Intra-Arterial Chemotherapy (Ophthalmic Artery Chemosurgery) for Group D Retinoblastoma

Aqueous VEGF-A Levels as a Liquid Biopsy Biomarker of Retinoblastoma Vitreous Seed Response to Therapy

Purpose

Regression of retinoblastoma vitreous seeds (VS) during intravitreal chemotherapy can be delayed, resulting in supernumerary injections. Similarly, VS relapse may not be clinically evident at first. A predictive biomarker of tumor regression and relapse could help guide real-time clinical decision making. Retinoblastoma is an oxygen-sensitive tumor; paradoxically, VS survive in the hypoxic vitreous. We hypothesized that VS elaborate pro-angiogenic cytokines. The purpose was to determine if pro-angiogenic cytokine signatures from aqueous humor could serve as a biomarker of VS response to treatment.

Methods

Multiplex ELISA was performed on aqueous from rabbit eyes with human retinoblastoma VS xenografts to identify expressed proangiogenic cytokines and changes in aqueous cytokine levels during intravitreal treatment were determined. Confirmatory RNAscope in situ hybridization for VEGF-A was performed on human retinoblastoma tumor sections and VS xenografts from rabbits. For human eyes undergoing intravitreal chemotherapy, serial aqueous VEGF-A levels measured via VEGF-A-specific ELISA were compared to clinical response.

Results

VEGF-A was highly expressed in human retinoblastoma VS in the xenograft model, and was the only proangiogenic cytokine that correlated with VS disease burden. In rabbits, aqueous VEGF-A levels decreased in response to therapy, consistent with quantitative VS reduction. In patients, aqueous VEGF-A levels associated with clinical changes in disease burden (regression, stability, or relapse), with changes in VEGF-A levels correlating with clinical response.

Conclusions

Aqueous VEGF-A levels correlate with extent of retinoblastoma VS, suggesting that aqueous VEGF-A may serve as a predictive molecular biomarker of treatment response.

MR Imaging of Adverse Effects and Ocular Growth Decline after Selective Intra-Arterial Chemotherapy for Retinoblastoma

This retrospective multicenter study examines therapy-induced orbital and ocular MRI findings in retinoblastoma patients following selective intra-arterial chemotherapy (SIAC) and quantifies the impact of SIAC on ocular and optic nerve growth. Patients were selected based on medical chart review, with inclusion criteria requiring the availability of posttreatment MR imaging encompassing T2-weighted and T1-weighted images (pre- and post-intravenous gadolinium administration). Qualitative features and quantitative measurements were independently scored by experienced radiologists, with deep learning segmentation aiding total eye volume assessment. Eyes were categorized into three groups: eyes receiving SIAC (Rb-SIAC), eyes treated with other eye-saving methods (Rb-control), and healthy eyes. The most prevalent adverse effects post-SIAC were inflammatory and vascular features, with therapy-induced contrast enhancement observed in the intraorbital optic nerve segment in 6% of patients. Quantitative analysis revealed significant growth arrest in Rb-SIAC eyes, particularly when treatment commenced ≤ 12 months of age. Optic nerve atrophy was a significant complication in Rb-SIAC eyes. In conclusion, this study highlights the vascular and inflammatory adverse effects observed post-SIAC in retinoblastoma patients and demonstrates a negative impact on eye and optic nerve growth, particularly in children treated ≤ 12 months of age, providing crucial insights for clinical management and future research.

Intravitreal Topotecan for Vitreous Seeds in Retinoblastoma: A Long-term Review of 91 Eyes

PURPOSE

To study the long-term efficacy of intravitreal topotecan (IVT) for vitreous seeds in eyes with retinoblastoma and risk factors for their recurrence.

DESIGN

Retrospective, non-comparative, interventional study.

PARTICIPANTS

Ninety-one eyes of 90 patients with retinoblastoma treated between January 2013 and April 2019.

METHODS

Patients with recurrent or refractory vitreous seeds after completion of intravenous or intra-arterial chemotherapy were treated with IVT (30 μg/0.15 ml) by the safety-enhanced technique. The injection was repeated every 4 weeks until the regression of seeds. Patients with a minimum follow-up of 12 months were included in the analysis.

MAIN OUTCOME MEASURES

Primary outcome measures were vitreous seed regression and eye salvage. Secondary outcomes were risk factors for vitreous seed recurrence after treatment with IVT, vision salvage, and complications of IVT.

RESULTS

The median age of the patients was 18 months, with most having group D (n = 58 [64%]) and group E (n = 26 [29%]) retinoblastoma. Vitreous seeds were refractory in 46 eyes (51%) and recurrent in 45 eyes (49%). A total of 317 IVT injections were administered, with the median being 3 injections. The median number of IVT injections required was 2.5 injections for dust, 3 injections for sphere, and 5 injections for cloud morphologic features. Recurrence of vitreous seeds after IVT was seen in 17 eyes (19%) at a mean follow-up of 7.9 months. At a mean follow-up 34 months, vitreous seed regression was achieved in 88 eyes (97%) and eye salvage was achieved in 77 eyes (85%). Older age (P = 0.018) and recurrence of retinal tumor (15/17 eyes; P < 0.01) significantly increased the risk of vitreous seed recurrence. Cataract was the most common complication seen in 17 eyes (9%).

CONCLUSIONS

Intravitreal topotecan at an every 3- to 4-week regimen is effective against both refractory and recurrent vitreous seeds. The vitreous seed morphologic features correspond to the number of injections required for regression. Increasing age and recurrence of retinal tumor increase the risk of vitreous seed recurrence after treatment with IVT.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

The Association of Race, Ethnicity, and Insurance Status with the Visual Acuity of Retinoblastoma Survivors in the IRIS® Registry

PURPOSE

To identify sociodemographic factors associated with the visual outcomes of retinoblastoma survivors.

METHODS

Retrospective cohort study using a US-based clinical data registry. All individuals < 18 years of age with a history of retinoblastoma in the Intelligent Research in Sight (IRIS®) Registry (1/1/2013-12/31/2020). The primary outcome was visual acuity below the threshold for legal blindness (20/200 or worse) in at least one eye. Multivariable logistic regression was used to evaluate the association between visual outcomes and age, sex, laterality, race, ethnicity, type of insurance, and geographic location.

RESULTS

This analysis included 1545 children with a history of retinoblastoma. The median length of follow-up was 4.1 years (IQR, 2.2-5.9 years) and the median age at most recent clinical visit was 12 years (IQR, 8-16 years). Retinoblastoma was unilateral in 54% of cases. Poor vision in at least one eye was identified in 78% of all children and poor vision in both eyes in 17% of those with bilateral disease. Poor visual outcomes were associated with unilateral diagnosis (OR, 1.55; 95% CI,1.13-2.12; p = .007), Black race (OR, 2.03; 95% CI, 1.19-3.47; p = .010), Hispanic ethnicity (OR, 1.65; 95% CI, 1.16-2.37; p = .006), and non-private insurance (OR, 1.47; 95% CI, 1.02-2.10; p = .037).

CONCLUSIONS

Poor visual outcomes appear to be more common among Black, Hispanic, and publicly insured children with a history of retinoblastoma, raising concerns regarding healthcare inequities. Primary care physicians should ensure that young children receive red reflex testing during routine visits and consider retinoblastoma in the differential diagnosis of abnormal eye exams.

Advanced Interventional Treatments in Retinoblastoma Management: A Comprehensive Review

Retinoblastoma is the most common eye malignancy in children that if left untreated can invade intraocular structures, metastasize, and rarely lead to death. Traditionally treated with systemic chemotherapy, Intra-arterial chemotherapy is gaining popularity as it allows for the direct administration of chemotherapy through the ophthalmic artery, thus reducing systemic side effects. Intra-arterial chemotherapy procedures have evolved, with refinements to reduce risks and radiation exposure. Intra-arterial chemotherapy boasts an impressive technical success rate and one year ocular survival even amongst advanced cases. This review offers a thorough examination of the technique, indications, contraindications, outcomes, and alternative options for Intra-arterial chemotherapy.

Update on chemotherapy modalities for retinoblastoma: Progress and challenges

Retinoblastoma stands as a paradigm of success in treating malignancies among pediatric patients. Over recent decades, the approach to managing retinoblastoma has evolved significantly, transitioning from the preservation of patients' lives to the preservation of eyes and vision while minimizing treatment-related complications. Chemotherapy, administered through diverse routes, has solidified its role as the cornerstone of retinoblastoma treatment. In addition to intravenous chemotherapy (IVC), alternative administration routes, including intraarterial (IAC), intravitreal, intracameral, and periocular delivery, have emerged as promising modalities for retinoblastoma management. Numerous studies have demonstrated outstanding outcomes, achieving nearly 100% salvage rates for eyes classified under groups A-C. However, for advanced intraocular retinoblastoma (groups D and E eyes), IAC appears to offer superior local control rates compared to IVC. Intravitreal injection of chemotherapeutic agents, when administered in a controlled and secure manner, holds promise in averting the need for enucleation and radiotherapy in advanced retinoblastoma cases presenting with vitreous seeds. The optimal chemotherapy strategy remains meticulously tailored based on numerous factors. This review provides a comprehensive update on chemotherapy across various routes, encompassing key considerations, dosages, administration methods, treatment outcomes, and potential complications. Furthermore, it explores emerging potential treatments and outlines future directions aimed at enhancing treatment outcomes.

