A multifactorial analysis of melanoma. IV. Prognostic factors in 200 melanoma patients with distant metastases (stage III).

A multifactorial analysis of 200 cutaneous melanoma patients with distant metastasis (stage III) was performed on 13 clinical and pathological factors using the Cox regression analysis. There were only three dominant prognostic variables that independently predicted the patient's clinical course: (1) number of metastatic sites (1 vs. 2 vs. greater than or equal to 3, p less than 0.00001), (2) remission duration (less than 12 mo vs. greater than or equal to 12 mo, p = 0.0186), and (3) the location of the metastases (visceral vs. nonvisceral vs. combined, p = 0.0192). Factors that were not significant in the multifactorial analysis included the patients' age and sex, the site of the primary melanoma, the sequence of metastases, and all histopathological features of the primary melanoma (thickness, level of invasion, ulceration, growth pattern, pigmentation, and lymphocyte infiltration). For a single metastatic site, the 1-yr survival rate was 36%, while it was only 13% for 2 sites, and 0% for greater than or equal to 3 sites (p less than 0.00001). The 1-yr survival for patients was 40% for nonvisceral sites (skin, subcutaneous, distant lymph nodes) compared to only 11% for visceral metastases and 8% for combined sites (p less than 0.00001). Pulmonary metastases were associated with a significantly higher survival rate than metastatic melanoma in any other visceral site. The most common first site of distant metastases (either alone or in combination) was skin (38%), lung (36%), liver (20%), and brain (20%). The skin, subcutaneous and distant lymph node group was the first site of metastases in 59% of patients. This finding emphasizes the importance of careful physical exams in routine metastatic evaluations. Only a minority (25%) of stage I patients progressed to stage III disease after a median interval of 2.8 years. In contrast, the majority (75%) of melanoma patients with nodal metastases (stage II) progressed to stage III disease after a median duration of only 11 mo. Of the patients who eventually developed stage III disease, 95% of those who initially presented with stage II disease progressed within 3 yr, while stage I patients who progressed to stage III did not reach a 95% cumulative incidence until 8 yr.