Comparative study of intraoperative mitomycin C and â irradiation in pterygium surgery

Aims—To compare the rate of recurrence and complication after surgery for primary pterygium performed by one surgeon using either intraoperative mitomycin C or â irradiation. Methods—A retrospective study was performed of 164 eyes in 164 patients who had undergone primary pterygium surgery. After the pterygium was excised, the bare sclera was covered by sliding adjacent superior conjunctiva. 103 eyes received intraoperative mitomycin C (0.04%, 150 seconds) and 61 eyes â irradiation (total dose 21.6 Gy). The mean follow up period was 20.2 (SD 17.9) months (range 1–66 months). Recurrence was defined as the postoperative regrowth of fibrovascular tissue crossing the corneoscleral limbus. Results—The recurrence rate after mitomycin C and â irradiation was 8.74% and 23.0% of eyes, respectively, after mean follow up of 17.9 and 31.2 months, respectively. The Kaplan–Meier survival analysis revealed a significantly better outcome for those who had intraoperative mitomycin C (Mantel–Cox log rank analysis, p=0.031). The mean interval to recurrence was not significantly diVerent between the two groups. During the follow up, none of the patients showed side eVects or reactions related to mitomycin C or â irradiation. Conclusions—The intraoperative administration of 0.04% mitomycin C is more eVective than â irradiation as an adjunctive treatment for pterygium surgery in the patient population examined in this study. (Br J Ophthalmol 2000;84:618–621) Since pterygium frequently recurs after simple surgical removal, numerous surgical procedures and adjunctive measures have been devised to prevent the recurrence, including a sliding conjunctival flap to cover the pterygium excisional site, conjunctival autograft transplantation, topical mitomycin C drops, 6–10 intraoperative application of mitomycin C, 7 11–13 and â irradiation. However, a direct comparison of the eYcacy of these techniques is diYcult, because various factors such as follow up period and the definition of recurrence vary among the studies. Both mitomycin C and â irradiation are thought to prevent the recurrence of pterygium by inhibiting the proliferation of fast growing cells such as fibroblasts and vascular endothelial cells after pterygium excision. However, to the best of our knowledge, no study so far has compared the eVectiveness of mitomycin C and â irradiation as adjunctive therapies for pterygium surgery. The purpose of this retrospective study was to investigate the rate of recurrence and complication after primary pterygium surgery performed by one surgeon using either intraoperative mitomycin C or â irradiation. Patients and methods A total of 204 consecutive primary pterygia were excised in 175 patients from January 1992 to December 1996. In 29 patients who were treated bilaterally, the eye operated on first was selected for the analysis. Eleven eyes were excluded from the analysis because those eyes were never observed by us after the surgery; 164 primary pterygia in 164 patients constituted the subjects of this retrospective study (Table 1). We did not perform pterygium surgery on patients under 40 years old during this period, because our previous analysis had shown that a pterygium frequently recurs in patients under 40 years old and a recurrent pterygium often has a more exuberant fibrovascular growth response than the original pterygium. The mean follow up period was 20.2 (SD 17.9) months (range 1–66 months). Patients received one of two treatments after the pterygium surgery: intraoperative mitomycin C (group 1) or â irradiation (group 2). As this was a retrospective study, no attempt was made to randomise the patients to either treatment. However, there was no bias in the choice of treatment. The surgery was performed from June 1993 to December 1996 in group 1, and from January 1992 to June 1996 in group 2. Each pterygium was graded into five groups depending on the degree of its invasion onto the cornea (Table 2). All surgeries were performed on an outpatient basis at Eguchi Eye Hospital by one surgeon (KE). The surgery technique was as follows: after topical anaesthesia (4% lignoTable 1 Preoperative characteristics of patients Mitomycin C â Irradiation p Value No of eyes 103 61 Age (SD) (years) 64.3 (9.1) 64.3 (9.8) 0.99* Range 41–90 41–90 Sex: 0.68† Male 49 27 Female 54 34 Pterygium grade: 0.45† Grade 1 13 3 Grade 2 50 32 Grade 3 26 17 Grade 4 13 7 Grade 5 1 2 *Unpaired t test. †÷ test. Br J Ophthalmol 2000;84:618–621 618 Department of Ophthalmology, University of Tokyo School of Medicine, Tokyo, Japan