S URGICAL MANAGEMENT OF MELANOMA : HAVE WE MADE ANY PROGRESS IN 100 YEARS ?

In the early 20th Century, excision of all primary melanomas with >5cm clearance margins was recommended, with amputation in selected cases – recommendations based on experience of a few patients with locally advanced disease. More recently, randomised trials showed that even thick (>4mm) primary melanomas require no more than 2-3cm clearance and thin (<1mm) and intermediate thickness (1-4mm) melanomas no more than 1-2cm margins to achieve good local control with no adverse effect on survival. The management of regional lymph nodes has also changed on the basis of clinical trial results. Elective node dissection, formerly regarded as necessary, has been abandoned. Today, most patients with intermediate thickness melanomas are offered a “sentinel” node biopsy procedure, with node dissection only if the sentinel node is positive. Sentinel node biopsy provides the most accurate staging and prognostic information currently available and achieves good local control of regional node disease. It may also confer a survival benefit in patients who are node positive but long-term results of clinical trials are awaited to confirm this. In the great majority of patients who present with thin primary melanomas, even sentinel node biopsy is generally considered unnecessary. Although substantial progress has been made over the past 100 years in defining evidence-based surgical management protocols for patients with melanoma, continuing efforts are needed to further improve surgical outcomes in the absence of reliably effective non-surgical therapies. criticised, mainly because of the failure to stratify by thickness, disproportions in gender and primary tumour site and failure to accurately identify the correct regional node field for dissection. Sappey in 1874 had categorically stated that lymphatic drainage never crossed the midline. He later modified this to exclude sites within 5cm of each side of the original vertical and horizontal dividing lines of the body. This concept was embraced by most practitioners until quite recently, when it became obvious from preoperative lymphoscintigraphy performed in large numbers of patients that, particularly on the trunk, drainage was quite diverse and unpredictable. It was shown that up to 30% of patients may have had inappropriate node field dissections when clinical prediction of the path of lymphatic spread was used to select the dissection field. Later, more carefully stratified randomised trials, the Intergroup Melanoma Surgical Trial and the WHO Melanoma Program Trial in which either blue dye or radio-colloid tracer were used to map the draining fields, found by multivariate analysis that routine ELND had no impact on overall survival. However, in the Intergroup trial, a small survival benefit emerged for patients 60 years of age or under. In the WHO trial, patients whose regional nodes became clinically and histologically postitive during follow-up had the poorest prognosis. The principal criticism of this latter trial was that the sample size did not allow sub-group analysis. The other crucial outcome in the WHO trial was that 36 patients with clinically negative but histologically postitive nodes who had an ELND (NO+), had a significantly better five-year survival rate (48% versus 27%; p<0.04) than those 25 patients with clinically negative nodes not undergoing ELND, who subsequently developed clinically and histologically overt lymph node disease (N1) (Figure 1). Thus the immediate dissection of positive but subclinical node metastases appeared to result in improved longterm survival. This clinical trial observation provided an incentive to pursue development and validation of the less invasive technique which has subsequently revolutionised the treatment of higher-risk patients – sentinel node (SN) biopsy. Lymphatic mapping and selective “sentinel”