External beam radiotherapy for retinoblastoma: II. Lens sparing technique

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.

Expression Changes and Impact of the Extracellular Matrix on Etoposide Resistant Human Retinoblastoma Cell Lines

Retinoblastoma (RB) represents the most common malignant childhood eye tumor worldwide. Several studies indicate that the extracellular matrix (ECM) plays a crucial role in tumor growth and metastasis. Moreover, recent studies indicate that the ECM composition might influence the development of resistance to chemotherapy drugs. The objective of this study was to evaluate possible expression differences in the ECM compartment of the parental human cell lines WERI-RB1 (retinoblastoma 1) and Y79 and their Etoposide resistant subclones via polymerase chain reaction (PCR). Western blot analyses were performed to analyze protein levels. To explore the influence of ECM molecules on RB cell proliferation, death, and cluster formation, WERI-RB1 and resistant WERI-ETOR cells were cultivated on Fibronectin, Laminin, Tenascin-C, and Collagen IV and analyzed via time-lapse video microscopy as well as immunocytochemistry. We revealed a significantly reduced mRNA expression of the proteoglycans Brevican, Neurocan, and Versican in resistant WERI-ETOR compared to sensitive WERI-RB1 cells. Also, for the glycoproteins α1-Laminin, Fibronectin, Tenascin-C, and Tenascin-R as well as Collagen IV, reduced expression levels were observed in WERI-ETOR. Furthermore, a downregulation was detected for the matrix metalloproteinases MMP2, MMP7, MMP9, the tissue-inhibitor of metalloproteinase TIMP2, the Integrin receptor subunits ITGA4, ITGA5 and ITGB1, and all receptor protein tyrosine phosphatase β/ζ isoforms. Downregulation of Brevican, Collagen IV, Tenascin-R, MMP2, TIMP2, and ITGA5 was also verified in Etoposide resistant Y79 cells compared to sensitive ones. Protein levels of Tenascin-C and MMP-2 were comparable in both WERI cell lines. Interestingly, Fibronectin displayed an apoptosis-inducing effect on WERI-RB1 cells, whereas an anti-apoptotic influence was observed for Tenascin-C. Conversely, proliferation of WERI-ETOR cells was enhanced on Tenascin-C, while an anti-proliferative effect was observed on Fibronectin. In WERI-ETOR, cluster formation was decreased on the substrates Collagen IV, Fibronectin, and Tenascin-C. Collectively, we noted a different ECM mRNA expression and behavior of Etoposide resistant compared to sensitive RB cells. These findings may indicate a key role of ECM components in chemotherapy resistance formation of RB.

Lens Dose-Response Prediction Modeling and Cataract Incidence in Patients With Retinoblastoma After Lens-Sparing or Whole-Eye Radiation Therapy

PURPOSE

We retrospectively assessed the incidence of cataracts in patients with retinoblastoma (Rb) treated with either lens-sparing radiation therapy (LSRT) or whole-eye radiation therapy (WERT). A secondary aim of this study was to model the dose-response risk of cataract.

METHODS AND MATERIALS

We reviewed 65 patients with Rb treated with radiation therapy (RT) at Children's Hospital, Los Angeles from 1997 to 2015. Eyes that were enucleated before RT or lacked follow-up eye examinations were excluded. All patients underwent computed tomography simulation, and mean lens dose data were collected. Follow-up ophthalmologic examinations and intraocular lens implant history were reviewed for cataracts. The primary event-free survival (EFS) outcome was cataract development. Eyes without cataracts were censored on the last date of eye examination or post-RT enucleation, if applicable. Kaplan-Meier estimates were used to compare EFS outcomes, and dose response was projected with Cox regression and logistic regression models.

RESULTS

Sixty-one patients (94 eyes) were analyzed with a median follow-up of 51.8 months. For eyes treated with WERT, cataracts developed in 71.7% versus 35.3% for LSRT. Median EFS for WERT and LSRT were 20.8 and 67.9 months, respectively. Compared with WERT, a significant EFS benefit was demonstrated for LSRT (P < .001). Mean lens dose had a significant effect on cataracts in both Cox regression and logistic regression models (P < .01). The mean lens dose of 7 Gy was projected to have a 5-year cataract incidence of 20% and 25% with the logistic and Cox regression models, respectively.

CONCLUSIONS

We report the first clinical data demonstrating significantly improved EFS in patients with Rb treated with LSRT. Through lens dose-response modeling, we validate a mean lens dose threshold of 7 Gy to keep cataract risk below 25%. Although RT is used less often for Rb owing to advances in chemotherapy delivery options, these findings are relevant for refining lens dose constraints, particularly in children who have received radiation dose near the orbit.

