Controversy surrounds what is the most appropriate surgical excision margin for skin melanomas thicker than 2mm. A trial published Online First by The Lancet suggests that a 2cm excision margin for such melanomas is safe and sufficient, since it results in similar levels of recurrence and death as a larger margin of 4cm. The Article is by Dr Peter Gillgren, Karolinska Institutet and Stockholm Söder Hospital, Stockholm, Sweden, and colleagues.
The incidence of skin melanoma is increasing in Scandinavia and other countries with predominantly white populations. In Sweden the average increase is around 4% per year for both men and women. Furthermore, the average age of patients diagnosed with a skin melanoma is low compared with other cancers. When operating to remove melanomas, a balance must be struck. There may be relapse-risk with a narrow excision, which could compromise disease-free survival or, worse, overall survival. However, the authors highlight that with a surgical margin of 2 cm, the skin can be closed without skin grafting or skin flaps in most cases. On the other hand, wide excisions might also lead to bad cosmetic results, lymphatic obstruction, long hospital stay, frequent need for skin grafts, or complicated skin flap reconstructions. Current recommendations vary between countries with 2cm and 3cm excision margins commonly recommended.
The authors carried out their randomised controlled trial in nine European centres across Sweden, Norway, Denmark, and Estonia. Patients with skin melanoma thicker than 2 mm, at clinical stage IIA–C, were allocated to have either a 2-cm or a 4-cm surgical resection margin. The primary endpoint was overall survival. A total of 465 patients were allocated to 2-cm resection, and 471 to receive 4-cm resection. One patient in each group was lost to follow-up but included in the analysis. After a median follow-up of around 7 years, similar numbers of patients in each group had died: 181 (39%) patients in the 2-cm group and 177 (38%) in the 4-cm group. 5-year overall survival was the same in both groups at 65%. Any 5-year-recurrence was also the same at 44% in both groups (or put another way, the proportion of relapse-free patients at 5 years was 56% in both groups).
They conclude: "Our large study shows that melanoma patients with a tumour thicker than 2 mm can be safely treated with a 2-cm margin without any effect on overall survival and recurrence…meta-analysis should be done of all randomised trials of cutaneous melanoma thicker than 2 mm."
In a linked Comment, Professor John F Thompson, Melanoma Institute Australia, North Sydney, NSW, Australia, and Dr David W Ollila, Division of Surgical Oncology and Endocrine surgery, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, USA, say: "The next question to be addressed is whether a 2-cm margin is preferable to a 1-cm margin or whether a 1-cm margin is sufficient and safe. Morbidity and healthcare costs could be decreased if a 1-cm margin is equivalent or non-inferior to a 2-cm margin. A proposal for such a large scale, multicentre trial is being developed."
Dr Peter Gillgren, Karolinska Institutet and Stockholm Söder Hospital, Stockholm, Sweden. T) +46 86162384 E) peter.gillgren@sodersjukhuset.se
Professor John F Thompson, Executive Director, The Melanoma Institute Australia, North Sydney, NSW, Australia. Currently travelling in UK so may be difficult to contact.T) +61 418 144582 E) john.thompson@smu.org.au
Alternative contact at Melanoma Institute Australia: Lisa Sampson, Development Manager. T) +61 406 523 324 E) Lisa.Sampson@melanoma.org.au
Journal
The Lancet