A 2 cm excision margin for melanomas thicker than 2 mm is just as safe as a 4 cm margin, suggest the results of a trial published online first in The Lancet today.
The smaller margin carries similar risks of recurrence and death as the larger margin, the study results show. Current recommendations for the optimal margin vary among countries.
A narrow margin has been thought to boost the chances of recurrence or death. But the authors point out that a margin of 2 cm means that the skin can be closed without skin grafting or skin flaps in most cases.
And wide excisions might also lead to bad cosmetic results, lymphatic obstruction, longer hospital stay, frequent need for skin grafts, or complicated skin flap reconstructions, they say.
The authors base their findings on just under 1000 patients in nine European centres in Scandinavia and Estonia.
Patients with a skin melanoma thicker than 2 mm, at clinical stage IIA–C, were allocated to have either a 2 (465) or a 4 cm (471) surgical resection margin.
After an average follow up of around seven years, similar numbers of patients in each group had died: 181 (39%) patients in the 2 cm group and 177 (38%) in the 4cm group. Five year overall survival was the same in both groups at 65%. Recurrence was also the same at 44% in both groups.
The authors conclude: “Our large study shows that melanoma patients with a tumour thicker than 2 mm can be safely treated with a 2cm 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 Thompson, of the Melanoma Institute Australia, in Sydney, and Dr David Ollila, of the University of North Carolina at Chapel Hill School of Medicine, in North Carolina, 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.”
The incidence of malignant melanoma is increasing in countries with predominantly white skinned populations. And on average, patients diagnosed with a malignant melanoma are younger than patients diagnosed with other types of cancer.