Malignant melanoma of the anorectum--a rare entity

Proceedings from the Melanoma Research Foundation Mucosal Melanoma Meeting (December 16, 2022, New York, USA)

Mucosal melanoma remains a rare cancer with high mortality and a paucity of therapeutic options. This is due in significant part to its low incidence leading to limited patient access to expert care and downstream clinical/basic science data for research interrogation. Clinical challenges such as delayed and at times inaccurate diagnoses, and lack of consensus tumor staging have added to the suboptimal outcomes for these patients. Clinical trials, while promising, have been difficult to activate and accrue. While individual institutions and investigators have attempted to seek solutions to such problems, international, national, and local partnership may provide the keys to more efficient and innovative paths forward. Furthermore, a mucosal melanoma coalition would provide a potential network for patients and caregivers to seek expert opinion and advice. The Melanoma Research Foundation Mucosal Melanoma Meeting (December 16, 2022, New York, USA) highlighted the current clinical challenges faced by patients, providers, and scientists, identified current and future clinical trial investigations in this rare disease space, and aimed to increase national and international collaboration among the mucosal melanoma community in an effort to improve patient outcomes. The included proceedings highlight the clinical challenges of mucosal melanoma, global clinical trial experience, basic science advances in mucosal melanoma, and future directions, including the creation of shared rare tumor registries and enhanced collaborations.

Extensive resection improves overall and disease-specific survival in localized anorectal melanoma: A SEER-based study

Background

Anorectal melanoma is a rare tumor with a dismal prognosis. The only promising treatment for anorectal melanoma is surgery, either extensive resection (ER) or local excision (LE). However, the optimal extent of resection is still controversial. The purpose of this study was to investigate whether the survival outcomes of anorectal melanoma at different stages are influenced by the surgical approaches (LE or ER) using the National Institute of Health's Surveillance, Epidemiology, and End Results Program (SEER) database.

Methods

The Surveillance, Epidemiology and End Results (SEER) database was queried to identify patients treated for anorectal melanoma (2000–2018). Overall survival (OS) and disease-specific survival (DSS) outcomes were compared for the two surgical approaches (ER or LE) stratified by stage (localized, regional and distant).

Results

A total of 736 patients were included in the study. Details of previous surgical procedures were available for 548 of the study patients: 360 (65.7%) underwent LE, and 188 (34.3%) underwent ER. In localized cases, 199 underwent LE, and 48 underwent ER. The OS (median 45 vs. 29 months, 5-year rate 41.7% vs. 23.4%) and DSS (median 66 vs. 34 months, 5-year rate 51% vs. 30.7%) of patients undergoing ER were significantly better (p = 0.009 and 0.041, respectively) than those who received LE. Multivariate analysis showed that the type of surgery was an independent prognostic factor for both OS and DSS. Among the regional cases, 89 cases had LE, and 96 cases had ER. Patients with regional disease who underwent ER had no significant differences in OS (23 vs. 21 months; p = 0.866) or DSS (24 vs. 24 months; p = 0. 907) compared to patients who underwent LE. In distant cases, 72 cases had LE, and 44 cases had ER. Patients with metastatic disease who had ER also had similar OS (median 11 vs. 8 months; p = 0.36) and DSS (median 11 vs. 8 months; p = 0.593) to those who underwent LE.

Conclusion

Extensive resection can improve the long-term prognosis of localized anorectal melanoma compared to local excision, but the prognosis of the two surgical techniques is comparable in both regional patients and distant patients.

Anorectal and Genital Mucosal Melanoma: Diagnostic Challenges, Current Knowledge and Therapeutic Opportunities of Rare Melanomas

Mucosal melanomas (MM) are rare tumors, being less than 2% of all diagnosed melanomas, comprising a variegated group of malignancies arising from melanocytes in virtually all mucosal epithelia, even if more frequently found in oral and sino-nasal cavities, ano-rectum and female genitalia (vulva and vagina). To date, there is no consensus about the optimal management strategy of MM. Furthermore, the clinical rationale of molecular tumor characterization regarding BRAF, KIT or NRAS, as well as the therapeutic value of immunotherapy, chemotherapy and targeted therapy, has not yet been deeply explored and clearly established in MM. In this overview, focused on anorectal and genital MM as models of rare melanomas deserving of a multidisciplinary approach, we highlight the need of referring these patients to centers with experts in melanoma, anorectal and uro-genital cancers treatments. Taking into account the rarity, the poor outcomes and the lack of effective treatment options for MM, tailored research needs to be promptly promoted.

Locally advanced anorectal malignant melanoma in septuagenarian patient treated by laparoscopic abdominoperineal resection: A case report

Introduction

Anorectal malignant melanoma (ARMM) is a rare disease with a poor prognosis. In cases involving locally advanced disease, the treatment strategy is difficult, especially in octogenarian patients, because the prognosis is poor, despite the corresponding decrease or loss of the anal function.

Presentation of case

A 78-year-old woman was admitted to a local hospital with chief complaints of severe anal discomfort due to an egg-sized tumor that was protruding out of the anus and melena. A diagnosis of ARMM was confirmed based on the examination of biopsy specimens and imaging study showed swollen lymph nodes on the dorsal side of the middle rectum and left internal iliac lymph nodes.

Laparoscopic abdominoperineal resection with left lateral lymph node dissection was performed. The examination of the resected specimen revealed two polypoid tumors with a maximum diameter of 38 mm and 14 mm with a metastatic lymph node of 62 mm in the mesorectum. The postoperative course was uneventful. Relapse and local recurrence free survival without any complaints was obtained for more than 12 months.