Challenges and differences in external radiation therapy for retinoblastoma: from standard techniques to new developments

AIMS

The purpose of this study is to calculate the treatment plans and to compare the dose distributions and dose-volume histograms (DVH) for 6 external radiotherapy techniques for the treatment of retinoblastoma as well as intensity-modulated radiotherapy (IMRT) and fractionated stereotactic radiotherapy (Cyberknife).

METHODS

Treatment plans were developed using 6 techniques, including an en face electron technique (ET), an anterior and lateral wedge photon technique (LFT), a 3D conformal (6 fields) technique (CRT), an inverse plan IMRT, tomotherapy, and conventional focal stereotactic external beam radiotherapy with Cyberknife (SBRT). Dose volume analyses were carried out for each technique.

RESULTS

All techniques except electron provided similar target coverage. When comparing conformal plan with IMRT and SBRT, there was no significant difference in planning target volume dose distribution. The mean volume of ipsilateral bony orbit received more than 20 Gy, a suggested threshold for bone growth inhibition. The V20 Gy was 73% for the ET, 57% for the LFT, 87% for the CRT, 65% for the IMRT, 66% for the tomotherapy, and 2.7% for the SBRT.

CONCLUSIONS

This work supports the potential use of IMRT and SBRT to spare normal tissues in these patients.

Leptomeningeal failure of retinoblastoma

Leptomeningeal (LM) failure of retinoblastoma (Rb) has not previously been reported. Upon review of our institutional experience of external beam radiotherapy (EBRT) for Rb, we found three LM failures. We sought to better define the clinical parameters of this type of recurrence. All children with LM failure had Reese-Ellsworth stage Vb eyes. Otherwise, no variables were significantly associated with LM failure. We theorize that this phenomenon is a function of the late-stage eyes for which EBRT is being reserved in the modern era.

Retinoblastoma

Retinoblastoma is the most common neoplasm of the eye in childhood, and represents 3% of all childhood malignancies. Retinoblastoma is a cancer of the very young; two-thirds are diagnosed before 2 years of age and 95% before 5 years. Retinoblastoma presents in 2 distinct clinical forms: (1) a bilateral or multifocal, heritable form (25% of all cases), characterized by the presence of germline mutations of the RB1 gene; and (2) a unilateral or unifocal form (75% of all cases), 90% of which are nonhereditary. The treatment of retinoblastoma is multidisciplinary and is designed primarily to save life and preserve vision.

Retinoblastoma: An overview

Retinoblastoma is the most common intraocular malignancy in children, with a reported incidence ranging from 1 in 15,000 to 1 in 18,000 live births. It is second only to uveal melanoma in the frequency of occurrence of malignant intraocular tumors. Pawius described retinoblastoma as early as in 1597 referred to the tumor as fungus hematodes and suggested enucleation as the primary mode of management. The discovery of ophthalmoloscope in 1851 facilitated recognition of specific clinical features of retinoblastoma. Initially thought to be derived from the glial cells, it was called a glioma of the retina by Virchow (1864). Flexner (1891) and Wintersteiner (1897) believed it to be a neuroepithelioma because of the presence of rosettes. Later, there was a consensus that the tumor originated from the retinoblasts and the American Ophthalmological Society officially accepted the term retinoblastoma in 1926. Retinoblastoma was associated with near certain death just over a century ago. There has been a dramatic change in the overall management of retinoblastoma in the last decade. Specific genetic protocols have been able to make pre natal diagnosis of retinoblastoma. Early diagnosis and advancements in focal therapy have resulted in improved eye and vision salvage. This article explains the complexity of retinoblastoma, genetic association, clinical features, management and prognosis.

Retinoblastoma in Turkey: results from a tertiary care center in Ankara

PURPOSE

To evaluate the presentation patterns and results of management of retinoblastoma at a tertiary care center in Ankara, Turkey, with special emphasis on globe conservation rate in unilateral and bilateral intraocular retinoblastoma.

METHODS

Patients were grouped according to the International Classification of Retinoblastoma. For intraocular retinoblastoma, group E and some group D eyes underwent primary enucleation. Secondary enucleation was performed after failure of chemoreduction, focal treatments, external beam radiotherapy (EBRT), and intra-arterial chemotherapy used in various combinations. For extraocular retinoblastoma cases, treatment consisted of enucleation/exenteration or orbital biopsy, high-dose chemotherapy, and EBRT to the orbit and metastatic sites.

RESULTS

During the study period from October 1998 to May 2010, 165 of 192 (85.9%) patients had intraocular disease and 27 (14.1%) patients had extraocular disease. In total, primary or secondary enucleation was performed in 70 of 94 eyes with unilateral retinoblastoma (74.5%) and in 34 of 142 eyes with bilateral retinoblastoma (23.9%). The overall globe conservation rate was 69.6%. Only one patient in the intraocular retinoblastoma group died of metastatic retinoblastoma to the central nervous system. Twenty of 27 patients (74.1%) with extraocular retinoblastoma were found to have metastasis to the central nervous system, bone, bone marrow, and/or lymph nodes. At a mean follow-up of 28.0 months (median: 12 months; range: 1 to 120 months), survival was 33.3% despite intensive treatment.

