The authors evaluated the effectiveness of radiation therapy after surgery in the management of desmoplastic melanoma (a rare kind of skin cancer).  

Desmoplastic melanoma is a rare form of skin cancer where the cancer cells are surrounded by fibrous tissues (e.g. tissues that make up ligaments, tendons or nerves). Local recurrence (return of cancer to the original site) of this melanoma is higher than other forms of melanomas. Determining the appropriate local therapy is important for this disease. Many studies have suggested that surgery followed by radiotherapy (directing a beam of radiation at the tumor site to kill cancer cells) improves local control of disease progression. 

However, a better understanding of the role of radiotherapy as an additional treatment for this disease is needed. 

The authors aimed to assess the role of radiotherapy after surgery in local control of desmoplastic melanoma.

277 patients with desmoplastic melanoma were included in this study. Cancer was confined to the original site in all patients. All patients underwent surgery to remove the tumors. 40.8% of patients received radiotherapy as an additional treatment after surgery. The median (midpoint) follow-up time was 43.1 months.

Overall, there was 85% reduced risk of cancer recurrence (return) when patients received radiotherapy after surgery. 35 patients had positive surgical margins. This means that cancer cells were still present at the tumor site following surgery. Among these 35 patients, local recurrence occurred in 14% who received radiotherapy. This was compared to 54% who did not receive radiotherapy. Patients who had melanoma in the head and/ or neck, negative surgical margins and tumor thickness (how far the cancer reached into the skin) of more than 4 mm had significant improvements in local control of the disease when treated with radiotherapy. 23% of patients experienced cancer spread (metastasis) to other parts of the body at a median of 17 months following surgery.

Common severe side effects included redness of the skin, pain, and fatigue. Long-term side effects included skin inflammation, widening of the blood vessels on the skin and skin color changes. 

The authors concluded that radiotherapy after surgery significantly improved local control in desmoplastic melanoma. They further indicated that patients with negative surgical margins and thicker tumors would benefit the most from this treatment.  

If you have negative surgical margins, a tumor thickness of more than 4 mm and do not have melanoma in the head and/ or neck region, talk to your doctor about additional treatment with radiotherapy.