Factors affecting recurrence and metastasis in conjunctival melanoma.

PURPOSE: To evaluate clinical and demographic characteristics and factors affecting recurrence, metastasis, and survival in conjunctival melanoma (CM).

METHODS: The clinical records of 45 patients who were treated for CM between October 1998 and June 2022 were retrospectively evaluated. Age, gender, presence of underlying conjunctival nevus-primary acquired melanosis (PAM), tumor stage according to the 8th edition of the American Joint Committee on Cancer (AJCC) staging system, tumor basal diameter, tumor thickness, lymph node (LN) involvement, metastasis, presence of tumor at the surgical margin, treatment method, need for adjuvant therapy, local tumor control, recurrence, and survival were recorded.

RESULTS: Twenty-one (46.7%) patients were female and 24 (53.3%) patients were male. The mean age at diagnosis was 53.2 ± 16.1 years. Median follow up time was 12 (1-300) months. Fifteen (33.3%) patients had conjunctival PAM; 2 (4.4%) patients had conjunctival nevus. The tumor stage was T1 in 24 (55.8%), T2 in 13 (30.2%), and T3 in 6 (14.0%) of the cases. The T stage in 2 cases could not be determined. For stage T1 and T2 CM, in addition to excisional biopsy (EB) and cryotherapy, alcohol epitheliectomy (AE) was performed in 17 cases (37.8%), superficial sclerectomy (SS) was performed in 7 (15.6%), and amnion membrane transplantation (AMT) due to a large conjunctival defect in 9 (20.0%). Six (14.0%) T3 cases underwent primary exenteration. Positive surgical margins were observed in 23 (51.1%) of the excised tumors at histopathologic examination. Adjuvant topical mitomycin-C (MMC) was used in 7 (30.4%) and strontium-90 episcleral brachytherapy in 4 (17.4%) of the 23 cases with tumor-positive borders. During the follow-up, recurrence was seen in 14 (31.1%) cases. According to Kaplan Meier analysis, the mean time to recurrence development was 90.5 ± 16.1 months and the 5-year recurrence free rate was 52.0%. Fourteen of the recurrent cases underwent EB + cryotherapy, 3 underwent AE + SS, and 3 underwent secondary exenteration. Metastasis and LN involvement occurred in 11 (24.4%) and 8 (17.8%) of the cases, respectively. Four (8.9%) cases expired during follow-up. According to Kaplan-Meier analysis, the mean time to metastasis was 106.2 ± 17.3 months and the 5-year metastasis free rate was 52.0%. While recurrence was more frequent in CM developing from PAM/nevus, metastasis was more frequent in men and those with LN involvement.

CONCLUSION: Conjunctival melanoma was a malignant tumor with high recurrence and metastasis rates. Precursor nevus/PAM is a risk factor for recurrence, while male gender and regional LN involvement were risk factors for metastasis in this study.