Radiotherapy for mucosal melanomas

Abstract

Twelve patients who were primarily irradiated at the Princess Margaret Hospital (PMH) for mucosal melanomas of the head and neck and 6 patients irradiated for mucosal melanomas of the vagina and anorectal region are reported. The PMH results of irradiation of mucosal melanomas of the head and neck are combined with the literature results for this type of melanoma. A total of 24 patients who had 25 areas irradiated are considered. The complete remission rate locally is 72% (18 of 25 areas treated). Seven of the 18 patients who achieved complete local remission subsequently relapsed locally (9 to 144 months post treatment); 11 are in maintained complete local remission (9 to 54 months). Four died of intercurrent disease without melanoma, 5 are alive and well post irradiation, one recurred regionally and was salvaged surgically and one died of distant metastases without local or regional relapse. Only 1 of 7 patients who failed to respond to irradiation was salvaged with subsequent surgery, the others all died very rapidly following unsuccessful irradiation. Analysis of local control versus fraction size revealed that 6 of 7 patients treated with a fraction size of 400 rad or more achieved complete remission as compared to 5 of 18 treated with a fraction size of 399 rad or less. The results of primary irradiation for mucosal melanomas of the head and neck are compared with the literature on radical surgery, it is concluded that in view of the poor results of radical surgery that large dose per fraction irradiation should be seriously considered as the initial treatment of choice for primary mucosal melanomas of the head and neck. Four patients with vaginal melanomas were treated at the PMH, all achieved complete remission locally, 2 recurred at 18 and 28 months, one is alive and well at 3 years and one died of intercurrent disease at 1 1/2 years. Two patients with anorectal melanoma had transient palliative benefit from irradiation. Since the treatment of both vaginal and thick (greater than 2 mm) anorectal melanoma is essentially palliative it is suggested that irradiation should be considered as an alternate treatment to radical treatment in these conditions.