Survival of patients with melanoma of the lower extremity decreases with distance from the trunk

BACKGROUND. Early stage melanoma of the lower extremity is generally associated with a favorable prognosis. However, several retrospective studies have suggested that melanoma on the foot portends poor survival. The authors hypothesized that the region of the lower extremity has prognostic importance. METHODS. Between January 1, 1971, and December 31, 1991, 652 patients were seen at the John Wayne Cancer Institute for a primary melanoma on the foot (92 patients), calf (336 patients), or thigh (224 patients). All patients had clinically or histopathologically negative regional lymph nodes. The duration of follow-up after first diagnosis was 9-302 months, with a minimum of 6 years for survivors. Survival curves were estimated by the Kaplan-Meier method. Pearson chi-square test was used to test differences associated with the regional site of the lower-extremity melanoma. The log rank test was used for univariate analysis, and Cox proportional hazards regression was used for multivariate analysis. RESULTS. Univariate analysis identified regional site, gender, Breslow depth, Clark level, and age at diagnosis as significant for both overall survival (OS) and disease free survival (DFS) (P = 0.0001). Multivariate analysis confirmed regional site as an independent prognostic variable for OS (P = 0.0002) and DFS (P = 0.0005). Ten-year rates of OS and DFS were 71% and 66%, respectively, for patients with foot melanomas, compared with 92% and 87% for those with calf melanomas and 95% and 94% for those with thigh melanomas. CONCLUSIONS. The prognosis for patients with primary melanoma of the lower extremity is affected by the distance of the lesion from the trunk. Thus, distal (foot) lesions carry a higher risk than thigh lesions. This difference should be considered as a covariate when stratifying patients in clinical trials.