5-Fluorouracil versus mitomycin C as adjuncts to conjunctival autograft in preventing pterygium recurrence

Pterygium recurrence following preoperative topical Mitomycin C and 5-Fluorouracil eyedrops

INTRODUCTION

Various adjuvant therapies have been used to prevent recurrence after pterygium excision. However, no single agent has been proven to be a gold standard for completely preventing recurrence with no associated complications.

PURPOSE

This study aims to compare the recurrence rate following preoperative topical mitomycin C (MMC) and 5-fluorouracil (5-FU) eye drops in pterygium excision surgery.

METHODS

In this interventional longitudinal comparative study, 90 patients with primary pterygium attending the Ophthalmology Clinic were enrolled and randomized into three equal groups of 30 each. Groups A, B, and C received preoperative 0.02% MMC eye drops, 1% 5-FU eyedrops, and placebo treatment respectively for one week before surgery followed by pterygium excision with conjunctival autograft and histopathological analysis. Patients were followed for 6months to identify recurrence.

RESULTS

At the end of the 6months, the recurrence rate in the preoperative MMC group (6.7%) was less than the 5-FU (13.3%) and placebo (20%) groups. The histopathological findings were consistent with pterygium tissues. There were high grades of inflammation, degeneration, and vascularization in both the MMC and 5-FU groups in the specimens which recurred within a period of 6months. Five patients had a novel finding of smooth muscle choristoma tissue with bundles of smooth muscle cells and fat cells clustered among the conjunctival tissue.

CONCLUSION

Based on our study results, we demonstrate that preoperative topical MMC and 5-FU eyedrops have efficacy in reducing recurrence in pterygium surgeries. The eyedrop route of administration has been proven to be an effective and easier alternative, enabling us to monitor for adverse effects of adjuvant drugs. Histopathological evaluation provides indices to predict features of future recurrence in pterygium specimens. This is the first study in which the efficacy of preoperative MMC and 5-FU is studied in eyedrop formulation along with histopathological correlation with recurrence.

Evaluating the Efficacy and Safety of Different Pterygium Surgeries: A Review of the Literature

The search for the "gold standard" in the surgical treatment of pterygium has been ongoing for over two decades. Despite the development of various surgical techniques, recurrence rates range from 6.7% to 88% depending on the method used. This review discusses the latest and most commonly used methods for the surgical removal of pterygium, primarily focusing on efficacy and safety. Moreover, this review includes articles that either evaluated or compared surgical methods and clinical trials for primary and recurrent pterygium. Limited data are available on combined methods as well as on the efficacy of adjuvant treatment. The use of adjuvant intraoperative mitomycin C (MMC) and conjunctival autografting (CAU) are the two most highly recommended options, as they have the lowest rates of postoperative recurrence.

5-Fluorouracil in primary, impending recurrent and recurrent pterygium: Systematic review of the efficacy and safety of a surgical adjuvant and intralesional antimetabolite

Pterygium is an ultraviolet-related disease characterized by an aberrant, wing-shaped and active wound-healing process. There is nothing quite as disheartening for the surgeon or patient as the recurrence of pterygium, and various adjuvants have been studied to ameliorate this. This systematic review provides a comprehensive summary of the efficacy and safety of 5-Fluorouracil (5-FU) as an antimetabolite agent for pterygium management. An appraisal of electronic searches of six databases identified 34 clinical studies reporting recurrence outcomes of 5-FU use in primary, impending recurrent and recurrent pterygia. In vitro and in vivo studies of 5-FU showed dose- and duration-dependent cytostatic and cytotoxic effects in human cells. 5-FU is relatively inexpensive, available, and easy to administer, making it attractive for resource-limited scenarios. However, the published evidence demonstrates a recurrence rate of 11.4-60% with the bare scleral technique, 3.5-35.8% with conjunctival rotational flaps, 3.7-9.6% with conjunctival autografts for intraoperative topical 5-FU, and 14-35.8% for preoperative and intraoperative injections. This suboptimal efficacy brings the role of 5-FU as an adjuvant for pterygium surgery into question and the authors do not recommend its use. In contrast, postoperative intralesional injections of 5-FU to arrest progression in impending recurrent pterygium and true recurrent pterygia were more promising, with success rates of 87.2-100% and 75-100%, respectively. Furthermore, 5-FU as a treatment modality, without surgery, effectively arrested progression in 81.3-96% of primary and recurrent pterygia. Other treatments such as topical and intralesional corticosteroids, cyclosporine and anti-VEGF agents are discussed. Complications of 5-FU increase with higher doses and range from transient and reversible to severe and sight-threatening. For pterygium, 5-FU has a predilection for causing scleral thinning, corneal toxicity, and graft-related complications. Additional study with extended follow-up is needed to elucidate the optimal dose, frequency, duration, and long-term safety of 5-FU injections. If 5-FU is used in the management of pterygium, it should be with caution, in selected patients and with vigilant long-term monitoring.

