Secondary Prevention of Retinoblastoma Revisited: Laser Photocoagulation of Invisible New Retinoblastoma.

PURPOSE: Invisible retinoblastoma tumors are now detected with screening for retinal tumors in at-risk neonates (those inheriting RB1 pathogenic alleles from affected parents) using handheld OCT. Laser photocoagulation is challenging, requiring exact localization of a tumor invisible to indirect ophthalmoscopy and standard imaging. We describe OCT-guided localization and photocoagulation of these invisible tumors with 1-year follow-up. DESIGN: Retrospective, noncomparative, single-institutional, observational case series. PARTICIPANTS: Children with any clinically invisible retinoblastoma tumor that was detected on OCT posterior pole screening. METHODS: OCT revealed round homogeneous invisible tumors within the inner nuclear layer. Software calipers placed beside anatomic retinal landmarks (branched/curved vessels, fovea, or optic disc) mapped the tumor location and extent. A single laser (532 nm) burn flagged the location, and OCT evaluated the tumor-laser burn relationship; laser treatment was then continued in the correct location. Post-laser OCT ensured complete treatment. MAIN OUTCOME MEASURES: Accuracy (frequency of geographic miss and skip areas), effectiveness (recurrence rate), and burden (scar size and characteristics at final follow-up) of laser treatment. RESULTS: Eleven new invisible posterior pole tumors in 7 eyes of 5 children were treated by this technique. Localization and tumor-laser burn relationships were accurate in 11 of 11 tumors (100%, 95% confidence interval [CI], 49.9-100), and all showed swelling and hyper-reflectiveness of the tumor in post-laser OCT. Two photocoagulation sessions (2 weeks apart) were sufficient to successfully manage 9 of 11 tumors (82%, 95% CI, 37.4-100) with resulting permanent flat scars. One tumor (9%, 95% CI, 0.2-50.6) developed OCT-detected subclinical recurrences within 3 months, treated by 1 laser session. No treatment scar showed gliosis, foveal involvement, or retinal traction at 1-year follow-up. Scar expansion occurred in 1 tumor (9%, 95% CI, 0.2-50.6), and all scars (100%, 95% CI, 49.9-100) showed pigmentary changes. CONCLUSIONS: The OCT-guided localization and photocoagulation technique is valuable in achieving precision results in managing invisible new retinoblastoma tumors. This technique shows a potential to improve outcomes of secondary prevention screening for retinoblastoma.

Seed-targeting anti-miR-21 inhibiting malignant progression of retinoblastoma and analysis of their phosphorylation signaling pathways.

MiR-21 acts as a ubiquitous oncogene in major classes of human cancers and is a potential target for therapeutic intervention. However, the relative expression of miR-21 in retinoblastoma is poorly understood. Here we detected miR-21 expression in HXO-RB44 cell line human normal retinal tissues and retinoblastoma (Rb) tissue specimens, and studied its function using an 8-mer tiny seed-targeting anti-miR-21 (t-anti-miR-21). RT-PCR revealed that miR-21 was highly overexpressed in HXO-RB44 cells and Rb tissue specimens compared with normal human retinal tissues. The localization and transfection efficiency of t-anti-miR-21 and the cell cycle distribution were detected by confocal microscopy and flow cytometry. In addition, we found that t-anti-miR-21 led to a significant inhibition of retinoblastoma cell proliferation, migration and colony formation in vitro, with a similar effect to anti-miR-21. Anti-miR-21 down-regulated the miR-21 level, whereas both 8-mer t-anti-miR-21 and 15-mer m-anti-miR-21 had no impact on miR-21 expression levels. Finally, the phosphorylation signaling pathway, down-regulated by t-anti-miR-21, was integrated by KEGG assay, which elucidated the potential mechanisms of inhibition of miR-21 in retinoblastoma. Taken together, knockdown of miR-21 in the HXO-RB44 cell is capable of inhibiting cancer progression in retinoblastoma. Seed-targeting t-anti-miR-21 was a novel strategy for mir-21-based therapeutics and drug discovery.

Integrating stages of change models to cast new vision on interventions to improve global retinoblastoma and childhood cancer outcomes.

