Photodynamic therapy of pigmented choroidal melanomas of greater than 3-mm thickness

Evaluation of eye melanoma treatments in rabbits: A systematic review

Melanomas are the most common cancer of the eye in canines, felines and humans. The treatment approaches vary, since no gold standard exists. Therefore, this systematic review aimed to compare the treatment modalities in ocular melanoma in rabbits. Medline/PubMed, Cochrane Library, Web of Science and Embase were searched for articles published until 21 April 2021 in English, Portuguese or Spanish, reporting animal studies evaluating photodynamic therapy (PDT), laser, radiotherapy or surgical excision. Twenty-seven articles were included for the qualitative synthesis, with publication dates from 1970 to 2018. Of the selected studies, 19 used PDT, six used radiotherapy and two used laser as treatment. No studies regarding surgical therapy that met the inclusion criteria were obtained. The tumour therapy results were evaluated in a heterogeneous manner for different periods and various methods, including microscopy, angiographic, histological examination, fundoscopy, ultrasound exam and electroretinogram. The treatment modalities analysed successfully treated the ocular melanoma, with tumour necrosis being commonly observed. Despite the therapeutic efficacy shown, side effects have been reported for all the therapies. The studies showed high heterogeneity, and therefore, in the future, new studies should be carried out to increase knowledge about ocular melanoma treatment. The analysed therapies can be used successfully in the treatment of ocular melanoma, with more conservative options such as PDT presenting great potential.

Long-term Outcomes of Small Pigmented Choroidal Melanoma Treated with Primary Photodynamic Therapy

PURPOSE

To report the long-term outcomes of patients with small, pigmented, posteriorly located choroidal melanoma undergoing primary treatment using photodynamic therapy (PDT) with verteporfin at the London Ocular Oncology Service.

DESIGN

Retrospective, interventional, consecutive case series.

PARTICIPANTS

All patients undergoing primary treatment using PDT with verteporfin from April 2014 to December 2015 and followed until December 2019.

METHODS

This is a long-term follow-up study of the same cohort of patients previously reported by our group in 2017 and 2018.

MAIN OUTCOME MEASURES

Local tumor control, visual outcomes, and metastasis-free survival.

RESULTS

Twenty-six patients were included with a mean (± standard deviation) age and tumor thickness of 62 ± 14 years and 1.3 ± 0.5 mm, respectively. Tumors were posteriorly located (mean distance to optic nerve and fovea = 2.0 ± 2.2 mm and 1.6 ± 1.5 mm, respectively), and the majority were fully pigmented (73%). Overall, patients were followed for a median (interquartile range [IQR], range) of 49.5 (15.3, 7.0-66.0) months from first PDT to last follow-up. Over the course of this study, 14 of 26 (54%) have developed a local recurrence at a median of 20.0 months (20.5, 4.7-60.9 months). The most common pattern of recurrence was an isolated increase in basal dimensions (9/14; 64%). Median (IQR) final logarithm of the minimum angle of resolution visual acuity of the whole cohort was 0.2 (0.5). The only statistically significant difference in baseline and outcome characteristics between treatment failures and nonfailures was the distance to the fovea (median [IQR], 0.5 [1.3] vs. 2.5 [2.8]; P = 0.002) and final logarithm of the minimum angle of resolution visual acuity (median [IQR], 0.50 [0.80] vs. 0.00 [0.14]; P = 0.002), respectively.

CONCLUSIONS

Although treatment of small pigmented posterior choroidal melanoma with PDT effectively preserves visual acuity, 5-year treatment-success calculated by Kaplan-Meier analysis was only 38.4%. Recurrences after PDT tend to occur along the tumor edges, often with minimal increase in thickness. Given the substantial risk of treatment failure, primary PDT with vertepofrin is recommended in exceptional cases of choroidal melanoma, for which other treatments with greater tumor control are not a feasible option.