Surgical Techniques and Adjuvants for the Management of Pterygium

OBJECTIVE

To provide an updated review of surgical techniques and adjuvants for the management of pterygium.

METHODS

A literature search was conducted in PubMed for studies published since January 2011. "Pterygium surgery" and the MeSH term "Pterygium/surgery" was used. The results were filtered for randomized controlled trials in English, yielding 60 citations.

RESULTS

One study compared topical anesthetic agents. One study compared methods of corneal polishing of the corneoscleral bed after pterygium excision. Numerous studies evaluated the use of conjunctival autograft versus amniotic membrane, superior versus inferior conjunctival autograft, and conjunctival versus limbal-conjunctival autograft. Many studies evaluated graft fixation methods. Several studies evaluated the adjuvant use of mitomycin C, 5-fluorouracil, and bevacizumab. A few studies evaluated the adjuvant use of steroids. Eleven studies evaluated various methods of postoperative management.

CONCLUSIONS

Current evidence supports pterygium excision with conjunctival autograft fixation using fibrin glue, followed by patching until the first postoperative visit. Surgical adjuvants and postoperative use of artificial tears and topical cyclosporine 0.05% may further reduce recurrence. Postoperative use of topical steroids is highly variable because there is no consensus regarding the optimal dose, frequency, and duration of treatment.

Anti-fibrosis potential of pirarubicin via inducing apoptotic and autophagic cell death in rabbit conjunctiva

This study investigated the potential efficacy of pirarubicin (THP) in modulating rabbit conjunctival fibrosis both in vitro and in vivo and characterized the underlying mechanisms. Primary rabbit conjunctival fibroblasts (RCF) were cultured and treated with THP or mitomycin C (MMC) for 5 min, followed by assaying for cell viability, cell cycle distribution, apoptotic and autophagic pathways. The production of reactive oxygen species (ROS) and chemotaxis of macrophages by RCF were evaluated using 2',7'-dichlorofluorescein diacetate (DCFH-DA) labeling and transwell migration assay, respectively. Limbal stem cell excision in combination with alkali burn was performed on the rabbits to establish a model of limbal deficiency and conjunctival fibro-vascular invasion. After three months, the modeled fibro-vascular tissue was excised combined with topical subconjunctival 5-min exposure to THP compared with MMC intraoperatively. The recurrence of postoperative fibrosis and the expression of apoptosis, autophagy, and inflammation markers were evaluated by immunohistochemistry. All modeled rabbits developed conjunctival fibro-vascular lesions, which were similar to human recurrent pterygium (HRP). Both THP and MMC inhibited RCF proliferation and arrested cell cycle at the G0/G1 phase. In particular, 7.5 μmol/L THP remarkably promoted RCF autophagy by upregulating the levels of Beclin 1, Atg 5/12 conjugate, and LC3B, whereas, 15 μmol/L THP significantly triggered a cascade of mitochondrial-associated RCF apoptosis. THP induced the production of ROS and enhanced the chemoattraction of macrophages by RCF. Similar to 600 μmol/L MMC, both 7.5 μmol/L and 15 μmol/L THP attenuated postoperative conjunctival fibrosis in the models; 7.5 μmol/L THP preferentially enhanced autophagy while causing fewer side effects. THP exerted its antifibrotic action by modulating autophagy in RCF, inducing cell cycle arrest, and mitochondrial-mediated apoptosis. THP at the dose of 7.5 μmol/L prevented postoperative conjunctival fibrosis in an animal model.

