Long-term dermoscopic follow-up of melanocytic naevi: clinical outcome and patient compliance.

Background: Digital dermoscopy for the follow-up of melanocytic naevi (MN) is becoming more common in dermatological private practice.

Objectives: To evaluate the clinical outcome, including the patient's compliance, in a long-term follow-up of single MN.

Methods: Criteria for the selection of MN for follow-up: clinically suspicious without dermoscopically atypical features, or typical for the patient. Clinical outcome measures: number of detected malignant melanomas (MM) and/or atypical MN; quantity, quality, and differences in morphological changes between 'low-risk' patients (no MM in history and < 50 MN) and 'high-risk' patients (MM in history and/or > 50 MN). Compliance: the number of patients who joined a recommended follow-up scheme.

Results: No MM was found in 145 consecutive patients (mean age 28 years, 54% female) during a 4-year period (median follow-up per patient: 24 months; ranging 4-45; at least three visits). In five patients (3%), seven histologically proven atypical MN were shown on whole body examination at sites other than those documented. A total of 1968 images in 177 'low-risk' and 95 'high-risk' MN were analysed: 37% (n = 65) of 'low-risk' and 32% (n = 30) of 'high-risk' MN showed dermoscopic changes (difference not statistically significant), none were suspicious for MM. Compliance, evaluated within a separate database of 303 consecutive patients (mean age 32 years, 52% female) over a 6-month period, was only 46%, although recall letters were used.

Conclusions: (i) In our setting of daily routines in dermatological private practices long-term follow-up of a single MN seems not to be helpful for the detection of MM. (ii) A whole body examination must be done at each visit. (iii) The clinician's experience of the type and number of possible morphological changes in MN is crucial in order to avoid unnecessary excisions. (iv) The patient's compliance might be an important problem. (v) Cost-effectiveness has yet to be analysed.