BACKGROUND: Retinoblastoma, the most common intraocular tumor globally, represents a curable cancer when diagnosed early and treated promptly. Delay to diagnosis, lag time prior to treatment initiation, and abandonment of treatment including upfront treatment refusal, represent stark causes of high retinoblastoma mortality rates in low- and middle- income settings, particularly regions in Africa. While a health delivery-based approach has been a historic focus of retinoblastoma treatments globally and is essential to quality care, this is necessary but not adequate. Retinoblastoma is a compelling disease model to illustrate the potential insights afforded in theory-informed approaches to improve outcomes that integrate public health and oncology perspectives, prioritizing both health service delivery and social efficacy for cure. DISCUSSION: Given that barriers to appropriate and timely diagnosis and treatment represent main contributors to mortality in children with retinoblastoma in resource-limited settings such as certain areas in Africa, an important priority is to overcome barriers to cure that may be predominantly socially influenced, alongside health delivery-based improvements. While Stages of Change models have been effectively utilized in cancer screening programs within settings of economic and cultural barriers, this application of health behavior theory has been limited to cancer screening rather than a comprehensive framework for treatment completion. Using retinoblastoma as a case example, we propose applying stage-based intervention models in critical stages of care, such as the Precaution Adoption Process Model to decrease delay to diagnosis and a Transtheoretical Model to increase treatment completion rates in resource-limited settings. SUMMARY: Stage-based theories recognize that improved cure and survival outcomes will require supportive strategies to progress households, communities, and social and economic institutions from being unaware and unengaged to committed and sustained in their respective roles. Applying a stage-based model lens to programmatic interventions in resource-limited settings has potential for visible improvement in outcomes for children with retinoblastoma and other cancers.

Sunlight exposure in infancy decreases risk of sporadic retinoblastoma, extent of intraocular disease.

BACKGROUND: Prior ecologic studies suggest that UV exposure through sunlight to the retina might contribute to increased retinoblastoma incidence. AIMS: Our study objectives were (1) to examine the relationship between exposure to sunlight during postnatal retinal development (prior to diagnosis of sporadic disease) and the risk of retinoblastoma, and (2) to examine the relationship between sun exposure during postnatal retinal development, and the extent of disease among children with unilateral and bilateral retinoblastoma. METHODS AND RESULTS: We interviewed 511 mothers in the EpiRbMx case-control study about their child's exposure to sunlight during postnatal retinal cell division by examining three time periods prior to Rtb diagnosis coinciding with developmental stages in which outdoor activities vary. Weekly sun exposure was compared by age period, between unilateral (n = 259), bilateral (n = 120), and control (n = 132) children, accounting for two factors affecting UV exposure: residential elevation and reported use of coverings to shield eyes. For cases, association between sunlight exposure and clinical stage was examined by laterality at each age period. After adjusting for maternal education and elevation, sun exposure was lower in cases than controls in all three age periods especially during the first 6 months, and in children 12-23 months whose mothers did not cover their eyes when outdoors. In children diagnosed after 12 months of age, sun exposure during the second year of life (age 12-23 months) appeared inversely correlated (r = -0.25) with more advanced intraocular disease in bilateral Rtb children after adjusting for maternal education, residential elevation, and age of diagnosis (p < .09) consistent with effects of Vitamin D exposure on intraocular spread in earlier transgenic murine models of retinoblastoma, and suggesting potential chemopreventive strategies. CONCLUSION: Sun exposure in early childhood is protective for retinoblastoma and may decrease degree of intraocular spread in children with bilateral Rtb.

TP53/miR-129/MDM2/4/TP53 feedback loop modulates cell proliferation and apoptosis in retinoblastoma.

Retinoblastoma (RB) is commonly-seen cancer in children. The p53 pathway dysfunction, which can lead to elevated MDM2 or MDM4 (p53 antagonists) protein expression, is frequently observed in almost all human cancers, including RB. The present study attempted to investigate the underlying mechanism from the perspective of non-coding RNA regulation. Here, we demonstrated that p53 and miR-129 were positively correlated with each other in RB. miR-129 directly targeted MDM2/4 to inhibit expression, therefore counteracting MDM2/4-mediated p53 signaling suppression and modulating RB cell proliferation and apoptosis. Moreover, p53 could activate the transcription of miR-129 via binding to the miR-129 promoter region, therefore forming a regulatory loop with MDM2/4 to affect RB progression. Altogether, the p53/miR-129/MDM2/4/p53 regulatory loop can modulate RB cell growth. We provide a solid experimental basis for developing novel therapies for RB.

Germ-line gene modification and disease prevention: some medical and ethical perspectives.

