Acral lentiginous melanoma treated with topical imiquimod cream: possible cooperation between drug and tumour cells

Abstract

An 85-year-old woman presented with a lesion on the sole of her right foot, which was histologically confirmed as acral lentiginous melanoma. Because of the large field involved and because the patient refused any invasive or painful treatment, topical treatment with imiquimod was commenced. At the 20-month follow-up, the patient was still continuing treatment with topical imiquimod, and no metastases to the lymph nodes or viscera were found, either clinically or in imaging studies. We believe that the success of the treatment cannot be explained only by the stimulation of the immune system induced by imiquimod. A possible explanation might be 'tumour dormancy', where a tumour grows very slowly because of a balance between the neoplasia and the immune (and nonimmune) mechanisms of tumour control. The use of imiquimod has so far allowed our patient to avoid surgery, and perturbation of the mechanisms of tumour regulation, such as local immunity and angiogenesis, has not taken place.

Subclinical persistence of residual acral melanoma in situ after treatment with topical imiquimod and retinoid creams

“…Unlike prior reports, 1 , 2 our findings demonstrate that imiquimod was not an effective therapy for our patient. A biopsy was required to detect disease persistence, given that the lesion had clinically faded and appeared markedly improved.…”

“…The literature is limited on the use of imiquimod in the management of ALM, though existing case reports suggest it may be an effective treatment. 1 , 2 In 1 case report, 1 a patient with ALM in situ declined surgery and was instead treated with 5% imiquimod for weeks. 1 The patient appeared clinically clear and there was no evidence of systemic disease after 8 months.…”

“… 1 , 2 In 1 case report, 1 a patient with ALM in situ declined surgery and was instead treated with 5% imiquimod for weeks. 1 The patient appeared clinically clear and there was no evidence of systemic disease after 8 months. However, a repeat biopsy was not performed and the follow-up time reported was limited.…”

“…There is a gap in the literature regarding the role of imiquimod in the management of acral lentiginous melanoma (ALM), though a few case reports suggest it may be an effective primary or adjuvant treatment option. 1 , 2 Herein, we report a case of subclinical persistence of residual ALM in situ following adjuvant therapy with imiquimod and retinoid creams and highlight the limitations of using imiquimod therapy in the management of ALM.…”

Nonsteroidal Topical Immunomodulators in Allergology and Dermatology

“…In order to achieve a moderate contact allergic response promptly, 0.01%−0.03% DPCP in aqueous cream was combined with 5% imiquimod cream 3x week: complete clearance of cutaneous disease was achieved in 46% and partial response in a further 38% of patients; mean DPCP treatment duration to clearance of all cutaneous lesions lasted 8 months (range 1–24); and mean duration of complete response was 17 months (range 1–78) [ 73 ]. Imiquimod has both immunomodulatory antiviral and antitumor Th1 effects, mediated via activation of Toll-like receptor 7 and 8 and increased production of IFN- α , IFN- γ , TNF- α , IL-1, IL-6, IL-8, IL-10, and IL-12 [ 73 ] and probably via enhanced inhibition of angiogenesis against micrometastases [ 74 ].…”