Lentigo maligna (melanoma): A systematic review and meta‐analysis on surgical techniques and presurgical mapping by reflectance confocal microscopy

Abstract

Because of an increased risk of local recurrence following surgical treatment of lentigo maligna (melanoma) (LM/LMM), the optimal surgical technique is still a matter of debate. We aimed to evaluate the effect of different surgical techniques and reflectance confocal microscopy (RCM) on local recurrence and survival outcomes. We searched MEDLINE, Embase and PubMed databases through 20 May 2022. Randomized and observational studies with ≥10 lesions were eligible for inclusion. Bias assessment was performed using the Methodological Index for Non‐Randomized Studies instrument. Meta‐analysis was performed for local recurrence, as there were insufficient events for the other clinical outcomes. We included 41 studies with 5059 LM and 1271 LMM. Surgical techniques included wide local excision (WLE) (n = 1355), staged excision (n = 2442) and Mohs' micrographic surgery (MMS) (n = 2909). Six studies included RCM. The guideline‐recommended margin was insufficient in 21.6%–44.6% of LM/LMM. Local recurrence rate was lowest for patients treated by MMS combined with immunohistochemistry (<1%; 95% CI, 0.3%–1.9%), and highest for WLE (13%; 95% CI, 7.2%–21.6%). The mean follow‐up varied from 27 to 63 months depending on surgical technique with moderate to high heterogeneity for MMS and WLE. Handheld‐RCM decreased both the rate of positive histological margins (p < 0.0001) and necessary surgical stages (p < 0.0001). The majority of regional (17/25) and distant (34/43) recurrences occurred in patients treated by WLE. Melanoma‐associated mortality was low (1.5%; 32/2107), and more patients died due to unrelated causes (6.7%; 107/1608). This systematic review shows a clear reduction in local recurrences using microscopically controlled surgical techniques over WLE. The use of HH‐RCM showed a trend in the reduction in incomplete resections and local recurrences even when used with WLE. Due to selection bias, heterogeneity, low prevalence of stage III/IV disease and limited survival data, it was not possible to determine the effect of the different surgical techniques on survival outcomes.

Topical and Intralesional Immunotherapy for Melanoma In Situ: A Review

“…Another study, with a mean follow-up of 5.1 years, reported a recurrence rate of 3% developed at mean 2.9 years [ 56 ]. This is a lower recurrence rate than previously reported in LM treated with WE (6–20%) [ 85 , 86 , 87 ], and closer to that reported in those treated by surgery with microscopic margin control, both MMS and SE (0–3%) [ 85 , 86 , 87 , 88 ].…”

Concordance between reflectance confocal microscopy and histopathology for the diagnosis of acral lentiginous melanoma

“…Many studies have explored the RCM characteristics of MM, 1 , 4 , 5 including melanoma in specific locations such as lentigo maligna melanoma. 6 , 7 , 8 However, monitoring acral skin using RCM is challenging because of the thick stratum corneum of the extremities; there are few reports describing the RCM characteristics of acral melanoma. In this study, RCM showed a sensitivity of 100% for the diagnosis of ALM, which was higher than that of histopathology.…”

Lentigo Maligna Treatment—An Update

“…However, surgical treatment of LM is associated with an increased risk of local recurrence compared with other subtypes of melanoma, as a result of incomplete resection. Unexpected positive margins are caused by the frequent subclinical extension of atypical cells [18]. Following WLE with the recommended 5 mm surgical margins, studies report recurrence rates that vary from 6% to 20%.…”

“…A systematic review and metaanalysis on surgical techniques in LM showed that a 5 mm surgical margin resulted in negative histological margins in 83% of cases following WLE or staged excision with partial margin assessment, while after complete histological assessment, the margins were found to be involved in 59% of cases. The weighted mean of a surgical margin needed for a negative histological margin was 7.7 ± 2.00 mm [18]. As a consequence, newer guidelines acknowledge the need to use clinically measured surgical margins larger than 5 mm (i.e., 5-10 mm) in order to achieve local control.…”

“…On the other hand, larger margins were reported by Kunishige et al when using MART-1, emphasizing the fact that atypical cells may be overlooked on initial H&E staining, and more likely to be identified with MART-1 staining, leading to an overall larger surgical defect [24]. Elshot et al conducted a meta-analysis on the surgical management of LM/LMM and showed that the use of MMS combined with IHC exhibited the lowest local recurrence rate [18]. Moreover, there is no consensus on the optimal use of immunostaining [18].…”