Topical 5-fluorouracil as monotherapy for ocular surface squamous neoplasia

Ocular surface squamous neoplasia (OSSN) comprises a gamut of diseases, which encompass conjunctival intraepithelial neoplasia, conjunctival carcinoma in situ, and squamous cell conjunctival neoplasia. Gold standard treatment for OSSN entails excision with cryotherapy. A lot of progress has been made recently that shows that chemotherapeutic drugs, such as mitomycin C, 5-fluorouracil (5-FU), and interferon alfa2b, can be just as effective. This is a case report that includes two cases: An 81-year-old Filipino female and a 65-year-old Filipino male who presented with a pinkish lesion on the bulbar conjunctiva. Documentation was done through clinical observation, slit-lamp examination, and the use of anterior segment optical coherence tomography (OCT). 1% topical 5-FU was given as chemotherapy administered at 1 drop 4×/day for 1 week with a 3-week drug holiday. During the course of treatment, we noted clinical resolution of the lesions grossly on slit-lamp examination. On anterior segment OCT, a decrease in diameter and thickness was noted, but with remaining areas of hyperreflectivity and thickened epithelium at the site of the lesion. No decrease in visual acuity was noted during the course of treatment, as well as any adverse effects such as eye pain or inflammation. Considering its safety and efficacy profile, 5-FU has great potential to be considered as a first-line therapy in the topical treatment of OSSN. Topical chemotherapy can target microscopic diseases that may be missed surgically and decrease adverse effects. As seen in this case report, 5-FU shows much promise as a possible alternative in the treatment of OSSN.