CONCLUSIONS

The overall risk of enucleation was 75% in eyes with unilateral retinoblastoma and 24% in eyes with bilateral retinoblastoma. Extraocular retinoblastoma carries a 75% risk of systemic metastasis and 67% risk of death.

Radiotherapy for ocular tumours

Ocular tumours present a therapeutic challenge because of the sensitive tissues involved and the necessity to destroy the tumour while minimising visual loss. Radiotherapy (RT) is one of several modalites used apart from surgery, laser, cryotherapy, and chemotherapy. Both external beam RT (EBRT) and brachytherapy are used. Tumours of the bulbar conjunctiva, squamous carcinoma and malignant melanoma, can be treated with a radioactive plaque: strontium-90, ruthenium-106 (Ru-106), or iodine-125 (I-125), after excision. If the tumour involves the fornix or tarsal conjunctiva, proton therapy can treat the conjunctiva and spare most of the eye. Alternatively, an I-125 interstitial implant can be used with shielding of the cornea and lens. Conjunctival mucosal-associated lymphoid tissue lymphoma can be treated with an anterior electron field with lens shielding and 25-30 Gray (Gy) in 2 Gy fractions. Discrete retinoblastoma (RB), too large for cryotherapy or thermolaser, or recurrent after these modalities, can be treated with plaque therapy, I-125, or Ru-106. For large RB, multiple tumours, or vitreous seeds the whole eye can be treated with an I-125 applicator, sparing the bony orbit, or with EBRT, under anaesthetic, using X-rays or proton therapy with vacuum contact lenses to fix the eyes in the required position. Post-enucleated orbits at risk for recurrent RB can be treated with an I-125 implant with shielding to reduce the dose to the bony orbit. Uveal malignant melanomas can be treated with plaque or proton therapy with excellent local control. Preservation of vision will depend on the initial size and location of the tumour.

Retinoblastoma major review with updates on Middle East management protocols

Many advances in the field of management of retinoblastoma emerged in the past few years. Patterns of presentation of retinoblastoma in the Middle East region differ from Western community. The use of enucleation as a radical method of eradicating advanced disease is not easily accepted by patient's family. We still do see stage E, failed or resistant retinoblastoma and advanced extraocular disease ensues as a result of delayed enucleation decision. In this review, we discuss updates in management of retinoblastoma with its implication on patients in our part of the world. Identifying clinical and high risk characteristics is important prognostically and are discussed for further management of retinoblastoma cases.

Consideraciones clínicas, diagnósticas y de tratamiento en retinoblastoma

El  retinoblastoma es el  tumor  intraocular  primario más frecuente en la infancia. Su detección temprana y el inicio del tratamiento adecuado permiten mejorar  dramáticamente la sobrevida en estos niños. En este artículo se hace una revisión general de la enfermedad. Se empleó PubMed y se revisaron artículos representativos del tema, que permitieran dar una idea general de los diferentes avances alcanzados. Dada su clínica característica, el médico de atención primaria, es pieza fundamental en la captación inicial del paciente.

Preliminary experience in treatment of papillary and macular retinoblastoma: evaluation of local control and local complications after treatment with linear accelerator-based stereotactic radiotherapy with micromultileaf collimator as second-line or salvage treatment after chemotherapy

PURPOSE

To determine the local control and complication rates for children with papillary and/or macular retinoblastoma progressing after chemotherapy and undergoing stereotactic radiotherapy (SRT) with a micromultileaf collimator.

METHODS AND MATERIALS

Between 2004 and 2008, 11 children (15 eyes) with macular and/or papillary retinoblastoma were treated with SRT. The mean age was 19 months (range, 2-111). Of the 15 eyes, 7, 6, and 2 were classified as International Classification of Intraocular Retinoblastoma Group B, C, and E, respectively. The delivered dose of SRT was 50.4 Gy in 28 fractions using a dedicated micromultileaf collimator linear accelerator.

RESULTS

The median follow-up was 20 months (range, 13-39). Local control was achieved in 13 eyes (87%). The actuarial 1- and 2-year local control rates were both 82%. SRT was well tolerated. Late adverse events were reported in 4 patients. Of the 4 patients, 2 had developed focal microangiopathy 20 months after SRT; 1 had developed a transient recurrence of retinal detachment; and 1 had developed bilateral cataracts. No optic neuropathy was observed.

CONCLUSIONS

Linear accelerator-based SRT for papillary and/or macular retinoblastoma in children resulted in excellent tumor control rates with acceptable toxicity. Additional research regarding SRT and its intrinsic organ-at-risk sparing capability is justified in the framework of prospective trials.

