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

Novel Combination Treatment for Melanoma: FLASH Radiotherapy and Immunotherapy Delivered by a Radiopaque and Radiation Responsive Hydrogel

Immunotherapies have become the standard treatment for melanoma. To further improve patient responses, combinations of immunotherapies and radiotherapy (RT) are being studied, since radiotherapies can potentially provide additional immune stimulation, in addition to direct antitumor effects. FLASH-RT is a novel, ultrahigh dose rate, radiation delivery approach, with the potential of at least equivalent tumor control efficacy and reduced damage to healthy tissue. However, the effects of combining FLASH-RT and immunotherapy have not been extensively studied in melanoma. Toll-like receptor (TLR) agonists, such as imiquimod (IMQ), are potent immunostimulatory agents, although their utility is limited due to poor solubility and systemic side effects. We therefore developed a novel combination therapy for melanoma consisting of IMQ delivered to the tumor via a radiopaque and radiation responsive hydrogel combined with FLASH-RT. We found that FLASH was able to effectively stimulate IMQ release from the hydrogel. In addition, we found that the combination of FLASH and released IMQ resulted in synergistic melanoma cell killing in vitro. The combination therapy reduced tumor growth compared to controls, enhanced survival, and resulted in remarkable enhancements in certain tumor cytokine levels. CT imaging allowed the hydrogel to be monitored in vivo. In addition, no adverse effects of the treatment were observed. Overall, this IMQ-gel and FLASH-RT combination may have potential as an improved treatment for melanoma and indicates that the interactions of FLASH-RT and TLR agonists merit further study.

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

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

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

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

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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.

Primary malignant melanoma of the vagina

Primary malignant melanoma of the vagina is a rare gynaecological neoplasm with an aggressive course of disease. Although not many cases have been reported in the literature, its manifestations appear to be fairly consistent. The challenge comes in knowing how to approach this cancer clinically, since information about its staging and treatment is limited. In this report, we present a case of an 84-year-old postmenopausal woman in whom a suspicious vaginal lesion was discovered incidentally during a procedure. Wide local excision was carried out at a later date and histopathology confirmed a malignant melanoma of the vagina contained locally with no radiological finding of distant metastases. No additional treatment was given, and three monthly follow-ups were arranged for this patient. We review the literature and briefly discuss the epidemiology, treatment approaches, prognostic factors and expected outcomes of this rare disease.

Primary Vaginal Melanoma, A Rare and Aggressive Entity. A Case Report and Review of the Literature

Malignant melanoma of the vagina is a rare, aggressive malignancy of poor prognosis. It principally affects post-menopausal women, with a mean age of 57 years, and the factors that contribute to its appearance are not well known. The first case of primary malignant vaginal melanoma was reported in 1887 and modern literature has noted about 500 cases, globally. Vaginal melanomas constitute 0.3% of all malignant melanomas and fewer than 3% of all vaginal carcinomas. To date there is no clear consensus regarding treatment. An early, accurate diagnosis and prompt investigation is essential in reaching appropriate treatment decisions. We present a clinical case of primary vaginal melanoma and review the literature briefly, presenting the current treatment plans and updates of this rare gynecological malignancy. Considerations, epidemiology, associated risk factors, response to therapy and expected outcome are also discussed.

CONCLUSION

Primary malignant vaginal melanoma is a rare but aggressive melanoma that affects women in their 6th and 7th decade of life. The tumor appears as a dark node or spindle but can also be amelanotic. The size of the tumor is indicative of the prognostic factors. Surgery seems to be the only efficient treatment. Postoperative adjuvant therapy might help in preventing recurrence of the tumor. The survival rate is largely dependent on nodal and distant metastasis of the disease after initial tumor resection. There is a dire need to form a proper therapeutic regime to control this disease.

[Melanomas of the female genital tract: state of the art]

Melanoma of the female genital tract is a rare location (less than 2% of melanomas all sites combined). These cancers have a very poor prognosis, due to the delay in diagnosis. Vulvar location is about 1% of melanomas then the vaginal location, uterine and ovarian. There is no consensus to date regarding their care, due to the rarity of the lesions. Their treatment must however be based on the current data concerning gynaecological cancers as well as standard management of cutaneous melanoma. The treatment is often based on conservative surgery, because radical resection does not improve survival. For the vulva and vagina, reconstructive surgery is possible. Treatment is sometimes supplemented by chemotherapy or radiotherapy, which could improve local control. The interest in the use of targeted therapy in these locations is not well known because of their rarity, but the study of genes c-Kit and BRAF provides new prospects for treatment. The objective of this review is to describe and report the current state of knowledge about gynaecologic melanomas.