Discussion

With respect to locoregional disease control, it has been reported that abdominoperineal resection can obtain better control of local disease in comparison to local resection. Laparoscopic surgery is advantageous in its facilitation of an early postoperative recovery for elderly patient.

Conclusion

Laparoscopic abdominoperineal resection may control locoregional disease and improve the patient's QOL with early postoperative recovery. —even in septuagenarian patients—may become a treatment strategy for advanced ARMM.

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Anorectal malignant melanoma is a rare disease with a poor prognosis.

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Surgical procedure for anorectal malignant melanoma is controversial.

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APR may achieve better local control for advanced anorectal malignant melanoma.

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Laparoscopic surgery is advantageous in its facilitation of an early recovery for elderly patient.

Clinical evidence, diagnostic approach and challenging therapeutic modalities for malignant melanoma of the anorectum

Primary anorectal malignant melanoma (ARMM) is a rare, aggressive tumour that accounts for approximately 1.2% of all melanomas. This rare entity represents less than 5% of anorectal malignant tumours and 0.05-1% of all malignant colorectal neoplasms. The incidence increases with age while there is a higher prevalence in Caucasians. ARMM is often asymptomatic or presents with no disease-specific evidence so that it can mimic other rectal disorders, malignant or benign. Colonoscopy is obligatory as a diagnosing mean for ARMM. Furthermore, endoscopic ultrasonography, computed tomography and magnetic resonance imaging can be utilized for the evaluation of tumour infiltration and lymph node metastases. Moreover, diagnostic establishment of ARMM requires an undeniable demonstration of essential melanocytic features in histology and immunohistochemistry. Even though the standard of treatment remains surgical resection, the choice between wide local excision and abdomino-perineal resection is still controversial. Recently, there have been recommendations regarding new techniques which could be utilized for the surgical treatment of ARMM. Newer treatments that have been proposed such as immune-checkpoint inhibitors and targeted therapies need further validation. A multicenter study would allow clarification of the most appropriate therapeutic strategy for this uncommon nosological entity.

Management and outcomes of primary anorectal melanoma in the United States

Aims: To analyze outcomes in primary anorectal melanoma, a rare disease with limited data and treatment guidelines. Materials & methods: We analyzed 305 subjects in the National Cancer Database from 2004 to 2015. The primary end point was overall survival (OS). Results: Surgery was predictive of OS (median 2.24 vs 1.18 years; p = 0.009) with no survival difference between local and transabdominal approaches (p = 0.77). No OS benefit was seen with chemotherapy (p = 0.16), radiotherapy (p = 0.31) or adjuvant therapy post surgery (p > 0.05 for all groups). Targeted therapy trended toward higher survival in metastatic patients (1.33 vs 0.55 years; p = 0.06). Conclusion: In nonmetastatic patients, surgery of any method is associated with a survival benefit. The trend for improved survival following targeted therapy in metastatic patients merits further exploration.

Anorectal melanoma treated with abdominoperineal resection

The diagnosis of primary malignant melanoma of the anorectum is extremely rare and carries a very poor prognosis. While it is the third most common site of a primary melanoma, it accounts for <1% of anorectal malignancies. We present cases of anorectal melanoma treated with abdominoperineal resection.

Anorectal mucosal melanoma

Anorectal melanoma is an uncommon and aggressive mucosal melanocytic malignancy. Due to its rarity, the pre-operative diagnosis remains difficult. The first symptoms are non-specific such as anal bleeding, anal mass or pain. Although anorectal melanoma carries a poor prognosis; optimal therapeutics strategies are unclear. Surgical resection remains the mainstay of treatment. The optimal surgical procedure for primary tumours is controversial and can vary from wide local excision or endoscopic mucosal resection (EMR) to an abdomino-perineal resection. A high degree of uncertainly exists regarding the benefit of radiation therapy or chemotherapy. The treatment of advanced melanoma is evolving rapidly with better understanding of the disease biology and immunology. Considerable effort has been devoted to the identification of molecular determinants of response to target therapies and immunotherapy.

Abdominal perineal resection or wilde local excision in primary anorectal malignant melanoma. Case report and review

Introduction

Primary anorectal malignant melanoma is a rare and aggressive tumor that carries a poor prognosis. Anorectal melanoma (ARM) is often misdiagnosed as hemorrhoids adenocarcinoma polips and rectal cancer. ARM spreads along sub-mucosal planes and is often to wide-spread for complete resection at time of diagnosis and almost all patients die because of metastases.

Presentation of the case

A 77-year-old male patient presented a history of recurrent rectal bleeding and whose histopathological diagnosis was melanoma.

Discussion

The treatment of choice remains controversial. Surgery with complete resection represents the typical treatment. However standard operative procedures related to the area of resection and lymph dissection have yet to be established. Abdominal perineal resection (APR) with or without bilateral inguinal lymphadenectomy or wide local excision (WLE) have been used to manage patients with ARM.

Conclusion

The higher serum levels of LDH and YKL-40 are suggestive for Anorectal Melanoma diagnosis. The decrease of these findings may be associated with good prognosis. The review of both APR and WLE options suggests no significant difference in survival among patients.

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Anorectal melanoma (ARM) is a systemic disease.

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Regardless how aggressive is ARM, no surgical treatment will truly change the outcome.

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If surgical teqchniques are available, patients should undergo to wide local excision.

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In case of recurrence, the abdominal resection should be considered as the best surgical treatment.