Primary photodynamic therapy with verteporfin for small pigmented posterior pole choroidal melanoma

PurposeThe purpose of the study was to investigate the outcomes of primary photodynamic therapy (PDT) for small pigmented posterior pole choroidal melanoma.Patients and methodsProspective interventional consecutive case series of 15 patients with small pigmented posterior pole choroidal melanoma, who were treated with three sessions of PDT and followed-up thereafter. Risk factors for failure were assessed and outcome measures at presentation were compared to those at last follow-up visit.ResultsTumor control was achieved in 12 (80%) patients in a median follow-up time of 15 months (mean 14, range 8-18). Three patients failed treatment, diagnosed in a median time of 5 months (mean 4, range 3-6), after first PDT. In all failed cases, lesions were 100% pigmented; de novo melanoma rather than transformed nevi and showed a radial growth pattern rather than increased thickness. All failed cases were subsequently successfully treated with radiotherapy. In this cohort, subretinal fluid (SRF) was significantly reduced (P<0.001), vision did not deteriorate (P=0.11) and even improved in patients with subfoveal SRF at presentation (P=0.018), tumor height significantly decreased (P=0.037) and no complications were recorded.ConclusionPrimary PDT was found to be a safe and efficient treatment modality for small pigmented posterior pole choroidal melanoma, achieving short-term tumor control in 80% of patients. PDT offers patients the opportunity to preserve vision by avoiding the retinopathy associated with conventional radiation treatments for choroidal melanoma. However, the long-term local control of these tumors remains uncertain.

Electrochemical lysis of an intraocular tumour using a combination of electrode placements

The objective of this experimental study was to develop a new combination technique for electrode placement and the histomorphological evaluation of its effectiveness for the electrochemical lysis of large intraocular tumours.

Treatment of amelanotic choroidal melanoma with photodynamic therapy

PURPOSE

To evaluate the effect of photodynamic therapy on amelanotic choroidal melanoma.

METHODS

Nine patients with posteriorly located amelanotic choroidal melanomas, one with a pigmented portion, underwent photodynamic therapy using verteporfin as the photosensitizing agent. The basal diameters ranged from 4 mm to 16 mm and the heights from 1.3 mm to 5.7 mm. Treatment was repeated until the melanoma was completely flat or its height had reached a stable end point. Tumor response was assessed by clinical examination, photography, and ultrasonography. Annual screening for hepatic metastases was performed.

RESULTS

Eight tumors demonstrated apparent complete regression over 1 month to 14 months. The amelanotic portion of the mixed tumor flattened, whereas the height of the pigmented part remained stable at 2 mm. In 8 patients there has been no recurrence during follow-up of between 34 months and 81 months. One case developed 2 separate local recurrences at 21 months and 34 months. There were no serious complications, no patient lost vision after treatment, and none developed metastatic disease.

CONCLUSION

In this series photodynamic therapy was highly effective in causing regression of posteriorly located amelanotic choroidal melanomas, without a detrimental effect on vision. While the short-term results are encouraging, there is some uncertainty regarding complete tumor destruction and long-term efficacy.

Clinical and histopathologic findings after photodynamic therapy of choroidal melanoma

BACKGROUND

Photodynamic therapy (PDT) has been used occasionally as an alternative treatment for uveal melanomas. The present study describes the clinical and histopathologic features of five choroidal melanomas after PDT.

METHODS

Three patients with pigmented choroidal melanomas were treated with PDT and intravitreal bevacizumab 1 week before undergoing biopsy and brachytherapy to minimize the risks of bleeding during the biopsy. Another two patients received PDT as a primary treatment for peripapillary amelanotic melanomas, one of them also in combination with bevacizumab.

RESULTS

The tumors treated with PDT and bevacizumab showed a marked reduction in tumor vascularity assessed by indocyanine angiography, and the biopsies were conducted without recognizable bleeding, showing viable tumor cells. The tumors receiving PDT as a primary treatment were followed by progressive tumor growth that led to enucleation years after. The histopathology revealed overlying fibrosis with invasion of sclera and optic nerve.

CONCLUSION

Photodynamic therapy and bevacizumab can induce closure of the superficial vasculature of a pigmented choroidal melanoma, but in none of our cases, there was evidence of tumor destruction from this treatment. Preoperative PDT may be useful to reduce the potential of bleeding at the time of tumor biopsy. Our cases do not support the use of a single session of PDT as a primary treatment for pigmented small choroidal melanomas.

Evaluation of verteporfin pharmakokinetics--redefining the need of photosensitizers in ophthalmology

INTRODUCTION

The benzoporphyrine derivative verteporfin has lost its importance to the treatment of the most frequent neovascular eye diseases. Nevertheless, it is still mandatory to define the remaining applications, role, and potential of verteporfin in ocular photodynamic therapy (PDT), including the dosages of administration, effectiveness, and safety profile.

AREAS COVERED

Although verteporfin PDT has forfeited the first-line status and value of treating subfoveal choroidal neovascularization (CNV) due to age-related macular degeneration or pathologic myopia, the treatment remains the standard of care for choroidal haemangioma and polypoidal choroidal vasculopathy. PDT is effective in less pigmented choroidal melanoma as well as in retinal vascular proliferations and retinal angioma. Verteporfin was granted the orphan drug designation for the treatment of chronic or recurrent central serous chorioretinopathy (CSC).