There has been considerable debate about the ethics of human germ-line gene modification. As a result of recent advances in the micromanipulation of embryos and the laboratory development of transgenic mice, a lively discussion has begun concerning both the technical feasibility and the ethical acceptability of human germ-line modification for the prevention of serious disease. This article summarizes some of the recent research on germ-line gene modification in animal models. Certain monogenic deficiency diseases that ultimately might be candidates for correction by germ-line intervention are identified. Several of the most frequently considered ethical issues relative to human germ-line gene modification are considered in the context of professional ethics, parental responsibility, and public policy. Finally, it is suggested that there is merit in continuing the discussion about human germ-line intervention, so that this technique can be carefully compared with alternative strategies for preventing genetic disease.

Development of retinoblastoma programs in Central America.

BACKGROUND: Retinoblastoma, a curable eye tumor, is associated with poor survival in Central America (CA). To develop a retinoblastoma program in El Salvador, Guatemala, and Honduras, twinning initiatives were undertaken between local pediatric oncology centers, nonprofit foundations, St. Jude Children's Research Hospital, and the University of Tennessee Hamilton Eye Institute. PROCEDURE: The retinoblastoma program focused on developing early diagnosis programs in Honduras with national vaccination campaigns, developing treatment protocols suited to local conditions, building local networks of oncologists and ophthalmologists, training local healthcare providers, using modern donated equipment for diagnosis and treatment, and the ORBIS Cybersight consultation program and Internet meetings to further education and share expertise. Pediatric ophthalmologists and oncologists worked with foundations to treat patients locally with donated equipment and Internet consultations, or at the center in Guatemala. RESULTS: Number of patients successfully treated increased after the program was introduced. For 2000-2003 and 2004-2007, patients abandoning/refusing treatment decreased in Guatemala from 20 of 95 (21%) to 14 of 123 (11%) and in Honduras from 13 of 37 (35%) to 7 of 37 (19%). Survival in El Salvador was good and abandonment/refusal low for both periods. Of 18 patients receiving focal therapy for advanced disease, 14 have single remaining eyes. CONCLUSION: Development of the program in CA has decreased abandonment/refusal and enabled ophthalmologists at local centers to use modern equipment to provide better treatment. This approach might serve as a guide for developing other multispecialty programs.

LncRNA NKILA Inhibits Retinoblastoma by Downregulating lncRNA XIST.

Purpose: Although retinoblastoma is rare but can be deadly in some severe cases. To find novel therapeutic targets for retinoblastoma, we explored the potential role of lncRNA NKILA in retinoblastoma. Results: We found that, comparing to healthy controls, NKILA was downregulated, while lncRNA XIST was upregulated in plasma of retinoblastoma patients and they were inversely correlated. Downregulation of NKILA distinguished early-stage patients from healthy controls. Overexpression of lncRNA NKILA mediated the downregulation of XIST in retinoblastoma cells, while XIST overexpression failed to significantly affect NKILA. Overexpression of NKILA resulted in decreased, while XIST overexpression resulted in increased proliferation, migration and invasion rates of retinoblastoma cells. In addition, rescue experiment showed that XIST overexpression attenuated the effects of NKILA overexpression on cancer cell behaviors. Conclusions: Therefore, NKILA inhibits retinoblastoma possibly by downregulating XIST, but the causality has not been fully validated.

Regulation of cell lineage specification by the retinoblastoma tumor suppressor.

Early studies of the retinoblastoma gene (RB) have uncovered its critical role as a regulator of the G(1)/S cell cycle phase progression. Surprisingly, genetic approaches in mammals and nematodes have also shown RB controls cell lineage specification and aspects of differentiation. The RB gene product accomplishes this by diverse mechanisms such as by interacting with tissue-specific transcription factors, enhancing RNA interference, and modifying chromatin structure. We review recent studies uncovering novel mechanisms by which RB works in several cell lineages and we provide perspectives on how these new findings might relate to RB tumor suppression.

Cell cycle control and beyond: emerging roles for the retinoblastoma gene family.

