Ablative fractional laser‐assisted photodynamic therapy for lentigo maligna: a prospective pilot study

Abstract

Background Lentigo maligna (LM) is an in situ form of melanoma carrying a risk of progression to invasive lentigo maligna melanoma (LMM). LM poses a clinical challenge, with subclinical extension and high recurrence rates after incomplete surgery. Alternative treatment methods have been investigated with varying results. Photodynamic therapy (PDT) with methylaminolaevulinate (MAL) has already proved promising in this respect. Objectives To investigate the efficacy of ablative fractional laser (AFL)‐assisted PDT with 5‐aminolaevulinic acid nanoemulsion (BF‐200 ALA) for treating LM. Methods In this non‐sponsored prospective pilot study, ten histologically verified LMs were treated with AFL‐assisted PDT three times at 2‐week intervals using a light dose of 90 J/cm2 per treatment session. Local anaesthesia with ropivacaine was used. Four weeks after the last PDT treatment the lesions were treated surgically with a wide excision and sent for histopathological examination. The primary outcome was complete histopathological clearance of the LM from the surgical specimen. Patient‐reported pain during illumination and the severity of the skin reaction after the PDT treatments were monitored as secondary outcomes. Results The complete histopathological clearance rate was 7 out of 10 LMs (70%). The pain during illumination was tolerable, with the mean pain scores for the PDT sessions on a visual assessment scale ranging from 2.9 to 3.8. Some severe skin reactions occurred during the treatment period, however. Conclusions Ablative fractional laser‐assisted PDT showed moderate efficacy in terms of histological clearance. It could constitute an alternative treatment for LM but due to the side effects it should only be considered in inoperable cases.

<p>Lentigo Maligna: Clinical Presentation and Appropriate Management</p>

“…139 A recent study investigated the efficacy of ablative fractional laser-assisted PDT (average dose 90 J/cm 2 ) with 5-aminolaevulinic acid nanoemulsion for treating LM. 140 The rationale for using ablative fractional laser is that it allows for the photosensitizer precursor to penetrate deep enough to reach all the atypical melanocytes. Seven out of ten lesions (70%) were histologically completely cleared after three sessions.…”

Ten-year Follow-up Study of Grenz Ray Treatment for Lentigo Maligna and Early Lentigo Maligna Melanoma

“…In a recent study by Räsänen et. al ( 29 ), the LM area was pretreated with fractional ablative laser before PDT treatment 3 times with 2 weeks’ interval. Four weeks after treatment LM is excised surgically using 5-mm margins.…”

“…Thus, GR has been used as a definitive or adjuvant treatment after finding positive margins following excision of LM/LMM ( 7 , 30 ). The GR doses penetrating the skin decreased exponentially with distance; thus, LM that histologically presents a depth of extension of more than 0.8 mm should not be treated with GR ( 8 , 29 ). Moreover, when using a machine with 10 kV voltage (D ½=0.5 mm), high doses (150–160 Gy) are recommended in areas with hyperplastic adnexal structures, such as the nose and bearded areas, to avoid relapse.…”

Melanocyte Density in the Diagnosis of Melanoma In Situ in Sun-Damaged Skin

“…10 The standard therapy is complete excision, 11,12 while radiotherapy, destructive, or topical therapies are secondline options. [13][14][15][16][17] Correct histologic evaluation is of paramount relevance because tumors are often extensive and located in very delicate facial anatomic sites (Fig. 1) where surgical intervention can be particularly distressing and disfiguring.…”