Frequency and duration of patient follow-up after treatment of a primary malignant melanoma.

To develop guidelines for the follow-up of patients with primary cutaneous melanoma (clinical Stage I), we studied 295 patients who had presented with a primary melanoma and who subsequently developed evidence of metastatic disease in the course of follow-up. Cox multivariate analysis was used to assess the influence of five variables in predicting the interval of time from the diagnosis of melanoma to the first clinical or laboratory evidence of metastatic disease (disease-free interval). The variables studied were tumor thickness, patient sex, patient age, elective lymph node dissection, and primary tumor location. Tumor thickness was found to be the major predictor of disease-free interval, which shortened progressively with increasing tumor thickness. Men had a shorter mean disease-free interval than women, although this effect did not reach statistical significance at the 0.05 level. Patient age, tumor location, and elective lymph node dissection were found not to be predictors of disease-free interval. The risk of recurrence of melanoma was tabulated, by year, for four intervals of tumor thickness. The increase in risk of recurrence associated with increases in tumor thickness above 1.5 mm was shown to occur predominantly in the early years following diagnosis-particularly in the first year. On the basis of our findings, we have suggested regimens of follow-up for melanoma.