Rb family proteins (pRb/p105, Rb2/p130 and p107) play a key role in cell cycle control and are worthily involved in transcription repression and tumor suppression. The mechanisms of transcriptional activation and repression by the Rb gene family has been extensively investigated: pRb, pRb2/p130 and p107 interact with different E2F family factors and can inhibit E2F responsive promoters, interfering with progression of cell cycle, gene transcription, initiation of apoptotic process and cell differentiation. Recent studies have indicated that Rb and Rb2/p130 may be involved in cellular response to DNA damage events, by influencing the transcription of factors involved in DNA repair pathways. In particular, evidences suggest that Rb loss and target gene deregulation impacts on the repair of UV-induced pyrimidine pyrimidone photoproducts (6-4 PP) by regulating the expression of several DNA damage factors involved in UV DNA damage repair processes, including proliferating cell nuclear antigen. Ongoing studies are focused on the mechanisms by which Rb family genes drive cell cycle exit following DNA damage induction, and how Rb gene family's interaction with chromatin remodeling factors can influence DNA repair dynamics.

Estimating the incidence of retinoblastoma in Texas.

The purpose of this study was to estimate the number of retinoblastoma cases anticipated each year in various urban and rural areas in Texas. We obtained the most recent data on the number of live births in Texas from the Texas Department of Health. Using those data and the retinoblastoma incidence rate of 1 in 15,000 live births, we estimated that 26 cases of the disease will be diagnosed in Texas each year. Nearly half of those cases will occur in infants in rural areas of the state. We compared those values with data from the Texas Cancer Registry. Primary care physicians, particularly in rural areas of Texas, must screen patients for retinoblastoma and consider arrangements for rapid referral when the diagnosis is suspected.

The antineoplastic effect of vitamin D in transgenic mice with retinoblastoma.

Vitamin D has been shown to inhibit growth of human retinoblastoma in tissue culture and nude mouse heterografts. We have described a heritable transgenic mouse model of retinoblastoma. The in vivo efficacy of 1,25-dihydroxycholecalciferol (vitamin D3) was examined by administering this agent to transgenic mice with retinoblastoma. Forty-six 8-10-week-old transgene-bearing mice were injected intraperitoneally for 5 wk. Experimental animals received 0.05 microgram (15 animals) or 0.025 microgram (15 animals) of vitamin D. Sixteen control animals received only a mineral oil vehicle. Eyes were enucleated at 5 mo and were examined histologically by two investigators in a masked fashion. All control animals demonstrated bilateral involvement of retinoblastoma. Four eyes in the low-dose group and six eyes in the high-dose group had no evidence of retinoblastoma. Eyes treated with vitamin D3 showed less extensive involvement of the retina by retinoblastoma. Vitamin D-treated animals demonstrated tumors confined to the retina, whereas control animals demonstrated larger tumors, more often invading the vitreous, anterior chamber, and choroid. Thus, Vitamin D inhibited the growth and local extension in a dose-dependent fashion.

Evaluation of chemoprophylaxis in patients with unilateral retinoblastoma with high-risk features on histopathologic examination.

OBJECTIVES: To identify risk factors for metastatic disease on histopathologic specimens of enucleated eyes from patients with unilateral retinoblastoma, and to evaluate the value of chemoprophylaxis in preventing disease dissemination. METHODS: Medical records from patients with unilateral retinoblastoma who underwent primary enucleation were reviewed at the University of California, San Francisco (1977-1998) and Bascom Palmer Eye Institute, University of Miami, Miami, Fla (1991-1998). All routine histopathologic specimens were reexamined. The extent of tumor invasion into the optic nerve or ocular coats and the prescribed chemoprophylactic regimen were recorded. RESULTS: This retrospective study included 129 patients followed for a median of 54 months. Three patients had tumor invading the sclera. The optic nerve was involved to some extent in 82 patients, 11 of whom had tumor extension beyond the lamina cribrosa. The surgical margin of the optic nerve was involved in an additional 4 patients. The choroid was involved in 43 patients, and was considered massively affected in 12 patients. Anterior segment involvement was observed in 10 patients. Postenucleation chemoprophylaxis was administered to 4 of 4 patients who had tumor cells at the surgical margin of the optic nerve and to 7 of 11 patients with postlaminar disease, all of whom had at least 1 mm of postlaminar tumor extension. External beam radiotherapy was administered to 3/4 and 1/11 of these patients, respectively. Chemoprophylaxis was not administered to patients with choroidal or anterior chamber involvement unless the optic nerve was also involved beyond the lamina cribrosa. One patient with tumor extending to the surgical margin of the optic nerve died of metastatic disease. CONCLUSIONS: Chemoprophylaxis is necessary for patients with tumor extending to the surgical margin of the optic nerve and is likely to be beneficial in preventing metastases in patients with tumor extending beyond the lamina cribrosa. We did not offer chemoprophylaxis to patients with prelaminar optic nerve disease or isolated choroidal involvement, and these patients remained free of disseminated disease.

