A follow-up study to investigate the efficacy of initial treatment of lentigo maligna with surgical excision

Recurrence rates following conventional surgery for lentigo maligna (LM) are reported to be between 7% and 15%. However, the studies are few, contain small numbers of patients and have relatively short follow-up. The principle aim of this study was to determine the efficacy of conventional surgery for LM in a large unbiased sample of all LM presenting in a defined geographical area. All LM cases occurring in Leicestershire between 1987 and 1996 were identified. Data were gathered from case notes, general practitioners and the Office for National Statistics (for any mortality data) and patients were invited to attend for examination. There were 89 evaluable patients treated with primary excision, representing the largest reported series to date. There was a false positive rate for diagnostic biopsy for LM (when the correct diagnosis was lentigo maligna melanoma, LMM) of 5% (95% confidence interval, CI: 1% to 14%). The initial excision was histologically incomplete in 9% (4% to 17%) of cases. In completely excised lesions (n = 81) the observed recurrence rate was 20% (CI: 12% to 30%) at a mean follow-up of 42 months, which is similar to previous reports. However, Kaplan-Meier analysis yielded an estimated probability of recurrence of 31% (CI: 19% to 50%); time to relapse was up to 66 months. The age and sex of the patient and the site of the lesion were not associated with outcome, but, surprisingly, smaller lesions were associated with incomplete excision and recurrence. Fifteen current lesions were excised with similar success rates: the incomplete re-excision rate was 7% (CI: 0.2% to 32%) and the recurrence rate was 31% (CI: 12% to 83%) at 28 months. The estimated rate of transformation to LMM after initial surgical treatment was 1.5% (CI: 0.3% to 8%), and LMM was not the cause of death in any patient. These recurrence rates following complete primary excision and re-excision following recurrence were high compared with general expectations, which is largely the result of the method of analysis and the long follow-up. The high rate calls into question the accuracy of the routine histological assessment of clearance. The development of LMM was rare following surgery. (C) 2002 The British Association of Plastic Surgeons. Published by Elsevier Science Ltd. All rights reserved.