Neurotropic Melanoma of the Head and Neck

Overview

This is a 2-armed randomised controlled trial comparing surgery alone with surgery plus post-operative radiation therapy for patients with completely resected primary melanoma showing histological features of neurotropism. Uncontrolled studies suggest that this form of primary melanoma has a high risk of local recurrence and that postoperative radiation therapy may substantially reduce that risk. Patients who are eligible on the basis of the pathology of the excised melanoma will be offered the opportunity to take part in the trial. Those randomised to receive radiation therapy will be treated with a simple technique encompassing the surgical bed plus a margin. Radiation will commence within 3 months of surgery (maximum of 14 weeks from surgery to start of radiotherapy).

Background Melanoma is a serious and common malignancy in Australia. It is the third most common cancer in Australia and approximately 1000 Australians will die of the disease each year.At least a quarter of these will be patients under the age of 40 years. Neurotropism, defined as invasion by melanoma of peripheral neural tissue, is a feature of the disease that may predispose towards a high local recurrence rate. Local recurrence, particularly in the head and neck region often requires more extensive, potentially morbid surgery. Neurotropism is especially likely to occur in desmoplastic melanoma where it may be as high as 40 - 60%.6-8 Desmoplastic melanoma tends to occur in a slightly older age group than conventional types of melanoma and most often occurs in the head and neck region in individuals with chronic sun damage. The management of localised neurotropic melanoma has traditionally been with surgery. Recommendations are that surgical margins should be at least 2 cm.There are some patients where this margin is not achievable due to the location of the tumour close to important anatomical structures. Uncontrolled studies suggest that radiation therapy may reduce the risk of local recurrence in those patients although there are no randomised trials to confirm this hypothesis. Postoperative adjuvant radiation therapy has been shown in a randomised trial led from Australia, to reduce regional recurrence rates in nodal melanoma.There are no previously conducted randomised controlled trials addressing a similar question for neurotropic melanoma. The only reports are in relation to retrospective reviews that suggest a benefit for postoperative radiation therapy after surgery. It is unlikely that this trial will be done outside of Australia. Hypotheses 1. Radiation therapy after surgery for neurotropic melanoma improves local control. 2. This can be achieved without a significant increase in treatment morbidity or reduction in quality of life. Primary Objective • To determine, in patients who have undergone surgery with curative intent for neurotropic melanoma, whether there is a difference in the rate and timing of local (in field) recurrence between patients who are treated with post-operative radiation therapy and those that are initially observed. Secondary Objectives * To determine, in these patients, whether there is a difference in progression-free survival, patterns of relapse and overall survival between patients treated with surgery alone and those treated by surgery plus adjuvant radiation therapy. * To determine, in these patients, whether there is a difference in morbidity and quality of life between patients treated with surgery alone and those treated with surgery plus adjuvant radiation therapy Methodology This is a 2-armed randomised controlled trial comparing surgery alone with surgery plus post-operative radiation therapy for patients with completely resected primary melanoma showing histological features of neurotropism. Patients who are eligible on the basis of the pathology of the completely excised melanoma will be offered the opportunity to take part in the trial. Those randomised to receive radiation therapy will be treated with a simple technique encompassing the surgical bed plus a margin within 3 months of surgery. The same regimen which was used in the nodal trial will be used in this study. Patients in the observation arm who subsequently recur in field may be offered further surgery followed by radiation therapy. Randomisation Methods Patients will be randomised in the ratio of 1:1 between the two arms, radiation therapy and no radiation therapy. Allocation to the treatment arm will be stratified by institution and tumour site (head or neck) using randomly permuted blocks. Patients who are eligible on the basis of their pathology of excised melanoma will be offered the opportunity to take part in the trial. While males and females will both be considered equally for participation on the trial, there is no way of knowing if the ratio will be 1:1.