Long-Term Sequential Digital Dermoscopy of Low-Risk Patients May Not Improve Early Diagnosis of Melanoma Compared to Periodical Handheld Dermoscopy

Simple Summary The combined use of total-body photography and sequential digital dermoscopy has been validated as a standard of care for the early detection of cutaneous melanoma in high-risk individuals. However, the exact impact of this approach in low-risk subjects is not clear. We conducted a retrospective study to evaluate whether there were any differences of prognostic significance between melanomas diagnosed with handheld dermoscopy and sequential digital dermoscopy. In our study, no significant differences were detected in terms of tumor thickness and stage distribution in low-risk patients followed in the long term. Our data contribute to shape the role of sequential digital dermoscopy in patients without risk factors for melanoma. Sequential digital dermoscopy (SDD) enables the diagnosis of a subgroup of slow-growing melanomas that lack suspicious features at baseline examination but exhibit detectable change on follow-up. The combined use of total-body photography and SDD is recommended in high-risk subjects by current guidelines. To establish the usefulness of SDD for low-risk individuals, we conducted a retrospective study using electronic medical records of low-risk patients with a histopathological diagnosis of cutaneous melanoma between 1 January 2016 and 31 December 2019, who had been referred and monitored for long-term follow-up of clinically suspicious melanocytic nevi. We sought to compare the distribution of "early" cutaneous melanoma, defined as melanoma in situ and pT1a melanoma, between SDD and periodical handheld dermoscopy in low-risk patients. A total of 621 melanomas were diagnosed in a four-year timespan; 471 melanomas were diagnosed by handheld dermoscopy and 150 by digital dermoscopy. Breslow tumor thickness was significantly higher for melanomas diagnosed by handheld compared to digital dermoscopy (0.56 +/- 1.53 vs. 0.26 +/- 0.84, p = 0.030, with a significantly different distribution of pT stages between the two dermoscopic techniques. However, no significant difference was found with respect to the distribution of pT stages, mean Breslow tumor thickness, ulceration, and prevalence of associated melanocytic nevus in tumors diagnosed on periodical handheld dermoscopy compared to SDD. Our results confirm that periodical dermoscopic examination enables the diagnosis of cutaneous melanoma at an earlier stage compared to first-time examination as this was associated in our patients with better prognostic features. However, in our long-term monitoring of low-risk subjects, Breslow tumor thickness and pT stage distribution did not differ between handheld periodical dermoscopy and SDD.