Therapy for Vitreous Seeding Caused by Retinoblastoma. A Review

Retinoblastoma is the most common primary malignant intraocular tumor in children. Seeding, specifically the dispersion of the tumor into the adjacent compartments, represents a major parameter determining the degree of retinoblastoma according to the International Classification of Retinoblastoma. In this article we focused on vitreous seeding, one of the main limiting factors in the successful "eye preservation treatment" of retinoblastoma. This article presents an overview of the history of vitreous seeding of retinoblastoma, established treatment procedures and new-research modalities. The introduction of systemic chemotherapy in the treatment of retinoblastoma at the end of the 1990s represented a significant breakthrough, which enabled the progressive abandonment of radiotherapy with its attendant side effects. However, the attained concentrations of chemotherapeutics in the vitreous space during systemic chemotherapy are not sufficient for the treatment of vitreous seeding, and the toxic effects of systemic chemotherapy are not negligible. A significant change came with the advent of chemotherapy in situ, with the targeted administration of chemotherapeutic drugs, namely intra-arterial and intravitreal injections, contributing to the definitive eradication of external radiotherapy and a reduction of systemic chemotherapy. Although vitreous seeding remains the most common reason for the failure of intra-arterial chemotherapy, this technique has significantly influenced the original treatment regimen of children with retinoblastoma. However, intravitreal chemotherapy has made the greatest contribution to increasing the probability of preservation of the eyeball and visual functions in patients with advanced findings. Novel local drug delivery modalities, gene therapy, oncolytic viruses and immunotherapy from several ongoing preclinical and clinical trials may represent promising approaches in the treatment of vitreous retinoblastoma seeding, though no clinical trials have yet been completed for routine use.

A multi-institutional feasibility study of intra-arterial chemotherapy in children with retinoblastoma. A Children's Oncology Group study (COG ARET12P1)

BACKGROUND

Intra-arterial chemotherapy (IA) as a treatment to salvage the eye with advanced retinoblastoma is increasingly utilized based on successes reported by institutions around the world mainly through retrospective studies.

OBJECTIVE

To study the feasibility of delivering melphalan directly into the ophthalmic artery in a multi-institutional prospective study in children with newly diagnosed unilateral group D retinoblastoma.

METHODS

The Children's Oncology Group (COG) initiated study ARET12P1 in 2014 and was open to nine institutions. Eligible patients older than six months of age were enrolled. The feasibility of delivering three injections of melphalan into the ophthalmic artery every 28 days was assessed.

RESULTS

Nine institutions participated in this trial. Fourteen patients were enrolled, two of whom were unevaluable for feasibility. Four patients experienced a feasibility failure. In two patients, the ophthalmic artery could not be accessed for the second IA injection, in one the artery could not be accessed for the first injection, and one patient experienced grade 4 hypotension during the procedure.

CONCLUSION

Delivery of prescribed therapy within the context of this study did not meet the feasibility goals of the study with only a 67% feasibility success rate. These results should caution centers that plan to initiate this treatment and suggest investment in training to achieve technical expertise or referral to centers with expertise.

Intra-arterial chemotherapy for retinoblastoma: Experience from the pediatric ophthalmology referral center in Malaysia with literature review

PURPOSE

We aimed to analyze our 4-year experience of intra-arterial chemotherapy (IAC) for retinoblastoma (RB) and to examine the tumor response, globe salvage, mortality, and safety profile of IAC in the Malaysian profile.

MATERIALS AND METHODS

This was a retrospective, interventional case series. A total of 22 eyes of 20 patients with RB who underwent IAC using melphalan and topotecan from January 2018 to December 2021 in Hospital Kuala Lumpur were retrospectively reviewed. Tumor response, globe salvage, mortality, and safety profile of IAC were compared based on the International Classification of Retinoblastoma.

RESULTS

The mean patient age at IAC was 21.3 months. An overall globe salvage rate of 63.6% was observed: more specifically, 100% for Group A, 75% for Groups B and C, 66.7% for Group D, and 42.9% for Group E. Poor tumor response after IAC was significantly associated with a lesser chance of globe salvage (P = 0.045). The overall rate of good tumor response following IAC was 77.3%. Specifically, rates of good tumor response in each group were 100%, 75%, 75%, 83.3% and 71.4% in group A, B, C, D and E, respectively. The mortality rate was 5%. Complications (per-catheterization) included cerebral infarct (2.2%), oxygen desaturation (2.2%), vomiting (26.1%), periorbital edema (8.8%), ptosis (6.5%), fever, femoral hematoma, and hyperpigmentation over lid (4.4% each).

CONCLUSION

Four-year experience showed that IAC is a safe and effective method for RB management. Patients with a poor response after IAC may have a lower chance of globe salvage. Careful patient selection is of utmost importance to achieve the best outcome in a setting of limited health-care resources.

Intravenous versus super-selected intra-arterial chemotherapy in children with advanced unilateral retinoblastoma: an open-label, multicentre, randomised trial

BACKGROUND

Super-selected intra-arterial chemotherapy has increasingly been used as conservative management for retinoblastoma during the past decade. However, the absence of evidence from randomised controlled trials engendered controversy in the administration route of chemotherapy. We aimed to assess the efficacy and safety of intra-arterial chemotherapy compared with intravenous chemotherapy.

METHODS

This open-label, multicentre, randomised trial was done at six hospitals in China. Patients with new-onset unilateral group D or E retinoblastoma (poorly defined, large, or very large tumours, according to the International Intraocular Retinoblastoma Classification) without high-risk clinical factors were included. Patients were randomly assigned (1:1) to receive intra-arterial chemotherapy (injections of 0·5 mg/kg [or depending on age] melphalan with 20 mg carboplatin [first and third cycles] or with 1 mg topotecan [second and fourth cycles]) or intravenous chemotherapy (0·05 mg/kg [or 1·5 mg/m2] vincristine, 5 mg/kg [or 150 mg/m2] etoposide, and 18·6 mg/kg [or 560 mg/m2] carboplatin for six cycles). After intra-arterial chemotherapy, patients received a subcutaneous injection of 0·1 mL nadroparin calcium twice at a 12 h interval. Both intra-arterial and intravenous chemotherapy cycles were completed every 4 weeks. No masking was done, except of independent statisticians, who were masked to the allocation information. The primary outcome was 2-year progression-free globe salvage rate, defined as the time from randomisation to tumour progression or enucleation, whichever occurred first, and was analysed by intention to treat. We also recorded predefined safety outcomes (myelosuppression and ophthalmic arterial stenosis or occlusion) and severe adverse events likely to be related to study treatment. The study is registered with the Chinese Clinical Trial Registry, ChiCTR-IPR-15006469, and is complete.

FINDINGS

Between June 1, 2015, and June 1, 2018, 234 patients with newly diagnosed retinoblastoma were screened and 143 eligible patients (median age 23·6 months [IQR 14·0-31·9]) were enrolled and randomly assigned to the intra-arterial chemotherapy group (n=72) or the intravenous chemotherapy group (n=71). At a median follow-up of 35·8 months (IQR 28·4-43·0), the 2-year progression-free globe salvage rate was 53% (38 of 72 patients) in the intra-arterial chemotherapy group and 27% (19 of 71 patients) in the intravenous chemotherapy group (risk ratio 1·97, 95% CI 1·27-3·07, p=0·0020). Myelosuppression was less common in the intra-arterial chemotherapy group than in the intravenous chemotherapy group (37 [51%] of 72 patients vs 50 [70%] of 71 patients; 0·73, 95% CI 0·56-0·96, p=0·021) and less severe (ptrend=0·0070). In the intra-arterial chemotherapy group, two (3%) of 72 patients had ophthalmic artery occlusion and 13 (18%) patients had ophthalmic artery stenosis.

INTERPRETATION

Our findings show that intra-arterial chemotherapy could significantly improve the globe salvage rate in children with advanced unilateral retinoblastoma compared with intravenous chemotherapy, with mild systemic complications and no difference in overall survival rate. Intra-arterial chemotherapy could be an acceptable first-line treatment in children with advanced unilateral retinoblastoma.

FUNDING

Scientific Research Program of the National Health and Family Planning Commission of China, the Clinical Research Plan of Shanghai Hospital Development Center, the National Natural Science Foundation of China, and the Science and Technology Commission of Shanghai Municipality.

Primary Subretinal Seeding in Retinoblastoma: Clinical Presentation and Treatment Outcomes

Introduction

The aim of this study was to describe the clinical features and treatment outcomes of primary subretinal seeding (SRS) in patients with intraocular retinoblastoma (RB).

Methods

Descriptive analysis of primary SRS in 47 patients (50 eyes) with RB was performed.

Results

Mean age was 19 months (range, 2-72 months), and 55% (n = 26) of the subjects were male. At presentation, the SRS involved two or more quadrants in 88% of eyes. Most seeds appeared yellowish gray (66%) and round to oval in shape (48%). Two-thirds of SRS were seen posterior to the equator and within 5 mm from the main tumor. Associated features included subretinal fluid in 50 eyes (100%), total retinal detachment in 28 eyes (56%), and vitreous seeds in 20 eyes (40%). Treatment included intravenous chemotherapy (IVC) (n = 47; 94%), enucleation (n = 2; 4%), and intra-arterial chemotherapy (n = 1; 2%). SRS treatment included adjunct use of focal transpupillary thermotherapy and/or cryotherapy (n = 20; 40%). Retinal tumor control was achieved in 36 eyes (76%) with 32 eyes (78%) showing a type 3 regression pattern, while SRS completely regressed in 24 (48%) eyes, partially in 15 (30%) and worsened in 2 (4%) eyes. Over a mean follow-up of 30 months (range, 3-68 months), SRS recurrence was noted in 12 eyes (29%), globe salvage was achieved in 39 eyes (78%), and 1 (4%) patient died of presumed metastasis.

Conclusion

Primary SRS pose a therapeutic challenge during RB treatment. The SRS responds moderately to systemic IVC, with one-third cases showing SRS recurrence and one-fifth ultimately requiring enucleation.

