Correlation of American Joint Committee on Cancer T category for eyelid carcinoma with outcomes in patients with periocular Merkel cell carcinoma.

Purpose: Merkel cell carcinoma is a rare but potentially deadly cancer of the eyelid. To date, no studies have reported on clinical parameters at initial presentation of the eyelid tumor that may correlate with disease-free survival (DFS). The purpose of this study was to determine whether the American Joint Committee on Cancer (AJCC) T category for eyelid carcinoma correlates with metastasis and DFS in patients with Merkel cell carcinoma of the periocular region.

Methods: This is a retrospective cohort study from a tertiary referral cancer center. All consecutive patients treated for eyelid or periocular Merkel cell carcinoma between November 1, 1998, and November 1, 2012, were reviewed. The main outcome measures included AJCC T category for eyelid carcinoma and Merkel cell carcinoma at presentation, nodal metastasis at presentation, metastasis during follow up, and DFS.

Results: The study included 18 patients, 7 men and 11 women, with median age of 68.5 years. The AJCC T categories for both eyelid carcinoma and Merkel cell carcinoma were significantly correlated with DFS. Using the T categories for eyelid carcinoma, when TX and T2a were grouped into a single category and T2b and T3a into another category, the estimated DFS rate at 3 years was 100% for patients with TX or T2a lesions and 57% for patients with T2b or T3a lesions (p=0.0298). Four patients (22%) had lymph node metastasis at presentation. Presence of lymph node metastasis at presentation was the strongest single predictor of shorter DFS and an increased risk of metastasis during follow up (p=0.0222).

Conclusions: The AJCC eyelid carcinoma T at presentation correlates with DFS in patients with Merkel cell carcinoma of the periocular region. The DFS rate at 3 years was significantly worse for patients with T2b or more extensive tumors by eyelid carcinoma T category. Presence of lymph node metastasis at presentation was predictive of shorter DFS and an increased risk of metastasis during follow up.