Retinoblastoma referral patterns in Saudi Arabia.

The purpose of this study was to review the patterns of referral and presentation of patients with retinoblastoma in Saudi Arabia from 1983-1994. Retinoblastoma represents a particularly high volume at the King Khaled Eye Specialist Hospital and the Hospital's Retinoblastoma Registry provided relevant data. Records of 257 registered patients were analyzed. Of these, 112 were bilateral whereas 145 were unilateral, resulting in a total of 369 eyes. Referral diagnosis accuracy was high, 75% of referring physicians ranking retinoblastoma at the top of their differential diagnosis. Delay in referral was found to average 9.4 weeks. However, 49.4% of eyes were staged at Reese-Ellsworth Stage V at presentation. Significantly, the number of patients presenting with extraocular disease fell from 22.8% (1983-1988) to 12.3% (1989-1994), highlighting increasing awareness of retinoblastoma and availability of services in Saudi Arabia.

Retinoblastoma tells the story of our health care system.

OBJECTIVE: To review cases of retinoblastoma. SETTING: Department of Pathology Aga Khan University Hospital Karachi. METHOD: Twenty-three specimens from cases of retinoblastoma received over a period of eight years were routinely processes and stained with haematoxylin and Eosin stain. Other stains were used for tuberculoses and melanin. Immunochemistry was resorted to in undifferentiated tumors. RESULTS: Over 60% cases of retinoblastoma were diagnosed after 5 years and nine cases showed involvement of optinerve. CONCLUSION: Late diagnosis of retinoblastoma effects the stage of the tumors and the prognosis.

[Structural features of retinoblastoma]. / Stukturnye osobennosti retinoblastomy.

The authors analyze the pathohistological archives of the Tashkent Research Institute of Ophthalmic Diseases for the years 1985-1994 and their own materials collected in recent years: 44 eyes enucleated for retinoblastoma. The microscopic picture of 44 tumors is as follows: retinoblastoma A in 12 (27.3%) cases, retinoblastoma B in 16 (36.3%), retinoblastoma C in 9 (20.4%), and mixed form in 7 (16%) cases. The total level of retinoblastoma A and B is almost 64%; this condition is positively life-threatening. The authors emphasize the necessity of health education of the population and improvement of primary health care and prophylactic check-ups of preschool children.

[Geographic occurrence of retinoblastoma]. / O geograficheskom rasprostranenii zabolevaemosti retinoblastomy.

The dot mapping technique was used to study the areas of retinoblastoma prevalence in Kazakhstan. A total of 344 retinoblastoma cases were analyzed. The landscape confinement of retinal tumors was taken into consideration. The tumors were more often seen in the children living near water, near the Alatau plain where chemical elements are accumulated, and in large industrial cities polluted by industrial waste products. The data of this study will be used to develop prophylactic measures and for early detection of retinoblastomas in children living in Kazakhstan.

Antineoplastic activity of a nutrient mixture in Y-79 malignant retinoblastoma cells.

Retinoblastoma is one of the most common ocular malignancies in children under the age of six. Occasionally, retinoblastoma metastasizes to extraocular organs including the bone, lung and brain. Left untreated, retinoblastoma is fatal. At present, there is no effective treatment for metastatic retinoblastoma. We investigated the antineoplastic activity of a nutrient mixture (NM) (lysine, proline, ascorbic acid and green tea extract) at concentrations of 10, 50, 100, 500 and 1,000 µg/ml in triplicate at each dose in the human malignant retinoblastoma Y-79 cell line. The parameters used were cell proliferation, expression of matrix metalloproteinases (MMPs), invasion through Matrigel, morphology and apoptosis. Cell viability was assessed by trypan blue dye exclusion test. Invasion was evaluated through Matrigel and MMP activity by gelatinase zymography. H&E staining for morphological cell alterations and apoptotic studies using the Live Green Poly Caspase Detection kit were also conducted. The nutrient mixture at 10-100 µg/ml demonstrated approximately 25% toxicity towards Y-79 retinoblastoma cells and significant toxicity at 500 and 1,000 µg/ml. The Y-79 cells secreted only MMP-2 as demonstrated by zymography; the nutrient mixture had no effect on MMP-2 expression up to 100 µg/ml, but completely blocked it at 500 µg/ml. Importantly, Y-79 retinoblastoma cells were not invasive through Matrigel. H&E staining showed cell morphological changes related to apoptosis, which was confirmed using the Live Green Poly Caspase Detection kit. Our results suggest that this nutrient mixture, which inhibited cell proliferation, expression of MMP-2 and induced apoptosis, may be a candidate for further exploration for its therapeutic potential in metastatic retinoblastoma.