Ten things you learned in your residency about retinoblastoma that have changed the 2023 Victor T. Curtin Lecture

Retinoblatoma is now the pediatric cancer with the highest cure rate. More than any other ocular malignancy the approach to this cancer has changed dramatically in the past 10 years. Most of the things taught to the majority of all Ophthalmology residents is out of date. Because few Ophthalmologists deal with retinoblastoma they are not aware of these seismic changes so this summary of my Curtin lectures outlines some of the major changes all Ophthalmologists should be familiar with.

Signaling pathways driving ocular malignancies and their targeting by bioactive phytochemicals

Ocular cancers represent a rare pathology. The American Cancer Society estimates that 3,360 cases of ocular cancer occur annually in the United States. The major types of cancers of the eye include ocular melanoma (also known as uveal melanoma), ocular lymphoma, retinoblastoma, and squamous cell carcinoma. While uveal melanoma is one of the primary intraocular cancers with the highest occurrence in adults, retinoblastoma remains the most common primary intraocular cancer in children, and squamous cell carcinoma presents as the most common conjunctival cancer. The pathophysiology of these diseases involves specific cell signaling pathways. Oncogene mutations, tumor suppressor mutations, chromosome deletions/translocations and altered proteins are all described as causal events in developing ocular cancer. Without proper identification and treatment of these cancers, vision loss, cancer spread, and even death can occur. The current treatments for these cancers involve enucleation, radiation, excision, laser treatment, cryotherapy, immunotherapy, and chemotherapy. These treatments present a significant burden to the patient that includes a possible loss of vision and a myriad of side effects. Therefore, alternatives to traditional therapy are urgently needed. Intercepting the signaling pathways for these cancers with the use of naturally occurring phytochemicals could be a way to relieve both cancer burden and perhaps even prevent cancer occurrence. This research aims to present a comprehensive review of the signaling pathways involved in various ocular cancers, discuss current therapeutic options, and examine the potential of bioactive phytocompounds in the prevention and targeted treatment of ocular neoplasms. The current limitations, challenges, pitfalls, and future research directions are also discussed.

Retinoblastoma gene expression profiling based on bioinformatics analysis

BACKGROUND

Retinoblastoma (RB) is frequently occurring malignant tumors that originate in the retina, and their exact cause and development mechanisms are yet to be fully comprehended. In this study, we identified possible biomarkers for RB and delved into the molecular mechanics linked with such markers.

METHODS

In this study GSE110811 and GSE24673 were analyzed. Weighted gene co-expression network analysis (WGCNA) was applied to screen modules and genes associated with RB. By overlapping RB-related module genes with differentially expressed genes (DEGs) between RB and control samples, differentially expressed retinoblastoma genes (DERBGs) were acquired. A gene ontology (GO) enrichment analysis and a kyoto encyclopedia of genes and genomes (KEGG) enrichment analysis were conducted to explore the functions of these DERBGs. To study the protein interactions of DERBGs, a protein-protein interaction (PPI) network was constructed. Hub DERBGs were screened using the least absolute shrinkage and selection operator (LASSO) regression analysis, as well as the random forest (RF) algorithm. Additionally, the diagnostic performance of RF and LASSO methods was evaluated using receiver operating characteristic (ROC) curves and single-gene gene set enrichment analysis (GSEA) was conducted to explore the potential molecular mechanisms involved with these Hub DERBGs. In addition, the competing endogenous RNA (ceRNA) regulatory network of Hub DERBGs was constructed.

RESULT

About 133 DERBGs were found to be associated with RB. GO and KEGG enrichment analyses revealed that the important pathways of these DERBGs. Furthermore, the PPI network revealed 82 DERBGs interacting with each other. By RF and LASSO methods, PDE8B, ESRRB, and SPRY2 were identified as Hub DERBGs in patients with RB. From the expression assessment of Hub DERBGs, it was found that the levels of expression of PDE8B, ESRRB, and SPRY2 were significantly decreased in the tissues of RB tumors. Secondly, single-gene GSEA revealed a connection between these 3 Hub DERBGs and oocyte meiosis, cell cycle, and spliceosome. Finally, the ceRNA regulatory network revealed that hsa-miR-342-3p, hsa-miR-146b-5p, hsa-miR-665, and hsa-miR-188-5p may play a central role in the disease.

CONCLUSION

Hub DERBGs may provide new insight into RB diagnosis and treatment based on the understanding of disease pathogenesis.

Sunitinib efficacy with minimal toxicity in patient-derived retinoblastoma organoids

BACKGROUND

Recurrence of retinoblastoma (RB) following chemoreduction is common and is often managed with local (intra-arterial/intravitreal) chemotherapy. However, some tumors are resistant to even local administration of maximum feasible drug dosages, or effective tumor control and globe preservation may be achieved at the cost of vision loss due to drug-induced retinal toxicity. The aim of this study was to identify drugs with improved antitumor activity and more favorable retinal toxicity profiles via screening of potentially repurposable FDA-approved drugs in patient-derived tumor organoids.

METHODS

Genomic profiling of five RB organoids and the corresponding parental tissues was performed. RB organoids were screened with 133 FDA-approved drugs, and candidate drugs were selected based on cytotoxicity and potency. RNA sequencing was conducted to generate a drug signature from RB organoids, and the effects of drugs on cell cycle progression and proliferative tumor cone restriction were examined. Drug toxicity was assessed with human embryonic stem cell-derived normal retinal organoids. The efficacy/toxicity profiles of candidate drugs were compared with those of drugs in clinical use.

RESULTS

RB organoids maintained the genomic features of the parental tumors. Sunitinib was identified as highly cytotoxic against both classical RB1-deficient and novel MYCN-amplified RB organoids and inhibited proliferation while inducing differentiation in RB. Sunitinib was a more effective suppressor of proliferative tumor cones in RB organoids and had lower toxicity in normal retinal organoids than either melphalan or topotecan.

CONCLUSION

The efficacy and retinal toxicity profiles of sunitinib suggest that it could potentially be repurposed for local chemotherapy of RB.

Spotlight on Targeted Chemotherapy in Retinoblastoma: Safety, Efficacy, and Patient Outcomes

As the most common primary intraocular malignancy of childhood, retinoblastoma (RB) has had a complex journey in its management, following a course from enucleation as the first life-saving treatment to numerous globe-salvaging therapies during the last century. Currently, this potentially lethal disease has achieved high survival rates owing to multidisciplinary management and the introduction of neoadjuvant and multimodal chemotherapy. Therefore, the goal of treatment is shifting toward conserving the globe and vision as much as possible. Up until recently, many advanced cases of RB were enucleated primarily; however, targeted chemotherapy via the ophthalmic artery and management of intraocular seeding by local administration of chemotherapeutic agents have revolutionized the globe-conserving therapies. The added benefit of avoiding systemic complications of cytotoxic drugs resulted in these methods gaining popularity, and they are becoming a main part of care in many referral centers. Initially, there were some safety concerns regarding these approaches; however, increasing experience has shown that these modalities are relatively safe procedures and many complications can be averted by changing the choice of the drug and using some prophylactic measures. It is hoped that, in the near future, with advances in early diagnosis and patient-targeted molecular therapies, as well as gene-editing techniques, the patient's vision can be saved even in advanced RB.

Naphthoquinones and derivatives as potential anticancer agents: An updated review

One of the leading global causes of death is cancer; even though several treatment methods have improved survival rates, the incidence and fatality rates remain high. Naphthoquinones are a type of quinone that is found in nature and has vital biological roles. These chemicals have anticancer (antineoplastic), analgesic, anti-inflammatory, antimalarial, antifungal, antiviral, antitrypanosomal, antischistosomal, leishmanicidal, and anti-ulcerative effects. Direct addition of a substituent group to the 1,4-naphthoquinone ring can alter the naphthoquinone's oxidation/reduction and acid/base characteristics, and the activity can be altered. Because of their pharmacological properties, such as anticancer activity and probable therapeutic application, naphthoquinones have greatly interested the scientific community. Some chemicals having a quinone ring in malignant cells have been found to have antiproliferative effects. Naphthoquinones' deadly impact is connected with the inhibition of electron transporters, the uncoupling of oxidative phosphorylation, the creation of ROS, and the formation of protein adducts, notably with -SH enzyme groups. This review article aims to discuss naphthoquinones and their derivatives, which act against cancer and their future perspectives. This review covers several studies highlighting the potent anticancer properties of naphthoquinones. Further, various proposed mechanisms of anticancer actions of naphthoquinones have been summarized in this review.

Bilateral enucleation for retinoblastoma: A study of 14 patients

PURPOSE

To study the clinical profile of patients who underwent bilateral enucleation for retinoblastoma (RB).

METHODS

Retrospective study of 14 cases.

RESULTS

Of >3000 RB cases, 14 (<1%) underwent bilateral enucleation for treatment of RB. The mean age at diagnosis of RB was 26 months (median, 24 months; range, 5-72 months). All patients had bilateral RB at presentation. Intraocular RB was evident in 23 (82%) eyes and orbital tumor extension was noted in 5 (18%) eyes. Based on the International Classification of Intraocular RB, tumors were classified as Group B (n = 1; 4%), D (n = 4; 14%), or E (n = 14; 50%) at presentation. Based on the International RB Staging System, tumors were classified as Stage 1 (n = 23; 82%) or Stage 3 (n = 5; 18%). Two patients (four eyes with intraocular RB) had undergone prior treatment before presenting to us and thus could not be classified. Primary treatment included systemic chemotherapy (n = 27; 96%) or enucleation (n = 1; 4%). Five patients were lost to follow-up for a mean duration of 15 months (median, 12 months; range, 7-24 months) during treatment and presented with the orbital extension of RB in one (n = 4; 29%) or both (n = 1; 7%) eyes. Secondary enucleation was performed in 27 (96%) eyes. Over a mean follow-up period of 49 months (median, 29 months; range, 3-340 months), there was no evidence of metastasis and 1 (7%) child died due to pneumonia.

