Management of Acral and Mucosal Melanoma: Medical Oncology Perspective

Abstract

Acral and mucosal melanomas (MM) are rare subtypes of melanoma that are biologically and clinically distinct from cutaneous melanoma. Despite the progress in the treatment of cutaneous melanomas with the development of targeted and immune therapies, the therapeutic options for these less common subtypes remain limited. Difficulties in early diagnosis, the aggressive nature of the disease, and the frequently occult sites of origin have also contributed to the poor prognosis associated with acral and MM, with substantially worse long-term prognosis. The rarity of these subtypes has posed significant barriers to better understanding their biological features and investigating novel therapies. Consequently, establishing standardized treatment guidelines has been a challenge. In this review, we provide a brief overview of the current knowledge regarding acral and MM, focusing on their epidemiology, genetic backgrounds, and unique clinical characteristics. Further discussion centers around the management of primary and advanced disease and the role of emerging targeted and immune therapies for these subtypes, specifically focusing on issues relevant to medical oncologists.

Single-cell RNA sequencing in melanoma: what have we learned so far?

“… 1 Mucosal and acral melanoma are very rare, accounting for only 1–2% of all melanoma cases in Caucasian populations, although they are more common in Asian countries. 2 Mucosal melanoma occur on the mucous membranes found in the mouth, nose, throat, anus and genital areas. Conversely, acral melanoma predominantly affects the extremities, including the palms of the hands, soles of the feet and nail beds.…”

Current State of Melanoma Therapy and Next Steps: Battling Therapeutic Resistance

“…Acral melanoma (AM) and mucosal melanoma (MM) have been noted to be biologically and clinically distinct from cutaneous melanoma (CM) [4]. Low incidence rates of these melanoma subtypes have made it very difficult to determine the effectiveness of treatment due to problems with patient recruitment and sample size.…”

“…For AM, current standard of care involves surgical removal of the tumor [4]. Given the specificity of this subtype, depending on the location of the tumor, plastic surgery is often required, and amputation could be an additional treatment option in the case of subungual melanomas.…”

“…Acral melanoma (AM) often presents on palms, soles, fingers, toes and under the nails; mucosal melanoma (MM) occurs in mucosal membranes, such as in the mouth and nasal cavities; and uveal melanoma (UM) originates in the ocular region. These rare melanoma types are very aggressive because they are difficult to detect and therefore are not diagnosed at early stages of tumor development [4].…”

The genetic evolution of acral melanoma

“…However, their absolute incidence is comparable across world populations, and acral melanoma represents the major melanoma subtype in populations with darker skin tones. Acral melanomas have a more aggressive course with greater mortality than cutaneous melanomas and respond less well to immune-based and targeted therapies 2–4 .…”