Targeted delivery of mitomycin C-loaded and LDL-conjugated mesoporous silica nanoparticles for inhibiting the proliferation of pterygium subconjunctival fibroblasts

Pterygium is a degenerative disease that characterized by excessive fibrovascular proliferation. To reduce the recurrence rate, surgery is the main strategy, in combination with adjacent procedures or adjunctive therapy. One of the most common adjunctive agents, mitomycin C (MMC), is known as an alkylating agent that inhibits fibroblast proliferation but is limitedly applied in pterygium due to various complications. A previous study demonstrated that activated pterygium subconjunctival fibroblasts overexpressed low-density lipoprotein (LDL) receptors. In this study, we designed and synthesized MMC-loaded mesoporous silica nanoparticles conjugated with LDL (MMC@MSNs-LDL) to deliver MMC into activated pterygium fibroblasts in a targeted manner. The MMC loading efficiency was approximately 6%. The cell viability test (CCK-8 assay) revealed no cytotoxicity for the empty carrier MSNs at a concentration of ≤1 mg/ml after administration for 48 h in subconjunctival fibroblasts. Primary pterygium and normal human subconjunctival fibroblasts with or without stimulation by vascular endothelial growth factor (VEGF) were treated as follows: 1) 10 μg/ml MMC@MSNs-LDL for 24 h (MMC concentration: 0.6 μg/ml); 2) 0.2 mg/ml MMC for 5 min then cultured for 24 h after MMC removal; and 3) normal culture without any drug treatment. At 24 h, the anti-proliferative effect of MMC@MSNs-LDL in activated pterygium fibroblasts was similar to that of MMC (cell viability: 46.2 ± 5.5% vs 40.5 ± 1.1%, respectively, P = 0.349). Furthermore, the cytotoxicity of MMC@MSNs-LDL to normal fibroblasts with or without VEGF stimulation was significantly lower than that of traditional MMC (cell viability: 75.6 ± 4.4% vs 36.0 ± 1.5%, respectively, P < 0.001; 84.7 ± 5.5% vs 35.7 ± 1.3%, P < 0.001). The binding of fluorescently labeled MMC@MSNs-LDL in fibroblasts was assessed using confocal fluorescence microscopy. The uptake of targeted nanoparticles in fibroblasts was time dependent and saturated at 6 h. VEGF-activated pterygium fibroblasts showed more uptake of MMC@MSNs-LDL than normal fibroblasts with or without VEGF activation (both P < 0.001). Our data strongly suggest that MMC@MSNs-LDL had an effective antiproliferative role in activated pterygium fibroblasts, with reduced toxicity to normal fibroblasts compared to traditional application of MMC. LDL-mediated drug delivery might have great potential in the management of pterygium recurrence.

Anti-fibrotic, anti-VEGF or radiotherapy treatments as adjuvants for pterygium excision: a systematic review and network meta-analysis

Background

Anti-fibrotic, anti-VEGF (vascular endothelial growth factor) medications, or radiotherapy, as adjuvant for pterygium surgical procedure, has been suggested for reducing recurrence, but difficulties may be experienced in deciding which treatment to use. The purpose of this study was to compare the efficacies of these different adjuvants for preventing recurrence following pterygium surgery.

Methods

We conducted a systematic review to identify randomized controlled trials of patients with primary or recurrent pterygium who received anti-fibrotic, anti-VEGF medication, or radiotherapy as adjuvants in combination with surgical procedure. The surgical procedure contained bare sclera technique or petrygium excision combination with tissue grafting. The primary outcome of this study was recurrence. Direct-comparison and Bayesian network meta-analyses were performed to assess direct and indirect evidence of efficacy.

Results

We obtained data from 34 randomized controlled trials, representing a total of 2483 patients. Adjuvants included bevacizumab, 5-FU (5-fluorouracil), MMC (mitomycin C), and β-RT (beta-radiotherapy). Compared with placebo, we found distinguishable improvement in recurrence with bevacizumab (odds ratio [OR] 0.38, 95% confidence interval [CI] 0.18–0.80), MMC (0.12, 95% CI 0.06–0.21), and β-RT (0.17, 95% CI 0.04–0.69), but not with 5-FU (0.41, 95% CI 0.12–1.39). MMC significantly reduced recurrence when compared to bevacizumab (0.31, 95% CI 0.13–0.77) and 5-FU (0.28, 95% CI 0.08–0.99). The probability of having the most recurrences after excision was lowest for MMC, followed by bevacizumab and β-RT. Similar results were found in subgroup analyses, including for primary pterygium, and the patients receiving bare sclera technique or conjunctival autograft.

Conclusions

Adjuvants such as MMC, bevacizumab, and β-RT could effectively prevent recurrence following pterygium excision. However, their efficacy and acceptability require further clarification in future randomized controlled trials.

Electronic supplementary material

The online version of this article (10.1186/s12886-017-0601-5) contains supplementary material, which is available to authorized users.