CONCLUSION

Bilateral enucleation is rare in the treatment of RB. Advanced tumor presentation or noncompliance to treatment necessitates bilateral enucleation.

Aqueous humor as a surrogate biomarker for retinoblastoma tumor tissue

PURPOSE

To demonstrate the feasibility of identifying a germline RB1 pathogenic variant in retinoblastoma (RB) from an aqueous humor (AH) sample.

METHODS

In this pilot case series, peripheral blood, fresh tumor tissue, and AH were obtained from 3 eyes of 3 RB patients who underwent enucleation at a tertiary eye care institute. After isolation of the cell-free DNA (cfDNA), sequence analysis of the RB1 core promoter and of exons 1 through 27, including nearby flanking intronic regions, was performed using a custom targeted hybridization protocol, followed by high-throughput sequencing.

RESULTS

The study cohort included 3 enucleated eyes with advanced RB (group E [n = 2], group D [n = 1]). In case 1, deletion of the RB1 promoter to exon 23 (delP->23) on both alleles was identified from tumor as well as AH samples and absent in the blood sample, indicative of absence of a germline RB1 pathogenic variant. In case 2, two heterozygous RB1 nonsense variants, c.610G>T p.(Glu204Ter) and c.751C>T p.(Arg251Ter), were identified in tumor and AH samples (allele frequency of 49% and 45%, resp.) and were absent in the blood sample, indicative of absence of a germline RB1 pathogenic variant. In case 3, a heterozygous c.2326-14T>A substitution on allele 1 and loss of heterozygosity on allele 2 were identified in the tumor and AH (allele frequency of 97%), with the same heterozygous mutation in the blood sample, indicating presence of a germline RB1 pathogenic variant.

CONCLUSIONS

The pathogenic RB1 variant results from AH in all 3 eyes were concordant with direct tumor DNA sampling, suggesting that AH can serve as a surrogate for tumor tissue. Because the AH can be accessed during treatment, specific testing can be performed even in the absence of enucleation.

Hematologic Complications Associated With Intra-arterial Chemotherapy for Retinoblastoma Treatment: A Single Institution Experience

Retinoblastoma (RB) is the most common intraocular pediatric malignancy. Advancements in intra-arterial chemotherapy (IAC) for treatment of RB have resulted in dramatic improvement in eye salvage rates. Data regarding IAC outcomes and associated hematologic toxicities are limited. The objective of this retrospective study was to analyze baseline characteristics, efficacy, and hematologic complications associated with IAC treatment in children with RB at a single international referral institution. Ninety-five sessions of IAC were performed in 28 patients. Mean age at RB diagnosis was 12.5 months (SD, 9.2 mo). Fourteen patients had bilateral RB. IAC agents included melphalan, carboplatin, and topotecan. The most common regimens were triple-agent IAC and single-agent melphalan (66.3% and 15.8%, respectively). Median number of IAC sessions was 3 (mean: 3.39, range: 1 to 9). Eye salvage rate was 83.7% with an overall survival rate of 100% at a median follow-up of 29 months (mean: 29.8 mo, range: 1 to 63 mo). A total of 26 patients (92.9%) experienced at least 1 hematologic toxicity during their treatment course Prevalence of neutropenia, anemia, and thrombocytopenia were 89.3%, 85.7%, and 25%, respectively. While IAC is effective in salvaging most eyes with advanced intraocular RB, over half of patients experienced clinically significant neutropenia and anemia. Clinicians should be vigilant in monitoring patients for IAC-related complications.

Intra-Arterial Chemotherapy as Primary Treatment for Advanced Unilateral Retinoblastoma in China

Purpose

This study aimed to evaluate the efficacy and complications of intra-arterial chemotherapy (IAC) as a primary treatment for advanced unilateral retinoblastoma in Chinese patients.

Methods

This study was a retrospective review of patients with advanced unilateral retinoblastoma treated with IAC as the primary treatment. The IAC procedures were performed using a balloon-assisted technique. The clinical status and treatment complications were recorded at each visit. Kaplan–Meier analysis was performed to estimate recurrence-free survival and ocular survival.

Results

In total, 116 eyes of 116 patients with advanced unilateral retinoblastoma were enrolled, including 66 eyes (57%) in group D and 50 eyes (43%) in group E. All treated eyes received a mean of 3 cycles of IAC (range, 3–5), and 66% of the eyes were combined with local consolidation therapy. The median follow-up time was 39 months (range, 22–57 months). The 3-year recurrence-free survival and ocular survival rates were 68.8% (95% CI, 59.2–76.6%) and 88.5% (95% CI, 80.9–93.2%), respectively. Moreover, the 3-year ocular survival rate in group D was significantly higher than that in group E (96.9%, 76.3%; P < 0.01). The common ocular complication was vitreous hemorrhage (19.8%). No deaths or severe systemic complications occurred.

Conclusion

Primary intra-arterial chemotherapy is effective for the treatment of advanced unilateral retinoblastoma, especially in group D, with acceptable toxicity.

Treatment of Retinoblastoma: What Is the Latest and What Is the Future

The management of retinoblastoma, the most common intraocular malignancy in children, has changed drastically over the last decade. Landmark developments in local drug delivery, namely, safer techniques for intravitreal chemotherapy injection and ophthalmic artery chemosurgery, have resulted in eye globe salvages that were not previously attainable using systemic chemotherapy or external beam irradiation. Novel drugs, oncolytic viruses, and immunotherapy are promising approaches in the treatment of intraocular retinoblastoma. Importantly, emerging studies of the pattern of tumor dissemination and local drug delivery may provide the first steps toward new treatments for metastatic disease. Here, we review recent advances in retinoblastoma treatment, especially with regard to local drug delivery, that have enabled successful conservative management of intraocular retinoblastoma. We also review emerging data from preclinical and clinical studies on innovative approaches that promise to lead to further improvement in outcomes, namely, the mechanisms and potential uses of new and repurposed drugs and non-chemotherapy treatments, and discuss future directions for therapeutic development.

Intravitreal HDAC Inhibitor Belinostat Effectively Eradicates Vitreous Seeds Without Retinal Toxicity In Vivo in a Rabbit Retinoblastoma Model

Purpose

Current melphalan-based regimens for intravitreal chemotherapy for retinoblastoma vitreous seeds are effective but toxic to the retina. Thus, alternative agents are needed. Based on the known biology of histone deacetylases (HDACs) in the retinoblastoma pathway, we systematically studied whether the HDAC inhibitor belinostat is a viable, molecularly targeted alternative agent for intravitreal delivery that might provide comparable efficacy, without toxicity.

Methods

In vivo pharmacokinetic experiments in rabbits and in vitro cytotoxicity experiments were performed to determine the 90% inhibitory concentration (IC₉₀). Functional toxicity by electroretinography and structural toxicity by optical coherence tomography (OCT), OCT angiography, and histopathology were evaluated in rabbits following three injections of belinostat 350 µg (2× IC₉₀) or 700 µg (4× IC₉₀), compared with melphalan 12.5 µg (rabbit equivalent of the human dose). The relative efficacy of intravitreal belinostat versus melphalan to treat WERI-Rb1 human cell xenografts in rabbit eyes was directly quantified. RNA sequencing was used to assess belinostat-induced changes in RB cell gene expression.

Results

The maximum nontoxic dose of belinostat was 350 µg, which caused no reductions in electroretinography parameters, retinal microvascular loss on OCT angiography, or retinal degeneration. Melphalan caused severe retinal structural and functional toxicity. Belinostat 350 µg (equivalent to 700 µg in the larger human eye) was equally effective at eradicating vitreous seeds in the rabbit xenograft model compared with melphalan (95.5% reduction for belinostat, P < 0.001; 89.4% reduction for melphalan, P < 0.001; belinostat vs. melphalan, P = 0.10). Even 700 µg belinostat (equivalent to 1400 µg in humans) caused only minimal toxicity. Widespread changes in gene expression resulted.

Conclusions

Molecularly targeted inhibition of HDACs with intravitreal belinostat was equally effective as standard-of-care melphalan but without retinal toxicity. Belinostat may therefore be an attractive agent to pursue clinically for intravitreal treatment of retinoblastoma.

Unilateral retinoblastoma; natural history and an age-based protocol in 248 patients

OBJECTIVES

We aimed to study the clinical state and prognosis of patients with unilateral retinoblastoma who were being treated at a paediatric comprehensive cancer centre in a limited-resource country, to assess the different phases of treatment and the success of different, more complex real-life models.

SUBJECTS

In this retrospective study, we created a snapshot of our retinoblastoma database for the period between 2007 and 2015. Patients whose data were included in the study were followed up until 2016. Out of a total of 744 screened patients, we included data of 248 patients who had been diagnosed with unilateral retinoblastoma.

RESULTS

As classified as per the International Retinoblastoma Classification, 1 patient presented with group A, 21 with group B, 39 with group C, 104 with group D and 83 with group E retinoblastoma. Chemotherapy was the initial line of treatment in 115 patients and enucleation in 133 others. Later, 141 patients (56.9%) required further management. Patients had a mean ocular survival time of 20.8 months. Nine patients developed extraocular disease at a later stage of management: five after upfront enucleation and four after neoadjuvant chemotherapy. Mean overall survival time stood at 90.2 months. Four and three deaths were recorded in groups D and E, respectively. A single patient died in the initial chemotherapy arm, while six passed away in the initial enucleation arm.

