Successful treatment of vulval melanoma in situ with topical 5% imiquimod cream

Topical Treatment of Melanoma In Situ, Lentigo Maligna, and Lentigo Maligna Melanoma with Imiquimod Cream: A Systematic Review of the Literature

INTRODUCTION

The classical management of melanoma is surgery, but this can be challenging because of several factors, such as age, body area, lesion size, among others. Topical imiquimod may be a therapeutic option for the treatment of melanoma in situ and lentigo maligna melanoma due to its efficacy, tolerability, and non-invasiveness. The purpose of this systematic review is to assemble current evidence on the treatment of non-metastatic melanoma with topical imiquimod.

METHODS

The PubMed/MEDLINE and Cochrane Library databases were searched as the primary sources using the main search terms "imiquimod" combined with "lentigo maligna" and "melanoma" with the command "AND." Articles were identified, screened, and extracted for relevant data, following the PRISMA guidelines.

RESULTS

A total of 87 studies covering 1803 lesions treated with imiquimod cream were identified and included in this sytematic review. Forty-nine studies were case reports, 16 were retrospective analyses, 3 were open label trials, six were case series; one study was a controlled randomized trial, one was a randomized trial, and one was a single-arm phase III trial. Because of the high number of low-evidence studies, the overall risk of bias resulted high. In 55 studies, imiquimod 5% was used in monotherapy as the primary treatment; only in one study was imiquimod 3.75% introduced. In most cases, the topical treatment was applied once daily, with the exception of nine cases where an increased daily dosage was prescribed. The total duration of the treatment regimen was extremely variable and depended on body area and tolerability, with differences among patients of the same study. In six studies, imiquimod was used as neoadjuvant therapy before the surgical excision, and in 11 studies it was used after surgery as complementary or adjuvant therapy. In total, 1133 of the 1803 (62.8%) lesions were reported to be cleared after the treatment, taking into account that not all of the patients completed the treatment. Of these 1133 lesions, histological clearance was achieved in 645 (56.9%) lesions and clinical clearance only was achieved in 490 (43.2%) lesions; relapse occurred in 107 lesions.

CONCLUSIONS

The heterogeneity of the studies included in this systematic review precludes the drawing of any relevant conclusions regarding the application of imiquimod. Its efficacy in melanoma in situ and lentigo maligna melanoma has been demonstrated, but further evidence from controlled studies concerning the modalities is missing.

Imiquimod treatment of vulvar melanoma in situ invading the urethra

•

Surgical approach is standard of care, topical imiquimod still experimental for mucosal melanoma.

•

Imiquimod beneficial for local control of disease if surgery not an option for MIS of vulva/ vagina.

•

In situ and invasive vulvovaginal melanoma have a high risk for recurrence even years later.

•

Long-term follow-up after topical imiquimod treatment needed as metastasis can arise years later.

The primary treatment of both in situ and invasive vulvar melanoma is wide local excision of the primary neoplasm. However, this can be a surgical challenge for size, multifocal presentation with proximity to urethra or anus and tendency for local recurrence. The data on adjuvant therapy for vulvar MIS is very limited.

A 69-year-old patient with melanoma of the vulva underwent a simple vulvectomy with positive margins in peri-clitoral area, followed by modified radical vulvectomy and bilateral inguinofemoral sentinel lymph node dissection with negative margins. She was later diagnosed with MIS of the vulva on different locations and had multiple wide local excisions over several years. One lesion was close to the urethra and a complete excision was difficult. Topical imiquimod × 16 weeks (5% cream) was given. The regimen was augmented from 3 to 5 times weekly. Complete resolution was found at 16 weeks and patient was disease free for 4 years. Recently however, a vaginal melanoma was detected.

Imiquimod appeared to be beneficial in the treatment of melanoma in situ of the vulva/ vagina when surgical options were not feasible producing local control of disease with the remaining risk for local and distant metastasis. Metastasis can appear years later, therefore long-term follow-up of patients treated with topical imiquimod is needed.

