Impact of digital dermoscopy analysis on the decision to follow up or to excise a pigmented skin lesion: a multicentre study

Background: The quality of early malignant melanoma (MM) diagnosis is dependent on the experience of dermatologists, tools like dermoscopy and histopathology, and awareness and education of the studied population. Does a higher rate of excision of pigmented skin lesions (PSL) increase the rate of detected melanomas? Material and Methods: The DB-MIPS objective tool, able to evaluate mathematical defined variables, has been used to verify the variability of measurements among PSL stored by five different centres located in Italy, Switzerland, and Germany. Results: The objective analysis showed low differences in terms of moles' features among the different groups, arguing for robustness of the dermatological patient's PSL inspection. Differences in terms of false positives and predictive positive values have been detected. The tendency to follow up a lesion was proportional to the percentage of thin MM (<0.75mm tumour thickness), while the interventism was proportional to the percentage of dysplastic moles. Similar percentage of thin melanoma has been observed in all the centres, indicating a standardization in early diagnosing among experienced dermatologists. The main difference among the centres was their mode of action, i.e. to follow up or remove suspicious PSL. Conclusion: Interventism depends neither on the geographic site nor on the features of the observed moles. Higher removal rates do not correspond to higher MM detections: this means that an in-depth knowledge of melanoma patterns is required and follow-up of suspicious moles is highly suggested.