CONCLUSION

Our study highlights the importance of initial chemotherapy and close follow-up after enucleation of classes D and E affected eyes even in absence of germline mutations.

Efficacy, Toxicity, and Pharmacokinetics of Intra-Arterial Chemotherapy Versus Intravenous Chemotherapy for Retinoblastoma in Animal Models and Patients

Purpose

Through controlled comparative rabbit experiments and parallel patient studies, our purpose was to understand mechanisms underlying differences in efficacy and toxicity between intra-arterial chemotherapy (IAC) and intravenous chemotherapy (IVC).

Methods

In rabbits, ocular tissue drug levels were measured following IAC and IVC. Retinal toxicity was assessed using electroretinography, fluorescein angiography, optical coherence tomography (OCT) and OCT angiography. Efficacy to eradicate retinoblastoma orthotopic xenografts was compared. In IAC and IVC patients, we measured blood carboplatin pharmacokinetics and compared efficacy and toxicity.

Results

In rabbits receiving IAC, maximum carboplatin levels were 134 times greater in retina (P = 0.01) and 411 times greater in vitreous (P < 0.001), and total carboplatin (area under the curve) was 123 times greater in retina (P = 0.005) and 131 times greater in vitreous (P = 0.02) compared with IVC. Melphalan levels were 12 times greater (P = 0.003) in retina and 26 times greater in vitreous (P < 0.001) for IAC. Blood levels were not different. IAC melphalan (but not IV melphalan or IV carboplatin, etoposide, and vincristine) caused widespread apoptosis in retinoblastoma xenografts but no functional retinal toxicity or cytopenias. In patients, blood levels following IVC were greater (P < 0.001) but, when adjusted for treatment dose, were not statistically different. Per treatment cycle in patients, IVC caused higher rates of anemia (0.32 ± 0.29 vs. 0.01 ± 0.04; P = 0.0086), thrombocytopenia (0.5 ± 0.42 vs. 0.0 ± 0.0; P = 0.0042), and neutropenia (0.58 ± 0.3 vs. 0.31 ± 0.25; P = 0.032) but lower treatment success rates (P = 0.0017).

Conclusions

The greater efficacy and lower systemic toxicity with IAC appear to be attributable to the greater ocular-to-systemic drug concentration ratio compared with IVC.

Translational Relevance

Provides an overarching hypothesis for a mechanism of efficacy/toxicity to guide future drug development.

Current Indications of Secondary Enucleation in Retinoblastoma Management: A Position Paper on Behalf of the European Retinoblastoma Group (EURbG)

Simple Summary

Although secondary enucleation (SE) is the treatment of choice for retinoblastoma eyes that did not respond favorably to conservative therapies, clear criteria for its indication are, however, currently missing. In this position paper on behalf of the European Retinoblastoma Group (EURbG), we discuss the available literature on SE, including its influence on metastases rate and survival, and propose guidelines to assist decision-making to interrupt eye-preserving therapies depending on the availabilities of advanced diagnostic and therapeutic modalities. Absolute indications to SE may be restricted to eyes with refractory tumor activity resisting all salvage treatments or eyes under apparent tumor control but no visual potential and irreducible complications. In contrast, eyes with an obscured optic nerve head and/or ocular complications amenable to specific surgical or medical management can be considered relative indications, provided that appropriate follow-up can be implemented and that parents are fully aware of a residual risk.

Abstract

Secondary enucleation (SE) puts an irreversible end to eye-preserving therapies, whenever their prolongation is expected to violate the presumed state of metastatic grace. At present, it must be acknowledged that clear criteria for SE are missing, leading to empiric and subjective indications commonly related to disease progression or relapse, disease persistence masking the optic nerve head or treatment-related complications obscuring the fundus view. This absence of evidence-based consensus regarding SE is explained by the continuously moving frontiers of the conservative management as a result of diagnostic and therapeutic advances, as well as by the lack of studies sufficiently powered to accurately stratify the risk of metastasis in conservatively treated patients. In this position paper of the European Retinoblastoma Group (EURbG), we give an overview of the progressive shift in the indications for SE over the past decades and propose guidelines to assist decision-making with respect to when SE becomes imperative or recommended, with corresponding absolute and relative SE indications. Further studies and validation of biologic markers correlated with the risk of metastasis are expected to set more precisely the frontiers of conservative management and thus consensual criteria for SE in the future.

Retrograde Approach for Intra-arterial Chemotherapy Delivery in Retinoblastoma

Intra-arterial chemotherapy (IAC) is currently, the first-line treatment for retinoblastomas with successful cure rates. In difficult access or unsuccessful catheterization of the ophthalmic artery (OA), the middle meningeal artery is a second alternative followed by the Japanese technique using balloon. Nevertheless, when a well-developed posterior communicating artery is present, a retrograde approach to the OA through this vessel can be performed to deliver the chemotherapeutic drugs.

We present a case of an unsuccessful catheterization of the OA through the internal carotid artery due to a challenging configuration of the OA/carotid siphon angle and describe an alternative form of navigation and catheterization through the posterior circulation.

To our knowledge, this is the third report of a successful retrograde catheterization of the OA for IAC and constitutes an alternative route to deliver chemotherapy.

Recent advancements in the management of retinoblastoma and uveal melanoma

Retinoblastoma in children and uveal melanoma in adults can pose a serious threat to both vision and life. For many decades, enucleation was often the only option to treat these intraocular malignancies. For retinoblastoma, intra-arterial chemotherapy is often utilized as the primary treatment at advanced academic centers and has dramatically improved local tumor control and eye salvage rates. For uveal melanoma, both plaque brachytherapy and proton beam irradiation have served as widely utilized therapies with a local failure rate of approximately 1–10%, depending on the series. Major recent advancements have allowed for a better understanding of the genomics of uveal melanoma and the impact of certain mutations on metastatic susceptibility. Gene expression profile stratifies uveal melanomas into two classes: low-risk (class 1) and high-risk (class 2). A loss-of-function mutation of BAP1 is associated with a class 2 gene expression profile and therefore confers worse prognosis due to elevated risk of metastasis. On the other hand, gain-of-function mutations of EIF1AX and SF3B1 correspond to a gene expression profile of class 1A and class 1B and confer a better prognosis. Preferentially expressed antigen in melanoma (PRAME) is an antigen that increases metastatic susceptibility when expressed in uveal melanoma cells. In addition to plaque brachytherapy and proton beam irradiation, both of which have demonstrated superb clinical outcomes, scientists are actively investigating newer therapeutic modalities as either primary therapy or adjuvant treatment, including a novel nanoparticle therapy and immunotherapy.

Publication Trends of Research on Retinoblastoma During 2001-2021: A 20-Year Bibliometric Analysis

Background: Retinoblastoma is the most common primary intraocular malignancy of childhood. Despite high survival and eye salvage as the result of various types of therapies, retinoblastoma remains a disease that places a considerable burden on developing countries. Our study attempted to analyse the research trends in retinoblastoma research and compare contributions from different countries, institutions, journals, and authors.

Methods: We extracted all publications concerning retinoblastoma from 2001 to 2021 from the Web of Science database. Microsoft Excel and VOSviewer were employed to collect publication data, analyse publication trends, and visualize relevant results.

Results: A total of 1,675 publications with 30,148 citations were identified. The United States contributed the most publications (643) and citations (16,931 times) with the highest H-index value (67) as of February 4, 2021. China ranked second in the number of publications (259), while ranking fourth in both citations (2,632 times) and the H-index (26) ranked fourth. The British Journal of Ophthalmology was the most productive journal concerning retinoblastoma, and Abramson DH had published the most papers in the field. Keywords were categorized into three clusters; tumor-related research, clinical research, and management-related research. The keywords “intravitreal,” “intraarterial,” and “intravenous” appeared the most frequently, with the average appearing year being 2018.1, 2017.7, and 2017.1, respectively. Management-related research has been recognized as a heavily researched topic in the field.

Conclusion: We conclude that the United States, China, and India made the most exceptional contributions in the field of retinoblastoma research, while China still has a disparity between the quantity and quality of publications. Management-related research, including intravitreal, intraarterial, and intravenous chemotherapy was considered as a potential focus for future research.

Selective Ophthalmic Artery Chemotherapy with Melphalan in the Management of Unilateral Retinoblastoma: A Prospective Study

PURPOSE

To determine prospectively the efficacy and to assess potential side effects of melphalan selective ophthalmic artery chemotherapy (SOAC) as first-line treatment for unilateral retinoblastoma.

DESIGN

Phase 2 nonrandomized, prospective study.

PARTICIPANTS

Patients with unilateral retinoblastoma group B, C, or D of the International Classification for Intraocular Retinoblastoma (IRC). Group D eyes with massive vitreous seeding were not eligible.

METHODS

Melphalan SOAC associated with diode laser thermotherapy, cryotherapy, or both at 4-week intervals (3-6 cycles). For persistent vitreous seeding, intravitreal melphalan chemotherapy also was used.

MAIN OUTCOME MEASURES

The primary outcome was globe preservation rate. Secondary outcomes were tumor relapse rate, occurrence of ocular or systemic adverse events, and measurement of the dose area product (DAP).

