Performing a wide local excision of a completely excised melanoma reduces the risk of local recurrence and may improve melanoma-specific survival. However, the amount of normal tissue that needs to be removed in order to reduce the risk of local recurrence to an acceptable level is uncertain, although the lack of benefit of wider margins over narrower ones in most studies has led to a move towards narrower margins for primary melanomas over the last two decades.
Today a maximum margin of 2cm is recommended for thick tumours and 1cm for thin tumours. MelTUMPs are generally well circumscribed, therefore unlikely to have microsatellites that will be removed by using a wider excision margin. However, in contrast to invasive melanomas, there has been an increase in the recommended margins for in situ melanoma from 0.5cm to 0.5–1.0cm, with the aim of ensuring complete histological clearance in order to minimise the local recurrence risk; this is most relevant to the lentigo maligna subtype of in situ disease in which tumour margins are often hard to define.
Since there have been no trials of adequate margins for MelTUMPS, the evidence that exists on this topic was systematically reviewed.
Systematic review evidence
In patients with MELTUMPs, what excision margins are appropriate?
One study of naevi and melanomas in children had only three lesions (described as atypical Spitz naevi) that would be regarded as MelTUMPs. The excision margins used were 2mm and there were no reported recurrences, however, the duration of follow-up was not stated.
One study included 28 MelTUMPs (all described as atypical Spitz naevi) diagnosed by a single dermatopathologist. The clinical data were obtained from questionnaires sent to the referring dermatologists for the cases. Of the 28 lesions, 19 (68%) were completely excised with the initial biopsy (size of margins not reported). Seven of the nine lesions incompletely excised on biopsy had a wider excision of up to 5mm achieving, a mean margin of 2.2mm (range 0.75–5.0mm), and two patients were simply observed. However, follow-up data was available for only 38% of all patients (89) and the mean duration of follow-up was only 2.8 months, making interpretation of the adequacy of excisions impossible.
One study included 43 patients with an unspecified mix of MelTUMPs. Margins of excision were available for 33 patients: 11 had excision biopsy alone, 10 had a 5mm wide local excision, 10 had a 10mm wide local excision and one had a 20mm wide local excision, whilst one patient had a shave biopsy and 2mm wide local excision. Follow-up data were available for only 29 patients, of whom 2 (4%) had a recurrence, but further details were not provided. The adequacy of excisions in this study could not be determined.
Evidence summary and recommendations
|There is insufficient evidence to recommend the optimal excision margins for MelTUMPs.||III-2||, , |
It is advisable to excise MelTUMPs with a 5mm clinical margin and ensure there is at least a 2mm histological margin.
It is advisable to follow up patients for at least five years following a diagnosis of MelTUMP, given the uncertainty surrounding the diagnosis. Six-monthly follow-up is advisable for the first 2 years.
Notes on these recommendations
A reasonable interval for follow-up visits would be six-monthly for the first two years, reducing to yearly thereafter if no concerns however there is no evidence to support this and this guidance has been developed by consensus.
Issues requiring more clinical research study
Longer term (at least five years) follow up of patients with MelTUMPs needs to be undertaken with reference to the excision margins and clinical outcome in order to determine what is an adequate margin.
- Veronesi U, Cascinelli N, Adamus J, Balch C, Bandiera D, Barchuk A, et al. Thin stage I primary cutaneous malignant melanoma. Comparison of excision with margins of 1 or 3 cm. N Engl J Med 1988 May 5;318(18):1159-62 Abstract available at http://www.ncbi.nlm.nih.gov/pubmed/3079582.
- Balch CM, Soong S, Ross MI, Urist MM, Karakousis CP, Temple WJ, et al. Long-term results of a multi-institutional randomized trial comparing prognostic factors and surgical results for intermediate thickness melanomas (1.0 to 4.0 mm). Intergroup Melanoma Surgical Trial. Ann Surg Oncol 2000 Mar;7(2):87-97 Abstract available at http://www.ncbi.nlm.nih.gov/pubmed/10761786.
- Cohn-Cedermark G, Rutqvist LE, Andersson R, Breivald M, Ingvar C, Johansson H, et al. Long term results of a randomized study by the Swedish Melanoma Study Group on 2-cm versus 5-cm resection margins for patients with cutaneous melanoma with a tumor thickness of 0.8-2.0 mm. Cancer 2000 Oct 1;89(7):1495-501 Abstract available at http://www.ncbi.nlm.nih.gov/pubmed/11013363.
- Khayat D, Rixe O, Martin G, Soubrane C, Banzet M, et al. Surgical margins in cutaneous melanoma (2 cm versus 5 cm for lesions measuring less than 2.1-mm thick). Cancer 2003 Apr 15;97(8):1941-6 Abstract available at http://www.ncbi.nlm.nih.gov/pubmed/12673721.
- Thomas JM, Newton-Bishop J, A'Hern R, et al. Excision margins in high-risk malignant melanoma. N Engl J Med 2004 Feb 19;350(8):757-66 Abstract available at http://www.ncbi.nlm.nih.gov/pubmed/14973217.
- Gillgren P, Drzewiecki KT, Niin M, Gullestad HP, Hellborg H, Månsson-Brahme E, et al. 2-cm versus 4-cm surgical excision margins for primary cutaneous melanoma thicker than 2 mm: a randomised, multicentre trial. Lancet 2011 Nov 5;378(9803):1635-42 Abstract available at http://www.ncbi.nlm.nih.gov/pubmed/22027547.
- Hayes AJ, Maynard L, Coombes G, Newton-Bishop J, Timmons M, Cook M, et al. Wide versus narrow excision margins for high-risk, primary cutaneous melanomas: long-term follow-up of survival in a randomised trial. Lancet Oncol 2016 Feb;17(2):184-92 Abstract available at http://www.ncbi.nlm.nih.gov/pubmed/26790922.
- Thompson JF, Friedman EB. Appropriate excision margins for cutaneous melanomas. Lancet 2019 Aug 10;394(10197):445-446 Abstract available at http://www.ncbi.nlm.nih.gov/pubmed/31280970.
- Utjés D, Malmstedt J, Teras J, Drzewiecki K, Gullestad HP, Ingvar C, et al. 2-cm versus 4-cm surgical excision margins for primary cutaneous melanoma thicker than 2 mm: long-term follow-up of a multicentre, randomised trial. Lancet 2019 Jul 4 Abstract available at http://www.ncbi.nlm.nih.gov/pubmed/31280965.
- Sladden MJ, Nieweg OE, Howle J, Coventry BJ, Thompson JF. Updated evidence-based clinical practice guidelines for the diagnosis and management of melanoma: definitive excision margins for primary cutaneous melanoma. Med J Aust 2018 Feb 19;208(3):137-142 Abstract available at http://www.ncbi.nlm.nih.gov/pubmed/29438650.
- Zangari A, Bernardini ML, Tallarico R, Ilari M, et al. Indications for excision of nevi and melanoma diagnosed in a pediatric surgical unit. J Pediatr Surg 2007 Aug;42(8):1412-6 Abstract available at http://www.ncbi.nlm.nih.gov/pubmed/17706506.
- Murphy ME, Boyer JD, Stashower ME, Zitelli JA. The surgical management of spitz nevi. Dermatol Surg 2002.
- Lim PN, Kotb I, Meredith F, Husain E. The clinical management and pathological diagnosis of atypical melanocytic lesions. BJD 2017.