Search

Twelve clinical and pathologic parameters were compared in two series of Stage I melanoma patients treated at the University of Alabama in Birmingham, USA (676 patients) and at the University of Sydney in New South Wales, Australia (1,110 patients). Actuarial survival rates were virtually the same at the two institutions over a 25-year follow-up period. The incidence of thin melanomas (less than 0.76 mm) was also similar at both geographic locations (25% vs. 26%). Other similarities of these two patient populations included the following: 1) tumor thickness (Breslow Microstaging). 2) level of invasion (Clark Microstaging), 3) surgical results, 4) sex distribution, and 5) age distribution. The greatest differences between the two patient populations were their 1) anatomic distribution, 2) growth pattern, and 3) incidence of ulceration. The trunk was the most common site of melanoma, and occurred more frequently among Australian patients (37% vs. 28%). A multifactorial analysis (Cox's regression model) was then performed that included a comparison of the two institutions as a variable (Alabama vs. Australia). The dominant prognostic factors (p less than 0.0001) were 1) ulceration, 2) tumor thickness, 3) initial surgical management (wide excision +/- node dissection), 4) anatomic location, 5) pathologic stage (I vs. II), and 6) level of invasion. The benefit of elective lymph node dissection was demonstrated in both series for patients with intermediate thickness melanoma (0.76 to 3.99 mm.) For melanomas ranging from 0.76 to 1.5 mm in thickness, the benefit of node dissection was primarily in male patients. Survival rates for melanoma at the two institutions were not significantly different in the multifactorial analysis, even after adjusting for all other variable. Thus, the biologic behavior of melanoma in these two different parts of the world was virtually the same, with only minor differences that did not significantly influence survival rates. Long-term follow-up exceeding eight to ten years after surgery is critical in the interpretation of these prognostic factors and the surgical results.

Clinical and pathologic characteristics of melanoma were compared among 1647 clinical Stage I patients treated at the University of Alabama in Birmingham (USA) and The University of Sydney (Australia) between 1955 and 1980 to determine what changes occurred over a quarter century. Over this period, the number of patients treated annually has increased substantially. There was a steady increase in the proportion of patients presenting with localized disease (clinical Stage I). Melanomas became thinner, less invasive, less ulcerative and thus more curable. They also exhibited more of a radial growth phase. The median thickness of melanomas decreased in Australia from 2.5 mm prior to 1960 to 1.1 mm during the period 1976 to 1980, while in Alabama it has decreased from 3.3 to 1.4 mm. There was a significant increase in melanomas located on the trunk in males and a corresponding decrease in male head and neck melanomas. No significant change in the site distribution was observed for any major anatomical area on female patients. There were minimal differences in the incidence of both clinical and pathologic parameters among melanoma patients in Alabama, USA and in New South Wales, Australia even when accounting for their year of diagnosis. Long-term survival rates in patients with localized disease were found to increase slightly during the 25 year time frame of this analysis. The changes that have occurred are likely due to earlier diagnosis and changes in the biological nature of the disease.