RESULTS

Between 2012 and 2017, 39 patients (39 eyes) with unilateral retinoblastoma were included prospectively. Three included patients did not receive SOAC (2 catheterization failures and 1 case of viral syndrome) and were considered failures. At diagnosis, IRC groups for the 36 treated patients were: B, n = 4 (11%); C, n = 13 (36%); and D, n = 19 (53%); median age was 21.5 months (range, 3.2-61.6 months). Median number of SOAC cycles was 3.9 (range, 1-6 cycles), and median melphalan dose was 4.9 mg/procedure. The median DAP was 1.24 Gy.cm²/procedure. Median follow-up was 63 months (range, 34-93 months). SOAC was associated with local treatments for 31 patients (86%): diode laser thermotherapy for all of them and cryotherapy or intravitreal chemotherapy for 10 (32%) and 9 patients (25%), respectively. SOAC treatment was interrupted in 5 patients because of severe ophthalmic (ptosis, n = 2; retinal ischemia, n = 2) or systemic (hypotension, n = 1) adverse events. At the cutoff date analysis, all patients were alive without metastasis. The 18-month eye preservation rate was 80% (range, 68.6%-94.6%). After a follow-up of at least 30 months, the ocular preservation rate was 69% (n = 24 preservations).

CONCLUSIONS

This first prospective trial demonstrated that SOAC with melphalan alone as first-line treatment for retinoblastoma is efficient and well tolerated with no metastatic events, although ocular ischemic complications were observed.

Evaluation of intravitreal topotecan dose levels, toxicity and efficacy for retinoblastoma vitreous seeds: a preclinical and clinical study

Background

Current melphalan-based intravitreal regimens for retinoblastoma (RB) vitreous seeds cause retinal toxicity. We assessed the efficacy and toxicity of topotecan monotherapy compared with melphalan in our rabbit model and patient cohort.

Methods

Rabbit experiments: empiric pharmacokinetics were determined following topotecan injection. For topotecan (15 μg or 30 µg), melphalan (12.5 µg) or saline, toxicity was evaluated by serial electroretinography (ERG) and histopathology, and efficacy against vitreous seed xenografts was measured by tumour cell reduction and apoptosis induction. Patients: retrospective cohort study of 235 patients receiving 990 intravitreal injections of topotecan or melphalan.

Results

Intravitreal topotecan 30 µg (equals 60 µg in humans) achieved the IC₉₀ across the rabbit vitreous. Three weekly topotecan injections (either 15 µg or 30 µg) caused no retinal toxicity in rabbits, whereas melphalan 12.5 µg (equals 25 µg in humans) reduced ERG amplitudes 42%–79%. Intravitreal topotecan 15 µg was equally effective to melphalan to treat WERI-Rb1 cell xenografts in rabbits (96% reduction for topotecan vs saline (p=0.004), 88% reduction for melphalan vs saline (p=0.004), topotecan vs melphalan, p=0.15). In our clinical study, patients received 881 monotherapy injections (48 topotecan, 833 melphalan). Patients receiving 20 µg or 30 µg topotecan demonstrated no significant ERG reductions; melphalan caused ERG reductions of 7.6 μV for every injection of 25 µg (p=0.03) or 30 µg (p<0.001). Most patients treated with intravitreal topotecan also received intravitreal melphalan at some point during their treatment course. Among those eyes treated exclusively with topotecan monotherapy, all eyes were salvaged.

Conclusions

Taken together, these experiments suggest that intravitreal topotecan monotherapy for the treatment of RB vitreous seeds is non-toxic and effective.

Effect of Intravenous Chemotherapy Regimen on Globe Salvage Success Rates for Retinoblastoma Based on Disease Class-A Meta-Analysis

Simple Summary

Intravenous chemoreduction (IVCRD) has been the standard of care for treatment of retinoblastoma (RB). Since survival rates exceed 95–98%, the goals of treatment have now shifted to emphasize eye salvage and vision preservation in addition to patient survival. Consequently, there has been a shift towards combining standard IVCRD with intravitreal chemotherapy or altogether replacing IVCRD with intra-arterial chemotherapy. As more data from intravitreal chemotherapy and intra-arterial chemotherapy are being published, there are claims of improved globe salvage rates resulting in more widespread use of these newer treatment modalities. However, there are no published randomized controlled trials comparing these to IVCRD head-to-head. To evaluate the relative efficacy of these new therapies, it is critical to determine the true success rates of IVCRD regimens alone. Therefore, it is both timely and essential to determine the baseline IVCRD success rates so that an evidence-based assessment of new and emerging therapies can be determined.

Abstract

To evaluate the relative efficacy of novel retinoblastoma treatments, eye classification-specific success rates for current standard-of-care intravenous chemotherapy regimens must be known. This meta-analysis included studies if: (1) patients received intravenous chemotherapy for retinoblastoma, (2) globe salvage data was reported, (3) only intravenous chemoreduction (with/without local consolidation) was used. The outcome measure was globe salvage success without need for salvage radiotherapy, subdivided by disease classification and chemotherapy regimen. Data from 27 studies (1483 eyes) were pooled. By Reese–Ellsworth classification, globe salvage rates were 85% (95%CI:73–92%) for Group I, 78% (95%CI:70–85%) for Group II, 68% (95%CI:56–78%) for Group III, 47% (95%CI:34–60%) for Group IV, and 35% (95%CI:26–45%) for Group V (Va: 35% [95%CI:21–54%]; Vb: 42% [95%CI:29–56%]; those without sub-classification: 31% [95%CI:19–47%]). By International Classification, globe salvage rates were 93% (95%CI:80–97%) for Group A, 83% (95%CI:73–89%) for Group B, 73% (95%CI:54–86%) for Group C, 40% (95%CI:31–51%) for Group D, and 19% (95%CI:5–50%) for Group E. Standard carboplatin-etoposide-vincristine out-performed two-drug regimens (odds ratio (OR) = 1.9 (95%CI:1.3–3.0) for Groups I-IV and OR = 2.1 (95%CI:1.3–3.4) for Group V; p = 0.002 for each). For eyes with diffuse vitreous seeds (Vb), an enhanced regimen out-performed standard chemotherapy (OR = 2.4 [95%CI:1.3–4.7]; p = 0.004). In conclusion, two-drug regimens were less effective for all eyes, whereas enhanced regimens were more effective for eyes with vitreous seeds. Novel therapies can now be compared to these baseline globe salvage rates.

Complete preclinical platform for intravitreal chemotherapy drug discovery for retinoblastoma: Assessment of pharmacokinetics, toxicity and efficacy using a rabbit model

Current melphalan-based intravitreal chemotherapy regimens for retinoblastoma vitreous seeds are effective, but cause significant ocular toxicity. We describe protocols for each step of a drug discovery pipeline for preclinical development of novel drugs to maximize efficacy and minimize toxicity. These protocols include: 1) determination of vitreous pharmacokinetics in vivo, 2) in vitro assessment of drug cytotoxicity against retinoblastoma based on empiric pharmacokinetics, 3) back-calculation of minimum injection dose to achieve therapeutic concentrations, 4) in vivo determination of maximum-tolerable intravitreal dose, using a multimodal, structural and functional toxicity-assessment platform, and 5) in vivo determination of drug efficacy using a rabbit orthotopic xenograft model of retinoblastoma vitreous seeds. We likewise describe our methodology for direct quantitation of vitreous seeds, and the statistical methodology for assessment of toxicity and efficacy in evaluating novel drugs, as well as for comparisons between drugs.•Multi-step pipeline for intravitreal chemotherapy drug discovery for retinoblastoma, using novel rabbit models.•Detailed protocols for determination of vitreous pharmacokinetics, calculation of optimal dose to inject to achieve therapeutic vitreous levels, determination of maximum tolerable dose using a novel complete toxicity-assessment platform, and in vivo efficacy against retinoblastoma using methodology to directly quantify vitreous tumor burden.•Associated statistical methodology is also presented.

Intravitreal melphalan hydrochloride vs propylene glycol-free melphalan for retinoblastoma vitreous seeds: Efficacy, toxicity and stability in rabbits models and patients

The use of intravitreal chemotherapy has revolutionized the treatment of advanced intraocular retinoblastoma, as intravitreal melphalan has enabled difficult-to-treat vitreous tumor seeds to be controlled, leading to many more eyes being saved. However, melphalan hydrochloride (MH) degrades rapidly in solution, increasing logistical complexity with respect to time between medication preparation and administration for intravitreal administration under anesthesia for retinoblastoma. A new propylene glycol-free melphalan (PGFM) formulation has greater stability and could therefore improve access and adoption of intravitreal chemotherapy, allowing more children to retain their eye(s). We compared the efficacy and toxicity of both formulations, using our rabbit xenograft model and clinical patient experience. Three weekly 12.5 μg intravitreal injections of MH or PGFM (right eye), and saline (left eye), were administered to immunosuppressed rabbits harboring human WERI-Rb1 vitreous seed xenografts. Residual live cells were quantified directly, and viability determined by TUNEL staining. Vitreous seeds were reduced 91% by PGFM (p = 0.009), and 88% by MH (p = 0.004; PGFM vs. MH: p = 0.68). All residual cells were TUNEL-positive (non-viable). In separate experiments to assess toxicity, three weekly 12.5 μg injections of MH, PGFM, or saline were administered to non-tumor-bearing rabbits. Serial electroretinography, optical coherence tomography (OCT) and OCT-angiography were performed. PGFM and MH both caused equivalent reductions in electroretinography amplitudes, and loss of retinal microvasculature on OCT-angiography. The pattern of retinal degeneration observed on histopathology suggested that segmental retinal toxicity associated with all melphalan formulations was due to a vitreous concentration gradient-effect. Efficacy and toxicity were assessed for PGFM given immediately (within 1 h of reconstitution) vs. 4 h after reconstitution. Immediate- and delayed-administration of PGFM showed equivalent efficacy and toxicity. In addition, we evaluated efficacy and toxicity in patients (205 eyes) with retinoblastoma vitreous seeds, who were treated with a total of 833 intravitreal injections of either MH or PGFM as standard of care. Of these, we analyzed 118 MH and 131 PGFM monotherapy injections in whom serial ERG measurements were available to model retinal toxicity. Both MH and PGFM caused reductions in electroretinography amplitudes, but with no statistical difference between formulations. Comparing those patient eyes treated exclusively with PGFM versus those treated exclusively with MH, efficacy for tumor control and globe salvage was equivalent (PGFM vs. MH: 96.2% vs. 93.8%, p = 0.56), but PGFM-treated eyes received fewer injections than MH-treated eyes (average 3.2 ± 1.9 vs. 6.4 ± 2.1 injections, p < 0.0001). Taken together, these rabbit experiments and our clinical experience in retinoblastoma patients demonstrate that MH and PGFM have equivalent efficacy and toxicity. PGFM was more stable, with no decreased efficacy or increased toxicity even 4 h after reconstitution. We therefore now use PGFM over traditional MH for our patients for intravitreal treatment of retinoblastoma.

