New factors of pterygium occurrence and recurrence after surgical treatment

Abstract

Background. Occurrence and recurrence of pterygium after surgical treatment are still urgent problems of modern ophthalmology. The purpose was to determine the main factors leading to the occurrence and recurrence of pterygium after surgical treatment. Materials and methods. We observed 203 patients (232 eyes) with pterygium. There were 108 men and 95 women. The age of patients ranged from 35 to 65 years. The duration of the disease is 2.5–2.7 years. Patients underwent surgical treatment for pterygium by the McReynolds’ method forming a cul-de-sac, by the Artl method with its incision, and the McReynolds and Artl methods using 0.02% solution of mitomycin C. The patients were examined in 3, 6 months, and one year after surgery. The statistical analysis of the results of clinical trials was performed using the software package SPSS 11.0, MedStat (Lyakh Y.E., Guryanov V.G., 2004–2012), MedCalc (MedCalc Software bvba, 1993–2013). Results. The results of clinical studies have found that the frequency of pterygium recurrence after traditional surgical interventions by the McReynolds method, the McReynolds method using 0.02% solution of mitomycin C, by the traditional Arlt method, the Arlt me-thod using 0.02% solution of mitomycin C in 3 months was 20, 17, 15, and 8.7 %, respectively; in 6 months — 29.5, 27, 27, and 26 %, respectively; after 1 year — 26.5, 26.5, 30.6, and 37 %, respectively. Long-term recurrence of pterygium did not differ significantly (p < 0.05). Viral infection was found in pterygium tissue in 50.9 % of cases, including herpesviruses (33.6 %) and human papillomavirus (HPV, 34.0 %). Among herpesviruses, herpes simplex virus (HSV) was found in 15.1 % of cases, cytomegalovirus (CMV) in 7.3 %, and Epstein-Barr virus (EBV) in 11.2 % of cases. The regression analysis showed an association of HSV with stage II and stage III pterygium (p < 0.05). No such dependencies were found for CMV and EBV. There was a relationship of HPV with the I–III stages of pterygium (p < 0.01). There were types 6 (34.2 %), 11 (24.1 %), 16 (21.5 %), and 18 (20.2 %) among HPV. Types 6 and 11 were mainly detected at the first stages and were not detected in stage IV; types 16 and 18 were not detected in stage I (p = 7.9e-04). Among other types, only HPV6 was associated with the I and III stages of pterygium (p < 0.05). Double mixed infection was detec-ted in 32.1 % of patients. The most common was the combination of HSV and HPV (30.6 % of all cases of mixed infection), three viruses — in 2.5 % of cases in the combination of HSV + CMV + HPV and HSV + EBV + HPV. It was first established that the V600E mutation of the BRAF gene was detected in 35.3 % of cases of pterygium. No significant difference in mutation frequency depending on the sex and age of patients was found. The frequency of mutation by stages increased from 21.3 % at stage I to 57.7 % at stage IV (p = 0.0003). The regression analysis showed a strong progressive association with the presence of the BRAF gene V600E mutation with the pterygium stage and, therefore, its progression. Conclusions. Thus, it was proved that the presence of HSV, HPV, and mutation V600E of the BRAF gene significantly influenced the occurrence and progression of pterygium after surgical treatment.