Topical treatment of melanoma metastases with imiquimod, plus administration of a cancer vaccine, promotes immune signatures in the metastases

INTRODUCTION

Infiltration of cancers by T cells is associated with improved patient survival and response to immune therapies; however, optimal approaches to induce T cell infiltration of tumors are not known. This study was designed to assess whether topical treatment of melanoma metastases with the TLR7 agonist imiquimod plus administration of a multipeptide cancer vaccine will improve immune cell infiltration of melanoma metastases.

PATIENTS AND METHODS

Eligible patients were immunized with a vaccine comprised of 12 melanoma peptides and a tetanus toxoid-derived helper peptide, and imiquimod was applied topically to metastatic tumors daily. Adverse events were recorded, and effects on the tumor microenvironment were evaluated from sequential tumor biopsies. T cell responses were assessed by IFNγ ELIspot assay and T cell tetramer staining. Patient tumors were evaluated for immune cell infiltration, cytokine and chemokine production, and gene expression.

RESULTS AND CONCLUSIONS

Four eligible patients were enrolled, and administration of imiquimod and vaccination were well tolerated. Circulating T cell responses to the vaccine was detected by ex vivo ELIspot assay in 3 of 4 patients. Treatment of metastases with imiquimod induced immune cell infiltration and favorable gene signatures in the patients with circulating T cell responses. This study supports further study of topical imiquimod combined with vaccines or other immune therapies for the treatment of melanoma.

A quantitative systematic review of the efficacy of imiquimod monotherapy for lentigo maligna and an analysis of factors that affect tumor clearance

BACKGROUND

The reported efficacy of imiquimod for lentigo maligna varies widely, without consensus on tumor or treatment factors that can impact tumor clearance.

OBJECTIVE

We sought to provide a more precise estimate of clearance rates in patients with lentigo maligna who are treated with imiquimod and to analyze factors that can impact tumor clearance.

METHODS

We performed a literature search for biopsy-proven lentigo maligna treated with imiquimod monotherapy, linked treatment and outcome data to individual tumors, calculated histologic and clinical clearance rates with 95% confidence intervals (CIs), and analyzed the impact of tumor and treatment factors on tumor clearance using logistic regression.

RESULTS

Based on 347 tumors from 45 studies, histologic and clinical clearance rates were 76.2% (95% CI, 71.4-81.0%) and 78.3% (95% CI, 73.6-82.9%), respectively. The incidence of clinical recurrence was 2.3% (95% CI, 0.5-4.2%), with a mean follow-up of 34.2 ± 11.8 months. Treatment with >60 total applications, or with >5 applications per week was associated with a higher likelihood of histologic clearance (odds ratio, 8.4 [95% CI, 2.9-24.1] and odds ratio, 6.0 [95% CI, 2.4-14.7], respectively).

LIMITATIONS

Our limitations included the accuracy and scope of published data, variable follow-up times, potential patient selection, and publication bias related to case series/cohort designs of previous studies.

CONCLUSION

Imiquimod offers a 76% histologic and 78% clinical clearance rate for lentigo maligna. Both cumulative dose and treatment intensity affect tumor clearance.

Topical treatment of recurrent vaginal melanoma in situ with imiquimod: A case report

► Vaginal melanoma in situ is a rare neoplasm with a paucity of data regarding the optimal management. ► More conservative approaches are needed to avoid the disfigurement, pain and postoperative complications associated with repeated surgical interventions. ► Imiquimod may prove to be a useful treatment modality for patients with vulvar or vaginal melanoma in situ.

Melanoma in situ treated successfully using imiquimod after nonclearance with surgery: review of the literature

BACKGROUND

The standard of care for melanoma in situ (MIS) is surgical removal by surgical excision with a 5-mm margin or Mohs micrographic surgery, but as more and more MIS is diagnosed in the head and neck region, surgeries may not be an option for patients when the lesions are large or less well defined. In addition, when negative margins cannot be achieved without grossly disfiguring the patient or when patients have medical comorbidities that preclude a surgical option, other treatment modalities may be considered. Recently, topical treatment with an immunomodulator, imiquimod, has been proposed as an alternative treatment for MIS.