Overexpression of low-density lipoprotein receptors stimulated by vascular endothelial growth factor in fibroblasts from pterygium

The activation of subconjunctival fibroblasts is believed to be responsible for the pathogenesis of pterygium. Vascular endothelial growth factor (VEGF) appears to be the most potent stimulator of formation and progression of pterygium. Pterygium excision is a common procedure, although the recurrence rates remain high. Various postoperative adjuvant therapies are now attempted to lower the recurrence rate, with severe side effects. To offer a greater therapeutic effect and lower side effects, it's necessary to discover a constant nanoparticle drug delivery targeting to subconjunctival fibroblasts in pterygium (PSFs). This study was designed to investigate the expression of low-density lipoprotein receptor (LDLr) stimulated by VEGF in PSFs. We found that after exposure to VEGF, mRNA and protein levels of LDLr were both increased significantly in PSFs, assessed using relative quantitative real-time RT-PCR and Western blot. Moreover, it's demonstrated that the expression of LDLr were positively correlated with the cells proliferation. Uptake of DiI-LDL via live PSFs was increased with time, estimated by confocal microscopy. The protein expression of LDLr in pterygium subconjunctival tissues was significantly higher than in normal subconjunctival tissues. These results suggest that LDLr in the activated PSFs may become a novel target receptor for controlled drug delivery to lower postsurgical recurrence rate.

5-Fluorouracil vs avastin as adjunct to conjunctival autograft in the surgical treatment of pterygium

BACKGROUND

The use of adjunct antimetabolite therapy along with conjunctiva autograft has been shown to be effective in preventing pterygium recurrence. There has however been fewer reports on the effect of anti-vascular endothelial growth factor on pterygium recurrence.

OBJECTIVE

To compare 5-fluorouracil with conjunctival autograft with bevacizumab (avastin) used along with autograft in the surgical treatment of pterygium.

METHODS

A randomized controlled prospective study of outcome of pterygium treatment using 5-fluorouracil with conjunctiva autograft as adjuvant treatment compared avastin with conjunctiva autograft.

RESULTS

A total of 70 eyes of 70 patients were recruited into the study with a mean age of 51.49 (±14.36) years. Thirty-five patients each were randomized into the 5-fluorouracil treatment group and into the avastin treatment group respectively. The mean follow-up was 18.35 months (18.44 for the 5-FU and 18.26 for the avastin group). Post operative, pterygium recurrence was observed in 1/27 (3.7%) eyes treated with 5-fluorouracil and 1/26 (3.9%) eyes of the avastin group. Both recurrences were observed at 1 year of follow-up and they were both female patients aged 46 and 52 years, respectively.

CONCLUSIONS

Both 5-fluorouracil and avastin are comparably effective as adjunct to conjunctival autograft. However, cost, availability, and convenience are other considerations with use of avastin.

In vitro study of cyclosporine A 0.05 % on primary and recurrent pterygium fibroblasts

To compare the cyclosporine 0.05 % exposure effect on fibroblasts from primary and recurrent pterygium. Primary culture of fibroblasts from primary and recurrent pterygium was performed until the third passage, which was exposed to cyclosporine 0.05 % in a group and the other remaining unexposed (control group), in triplicates. After 3, 6, 12, and 17 days of exposure the viable cell counting was performed by hemocytometer. The results were statistically analyzed using the technique of analysis of non-parametric variance model for repeated measures with three factors. There was a significant reduction in both fibroblast proliferation, in primary as in the recurrent pterygium cultures exposed to cyclosporine when compared not exposed cultures, with statistical significance (P < 0.05). Comparing primary and recurrent pterygium that received the drug, there was no significant difference in cell proliferation in relation to primary or recurrent pterygium. Cyclosporine 0.05 % is effective in inhibiting fibroblast proliferation in culture, both in primary and as in recurrent pterygium.

Recurrence rate with use of intraoperative Mitomycin C versus Conjunctival Autograft following pterygium excision

Objectives: To determine the recurrence rate following Conjunctival Autograft versus Mitomycin C for pterygium excision.

Methods: Fifty Patients in this Randomized Clinical Trial who underwent pterygium excision from July 2013 to October 2013 at Department of Ophthalmology, Ziauddin University Hospital, Keamari, Karachi were included. All patients underwent detailed ophthalmic examination before surgery. Few drops of lidocaine were instilled, subconjunctival xylocaine 2% was injected. The pterygium was then excised from bulabar conjunctiva and peeled off from the corneal surface. Mitomycin C was applied to bare sclera in group A and Conjunctival autograft taken from superior bulbar conjunctiva of same eye was sutured to the bare sclera in group B. Data for pterygium recurrence was collected and analyzed using SPSS version 17.