Retinoblastoma infantil, deteccion temprana de un caso inusual / Children's retinoblastoma early detection in an unusual case

El retinoblastoma es el cáncer de retina más frecuente en la infancia. Representa el 4% de los tumores en menores de 15 años. Su diagnóstico se realiza generalmente entre los 12 y 18 meses de vida, con buen pronóstico si no se ha diseminado. Objetivo: resaltar la importancia de la sospecha clínica para detección temprana de esta enfermedad. Caso clínico: paciente masculino de 4 meses de vida, procedente de Tegucigalpa, Honduras; con alteración en el reflejo pupilar del ojo izquierdo (leucocoria), acompañado de estrabismo divergente del mismo ojo. Fue evaluado por oftalmología y remitido al Hospital Escuela Universitario por sospecha de retinoblastoma de ojo izquierdo. Al examinar fondo de ojo se encontró lesión de 4 mm que ocupa 2/3 partes de la retina, por lo que se realizó tomografía axial computarizada cerebral y de órbita de ojo izquierdo, que reportó hipotrofia cortical frontotemporal bilateral y masa sólida calcificada que no se extiende fuera del globo ocular. Se indicó resonancia magnética nuclear de órbita, encontrándose masa hipodensa irregular en cámara posterior de ojo izquierdo. Posteriormente se realizó retino cámara, mostrando lesión que cubre casi totalidad de la retina. Con estos hallazgos el Servicio de Oftalmología Pediátrica, lo intervino quirúrgicamente realizando enucleación de ojo afectado; sin complicaciones, evolución satisfactoria y seguimiento en consulta externa de Hematoncológica Pediátrica. Conclusión: en este caso, la enfermedad se diagnosticó en etapa temprana, algo que generalmente no ocurre, logrando salvar la vida del paciente y evitó la diseminación a órganos adyacentes.

Postenucleation adjuvant chemotherapy with vincristine, etoposide, and carboplatin for the treatment of high-risk retinoblastoma.

BACKGROUND: Analysis of 52 eyes with high-risk retinoblastoma managed with postenucleation adjuvant chemotherapy using vincristine sulfate, etoposide phosphate, and carboplatin showed no evidence of systemic metastasis in any case during a mean (range) follow-up of 66 (12-202) months. PURPOSE: To determine the efficacy of postenucleation adjuvant chemotherapy with vincristine, etoposide, and carboplatin in the prevention of metastasis for patients with high-risk retinoblastoma. METHODS: Retrospective, nonrandomized, interventional case series of 52 eyes in 51 patients with high-risk retinoblastoma consisting of tumor invasion into the anterior segment, posterior uvea 3 mm or greater, postlaminar optic nerve, or any combination of posterior uvea and optic nerve involvement. RESULTS: Of 51 consecutive patients with high-risk retinoblastoma, there were 30 males (59%) and 21 females (41%), with a median age of 28 months at diagnosis. All 52 eyes were classified as group E. The main histopathologic risk factors included anterior segment invasion (7 [13%]), isolated massive posterior uveal invasion of 3 mm or greater (6 [12%]), isolated postlaminar optic nerve invasion (15 [29%]), or any posterior uveal invasion with any optic nerve involvement (24 [46%]). There was additional invasion into the sclera (3 [6%]) and extrascleral structures, including the orbit (1 [2%]). A single histopathologic high-risk factor was present in 32 eyes (62%), whereas 20 eyes (38%) manifested 2 or more high-risk characteristics. Based on previously published series, untreated high-risk retinoblastoma carries at least a 24% risk for metastatic disease. In the present series, using vincristine, etoposide, and carboplatin in all cases, there was no metastasis during a mean follow-up of 66 months (median [range], 55 [12-202] months). CONCLUSIONS: Retinoblastoma with invasion into the postlaminar optic nerve and/or posterior uvea is at high risk for metastasis and death. In this study, postenucleation chemotherapy using vincristine, etoposide, and carboplatin was effective in preventing metastasis in every case (100%).