Speed of growth of melanoma: statistical analysis of the average ages of patient groups

Based on data from 1,657 cases, the average age of patients with melanoma of the same type, level, resp. thickness was calculated. It was shown that the average age of the melanoma patients increased with progressive tumor growth, i.e., with increasing level and thickness. The time span for thin (less than 0.75 mm thickness), superficial spreading melanoma (SSM) to reach the level of a far-advanced tumor with a thickness of more than 3.00 mm was 7.8 years. For nodular melanomas (NM), the corresponding period was 9.5 years. Longer intervals were determined by analysis of the data according to tumor levels. The difference in the average age of patients with early invasive SSM (level II) as compared with patients with level V tumors was 11.4 years. Patients with level V NM were on the average 10.0 years older than patients with level III NM. Differences in the average age of patients with SSM or NM from one level to the other ranged between 3 and 4 years (median: 3.9 years). The differences in the thickness of the groups were similar (median: 3.1 years).