Although conjunctival melanoma is uncommon, when diagnosed late it can lead to metastatic disease and even death. It is classified according to the American Joint Committee on Cancer Classification (AJCC) into clinical and pathologic categories. The research papers discussed below are based on the AJCC 8th edition of clinical staging (T-category subclassification) of conjunctival melanoma (Table 1).
Table 1. America Joint Committee on Cancer (AJCC) classification of conjunctival melanoma
Conjunctival melanoma: risk factors for recurrent or new tumour
Eur J Ophthalmol.2020 Nov
Vaidya et al
Design: A retrospective review to identify factors predictive of recurrent or new tumour in 540 patients with conjunctival melanoma managed at the Wills Eye Hospital from 1974 to 2019. ‘Recurrent tumour’ was defined as presence of new tumour at the site of previous melanoma and ‘new tumour’ included one at any other site on the conjunctiva, adnexa, or orbit. Demographic and clinical features of patients with recurrence or new tumour were compared to those without recurrence.
Outcome: The mean follow-up period was 57.6 months and 180 (33%) patients were found to have recurrent or new tumour formation during that time. Risk factors for recurrent or new tumour included presentation at older age (OR: 1.02 per 1-year increase in age, p = 0.002), history of prior conjunctival surgery (OR: 1.62, p = 0.03), worse visual acuity at presentation (OR: 1.76 per 1 log-unit increase, p = 0.04), more advanced AJCC clinical T-subcategory (OR: 1.08 per 1 subcategory increase, p = 0.01), primary location of tumour in tarsal conjunctiva (OR: 1.80, p = 0.02), and secondary tumour involvement of the fornix (OR: 1.68, p = 0.03), and eyelid (OR: 1.92, p = 0.03). Risk factors on multivariate analysis demonstrated presentation at older age (OR: 1.02, p = 0.01), history of prior conjunctival surgery (OR: 1.84, p = 0.01), and more advanced AJCC clinical T-subcategory (OR: 1.07 per one subcategory increase, p = 0.03) were more likely to have recurrent or new tumour.
Comment: This was a large study on patients with conjunctival melanoma and the risk factors for recurrent and new tumour were identified. The same risk factors that were identified in both univariate and multivariate analyses were: older age, more advanced AJCC clinical T-subcategory, and history of prior conjunctival surgery. This study reiterates that early diagnosis and meticulous management during the first conjunctival surgery is essential in the prevention of recurrence or new tumour formation.
Conjunctival melanoma: outcomes based on the AJCC
Asia Pac J Ophthalmol (Phila).2020 Dec
Shields et al
Design: A retrospective study to evaluate the outcomes of conjunctiva melanoma based on the American Joint Committee on Cancer Classification (AJCC) 8th edition at a single ocular oncology centre.
Outcome: A total of 425 patients with conjunctival melanoma were included in this study, of whom 266 (63%) had tumour of the bulbar conjunctiva, 75 (18%) had tumour of the non-bulbar conjunctiva (including forniceal, tarsal, palpebral and caruncle), 84 (20%) had tumour with local invasion, and zero (0%) had tumour with invasion of the central nervous system. Of 381 patients with a mean of 57.6 months follow-up period, comparison revealed higher T category with increasing local recurrence/new tumour, increasing exenteration, increasing melanoma-related locoregional lymph node metastasis, increasing melanoma-related systemic metastasis, and increasing melanoma-related death. A comparison at 10 years revealed visual acuity loss of >3 lines, melanoma recurrence/new tumour, exenteration, melanoma-related locoregional lymph node metastasis, melanoma-related systemic metastasis and melanoma-related death were greater in the higher T category.
Comment: The eighth edition of AJCC classification of conjunctival melanoma is used for standardised grading for patients with conjunctival melanoma. This study demonstrated that higher T category is associated with greater morbidity and mortality.
Conjunctival melanoma treatment outcomes in 288 patients: an international data-sharing study
Br J Ophthalmol.2020 Sep
Puneet et al
Design: A retrospective, registry-based study from 10 ophthalmic oncology centres from nine countries. The study aimed to investigate the cumulative five-year and 10-year local recurrence rates of conjunctival melanoma based on the AJCC eighth edition staging system following primary and adjuvant treatment.
Outcome: A total of 288 patients with a mean age of 59.7 years at the first clinic visit were included in the study, of whom 218 (75.7%) had tumour of the bulbar conjunctiva, 34 (11.8%) had tumour of the non-bulbar conjunctiva (including forniceal, tarsal, palpebral and caruncle), 15 (5.2%) had tumour with local invasion, 21 (7.3%) had primary tumour that cannot be assessed, and zero (0%) had tumour with invasion of the central nervous system. Local recurrence was noted in 19.1% (median=3.6 years). Cumulative local recurrence was 5.4%, 19.3% and 36.9% at one, five and 10 years, respectively. The higher grading on AJCC classification was associated with greater risk of local recurrence. Tumours with local invasion (T3) were twice as likely to recur compared to patients with tumour affecting only the bulbar conjunctiva (T1) (p=0.013).
Comment: Conjunctival melanoma can be addressed with primary treatment only or in combination with adjuvant therapy. Primary treatments included in this study were local excision, excision with cryotherapy and exenteration, while adjuvant treatments included in this study were topical chemotherapy, brachytherapy, proton and external beam radiotherapy (EBRT). This study demonstrated approximately a third of patients had local recurrence at 10 years despite having primary and/or adjuvant treatment for conjunctival melanoma.
Dr Yi Wei Goh is a consultant ophthalmologist at Manukau Super Clinic and Waitakere Hospital, and with Eye Surgery Associates in Auckland, New Zealand