Original article
In vivo reflectance confocal microscopy to monitor the response of lentigo maligna to imiquimod

https://doi.org/10.1016/j.jaad.2014.02.043Get rights and content

Background

Imiquimod has been used for treating lentigo maligna (LM) in selected cases when surgery is not an appropriate option because of functional or aesthetic impairment. Reflectance confocal microscopy (RCM) is a noninvasive method that has not been validated for monitoring the treatment of LM with imiquimod.

Objective

We sought to evaluate the use of in vivo RCM to accurately monitor the response of LM to nonsurgical treatment with topical imiquimod.

Methods

Twenty patients with confirmed facial LM, not amenable to surgical treatment or radiation therapy, were included prospectively. Clinical evaluation was performed by dermoscopy, RCM, and histopathology. Patients applied imiquimod 5% for 8 weeks. The affected area was assessed using the previously described LM score on RCM, and target sample biopsies were performed to confirm or discard RCM findings.

Results

Fifteen of the 20 patients (75%) presented histologic tumor clearance. Confocal microscopy identified 70% of these responders with no false-negative results, and when compared with histopathology, there was no significant difference in evaluating the response to imiquimod.

Limitations

The impossibility of examining the entire lesion by means of histopathology is a limitation.

Conclusion

In vivo RCM evaluation was useful in accurately monitoring the response of LM to nonsurgical treatment with topical imiquimod in patients when surgery is contraindicated.

Section snippets

Methods

A prospective study of 20 patients referred for treatment of LM was conducted at the Melanoma Unit of Hospital Clinic in Barcelona, between June 2007 and June 2011. All lesions were histologically confirmed facial LM, not amenable to surgical treatment or radiation therapy. Immunocompromised patients and those with clinical and histologic evidence of LM melanoma were excluded. Informed consent for acquiring the images, taking sample biopsy specimens, and treatment was obtained after discussing

Results

The study comprised a total of 20 patients (14 women and 6 men) aged from 33 to 90 years (median 76.5) recruited at the Melanoma Unit of Hospital Clinic in Barcelona, between May 2008 and June 2011. Most tumors were located on the face and the anatomic location of the lesions included the buccal region (14 patients), nasal region (3 patients), scalp (1 patient), forehead (1 patient), and periorbital region (1 patient). Although the clinical diameter of the lesions ranged from 0.8 to 4 cm, the

Discussion

According to a review of the literature regarding treatment of LM with topical imiquimod,4 the studies showing the highest clearance rates for imiquimod (up to 91%) were those where the evaluation of tumor clearance was based on clinical evaluation20 or after treatment biopsies, with the risk of overvaluing the response. The efficacy rates reported by studies performing standard wide local excision22, 23 or staged excision17 after imiquimod treatment were lower: 53%,22 68%,23 and 75%17 of

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  • Cited by (0)

    The research at the Melanoma Unit in Barcelona is partially funded by grants 09/1393 and 12/00840 from Fondo de Investigaciones Sanitarias, Spain; by the Centro de Investigación Biomédica en Red (CIBER) de Enfermedades Raras of the Instituto de Salud Carlos III, Spain, cofunded by “Fondo Europeo de Desarrollo Regional, Unión Europea, Una manera de hacer Europa”; by the Agència de Gestió d'Ajuts Universitaris i de Recerca (AGAUR) 2009 SGR 1337 of the Catalan Government, Spain; by the European Commission under the Sixth Framework Programme, Contract no. LSHC-CT-2006-018702 (GenoMEL); and by the National Cancer Institute of the US National Institutes of Health (CA83115). The sponsors had no role in the design and conduct of the study; in the collection, analysis, and interpretation of data; or in the preparation, review, or approval of the manuscript.

    Conflicts of interest: None declared.

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