Adjuvant Radiotherapy Fails to Increase High-Risk Melanoma Survival After Lymphadenectomy

Adjuvant radiotherapy extends lymph-node field relapse-free survival but not overall survival in resected high-risk melanoma patients after lymphadenectomy

medwireNews: Adjuvant radiotherapy does not extend survival for patients with stage III melanoma at high risk of recurrence after lymphadenectomy, say researchers who believe this population should be considered for clinical trials of adjuvant systemic therapy.

After a median of 73 months, lymph-node field relapse as first relapse occurred in 21% of 109 patients randomly assigned to receive 48 Gy of radiation versus 36% of 108 patients who were under observation only, giving a significant hazard ratio (HR) of 0.52.

However, there was no significant difference between the groups with regard to the likelihood of any relapse or distant relapse or overall survival,, report Michael Henderson, from the University of Melbourne in Victoria, Australia, and co-workers.

Minor radiotherapy side effects, such as pain and skin fibrosis, were “common”, the team writes, with 18 patients developing grade 3 toxicity, mostly to skin or subcutaneous tissue. Two patients experienced grade 4 toxicity to a major nerve and the inner ear.

And after 5 years, patients given radiotherapy had a significant increase in their mean lower limb, but not upper limb, volume compared with the observation group.

Nevertheless, questionnaire results indicated that adjuvant radiotherapy had a “negligible effect on quality of life”, the researchers report in The Lancet Oncology.

Follow-up surveys conducted 3 to 60 months after surgery showed that quality of life after surgery improved for patients in both treatment arms, although this took longer for the radiotherapy group, as demonstrated by lower scores in the radiotherapy versus observation patients for physical well being at 3 months and the total Regional Symptomatology Questionnaire scores at 3, 6 and 12 months.

The researchers observe that the trial was conducted at a time when interferon was the only available systemic adjuvant treatment but that the current targeted therapies and immune checkpoint inhibitors may “herald a new framework” for patients with high-risk melanoma.

They therefore conclude: “At the present time and until further information is available, patients with stage III melanoma at high risk of lymph-node field relapse should be considered for adjuvant systemic therapy trials in the first instance.

“The decision for adjuvant radiotherapy should be made with an appreciation of the risks and benefits of treatment, but for patients who do not receive radiotherapy, observation only with further surgery and radiotherapy reserved for another lymph-node field relapse might be an acceptable strategy.”

Reference

Henderson MA, Burmeister BH, Ainslie J, et al. Adjuvant lymph-node field radiotherapy versus observation only in patients with melanoma at high risk of further lymph-node field relapse after lymphadenectomy (ANZMTG 01.02/TROG 02.01): 6-year follow-up of a phase 3, randomised controlled trial. Lancet Oncol 2015; Advance online publication 20 July. dx.doi.org/10.1016/S1470-2045(15)00187-4

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