Lentigo Maligna: Treatment When Surgical Excision Fails to Achieve Clear Histological Margins

Clinical Scenario

Lentigo maligna is an in-situ melanocytic lesion for which complete removal is the primary objective. This protocol applies when the first-line surgical approach has not achieved its intended endpoint, or when surgery is not a viable option, and an alternative treatment path is needed.

Why This Protocol Is Triggered

First-line management involves surgical removal of the lesion — wide local excision, Mohs micrographic surgery, or staged excision — with the goal of achieving clear (negative) histological margins. When that goal is not reached, or when surgery is not feasible or not accepted by the patient, escalation to this protocol is indicated.

Treatment Approach — Partial Overview

The protocol specifies a topical monotherapy applied directly to the lesion with an extended margin. The clinical goal is to sustain a visible inflammatory response at the treated site over the course of treatment — the intensity and duration of that response are directly linked to treatment outcome. The complete regimen, including application schedule, margin specification, criteria for dose adjustment, and monitoring guidance, is detailed in the full protocol.

Instant Access to Structured Evidence-Based Regimens

References

DOI: 10.3390/jcm13092527

According to experts, when surgery is not feasible or not accepted by the patient, imiquimod 5% cream as a monotherapy represents the treatment of choice, while radiotherapy represents a possible alternative treatment, but other topical treatments have also been used with inconsistent results, including cryotherapy, laser therapy, photodynamic therapy, 5-fluorouracil and tazarotene.

In patients who are not eligible for surgery or radiotherapy, imiquimod 5% can be used as a primary treatment option according to the published literature and in the experts' opinion.

Although there is no standardized regimen, the application of imiquimod with 1–2 cm margins for 5–7 days per week, over 12 weeks, leads to the best outcomes.

If the inflammation is extremely severe, leading to unacceptable pain or ulcerations, imiquimod should be stopped for a few days and resumed at a lower dose 2–3 days per week.

The objective of the treatment is to achieve visible inflammation for at least 10–11 weeks, with the intensity of the inflammatory response being directly associated with the clearance rate.

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