CRITICAL ANALYSIS OF THE CURRENT AMERICAN JOINT COMMITTEE ON CANCER STAGING SYSTEM FOR CUTANEOUS MELANOMA AND PROPOSAL OF A NEW STAGING SYSTEM

Purpose: To critically review the accuracy of the current American Joi nt Committee on Cancer (AJCC) staging system for cutaneous melanoma an d propose a more useful staging system. Methods: Retrospective evaluat ion of the published data as well as a reanalysis of the University of Alabama and Sydney Melanoma Unit (UAB/SMU) data bases (n = 4,568) for patients with primary melanoma was performed to examine specifically the impact of level of invasion and ulceration on the prognostic value of tumor thickness. In addition, an overlay graphic technique was use d to compare the Kaplan-Meier survival curves of patients with local r ecurrences, satellites, in-transit metastases, and nodal metastases re ported in the literature. Results: Tumor thickness and ulceration rema ined the most powerful prognostic indicators in patients with stage I and II disease. Level of invasion provided statistically significant p rognostic information only in the subgroup of patients with tumor thic kness less than or equal to 1 mm, but the absolute 10-year survival di fferences were small and inconsistent (level II, 95%; level III, 85%; level IV, 89%). The best statistical fit for tumor thickness cutoffs w ets at 1 versus 2 versus 4 mm. The overlay graphic technique showed th at patients who developed satellite lesions or local recurrence had pr ognoses similar to those of patients with stage III disease. The most important prognostic factor for patients with nodal metastases was num ber of involved nodes rather than size. Conclusion: Our analysis showe d their the current AJCC staging system has many inaccuracies that sho uld be modified to conform to published data. On the basis of our anal ysis and review of the literature, we propose a new and more accurate staging system. (C) 1997 by American Society of Clinical Oncology.