Small but Challenging Conjunctival Melanoma: New Insights, Paradigms and Future Perspectives

SIMPLE SUMMARY: Conjunctival melanoma (CM) is a small but highly aggressive and infiltrative periocular malignancy. Despite wide surgical excision followed by adjuvant therapy, about one third and one quarter of patients will experience local recurrence and metastatic spread, respectively. The management of locally advanced (≥T2) tumours may require mutilating surgeries such as orbital exenteration to achieve local control. The last decade has been marked by the emergence of eye-sparing strategies based on wide surgical excision followed by adjuvant proton beam therapy. More recently, new genetic and immunological insights have incriminated several signalling pathways (MAPK, PI3K-AKT) and immune cells, making CM a “targetable” malignancy. Anti-BRAF and anti-MEK targeted therapies and immunotherapies have revolutionized the current management of CM through the use of new eye-sparing strategies and treatment of metastases. ABSTRACT: Although its incidence has increased over the last decades, conjunctival melanoma (CM) remains a rare but challenging periocular malignancy. While there is currently no recognized standard of care, “no-touch” surgical excision followed by adjuvant treatments is usually recommended. Despite its small size, managing CM is challenging for clinicians. The first challenge is the high risk of tumour local recurrence that occurs in about one third of the patients. The management of locally advanced CM (≥T2) or multiple recurrences may require mutilating surgeries such as orbital exenteration (OE). The second challenge is the metastatic spread of CM that occurs in about one quarter of patients, regardless of whether complete surgical excision is performed or not. This highlights the infiltrative and highly aggressive behaviour of CM. Recently, attention has been directed towards the use of eye-sparing strategies to avoid OE. Initially, wide conservative surgeries followed by customized brachytherapy or radiotherapy have appeared as viable strategies. Nowadays, new biological insights into CM have revealed similarities with cutaneous melanoma. These new findings have allowed clinicians to reconsider the management of locally advanced CM with “medical” eye-sparing treatment as well as the management of metastatic spread. The aim of this review was to summarize the current and future perspectives of treatment for CM based on recent biological findings.