Immunotherapy for local/regional control of locally advanced orbital and periocular squamous cell carcinoma.

Abstract

e18034 Background: Periocular squamous cell carcinoma can be of eyelid skin, ocular surface (bulbar) or palpebral conjunctival, or of lacrimal sac/nasolacrimal duct mucosal origin, is relatively rare, and presents unique anatomic considerations due to proximity to the eye and inherent risk to ocular structures associated with high dose radiation therapy. We herein report on 17 patients with orbital or periocular SCC who were treated with immunotherapy (IO) to decrease surgical morbidity or to avoid high dose radiation therapy. Methods: Retrospective review of all previously unreported patients with orbital, conjunctival, or periocular SCC who were treated with IO either in the neoadjuvant setting prior to surgery or for treatment of periocular SCC with perineural spread into the orbit and skull base. Results: 17 patients, 12 men and 5 women (Age range: 44-92; median=70 years old) with orbital (n=6), conjunctival (n=5), or lacrimal sac/duct (n=2) squamous cell carcinoma (SCC), or periocular SCC with perineural spread into the orbit and skull base (n=4) who were treated with IO either as single drug (n= 11) or in combination with chemotherapy (n= 6 ). In all patients either cemiplimab or pembolizumab was used. In 13 patients IO was used in the neoadjuvant setting prior to planned surgery. In 4 patients with perineural spread as they had non surgically resectable disease, IO was used to avoid high dose radiation therapy with its inherent significant risk of ocular toxicity. Overall, 3 patients achieved complete response, 10 patients achieved partial response, and 4 patients had stable disease, using RECIST criteria. One of 5 patients with conjunctival SCC also had nodal metastasis at presentation and achieved a dramatic complete response of both the conjunctival tumor and the nodal metastasis and managed to avoid surgery altogether. This patient had a very high tumor mutation burden (TMB). One patient developed diabetic ketoacidosis as a side effect of IO; otherwise the adverse effects were low grade. Conclusions: IO either as single drug or in combination with chemotherapy has a fairly high response rate in patients with ocular adnexal, conjunctival or orbital SCC and in patients with periocular SCC with perineural spread in the orbit and skull base. Future prospective trails using IO for orbital and ocular adnexal SCC should be planned and should aim to correlate molecular data such as TMB with response.