Results: Among the 50 patients operated 64% (n=32) were male and 36% (n=18) female. Their age ranged from 28 -58 years with mean age 44.8yrs. Right eye was affected in 54% (n= 27) patients and left in 46% (n= 23). In group “A” (intraoperative MMC) conjunctival granuloma was noted in 1(4%), pterygium recurrence 4(16%) and ocular irritation was experienced by 5 (20%) patients. In group “B” (CAG) graft retraction was seen in 2(8%), patients, 1(4%) patients experienced persistent redness over the grafted tissue and pterygium recurrence was seen in 2(8%) patient. All of them were followed at day 1, week1, week 4 and week 12.

Conclusion: Both Conjunctival Autograft and Mitomycin C are effective in reducing the recurrence of pterygium but CAG gives better cosmetic results, the only drawback with it is the duration of the procedure.

Management of diffuse ocular surface squamous neoplasia: efficacy and complications of topical chemotherapy

BACKGROUND

Ocular surface squamous neoplasia (OSSN) characterized by diffuse conjunctival or corneal spread is much less common than localized conjunctival disease. However, it is an important subcategory of the disease because of the difficulty it poses to treatment. It is rarely amenable to simple excision, and a purely surgical approach usually necessitates ocular surface reconstruction. Primary treatment with topical chemotherapy is an alternative, but its efficacy for these lesions is not well understood.

DESIGN

Retrospective case series.

PARTICIPANTS

Thirty-eight eyes treated for diffuse OSSN, defined as a lesion extending over five or more limbal clock hours or by extensive central or paracentral corneal spread.

METHODS

Treatment utilized either topical 5-FU 1% or mitomycin-C (MMC) 0.04%.

MAIN OUTCOME MEASURES

(i) Disease remission; (ii) complications.

RESULTS

Thirty-two patients were treated for a primary diffuse OSSN. Ten patients (31%) required further treatment for disease persistence or recurrence. Thirteen patients had previously undergone a single unsuccessful treatment course for diffuse OSSN. Administration of a second treatment course (whether MMC or 5FU) was successful in 46% (six) of patients. 5-FU 1% resulted in drug-related complications in seven of 12 cases, and included a single case of focal paracentral corneal stromal melt. MMC 0.04% resulted in transient drug related complications in 23 of 39 cases.

CONCLUSION

Diffuse OSSN is often recalcitrant to initial treatment with either 5-FU 1% or MMC 0.04%, and a pragmatic and vigilant approach to this heterogenous disease is required. Compared to localized disease, diffuse disease often requires multiple treatment efforts.

An update on the surgical management of pterygium and the role of loteprednol etabonate ointment

Pterygium, a sun-related eye disease, presents as wing-shaped ocular surface lesions that extend from the bulbar conjunctiva onto the cornea, most commonly on the nasal side. Pterygia show characteristic histological features that suggest that inflammation plays a prominent role in their initial pathogenesis and recurrence. Appropriate surgery is the key to successful treatment of pterygia, but there is also a rationale for the use of anti-inflammatory agents to reduce the rate of recurrence following surgery. Multiple surgical techniques have been developed over the last two millennia, but these initially had little success, due to high rates of recurrence. Current management strategies, associated with lower recurrence rates, include bare sclera excision and various types of grafts using tissue glues. Adjunctive therapies include mitomycin C and 5-fluorouracil, as well as the topical ocular steroid loteprednol etabonate, which has been shown to have a lower risk of elevated intraocular pressure than have the other topical ocular steroids. Here, the surgical management of pterygium is presented from a historical perspective, and current management techniques, including the appropriate use of various adjunctive therapies, are reviewed, along with an illustrative case presentation and a discussion of the conjunctival forceps designed to facilitate surgical management. Despite thousands of years of experience with this condition, there remains a need for a more thorough understanding of pterygium and interventions to reduce both its incidence and postsurgical recurrence. Until that time, the immediate goal is to optimize surgical practices to ensure the best possible outcomes. Loteprednol etabonate, especially the ointment formulation, appears to be a safe and effective component of the perioperative regimen for this complex ocular condition, although confirmatory prospective studies are needed.