EXPERT OPINION

Evidence-based data regarding optimized parameters (low fluence, reduced dose, fractionated irradiation) adapted to the treated diseases (target structure, dosimetry, blood supply) are scarce. Prospective and large clinical trials are missing, although the scientific community agrees on the fact that the standard treatment protocol does not necessarily provide the optimal efficacy to the specific disease or individual patient. Within the reviewed indications, the adverse effect profile is favorable compared with other therapies.

Review of photodynamic therapy

INTRODUCTION

Photodynamic Therapy (PDT) is an emerging treatment for a variety of conditions including ocular and extra ocular diseases. The porphyrins have been used extensively, as dyes, which are laser-activated to achieve desired clinical effects. Commonly used agents are verteporfin and porfimer sodium.

METHODS

We performed a literature search of the PubMed database using the medical search headings: photodynamic therapy, photosensitizer verteporfin, visudyne, porfimer sodium and photofrin. We also performed a manual search using references from these articles, review articles and manufacturers' product monographs.

RESULTS

Verteporfin and porfimer sodium are commonly used photosensitizing agents with their wide applications in different fields of medicine. Both have well established safety profiles. They are most commonly used in wet age-related macular degeneration, gastrointestinal diseases and bronchial cancers.

CONCLUSION

PDT is a well established treatment entity in ophthalmology and other medical fields. In ophthalmology, it has rekindled interest and hopes in the common yet sight-threatening problem of age-related macular degeneration (AMD). This problem is still considered to be a serious issue as far as management is concerned. However in selective cases of AMD, it has shown success in restoring sight, especially in the 'classic' form of the disease. PDT is also being used to treat a range of solid cancers and non malignant conditions

Photodynamic treatment in a rabbit model of glaucoma surgery

PURPOSE

To evaluate the safety and efficacy of postoperative verteporfin photodynamic treatment as an adjunct to glaucoma experimental filtration surgery in rabbits.

METHODS

Dutch belted (n = 15) rabbits underwent full thickness sclerectomy in one eye. The experimental group (group 1, n = 7) underwent i.v. injection of verteporfin and subsequent photoactivation at the operative site on postoperative day 1 (POD 1). Control groups of animals received either light exposure (group 2, n = 4) or verteporfin (group 3, n = 2), or no intervention (group 4, n = 2). Intraocular pressure (IOP) was measured prior to the procedure (POD 0) and daily thereafter for the first week after sclerectomy (PODs 1-7) and every other day for the second week (PODs 9, 11, 13, 15). Percentage IOP reductions of operated over contralateral control eyes were compared among the various groups. Success rates (percentage IOP reduction > 15%) were also compared between the experimental and control groups. Eyes were histologically examined for evaluation of fibrosis.

RESULTS

Rabbits in the experimental group (group 1) had a mean +/- SEM percentage IOP reduction of 25 +/- 3% during the follow-up period. In contrast, groups 2, 3 and 4 had IOP reductions of 4 +/- 5%, 12 +/- 7% and 4 +/- 6%, respectively (p < 0.005, anova among all four groups). Successful IOP reduction (> or = 15%) over the contralateral eye at POD 15 was achieved in six of seven experimental animals, but only in one of eight control animals (p < 0.02, chi-squared test). Bleb failure occurred significantly earlier in the control eyes compared with eyes receiving PDT (p < 0.003, log rank test). Blebs in the experimental group differed from those in the control groups histologically, lacking significant collagen deposition in the area of the sclerostomy.

CONCLUSIONS

Wound healing in glaucoma surgery may be successfully modulated postoperatively using photodynamic therapy with i.v. administered photosensitizer.

The future of photodynamic therapy in oncology

The medicinal properties of light-based therapies have been appreciated for millennia. Yet, only in this century have we witnessed the birth of photodynamic therapy (PDT), which over the last few decades has emerged to prominence based on its promising results and clinical simplicity. The fundamental and distinguishing characteristics of PDT are based on the interaction of a photosensitizing agent, which, when activated by light, transfers its energy into an oxygen-dependent reaction. Clinically, this photodynamic reaction is cytotoxic and vasculotoxic. While the current age of PDT is based on oncological therapy, the future of PDT will probably show a significant expansion to non-oncological indications. This harks back to much of the original work from a century ago. Therefore, this paper will attempt to predict the future of PDT, based in part on a review of its origin.

