Cutaneous malignant melanoma in West Yorkshire: II. A prospective study of recurrence and prediction of lymph nodal metastasis.

One hundred and fifty patients with cutaneous malignant melanoma, in clinical stage I at diagnosis, were studied prospectively to determine the lymph nodal metastatic pattern of the disease, and to find that combination of clinical and pathological variables best predictive of the probability of its occurrence when combined in a linear logistic regression equation based upon a model by Cox. Details of the general pattern of melanoma recurrence are included to provide a necessary background to the nodal metastatic study. Of 66 patients showing melanoma recurrence in 48 (19 males and 29 females) it took the form of lymph nodal metastasis. Of these 50% showed lymph nodal metastasis within 1.1 years of the primary operation and 90% within 3.8 years. Nineteen clinical and pathological variables were tested for association with lymph nodal metastasis, 15 of which showed a significant association and in 7 of these the association was highly significant (P less than or equal to 0.0001). All 19 variables were included in the logistic regression analysis, 6 being selected as providing the best regression 'goodness of fit' and of these 'maximum tumour thickness (Breslow' and 'sex' emerged as the dominant variables. It is concluded that the analysis described provides surgeons, oncologists, and pathologists with a practical method to assess the likelihood in an individual patient of melanoma recurrence to regional lymph nodes. This should enable surgery or other adjunctive therapeutic regimens to be selected at an early stage.