The Use of Alternative Routes for the Delivery of Intra-Arterial Chemotherapy for Retinoblastoma

BACKGROUND

The introduction of intra-arterial chemotherapy (IAC) for treatment of retinoblastoma considerably changed the paradigm by which this disease is managed, with event-free survival rates being above 70%.

OBJECTIVE

To analyze efficacy of IAC treatment using alternative approaches to ophthalmic artery catheterization (OAC), such as external carotid artery approach or balloon-assisted drug delivery.

METHODS

This is a retrospective chart review for subjects receiving IAC for retinoblastoma. The primary approach was OAC. In cases in which selective OAC was not feasible, alternative routes including catheterization of the external carotid artery or use of a balloon-assisted drug infusion were used.

RESULTS

This study included 197 consecutive patients with 207 retinoblastomas who underwent 658 IAC procedures overall. The mean age at diagnosis was 24 mo, and 54.5% of the study population was male. Success rate with IAC was 97% (639). Alternative approaches to OAC were, in total, 42 cases (6.4%)-external carotid artery catheterization and use of ICA balloon were performed in 22 (3.3%) and 20 (3%) cases, respectively. A mean of 3.1 IAC cycles were performed for each patient. In total, there were 23 technical failures of the primary OAC technique (3.4%). Periprocedural adverse events occurred in 4 procedures (0.6%). Use of an alternative technique for chemotherapy delivery other than selective OAC in at least one IAC cycle was not a predictor of enucleation.

CONCLUSION

IAC is a safe and effective treatment option for retinoblastoma. Chemotherapy delivery using alternative techniques is as effective as selective OAC.

Eye Salvage with Intra-Arterial and Intra-Vitreal Chemotherapy in Patients with Retinoblastoma: 8-Year Single-Institution Experience in Colombia

Introduction

Intra-arterial chemotherapy (IAC) is useful for eye preservation in advanced retinoblastoma (Rb). Intra-vitreal chemotherapy (IvitC) is the latest treatment for vitreous seeds.

Methods

The present study is a retrospective assessment of 100 eyes, treated with primary or secondary IAC alone or with IvitC. We evaluated demographic and clinical variables, eye salvage, associated adverse events, and patient survival. Data were analyzed using descriptive statistics. Kaplan-Meier survival curves and Cox hazard ratios were utilized to assess the effect of demographic and clinical variables over eye salvage.

Results

Bilateral Rb was observed in 61% of patients, and 57% of eyes received secondary treatment. Forty eyes needed intra-arterial plus IvitC and 62 presented advanced disease (group D and E). Three- and 5-year ocular survival probabilities were 75 and 68%. We found a higher risk in group D and E eyes and those requiring 2 or more routes for ophthalmic artery catheterization. Patients coming from other countries also showed increased risk. Using primary or secondary treatment, or IvitC, did not affect this risk. Overall rates of survival and eye salvages were 98.8 and 73%, and we had a 100% catheterization success and none ophthalmic arterial occlusions.

Conclusions

In an upper middle-income country such as Colombia, a specialized institution counting with therapeutic alternatives and a multidisciplinary team can reach rates of patient survival and eye salvage similar to those of high-income countries.

Interventional neuro-oncology

Interventional neuro-oncology encompasses an array of image-guided therapies-intra-arterial chemotherapy, regional drug delivery, chemoembolization, tumor ablation-along with techniques to improve therapy delivery such as physical or chemical blood-brain barrier disruption and percutaneous catheter placement. Endovascular and percutaneous image-guided approaches to the treatment of the brain, eye, and other head and neck tumors will be discussed.

Correlation of Technical and Adjunctive Factors with Quantitative Tumor Reduction in Children Undergoing Selective Ophthalmic Artery Infusion Chemotherapy for Retinoblastoma

BACKGROUND AND PURPOSE

Selective ophthalmic artery infusion chemotherapy has improved ocular outcomes in children with retinoblastoma. Our aim was to correlate quantitative tumor reduction and dichotomous therapeutic response with technical and adjunctive factors during selective ophthalmic artery infusion chemotherapy for retinoblastoma. An understanding of such factors may improve therapeutic efficacy.

MATERIALS AND METHODS

All patients with retinoblastoma treated by selective ophthalmic artery infusion chemotherapy at a single center during a 9-year period were reviewed. Only first-cycle treatments for previously untreated eyes were studied. Adjunctive factors (intra-arterial verapamil, intranasal oxymetazoline external carotid balloon occlusion) and technical factors (chemotherapy infusion time, fluoroscopy time) were documented by medical record review. Quantitative tumor reduction was determined by blinded comparison of retinal imaging acquired during examination under anesthesia before and 3-4 weeks after treatment. The dichotomous therapeutic response was classified according to quantitative tumor reduction as satisfactory (≥ 50%) or poor (<50%).

RESULTS

Twenty-one eyes met the inclusion criteria. Patients ranged from 2 to 59 months of age. Adjuncts included intra-arterial verapamil in 15, intranasal oxymetazoline in 14, and external carotid balloon occlusion in 14. Quantitative tumor reduction ranged from 15% to 95%. Six showed poor dichotomous therapeutic response. A satisfactory dichotomous therapeutic response was correlated with intra-arterial verapamil (P = .03) in the aggregate cohort and in a subgroup undergoing treatment with single-agent melphalan at a dose of <5 mg (P = .02). In the latter, higher average quantitative tumor reduction correlated with intra-arterial verapamil (P < .01).

CONCLUSIONS

Intra-arterial verapamil during selective ophthalmic artery infusion chemotherapy is correlated with an improved therapeutic response, particularly when treating with lower doses of single-agent melphalan.

Prospective phase II study of children affected by bilateral intraocular retinoblastoma with macular involvement of both eyes or in the only preserved eye. Macular tumor control, eye preservation rate, and visual outcome

BACKGROUND

Conservative treatments of intraocular retinoblastoma often consist of chemotherapy and focal treatments. The protocols vary and currently may combine two or three drugs, with different number of cycles, associated to the ocular treatments. In case of macular/paramacular involvement, tumor location and retinal scars induced by focal treatments often have a major negative impact on final visual outcome.

METHODS

This study aimed to include children affected by bilateral intraocular macular/paramacular retinoblastoma in a prospective phase II study. The protocol consisted of six cycles of a three-drug combination (vincristine, etoposide, carboplatin), and the addition of macula-sparing transpupillary thermotherapy (TTT) to the third cycle. The primary endpoint was the local control rate without external beam radiotherapy (EBR) and/or enucleation.

RESULTS

Nineteen patients (26 eyes) were included from July 2004 to November 2009. Thirteen eyes belonged to group V of the Reese-Ellsworth classification and 10 to group D of the International Intraocular Retinoblastoma Classification. Macular/paramacular tumors were treated with chemotherapy alone in nine eyes, and with chemotherapy associated with macula-sparing TTT in 17 eyes. Four eyes experienced macular relapse. At a median follow up of 77 months, 23 eyes (88.5%) were saved without EBR, two were enucleated and one received EBR. The median visual acuity of the 24 saved eyes was 20/50. No severe adverse effect was observed.

CONCLUSION

Six cycles of a three-drug combination associated with macula-sparing TTT achieved good tumor control, improved eye preservation rates without EBR, and decreased macular damage, often providing satisfactory visual results with long-term follow up.

Globe salvage treatment in group D and group E retinoblastoma

Importance: Globe salvage marks the treatment success of retinoblastoma. Background: To evaluate four treatment strategies in group D and group E retinoblastoma. Design: Retrospective case series in a tertiary hospital. Participants: 81 patients with Group D and Group E retinoblastoma. Methods: Participants were divided into four sets. In set I, eyes received primary intravenous chemotherapy (IVC), cryotherapy (CT), laser therapy (LT) and Intravitreal Chemotherapy with Melphalan (IViC). In set II, primary IVC was combined with second line IVC, CT, LT and IVT-M. Set III eyes received primary IVC and Intra-arterial chemotherapy (IAC), CT, LT and IViC. Set IV eyes received IAC, CT, LT and IViC. Treatment failure was defined as inadequate response during or after IVC or IAC. Main Outcome Measures: globe salvage and enucleation rates. Results: 52 eyes were included in group D and 29 in group E. In group D, globe salvage was obtained in 8 out of 11 eyes in Set I, 13 out of 19 eyes in set II, 5 out 6 eyes in set III, and 13 out of 16 eyes in set IV. In group E, enucleation was performed in 17 eyes. Global salvage was obtained in 0 out of 2 eyes in set I, 2 out of 3 eyes in set II, 3 out of 5 in set III, and in 1 out of 2 eyes in set IV. Conclusions: IVC with adjuvant IAC, LT, CT and IViC has shown favorable results as a treatment method for group D and group E retinoblastoma.

