Radiotherapy for Cutaneous Malignant Melanoma: Rationale and Indications
January 01, 2004
The use of radiation as adjuvant therapy for patients with cutaneousmalignant melanoma has been hindered by the unsubstantiatedbelief that melanoma cells are radioresistant. An abundance of literaturehas now demonstrated that locoregional relapse of melanoma iscommon after surgery alone when certain clinicopathologic featuresare present. Features associated with a high risk of primary tumor recurrenceinclude desmoplastic subtype, positive microscopic margins,recurrent disease, and thick primary lesions with ulceration or satellitosis.Features associated with a high risk of nodal relapse include extracapsularextension, involvement of four or more lymph nodes, lymphnodes measuring at least 3 cm, cervical lymph node location, and recurrentdisease. Numerous studies support the efficacy of adjuvant irradiationin these clinical situations. Although data in the literatureremain sparse, evidence also indicates that elective irradiation is effectivein eradicating subclinical nodal metastases after removal of theprimary melanoma. Consequently, there may be an opportunity to integrateradiotherapy into the multimodality treatment of patients at highrisk of subclinical nodal disease, particularly those with an involvedsentinel lymph node. Such patients are known to have a low rate ofadditional lymph node involvement, and thus in this group, a shortcourse of radiotherapy may be an adequate substitute for regional lymphnode dissection. This will be the topic of future research.