OBJECTIVE

We report a case of MIS successfully treated with topical imiquimod cream. In addition, because there has not been any comprehensive review of the use of topical imiquimod on melanoma and MIS, we conducted an extensive literature search and reviewed the topic in detail.

MATERIALS AND METHODS

Using the keywords "imiquimod," "melanoma," "melanoma-in-situ," and "lentigo maligna," we searched the literature using PubMed in an attempt to find all relevant articles on the use of imiquimod on MIS or melanoma.

RESULTS

There were 46 reports involving 264 patients on the use of imiquimod on MIS or lentigo maligna. Twenty-three reports were published on the use of imiquimod on metastatic melanoma involving 55 patients, and two articles were on melanoma, with two patients in total. In addition, there were two articles on the use of imiquimod on dysplastic or atypical nevi with a total of 13 subjects.

CONCLUSION

Imiquimod appears to be beneficial in the treatment of MIS and melanoma metastases when surgical options are not feasible. Imiquimod should not be used for removal of dysplastic or atypical nevi. The treatment regimens varied from study to study, and there are no randomized controlled trials in the literature. More studies are needed to develop a reliable and reproducible treatment regimen, to fully elucidate the role of imiquimod in the treatment of MIS and melanoma, and to determine the prognostic predictors for favorable responses to imiquimod.

Imiquimod 3.75% cream (Zyclara) for the treatment of actinic keratoses

INTRODUCTION

actinic keratosis is a premalignant disease with a high incidence and is a strong predictor for the development of squamous cell carcinoma. Various treatment options have been established over recent years, including topical treatment with imiquimod, 5-fluorouracil, diclofenac or photodynamic therapy, cryotherapy and surgical procedures.

AREAS COVERED

this review covers basic and clinical experiences with imiquimod 3.75% for topical treatment of actinic keratosis of the face and balding scalp and its comparators with special focus on imiquimod 5%. It also covers pharmacology of imiquimod 3.5% and its contribution to the current treatment options of actinic keratoses.

EXPERT OPINION

imiquimod 3.75% is an interesting, safe and well-tolerated treatment option for actinic keratoses of the face or balding scalp especially in respect of compliance, as it is indicated for daily use for a shorter time period (2 times, 2-week cycles) and approved for use on larger areas compared with imiquimod 5%. Data from current trials indicate lower efficacy compared with imiquimod 5% cream when applied three times a week for 16 weeks or for two 4-week cycles with a 4-week no-treatment interval, but indicate similar efficacy when compared with a twice-weekly schedule for 16 weeks. An additive effect was observed when combining cryosurgery followed by imiquimod 3.75%.

TLR7 and TLR8 as targets in cancer therapy

Small-molecule agonists at Toll-like receptor 7 (TLR7) and TLR8 have sparked a vivid interest in cancer research owing to their profound antitumoral activity. The lead compound of the imidazoquinoline family, imiquimod, is marketed as a topical formulation. It is efficacious against many primary skin tumors and cutaneous metastases. Using different imidazoquinoline species, distinct functions of TLR7 and TLR8 have been discovered. The predominant antitumoral mode of action of these agents is TLR7/8-mediated activation of the central transcription factor nuclear factor-kappaB, which leads to induction of proinflammatory cytokines and other mediators. Cutaneous dendritic cells are the primary responsive cell type and initiate a strong Th1-weighted antitumoral cellular immune response. Recent research has shown that dendritic cells themselves acquire direct antitumoral activity upon stimulation by imiquimod. In addition, there are a number of secondary effects on the molecular and cellular level that can be explained through the activation of TLR7/8. The proinflammatory activity of imiquimod, but not resiquimod, appears to be augmented by suppression of a regulatory mechanism, which normally limits inflammatory responses. This is achieved independently of TLR7/8 through interference with adenosine receptor signaling pathways. Finally, at higher concentrations imiquimod exerts Bcl-2- and caspase-dependent proapoptotic activity against tumor cells.