Five-year experience in treatment of retinoblastoma with intra-arterial chemotherapy: A single-center analysis

Purpose:

To report our 5-year experience in treating retinoblastoma (RB) with intra-arterial chemotherapy (IAC) as a primary or secondary therapy, without adjuvant intravitreal chemotherapy.

Methods:

A retrospective study was conducted on 70 eyes with intraocular RB that were treated with primary or secondary IAC from December 2010-2015. Demographic characteristics, clinical features, tumor control, and treatment complications were compared and reported.

Results:

Thirty-seven eyes had received IAC as a secondary therapy after failed/incomplete response to systemic chemotherapy, and 33 eyes had received IAC as a primary treatment. The mean age of patients was 25 ± 8.9 months, and the patients were followed for a mean of 24.5 ± 16.26 months. Overall, enucleation rates were significantly higher in advanced tumors (Group D and E) in both groups (both P < 0.05). The main reason for enucleation in this study group was being unresponsive to treatment (27.4%), with 76% of latter patients having vitreous seeds at the time of enucleation. Enucleation rates did not differ significantly between patients receiving primary (18/33, 54%) or secondary IAC (18/37, 48%) (P = 0.06). In addition, recurrence and complication rates did not differ significantly between eyes receiving IAC as their primary or secondary treatment (P > 0.05).

Conclusion:

In primary and secondary treatment of RB with IAC, the main findings that are globe salvage, recurrence, and complication rates were comparable when no adjuvant intravitreal chemotherapy was used.

Ophthalmic artery chemosurgery for retinoblastoma: an initial 3-year experience from two major institutes in Egypt

Background

Intra-arterial chemotherapy has shown promising results and improved the prognosis of retinoblastoma in the developed countries. Here, we aim to report our initial experience, in Egypt, in the treatment of all stages of naïve retinoblastoma with ophthalmic artery chemosurgery (OAC), using melphalan.

Results

The technique was successful in 23 out of 26 eyes. Overall, a total of 63 treatment sessions were performed. Ophthalmic artery catheterization was performed in 59 treatment sessions, whereas middle meningeal artery catheterization was performed in 4 treatment sessions. Adequate tumor control was achieved in 95.6%. Progression has developed in one eye after the third OAC session. The mean follow-up period was 18.5 months. Recurrence of the main tumor as well as vitreous and subretinal seeds was reported in one eye after 19-month duration. A globe salvage rate of 91.3% was attained. No metastasis was recorded, and all patients were alive within the stated follow-up period.

Conclusion

A high globe salvage rate along with metastasis free survival and mild complications were achieved. Therefore, our initial experience with OAC in primary retinoblastoma proved to be safe and effective.

Modern treatment of retinoblastoma: A 2020 review

Retinoblastoma management remains complex, requiring individualized treatment based on International Classification of Retinoblastoma (ICRB) staging, germline mutation status, family psychosocial factors and cultural beliefs, and available institutional resources. For this 2020 retinoblastoma review, PubMed was searched for articles dated as early as 1931, with an emphasis on articles from 1990 to the present day, using keywords of retinoblastoma, chemotherapy, intravenous chemotherapy, chemoreduction, intra-arterial chemotherapy, ophthalmic artery chemosurgery, intravitreal chemotherapy, intracameral chemotherapy, cryotherapy, transpupillary thermotherapy, laser, radiation, external beam radiotherapy, plaque radiotherapy, brachytherapy, and enucleation. We discuss current treatment modalities as used in the year 2020, including intravenous chemotherapy (IVC), intra-arterial chemotherapy (IAC), intravitreal chemotherapy (IvitC), intracameral chemotherapy (IcamC), consolidation therapies (cryotherapy and transpupillary thermotherapy [TTT]), radiation-based therapies (external beam radiotherapy [EBRT] and plaque radiotherapy), and enucleation. Additionally, we present a consensus treatment algorithm based on the agreement of three North American retinoblastoma treatment centers, and encourage further collaboration amongst the world's most expert retinoblastoma treatment centers in order to develop consensus management plans and continue advancement in the identification and treatment of this childhood cancer.

Risk Factors for Acute Choroidal Ischemia after Intra-arterial Melphalan for Retinoblastoma: The Role of the Catheterization Approach

PURPOSE

To identify risk factors for acute choroidal ischemia (ACI) after intra-arterial chemotherapy (IAC) for retinoblastoma.

DESIGN

Retrospective cohort study.

PARTICIPANTS

Two hundred twenty patients (248 eyes) treated with IAC in Lausanne between November 2008 and September 2019 (665 procedures). All patients were evaluated on a monthly basis with fundus photography and fluorescein angiography before and after each IAC injection.

METHODS

Acute choroidal ischemia, defined as any new choroidal ischemia clinically diagnosed within 35 days after an IAC injection, were noted. Eyes with choroidal complications diagnosed later than 35 days after the last IAC injection (n = 7) or those for which the status of the choroid was not assessable (n = 35) were excluded. Specific procedure parameters and treatment regimens were compared between the group of eyes with and without ACI.

MAIN OUTCOME MEASURES

Procedure-related risk factors for ACI after IAC injection and visual acuity assessment in the group of eyes with ACI.

RESULTS

Acute choroidal ischemia developed in 35 of 206 included eyes after a mean of 2 injections. No differences were found between the two study groups regarding age at first IAC injection, disease grouping at diagnosis, previously administered treatments, number of IAC injections, drug dose, mean injection time, injection method (pulsatile vs. continuous), or concomitant intravitreal melphalan use. Treatment regimen (melphalan vs. combined melphalan plus topotecan; P < 0.05), catheterization route (internal carotid artery vs. external carotid or posterior communicating artery; P < 0.001), and catheterization type (occlusive into the ophthalmic artery [OA] vs. nonocclusive; P < 0.001) were included in multivariate analysis, and occlusive catheterization was identified as an independent risk factor for ACI (P < 0.001). In the subgroup undergoing an occlusive procedure, placement of the catheter tip into the OA distal third versus medial and proximal thirds (P = 0.04) and a mean catheter diameter-to-OA lumen ratio of 0.6 or more (P < 0.001) were correlated significantly with ACI. Complete vision loss was noted in 27% of the eyes with ACI that were old enough for visual assessment (n = 9/33), whereas 33% maintained a useful vision ranging between 0.1 and 0.8 (n = 11/33).

CONCLUSIONS

Catheterization of the OA should be attempted from an ostial position or an external carotid approach to minimize the risk of potentially vision-threatening choroidal complications.

Intra-arterial Chemotherapy as Primary Treatment for Cavitary Retinoblastoma: Excellent Response in Eight Tumors

PURPOSE

The "cavitary" form of retinoblastoma has historically demonstrated minimal treatment response with intravenous chemoreduction, showing less robust regression and less reduction in tumor size. Intra-arterial chemotherapy (IAC) has been reported to more effectively treat retinoblastoma, allowing many previously unsalvageable eyes to now be saved. The purpose was to report treatment response of cavitary retinoblastoma tumors to IAC.

DESIGN

Retrospective case series.

PARTICIPANTS

Patients presenting with cavitary retinoblastoma who were treated with IAC.

METHODS

Retrospective case series of all patients presenting with cavitary retinoblastoma between August 2014 and January 2019 who were treated with primary IAC.

MAIN OUTCOME MEASURES

Tumor regression, recurrence, resolution of vitreous and subretinal seeds, number of treatments required, globe salvage, metastasis, and death.

RESULTS

Eight cavitary retinoblastoma tumors in 6 eyes of 4 patients were treated with IAC. One hundred percent of the cavitary tumors regressed (8/8 tumors, in 6/6 eyes), and 100% of vitreous and subretinal seeds regressed, with 100% globe salvage. None of the tumors recurred, no patients developed metastases, and no patients died. Eyes were treated with a median of 4.5 cycles of IAC (range, 1-7), with fewer IAC treatments used in the later patients (1-3 treatments per eye for the most recent 3 eyes, compared with 6-7 treatments per eye for the earliest 3 eyes). Mean reduction in thickness was 73.4% (range, 59.7%-84.6%). Mean reduction in basal diameter was 45.5% (range, 24.8%-56.0%).

CONCLUSIONS

Treatment with IAC results in regression of cavitary retinoblastoma, often with greater reduction in tumor size than has been reported previously with intravenous chemotherapy (IVC). Using up-front triple therapy (e.g., melphalan 0.4 mg/kg, carboplatin 50 mg, and topotecan 2 mg) and noting certain subtle signs of early regression can help to minimize unnecessary additional cycles of treatment.

Retinoblastoma: Etiology, Modeling, and Treatment

Retinoblastoma is a retinal cancer that is initiated in response to biallelic loss of RB1 in almost all cases, together with other genetic/epigenetic changes culminating in the development of cancer. RB1 deficiency makes the retinoblastoma cell-of-origin extremely susceptible to cancerous transformation, and the tumor cell-of-origin appears to depend on the developmental stage and species. These are important to establish reliable preclinical models to study the disease and develop therapies. Although retinoblastoma is the most curable pediatric cancer with a high survival rate, advanced tumors limit globe salvage and are often associated with high-risk histopathological features predictive of dissemination. The advent of chemotherapy has improved treatment outcomes, which is effective for globe preservation with new routes of targeted drug delivery. However, molecularly targeted therapeutics with more effectiveness and less toxicity are needed. Here, we review the current knowledge concerning retinoblastoma genesis with particular attention to the genomic and transcriptomic landscapes with correlations to clinicopathological characteristics, as well as the retinoblastoma cell-of-origin and current disease models. We further discuss current treatments, clinicopathological correlations, which assist in guiding treatment and may facilitate globe preservation, and finally we discuss targeted therapeutics for future treatments.