Safe surgical margin and management of lymph nodes in skin melanoma

The objective of this study was to determine the safe surgical margin in skin melanoma (2-4 mm thickness) and provide guidelines on the management of affected adjacent lymph nodes.

Melanoma is a type of cancer that starts in color-producing cells of the skin. It can grow deep into the inner layers of skin and spread into lymph nodes (tiny, bean-shaped organs that help fight infections). The standard treatment for skin cancer remains surgical removal of the tumor along with some of the surrounding normal skin. Removal of the normal skin is known as the safety margin/surgical margin intended to prevent relapse of cancer in these surrounding tissues. Safety margins are determined by the thickness (how deep a melanoma reaches into the skin layer) of the primary tumor. Several guidelines for safety margins exist for melanoma thickness of 2 – 4 mm (stage T3), but none of these adequately reflect disease outcome in patients.

Sentinel lymph node biopsy (SLNB) is a diagnostic procedure to find out if the skin cancer has reached the lymph nodes. It is now part of the standard treatment for T3 melanoma patients. However, not much information has been obtained on how SLNB influences the outcome of the disease.

The authors reanalyzed published data on melanoma patients to determine the adequate safety margins in tumor surgeries and consequences of SLNB.

Overall, data from 1,587 patients with 2-4 mm thick melanoma was examined. Patients were divided into two groups: those who had surgical margin of ≥ 1 cm and those who had surgical margin of < 1 cm.

The risk of the disease returning was reduced by 41% in those whose surgical margin was > 1 cm. The risk of local return (cancer returns near to the original site) or in-transit return (cancer returns further away from the site) was reduced by 46% in the ≥ 1 cm group  compared to the <1 cm group. 

The rates of survival were reduced in patients whose cancer had spread to lymph nodes (positive SLN) compared to negative SLN. In general, those who underwent the SLNB procedure had better survival compared to those who did not.

The authors concluded that a surgical margin of ≥ 1 cm combined with SLNB  in T3 melanoma patients provided optimum survival benefits.