FACTORS RELATED TO THE PRESENTATION OF PATIENTS WITH THICK PRIMARY MELANOMAS

Objective: To identify any characteristics of patients that are associated with presentation with thick primary melanoma. Design: This was a retrospective survey of the clinical records of 1300 patients attending the Newcastle Melanoma Unit. Characteristics of 131 patients with thick melanomas (defined as 3 mm or greater in thickness) were compared with those of 543 patients with thin melanomas (defined as 0.75 mm or less in thickness). Comparisons were made using contingency table analysis, Wilcoxon rank sum tests, log rank analysis and logistic regression. Setting: The Newcastle Melanoma Unit is a tertiary referral centre for the treatment of primary melanoma. Patients: We surveyed all 1300 patients attending the Newcastle Melanoma Unit over the years 1981-1990. They represented approximately 90% of the patients in the Hunter region of New South Wales who developed melanoma during this period. Excluded from analysis were 39 patients with occult primary melanomas, 79 with multiple primary melanomas, 51 with primary melanomas of unknown thickness and seven with incomplete records, leaving 1124 patients in the study. Main outcome measures: These were selected before the results were known. The hypothesis was generated following analysis of the data. Results: Patients with thick primary melanoma were more likely to be men (68% men and 32% women in the thick melanoma group, compared with 45% and 55% respectively in the thin melanoma group, P < 0.005) over 60 (75% were over 50 years of age in the thick group versus 33% in the thin melanoma group, P < 0.001) with nodular melanoma (62%, versus 2% in the thin melanoma group, P < 0.001) and with melanoma on the head and neck (27%, versus 12% in patients with thin melanoma, P < 0.005). The time from detection of a change in skin to diagnosis was not longer for those with thick compared to those with thin melanomas. Conclusion: The greatest problem of detecting melanoma at an early (surgically curable) stage appears to be in patients over the age of 50 who have nodular melanoma, particularly in the head and neck.