The regression time of ocular surface squamous neoplasia using topical interferon alfa-2b does not depend on the initial tumor size

ABSTRACT Purpose: The aim of this study was to determine if the initial tumor size correlates with the time to regression after topical interferon alfa-2b (1 million IU/mL) therapy in the treatment of ocular surface squamous neoplasia. Methods: A retrospective study was performed in 15 patients clinically diagnosed as having ocular surface squamous neoplasia and treated with topical interferon alfa-2b (1 million IU/mL, four times a day). All the cases of ocular surface squamous neoplasia included in the study had corneo-limbal involvement. The initial extension of the ocular surface squamous neoplasia was measured in square millimeters using the program ImageJ (LOCI, University of Wisconsin, Madison, USA) on images taken from the eyes of each patient immediately before the beginning of the treatment. The time until tumor resolution was measured for each case. Results: Complete tumor resolution was achieved in all the cases, with a mean initial tumor extension of 26.71 mm² (standard deviation ± 17.21 mm²) and a mean time until resolution of 77 days (standard deviation ± 32 days). An increased tumor volume after 15 days of treatment was obser ved in 2 patients, which completely resolved. No significant correlation was found between the time to resolution and the initial tumor extension measured in square millimeters (Spear man test, p=0.347). Conclusions: Our study suggests that the duration of topical interferon alfa-2b treatment required does not depend on the initial tumor size of the ocular surface squamous neoplasia usually found in clinical practice.