A Review on Imiquimod Therapy and Discussion on Optimal Management of Basal Cell Carcinomas

Abstract

Basal cell carcinoma (BCC) is the most common type of skin cancer with an increasing incidence. However, it is still poorly researched compared to many other human diseases. Today, cutaneous neoplasms are a frequent, major problem faced by medical professionals. BCC tumors can cause extensive cosmetic distress as well as disfigurement to patients especially when on the face. Treatment options include surgery, systemic agents, and topical agents. Over the past few decades more studies have been performed to evaluate the utility of topical imiquimod therapy for treatment of BCC. Imiquimod is a toll-like receptor that modifies the immune response via the up-regulation of cytokines and has the capacity to improve a person's immune response. Multiple clinical studies have demonstrated the ability of topical imiquimod to diminish or even eradicate basal cell carcinoma. Given this variety of treatment options and the need for noninvasive options, this review is focused on summarizing the existing information available on the use of imiquimod for BCC and comparing it to other treatment modalities. While excision is the first line treatment and often has greater success with regards to clearance, imiquimod has been shown to be an efficacious treatment modality for BCC. Imiquimod therapy has been shown to be a less invasive and cheaper option than many other treatment modalities. It may be used as either monotherapy or in combination with other treatments, though occlusion has not been shown to be helpful. Several dosing regimens have been studied in the literature. Dosing should take into account factors such as the type of BCC, location, and physician/patient comfort with the regimen. Variability in response to treatment with imiquimod amongst studies suggests that response to treatment may depend on location of lesion, thus more research must be done in this area.

Complete response of cutaneous SCC to topical treatment with ascorbic acid solution: A case report

“…Of these, may be the most important example is represented by the topical application of Imiquimod 5% that has shown good efficacy against superficial BCC and solar keratosis. 6,7 The use of a topical solution of ascorbic acid, as in our case, has been reported in the literature only once by Holló et al 8 In their experience, 7 BCCs (1 nodular and 6 superficial) were treated once daily with a topical ascorbic acid solution (33 g/100 mL water), by means of a local bandage placed for at least 12 hours, for a total of 22 weeks. In an 18-month follow-up period, they achieved a resolution of five cases of BCC, confirmed by a post-therapy biopsy, and only one case of these has relapsed.…”

“…Currently surgery and radiotherapy are the first‐line treatments for these tumors but recently new pharmacological treatments have been employed. Of these, may be the most important example is represented by the topical application of Imiquimod 5% that has shown good efficacy against superficial BCC and solar keratosis 6,7 …”

In Vitro Enhanced Skin Permeation and Retention of Imiquimod Loaded in β-Cyclodextrin Nanosponge Hydrogel

“…Imiquimod (IMQ,1-[2-methylpropyl]-1 H -imidazo [4,5-c]quinolin-4-amine; Scheme 1) is an immune response modifier able to stimulate the production of Interferon-α (IFN-α) and other proinflammatory cytokines, inducing a cell-mediated immune response and increased collagen breakdown. In addition, IMQ can modify the expression of genes associated with apoptosis [1,2] and is clinically used for the treatment of neoplastic skin diseases [3]. In 2004, the Food and Drug Administration (FDA) approved the 5% IMQ cream, Aldara ® , for the treatment of actinic keratosis and superficial basal cell carcinoma in adults.…”

Adjuvant Effect of Toll-Like Receptor 9 Activation on Cancer Immunotherapy Using Checkpoint Blockade

“…Worth to note, although this review is focused on the antitumor effect of TLR9 activation, agonists of other TLRs were also shown to have antitumor activities. Imiquimod, a TLR7 agonist had FDA approved for treatment of superficial basal cell carcinoma in 2004 (3)(4)(5). Others including CADI-05 (TLR2 agonist), BO-112 (TLR3 agonist) and G100 (TLR4 agonist) were investigated in clinical trials for their antitumor effects (208)(209)(210).…”

“…Major advances have been made in the field of cancer immunotherapy in the past two decades (1,2). Imiquimod, a toll-like receptor (TLR)7 agonist, was FDA-approved in 1997 under the brand Aldara for treating genital warts and later approved for treating superficial basal cell carcinoma in 2004 (3)(4)(5). Three anti-cancer vaccines have been approved by the FDA.…”