Conjunctival intraepithelial neoplasia (CIN) is the most common conjunctival malignancy in the United States. It occurs in exposed areas of the bulbar conjunctiva with frequent involvement of the adjacent corneal epithelium. Recent studies¹ have noted a recurrence rate of about 50% when there is pathological evidence of residual tumour in the surgical margin and a 5–33% recurrence rate with clear margins.² We describe two cases of primary CIN successfully treated with topical INFα-2b. This chart review was conducted with a waiver from the Ochsner Clinic Foundation’s institutional review board, and conforms to HIPPA regulations.

Patient 1

A 65 year old retired welder was referred for further treatment of a partially resected CIN 1 month earlier. The patient had a long history of ultraviolet light exposure, multiple skin cancers of the face and hands, and tobacco use. He complained of redness and foreign body sensation in the right eye. Examination revealed a best corrected visual acuity of 20/25 in both eyes. The left eye examination was unremarkable. Slit lamp examination of the right eye showed an elevated white corneal and conjunctival plaque extending 90 degrees along the limbus (fig 1A). The referring physician had performed a biopsy of the central portion of the lesion which, upon pathological examination, was consistent with severely dysplastic conjunctival intraepithelial neoplasia with chronic subconjunctival inflammation, suggestive but not diagnostic of squamous cell carcinoma. After punctual plugs were placed, treatment with INFα-2b (1 million units/ml) four times a day was initiated. The lesion regressed completely after 44 days of treatment (fig 1B). The interferon drops were discontinued after 70 days. No recurrences have been seen after 6 months of follow up.

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Figure 1

 Patient 1. (A) Clinical appearance of conjunctival squamous cell carcinoma before treatment with INFα-2b. (B) Regression of conjunctival squamous cell carcinoma 70 days after starting treatment with INFα-2b.

Patient 2

A 73 year old white male was referred for an asymptomatic left corneal/conjunctival mass. There was no history of skin cancer, but there was a long history of sun exposure. The best corrected visual acuity was 20/50 in both eyes. Slit lamp examination showed an elevated, gelatinous conjunctival/corneal lesion with feeder vessels extending 150 degrees along the limbus (fig 2A). A biopsy revealed moderate to severe dysplasia. The patient was treated with INFα-2b (1 million units/ml) four times a day after placement of upper and lower lid punctal plugs. The lesion resolved after 84 days (fig 2B). No recurrence was been observed after 3 months of treatment.

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Figure 2

 Patient 2. (A) Clinical appearance of CIN before treatment. (B) Complete regression of CIN with topical INFα-2b 84 days after treatment.

Traditional therapy for CIN has involved wide surgical excisions with adjunctive cryotherapy, β radiation, mitomycin C, and 5-fluorouracil. All of these treatments may cause ocular surface inflammation, limbal stem cell deficiency, and epitheliopathy. Combination therapy of intralesional/subconjunctival injections and topical application of interferon effectively treats CIN.³ However, perilesional interferon has systemic side effects that include transient fevers and myalgias; therefore, topical therapy is preferred.^4,5 While presumptive treatment of CIN with topical IFNα-2b has demonstrated good results, to our knowledge there is only one case series of regression of biopsy proved primary and recurrent CIN with treatment with IFNα2b.^4,5

Here we report treatment of CIN using INFα-2b that was extremely well tolerated and had minimal side effects. At approximately $US300 per treatment, INFα-2b costs three and two times more than 5-fluorouracil and mitomycin C, respectively. However, the enhanced safety and reduced side effects should offset the additional expense. In conclusion, topical INFα-2b offers an effective alternative for the treatment of primary CIN. Larger population studies with longer follow up would better assess the risk of side effects or recurrence.