiotherapy, CO2 laser or electrochemotherapy may be an alternative. This is particularly relevant for elderly patients.
Surgical treatment for lymph node metastases
All patients with invasive melanoma are in danger of having metastases to the local nymph nodes. Involved nodes are firm or hard, with a rounded or slightly buckled surface and most frequently is the lymph node nearest to the primary lesion. Lymph node metastases are rare for melanomas with a thickness of <1 mm. For melanomas of 1 mm or thicker the tendency for metastasizing increases with increasing thickness.
In cases of clinical suspicion of lymph node metastases, cytological examination (FNAC) can confirm the diagnosis. A negative FNAC should be repeated if the node is continuously suspicious during a short observation periode. Open biopsy may increase the risk for tumour soiling. When excision biopsy in rare cases has to be performed, the inscision should be put in a way that it is easily resected with the specimen in a later radical lymph node dissection. This is done in a curative intent or for local control.
For curative intention, meaning no distant metastases, an adequate local resection should be performed if at all possible. Local control is especially desirable when there is a danger of tumor perforation.