Topical 5-fluorouracil demonstrates long-term safety, efficacy for surface squamous neoplasia

The authors conducted this prospective study to evaluate the long-term corneal toxicity of topical chemotherapy with 1% 5-fluorouracil (5-FU) as a sole or adjuvant treatment for ocular surface squamous neoplasia (OSSN). Patients with OSSN were treated with one course of 1% 5-FU four times a day for four weeks, with adjunctive courses repeated until clinical and cytological tumor regression. After a mean follow-up of 89.7 months, three tumors (7.3 percent) given 5-FU alone developed early recurrences and were successfully treated with additional 5-FU courses. Clinical confocal microscopy indicated no long-term corneal toxicity in treated eyes. The authors conclude that topical 5-FU should be considered a long-term safe and effective sole or combined treatment for selected OSSN.

Subjects in the study were 41 consecutive OSSN patients (41 eyes). Topical 5-FU was the sole treatment in 22 patients (53.7 percent). It was used as adjuvant and/or debulking therapy in 19 patients (46.3 percent). The mean number of 5-FU cycles was 1.9, with a range from one to five.

Follow-up ranged from 63 to 122 months. Complete regression was achieved in all patients. Confocal microscopy showed no long-term difference between treated eyes and fellow control eyes in terms of endothelial cell count, pleomorphism and polymegatism, anterior stromal keratocyte density, sub-basal nerve plexus fiber number, density, and beadings and central cornea epithelium thickness.

This is believed to be the first study to focus on the long-term safety of topical chemotherapy using full-thickness clinical confocal microscopy. The results demonstrate that 5-FU is selective for neoplastic cells and topical 5-FU had no adverse corneal effects when treating OSSN, even when multiple treatment courses were given.