Treatment of recurrent vaginal melanoma with external beam radiation therapy and palladium-103 brachytherapy

The Role of Radiotherapy in the Management of Vaginal Melanoma: A Literature Review with a Focus on the Potential Synergistic Role of Immunotherapy

Among the mucosal melanomas, vaginal melanomas are very rare tumors, accounting for less than 20% of melanomas arising from the female genital tract. They occur most frequently in women in post-menopausal age, but younger patients may also experience this neoplasm, mainly located in the lower third of the vagina or the anterior wall. The optimal management of this tumor remains controversial, with surgery reported as the most frequently adopted approach. However, a clear benefit of surgical treatment in terms of survival has not yet been demonstrated. Conversely, radiotherapy may represent an attractive non-invasive alternative, and there are several favorable reports of the role of radiation therapy, either delivered with photons, brachytherapy, or hadrontherapy. A wide range of techniques and fractionation regimens are reported with substantially good tolerance to the treatment, and acute G3 or higher toxicities are reported only in the case of concurrent immunotherapy. Of note, due to the rarity of the disease, there is a lack of high-level evidence for the optimal therapeutic option. In this scenario, recent studies theorize the possibility of developing combinatorial approaches of radiotherapy with immunotherapy based on cutaneous melanomas reports. In this review, we aim to summarize the evidence available in the literature supporting the role of definitive radiotherapy for vaginal melanomas, with a focus on the combination of RT with immunotherapy, in terms of optimal timing and biological rationale.

Investigating the role of immunotherapy in advanced/recurrent female genital tract melanoma: a preliminary experience

Objective

immunotherapy with immune checkpoint inhibitors has become one of the standard therapeutic modalities for patients with advanced melanoma. Melanoma of the female lower genital tract is a rare and aggressive disease, with poor long-term clinical outcomes. To date, no study evaluated the role of immunotherapy in metastatic melanoma of the lower genital tract.

Methods

Data of women with metastatic melanoma of the lower genital tract were prospectively collected. Survival outcomes over time was assessed using Kaplan-Meier model.

Results

Seven cases of metastatic melanoma of the lower genital tract (vulva [n=2], vagina [n=4], and uterine cervix [n=1]) treated with immune checkpoint inhibitors are reviewed. Two patients had metastatic disease at diagnosis, while 5 patients developed metastatic disease at a mean (standard deviation) time of 9.9 (±3.0) months from primary diagnosis. Four patients received an anti-cytotoxic T lymphocyte-associated antigen 4 (CTLA4) (ipilimumab) and 3 received an anti-programmed cell death 1 (PD-1) (pembrolizumab [n=2], nivolumab [n=1]) therapy. The response rate to immunotherapy was 28.5%. Patients receiving an anti-PD-1 experienced a better progression-free survival than patients treated with anti-CTLA4 (p=0.01, log-rank test). Although not reaching statistical significance, overall survival was better in patients having an anti-PD-1 therapy in comparison to anti-CTLA4 (p=0.15, log-rank test).

Conclusion

Results from our series confirm the poor prognosis of women with metastatic melanoma of the lower genital tract, thus supporting the need of exploring new treatment modalities. Further studies are warranted to improve knowledge on the role of immunotherapy in metastatic melanoma of the lower genital tract.

Mucosal Melanoma: a Literature Review

PURPOSE OF REVIEW

Mucosal melanoma is of great interest due to its aggressive behavior and less favorable prognosis. The literature is mainly case reports and case series. Here, we will collect the knowledge on mucosal melanoma from the last decade and review the literature. The main focus is being site-specific clinical features, treatment, and prognosis.

RECENT FINDINGS

The use of immunotherapy gain ground as for others subsets of melanoma. Anti-CTLA-4 and anti-PD-1/ PD-L1 blockade in mucosal melanoma have been evaluated in recent studies. Clinical trials are ongoing. The etiology of mucosal melanomas remains unknown. Head and neck mucosal melanomas are most common. Wide excision surgery is the treatment of choice. The effect of adjuvant therapy on survival remains questionable due to the limited knowledge. Radiotherapy seems to give better local control. The overall five-year survival rate for mucosal melanomas is 0-45%. Recent data indicates that this may be improved by the immunotherapy in the years to come.

Role for radiation therapy in melanoma

Although melanoma is generally considered a relative radioresistant tumor, radiation therapy (RT) remains a valid and effective treatment option in definitive, adjuvant, and palliative settings. Definitive RT is generally only used in inoperable patients. Despite a high-quality clinical trial showing adjuvant RT following lymphadenectomy in node-positive melanoma patients prevents local and regional recurrence, the role of adjuvant RT in the treatment of melanoma remains controversial and is underused. RT is highly effective in providing symptom palliation for metastatic melanoma. RT combined with new systemic options, such as immunotherapy, holds promise and is being actively evaluated.