Successful implementation of handheld reflectance confocal microscopy as the standard of care in the (surgical) management of lentigo maligna (melanoma).

ABSTRACT

BACKGROUND: Reflectance confocal microscopy (RCM) has shown promise in predicting surgical outcomes by non-invasively detecting subclinical lentigo maligna (melanoma) (LM/LMM). OBJECTIVES: To assess the effects of presurgical mapping using handheld RCM (HH-RCM) on surgical treatment, follow-up outcomes and management decisions. METHODS: A total of 117 consecutive LM/LMM cases (2015-2023) were included. The diagnostic accuracy of HH-RCM in detecting subclinical LM and invasive components was evaluated. The primary endpoints included histological margin status and changes in management based on the outcomes of the HH-RCM mapping procedure. Margin and follow-up outcomes were compared to a historical cohort before HH-RCM was introduced in our center (n = 94) (2003-2014). RESULTS: HH-RCM detected subclinical LM in 60% (n = 60) of cases. The median mapping duration was 14 min (range 4-50). In 27% (n = 33), the mapping procedure resulted in modified management, the majority consisting of limited surgery with adjuvant imiquimod (n = 15) or imiquimod monotherapy (n = 14). The remaining cases (n = 84) underwent HH-RCM-assisted surgery. Histological margins were cleared in 96.5% of the patients with a median histological margin of 3.0 mm, significantly higher than 81% in the historical cohort (median 2.0 mm) (p = 0.001). The sensitivity and specificity for detecting the extent of subclinical LM were 94% (95% CI 80.4-99.3) and 84% (95% CI 70.3-92.7), respectively. The negative predictive value for the detection of LMM was 94% (95% CI 84.4-97.7), and 75% of the initially missed LMM (n = 12) were identified during the HH-RCM mapping procedure. The study cohort had a 1.6% local recurrence rate compared with 25% in the historical cohort. CONCLUSIONS: Integrating HH-RCM as the standard of care could lead to more personalized treatment strategies for LM/LMM and allows for the selection of patients suitable for nonsurgical treatment.