Investigating Lentigo Maligna

Lentigo maliga is a type of in-situ (superficial) melanoma which often presents a treatment challenge as it commonly occurs on cosmetically sensitive areas of the head and neck of elderly patients and may require several surgical procedures to achieve adequate clearance. Whilst in-situ disease does not pose a risk of spreading (metastasis), if left untreated it can become invasive and more dangerous. Surgery is therefore the gold-standard for treatment, however topical imiquimod cream and radiotherapy are other options.

Imiquimod cream works by activating the immune system to fight the superficial melanoma. The Victorian Melanoma Service conducted a trial of the use of imiquimod cream for treatment of LM followed by complete surgical excision of the lesion 1 month post treatment to assess histological clearance1. Whilst the cream is successful in treating the disease for some patients, it is not effective in all.

This MMP study aims to better understand the immunological characteristics in patients who respond to imiquimod treatment compared to those who do not respond. This will involve both immunohistochemical and gene expression assays to explore immunological and microenvironmental predictors of response. This may give some insight into which immune regulators are important in fighting early stage melanoma and which patients are more likely to respond to topical immunotherapy for in-situ disease and can therefore safely avoid potentially disfiguring surgery.

1. Ly L, Kelly JW, O’Keefe R, et al. Efficacy of imiquimod cream, 5%, for lentigo maligna after complete excision: a study of 43 patients. Arch Dermatol. Oct 2011;147(10):1191-1195.