Eyeworld

76 | EYEWORLD | DECEMBER 2022 C ORNEA References 1. Nanji AA, et al. Surgical versus medical treatment of ocular surface squamous neoplasia: a comparison of recurrences and complications. Ophthalmology. 2014;121:994–1000. 2. Frucht-Pery J, Rozenman Y. Mitomycin C therapy for corneal intraepithelial neoplasia. Am J Ophthalmol. 1994;117:164–168. Relevant disclosures Gombos: None Shields: None "It's impressive, but usually by the second week patients are calling and saying it's burn- ing. You have to hold their hand as they're using it because it's 'burning' the epithelium off the eye," Dr. Shields said. "I'm very sensitive to OSSN because it is the elderly population. We want quality of life for these people. We don't want them to have medications that cause tear- ing, redness, or pain, and that is why interferon was such a great drug. Patients would say each drop was soothing. We had tumors that were gi- gantic … we would inject these patients and put them on topical, and by the time we finished their course, 3–4 months, it was gone." If a patient has established OSSN, recur- rence, positive margins, a large OSSN of 6 or more clock hours, or is not a surgical candidate, pharmacological therapy is used, Dr. Shields said. When pharmacotherapy was needed, there was a strong preference for IFNα-2b (given both topically and via injection), Dr. Shields said. Despite some of its considerations—it could cost the patient $200–400 out of pocket each month they were on it, and it can't be shaken or it loses efficacy—Dr. Shields said patients "hugely benefited" from it. When interferon became unavailable during the pandemic, physicians treating OSSN were left with alternative pharmacotherapies—topical 5-fluorouracil (5-FU) and mitomycin C (MMC). "Right now, we're in a lull where we don't have interferon, so all of us who treat OSSN are scrambling to find the second best pharma- cotherapy, and we think it's 5-FU," Dr. Shields said, noting that MMC is more toxic to the epi- thelial surface and causes complications. Dr. Shields said that 5-FU and MMC are chemotherapeutic agents where you have to be "100% sure the conjunctiva is sealed" before using them. She said she waits at least a month or two after surgical resection before starting chemotherapeutic agents. If these were to enter the eye, they could cause a scleral or corneal melt. Dr. Shields said that she uses 5-FU 1% but that she knows of other ocular oncologists who use the 0.5% dose with success. While 5-FU can cause limbal stem cell loss, Dr. Shields said complications are less frequent compared to those that can occur with use of MMC. MMC can cause nasal lacrimal duct occlu- sion, so many physicians use punctal plugs. The tradeoff is that the MMC can drip on the cheek and can cause periocular redness and scaling, but Dr. Shields said this heals better than eyes with nasolacrimal duct obstruction and chron- ic epiphora needing reconstruction. MMC still seems to result in an abnormal epithelium with atypical cells. It's unknown whether these cells are atypical from the MMC or the OSSN. In general, Dr. Shields said that IFNα-2b can take 3 or so months to resolve OSSN. For a small lesion, 5-FU could take 2 weeks (when used 4 times a day), and larger lesions could take 4 weeks. History of MMC for OSSN While MMC is not her preferred first-line therapy, Dr. Shields said its application for OSSN changed the world. She said its use as a pharmacotherapy was dis- covered by Joseph Frucht-Pery, MD, and Yaacob Rozenman, MD, who published about its success as a topical treatment for patients with squamous neoplasia in 1994. 2 "They changed the world with this one innovative thought," Dr. Shields said. "Back in the 1980s before we had phar- macotherapy, exenterations were done for patients with advanced squamous neoplasia, but now we use pharmaco- therapy." Dr. Shields said one of her first experi- ences with MMC for OSSN was in the 1990s in a bilateral case of extensive OSSN treated with wide surgical resec- tion and reconstruction for one eye and with MMC for the other eye. "It totally cleared up. I have been a be- liever since then, and I always thank Dr. Frucht-Pery and Dr. Rozenman for their courage and thinking outside the box," she said. continued from page 74

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