Prognostic evaluation of intracranial metastasis in malignant melanoma.

BACKGROUND: Malignant melanoma (MM) is often reported as the third most common cause of intracranial metastasis (IM) after carcinoma of the breast and lung. Most patients with advanced MM will have widespread extracranial disease, but the majority will die from intracerebral spread.

METHODS: A retrospective review of 117 patients with documented IM from MM over the past 25 years was undertaken. Various factors (including age, race, sex distribution, primary lesions with Clark's level, Breslow's thickness, primary sites and staging at initial presentation, diagnosis of IM and its various treatment methods, survival data, and autopsy findings) were analyzed. Prognostic indicators were clarified from this analysis as a predictor of central nervous system (CNS) metastasis. An ideal treatment plan was also analyzed in order to predict a better survival.

RESULTS: Fifty-eight percent of patients were male; 42% were female. Seventy-one percent of the primary lesions were of Clark's level IV and V, with mean Breslow's thickness of 3.5 mm. Median time interval between the initial diagnosis and development of IM was 3.5 years. Complete surgical resection of the intracranial lesion in the brain resulted in the longest mean survival of 10.3 months, whereas mean survival for the group with no treatment was only 3 weeks. Patients with primary lesions of the head and neck had the lowest mean survival of 3.3 months, whereas those whose primary sites were unknown had the longest mean survival of 7.5 months. One- and 2-year survival were 9% and 3%, respectively. All but one of the 30 patients at autopsy were found to have visceral metastasis, namely of the lung, liver, and bone.

CONCLUSION: An aggressive search for metastasis should be undertaken in patients at high risk of developing CNS metastasis, e.g., male, head and neck primary, Clark's level IV and V, Breslow's thickness of > 3 mm, and presence of visceral metastases, mainly lung. A complete surgical resection should be attempted whenever possible, with adjunctive use of whole-brain irradiation, along with systemic chemotherapy for further control of recurrence and to prolong survival.