Surgical treatment of melanoma

In case of dysplastic pigmented lesions, with low grade dysplasia, a surgery will not be necessary. In case of pigmented lesions with high grade dysplasia with uninjured margins, at the discretion of the clinician and according to different aspects, an enlargement will be proposed to the patient in case of uninjured margins ≤ 0.9 mm (always taking into account the anatomical site, age of the patient, comorbidities of the patient). According to WHO 4 ed. 2018, high grade also includes MelTUMP (melanocytic tumor of unknown malignant potential) which should be treated as melanomas. In case of patients with intermediate lesions it is recommended that the margins in healthy tissue should be 2 mm, in case of high-grade lesions and melanoma in situ a margin widening of 5 mm is recommended, and in pT1a a widening of resection margins of 1 cm will be performed. In case of melanomas ≥ pT1b a 1 cm widening and sentinel lymph node search will be performed (after total body CT scan + brain with contrast medium and surgical examination). In case of positivity of the sentinel lymph node, the patient will be a candidate or not to adjuvant therapy, with BRAF and MEK inhibitors in case of BRAF gene mutation or immunotherapy with anti-PD-1.

Surgery is the treatment of choice in localized cutaneous melanoma. After the removal of the primary lesion, the surgical treatment is based on RADICALIZATION (wide excision) and SENTINEL LINFONODE BIOPSY (BLS).

Radicalization aims to reduce the risk of local recurrence of disease and consists in the removal of skin and subcutaneous tissue adjacent to the surgical scar related to the primary lesion, extending the resection to expose the muscle fascia.

The margins of resection in relation to the scar depend on the thickness of the melanoma (according to Breslow).

According to the main international guidelines, the indicated resection margins are as follows:

• Melanoma in situ: 0.5 - 1 cm
• Breslow < 1 mm: 1 cm
• Breslow 1 - 2 mm: 1 - 2 cm
• Breslow > 2.0 mm: 2 cm

In particular areas, for functional and/or aesthetic reasons, more limited resection margins are maintained, with eventual extemporaneous histological examination of resection limits.

Sentinel lymph node biopsy (BLS) is normally indicated in melanomas with Breslow > 1 mm, but it can be proposed also in the pT1b stage (Breslow 0.8 - 1 mm or less than 1 mm but with presence of ulceration). In the latter case, in fact, the risk of sentinel node positivity is not irrelevant (5-12%).