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.