Primary treatment of choroidal amelanotic melanoma with photodynamic therapy

The management of choroidal melanoma involves a delicate balance between preserving vision and preventing metastasis. Plaque brachytherapy has become standard management of most small lesions; however, this can result in radiation retinopathy and optic neuropathy. Transpupillary thermotherapy avoids these side-effects; however, it can also result in visual loss and its effectiveness is limited in amelanotic lesions. Photodynamic therapy with verteporfin has shown promise in animal studies of choroidal melanoma, and has recently been used in the management of lesions that have failed to respond to conventional therapy. The authors report a case of primary treatment of a small choroidal amelanotic melanoma with photodynamic therapy using verteporfin.

Applications of liposomes in ophthalmology

This review outlines the applications of liposomal formulations in ophthalmology. In ophthalmology, liposomes have been used to treat disorders of both the anterior and posterior segments. These include dry eyes, keratitis, corneal transplant rejection, uveitis, endophthalmitis, and proliferative vitreoretinopathy. Liposomes also have shown promise as vectors for genetic transfection and monoclonal antibody-directed vehicles. Furthermore, heat-activated liposomes have spurred research in focal laser and heat-induced release of liposomal drugs and dyes for selective drug delivery. These techniques have been useful in selective tumor and neovascular vessel occlusion, angiography, and retinal and choroidal blood-flow studies. Although verteporfin is the only liposomal drug currently approved for use in the eye, the benefits of liposomes will likely be applied widely in all treatment, diagnostic, and research aspects of ophthalmology in the future.

Photodynamische Therapie mit Verteporfin beim Aderhautmelanom

BACKGROUND

The aim of this study was to evaluate whether photodynamic therapy (PDT) with verteporfin is able to induce tumor cell necrosis in human uveal melanomas.

METHODS

On four eyes with an uveal melanoma, PDT with verteporfin was performed on the tumor 2-3 days before planned enucleation. The eyes were evaluated histologically.

RESULTS

In two melanomas with only mild pigmentation some effects after PDT were detected on tumor tissue in a depth up to 2.5 mm at light doses > or =100 J/cm(2). Histologically, vascular occlusion and thrombosis in tumor vessels were observed. In the heavily pigmented melanoma no tumor necrosis was induced with the above-mentioned parameters.

CONCLUSION

Depending on treatment parameters and tumor pigmentation, PDT with verteporfin is able to induce tumor necrosis in human uveal melanomas. Based on these results it is possible that PDT can become an adjuvant treatment method for uveal melanoma.

MRI of blood volume with superparamagnetic iron in choroidal melanoma treated with thermotherapy

Functional magnetic resonance imaging (MRI) with a new intravascular contrast agent, monocrystalline iron oxide nanoparticles (MION), was applied to assess the effect of transpupillary thermotherapy in a rabbit model of choroidal melanoma. 3D-spoiled gradient recalled sequences were used for quantitative assessment of blood volume. The MRI-parameters were 5/22/35 degrees (time of repetition (TR)/echo delay (TE)/flip angle (FA)) for T(1)- and 50/61/10 degrees for T(2)-weighted sequences. Images were collected before and at different times after MION injection. In all untreated tissues studied, MION reduced the T(2)-weighted signal intensity within 0.5 h and at 24 h (all p <== 0.012), whereas no significant changes were detected in treated tumors. T(1)-weighted images also revealed differences of MION-related signal changes between treated tumors and other tissues, yet at lower sensitivity and specificity than T(2). The change of T(2)-weighted MRI signal caused by intravascular MION allows early distinction of laser-treated experimental melanomas from untreated tissues. Further study is necessary to determine whether MRI can localize areas of tumor regrowth within tumors treated incompletely.

Necrotic and apoptotic cell death of human malignant melanoma cells following photodynamic therapy using an amphiphilic photosensitizer, ATX-S10(Na)

BACKGROUND AND OBJECTIVES

To investigate the phototoxic effect on and cell death modes of human malignant melanoma cells following photodynamic therapy (PDT) using ATX-S10(Na), an amphiphilic photosensitizer.

MATERIALS AND METHODS

Cultured human malignant melanoma cells were incubated in a medium containing various concentrations of ATX-S10(Na) and irradiated with a 670 nm wavelength diode laser. Phototoxicity was analyzed by a 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium inner salt (MTS) assay, and cell death modes were investigated by fluorescence microscopy using a Hoechst 33342-propidium iodide double-staining method as well as by static gel electrophoresis. The subcellular localization of ATX-S10(Na) and mitochondrial destabilization following PDT were observed by fluorescence microscopy.

