A nationwide study of treatment of lentigo maligna and its recurrence rate in the Netherlands.

Abstract

The treatment of lentigo maligna (LM) can be challenging in older patients and in delicate facial areas. Previous studies have shown that LM in 10% of patients is upstaged to LM melanoma (LMM) after surgery. To identify, via a nationwide cohort study, the diagnostic modalities and available treatments for LM in the Netherlands, and to investigate the rates of postoperative upstaging to LMM and recurrence post-treatment. To investigate the modalities used to diagnose LM and the rate of upstaging to LMM after surgery, data from 2020 were retrieved from the Dutch Nationwide Pathology Databank ('Palga'). To investigate the available treatments for LM, data were retrieved from the Netherlands Cancer Registry between 2013 and 2016. To investigate post-treatment recurrences, all reports of LM from 2013 to 2021 were retrieved from Palga. In 2020, 1422 patients in the Netherlands were diagnosed with primary LM. Diagnoses were made using a punch biopsy in 60.8% of cases (n = 864) and with an excisional biopsy in 37.1% (n = 527). Half of the patients (n = 713; 50.1%) were treated surgically and 14.2% (n = 101/713) were upstaged to LMM/melanoma after surgery. Between 2013 and 2016, wide local excision (WLE) was performed in 79.7% (n = 2860/3587) of cases of histopathologically confirmed primary LM, staged excision was chosen in 1.6% (n = 58), watchful waiting in 1.5% (n = 55) and noninvasive treatments in 4.5% (n = 162). With a median follow-up until death or censoring at 5.7 years, there were 247 (6.9%) recurrences, with a median time to recurrence of 2.4 years. In the Netherlands, patients with LM are most often diagnosed with a punch biopsy and most are treated with WLE, in line with Dutch melanoma guidelines. Using a nationwide database, 14% of histologically proven cases of LM were upstaged to LMM postsurgery. This should be considered when choosing treatment, especially when considering nonsurgical treatments. The significant number of recurrences in patients who received nonsurgical treatment demonstrates the complexity of treating LM and the importance of balancing histological clearance with sometimes disfiguring surgery in the head-and-neck region.