Author reply

Dear Editor:

We thank Dr Huerva for his interest in our manuscript,¹ in which we found no difference in the recurrence rates of ocular surface squamous neoplasia after treatment with interferon (IFN) α2b or surgical excision. Several important points are raised in his response.

In the current study, the IFN group is a heterogeneous group, composed of patients who received topical IFN α2b drops only (n = 40) in either the 1 or 3 million IU/ml dose, patients who received a combination of topical IFN α2b drops and subconjunctival IFN α2b injections, and 1 patient who received subconjunctival injections alone. Because the majority of our medically treated patients received topical drops in a 1 million IU/ml dose, we were unable to evaluate whether there was a difference in recurrence rates between the different subgroups. Previous work, however, has shown no difference in recurrence rates after topical drop treatment with the 1 or 3 million IU dose.² No direct comparison of recurrence rates has been made between patients treated with IFN α2b injections versus drops, although it would certainly be of interest to determine in the future whether such a difference exists.

With respect to which modality is chosen for treatment, there are advantages to each of the options. The advantage of surgery is that it is both diagnostic and therapeutic, although patients may require subsequent medical treatment or further surgery if the specimen margins are positive. Additionally, there are risks of surgery, including limbal stem cell deficiency and symblepharon formation. Advantages to medical therapy include treatment of the entire ocular surface, including areas of subclinical disease, and avoidance of surgical and anesthesia risks. For these reasons, topical medications are often the preferred method of treatment for ocular surface squamous neoplasia, especially in diffuse lesions and those involving large areas of the limbus or cornea. IFN α2b, specifically, is our preferred method of topical treatment because it is not only effective but also, as Huerva and others have shown, extremely well tolerated.³ For patients who have difficulty complying with the topical drop regimen, IFN α2b injections are also an option, although these patients do need to be warned about the high likelihood of transient post injection flu-like symptoms and the need for at least weekly injections until resolution. Time to resolution is shortest with surgery, followed by IFN α2b injection, and then topical IFN α2b, which may also play a role in the decision of which treatment to use. Last, cost and insurance coverage may factor in to the decision process. The choice of therapy for ocular surface squamous neoplasia, therefore, depends on a combination of lesion characteristics, patient characteristics, and patient preference. No single modality of treatment has yet proved to be superior in terms of future recurrence.