RESULTS

Higher phototoxicity was obtained with higher dye and/or laser doses. Most of the dead cells appeared apoptotic with dye and irradiation doses that induced less than 70% cytotoxicity. In contrast, most of them appeared necrotic with doses that induced 99% cytotoxicity. Cells receiving PDT showed disturbances of mitochondrial trans-membrane potential, although the primary site of ATX-S10(Na) accumulation was in lysosomes.

CONCLUSIONS

ATX-S10(Na) has a phototoxic effect on malignant melanoma cells and, therefore, potential as a photosensitizing agent for PDT designed to kill these cells. Apoptotic pathways may be activated via mitochondrial destabilization following the damage of lysosomes by PDT. Further study, including investigation of therapeutic efficacy in vivo, is warranted.

MRI of blood volume with MS 325 in experimental choroidal melanoma

Functional magnetic resonance imaging (MRI) allows quantitative blood volume imaging in vivo at high tissue resolution. The purpose is to apply this technique for untreated and hyperthermia-treated experimental choroidal melanoma. MS 325 was used as new intravascular albumin-bound gadolinium-based contrast agent. Pigmented choroidal melanomas were established in albino rabbits. MRI was performed in 7 untreated eyes and 7 eyes treated with a Neodymium:Yttrium-Lanthanum-Fluoride-laser at 1047 nm. 3D-spoiled gradient echo pulse sequences were used to acquire T' weighted axial images. First, a set of images was collected without contrast agent. MS 325 was then injected i.v. and images were obtained within 12 min after injection. Signal intensities were measured within tumor, ciliary body, choroid, and iris and relative signal intensities were determined for these tissues in relation to vitreous. In untreated tumors, the relative signal intensity was higher after injection of MS 325 (5.61+0.70) than without MS 325 (2.90+0.33; p = 0.0002). In contrast, the relative signal intensity of treated tumors did not differ significantly before and after MS 325 (6.19+1.59 and 6.13+1.64). Histopathological sections indicated vascular occlusion in treated tumors. All other studied tissues of untreated and treated eyes showed a significant increase of relative signal intensities in the presence of MS 325. An animal model for the research on contrast agents in MRI is presented. Blood volume measurement with MS 325 was adapted for experimental choroidal melanomas. Reduced change of relative signal intensity indicates compromised blood volume after vascular occlusion in hyperthermia-treated melanoma. Further studies are needed to investigate whether this technique allows the evaluation of tumor viability following treatments.

Photodynamic modulation of wound healing in glaucoma filtration surgery

AIM

To report a clinical pilot study investigating photodynamic therapy (PDT) in combination with glaucoma filtration surgery. BCECF-AM was used as the photosensitising substance. The clinical safety and tolerability of BCECF-AM, and its efficacy in controlling postoperative intraocular pressure (IOP) were assessed.

METHODS

Before trabeculectomy (TE), 42 consecutive eyes of 36 glaucoma patients received one subconjunctival injection of 80 micro g BCECF-AM (2,7,-bis- (2-carboxyethyl) -5- (and-6) -carboxy-fluorescein, acetoxymethyl-ester) followed by an intraoperative illumination with blue light (lambda = 450-490 nm) for 8 minutes. Antifibrotic efficacy was established as postoperative IOP reduction of >20% and/or an IOP constantly < 21 mm Hg without antiglaucomatous medication. Follow up of the filtering bleb was documented by slit lamp examination.

RESULTS

Eyes had mean 1.1 preoperative surgical interventions (filtration and non-filtration glaucoma surgery). Mean preoperative IOP was 31.6 (SD 9.7) mm Hg. Patients were followed for mean 496 days (range 3.5-31.8 months). Of the 42 eyes, 25 eyes had an IOP decreased to 15.8 (3.4) mm Hg without medication (complete success: 59.5%; p<0.001; t test). Seven eyes showed good IOP reduction < 21 mm Hg under topical antiglaucomatous medication (qualified success: 16.7%). 10 eyes failed because of scarring within 2-67 weeks (23.8%). Clinical follow up examinations revealed no local toxicity, no uveitis, and no endophthalmitis.

CONCLUSIONS

This method is a new approach in modulating postoperative wound healing in human eyes undergoing glaucoma filtration surgery. The data of the first human eyes combining TE with PDT underline the clinical safety of this method and its possible potential to prolong bleb survival.