Outcomes after cataract extraction in young children with radiation-induced cataracts and retinoblastoma

BACKGROUND

An expected side effect of external beam radiation therapy for retinoblastoma is cataract formation, which impairs a child's visual development and an ophthalmologist's ability to examine the eye. When surgery is indicated, the potential complications can be vision-or life-threatening. Here we report the results of cataract extraction with intraocular lens placement in young children with retinoblastoma.

METHODS

A retrospective chart review of all patients at St. Jude's Children's Research Hospital who had undergone external beam radiation therapy for retinoblastoma during a 25-year period was performed. Patients who required cataract extraction with IOL placement were included. Preoperative and postoperative visual acuity and ocular complications were recorded.

RESULTS

The chart review identified 40 patients (53 eyes) with cataracts, of whom 15 (19 eyes) had surgery. Of the 19 eyes, 2 (10.5%) developed a vitreous hemorrhage (one of which was subsequently enucleated secondary to phthisis, whereas the other resolved without further complications). A total of 12 eyes (63.2%) required Nd:YAG laser capsulotomies (mean, 3.6 months; range, 1-7 months). None developed recurrence or spread of disease. Thirteen eyes (68.4%) had improved visual acuity after cataract extraction and intraocular lens placement, 4 of which (30.8%) subsequently lost vision as the result of other complications of retinoblastoma treatment. Visual acuity outcomes were 20/20 to 20/60 in 3 eyes (15.8%); 20/70 to 20/200 in 4 (21.1%); and 20/400 or less in 10 (52.6%). One patient (5.2%) required enucleation.

CONCLUSIONS

Patients who underwent cataract extraction after treatment for retinoblastoma had few postoperative adverse outcomes, and visual acuity improved in most patients immediately after surgery. However, some patients who showed initial improvement subsequently lost vision as the result of other complications from retinoblastoma treatment.

Treatment of retinoblastoma: Current status and future perspectives

Treatment of retinoblastoma must be individualized. Most patients with unilateral, non-metastatic retinoblastoma can be cured with enucleation alone. In patients with histologic risk factors, adjuvant chemotherapy is recommended, with the addition of orbital radiation for patients with trans-scleral involvement or tumor present at the level of the cut end of the optic nerve. Patients with metastases require intensive chemotherapy and consolidation with autologous hematopoietic stem cell rescue. Patients with bilateral or multifocal disease represent a major challenge. Cure of the disease is the first priority, but the therapeutic approach also has to consider eye and vision preservation. The approach is conservative, and only eyes with very advanced disease are enucleated upfront. Patients are treated with chemotherapy and intensive focal treatments, with the aim of delaying or avoiding radiation therapy and enucleation. For patients with early intraocular stage (Reese-Ellsworth groups I-III and International Groups A-B), the two-drug combination of vincristine and carboplatin is recommended. Patients with more advanced intraocular disease (Reese-Ellsworth groups IV-V and International Groups C-D) require more intensive chemotherapy. Standard of care for these patients incorporates etoposide into the regimen. Effective agents with good intraocular penetration, such as topotecan, are being investigated. Because most failures are secondary to progression of the vitreous seeds, subconjunctival carboplatin is added in cases with poor response of the vitreous tumors. Patients must be monitored very closely, with examinations under anesthesia every 4 to 6 weeks, and focal treatments are applied during the procedure. These include cryotherapy for small anterior tumors, thermotherapy and laser photocoagulation for small posterior tumors, and brachytherapy for larger tumors. New treatment approaches under development include the refinement of periocular chemotherapy administration using slow-release devices, the use of suicide gene therapy with local delivery of the herpes simplex thyrosine kinase gene (followed by systemic administration of ganciclovir), and the development of small-molecule inhibitors of the MDMX-p53 interaction.

Diagnosis and management of retinoblastoma

BACKGROUND

Retinoblastoma is a highly malignant tumor of the eye that manifests most often in the first 3 years of life.

METHODS

Published articles were reviewed to evaluate the clinical features and current methods of diagnosis and to assess the trends in management.

RESULTS

This malignancy leads to metastatic disease and death in 50% of children worldwide but in less than 5% of children in the United States and other developed nations with advanced medical care. Over the past decade, there has been a trend away from enucleation and external beam radiotherapy and toward chemoreduction followed by focal therapies. This is largely due to more effective chemotherapeutic regimens, improved focal treatment modalities, and the desire to avoid loss of the globe and/or exposure to radiotherapy. Chemoreduction and focal therapies are most successful for eyes with minimal to moderate retinoblastoma, with enucleation needed in less than 15% of cases. Eyes with very advanced retinoblastoma require enucleation in approximately 50% of cases.

CONCLUSIONS

Progress in the clinical recognition and management of retinoblastoma has led to high survival rates. Improved methods of treatment using chemoreduction and focal treatments without the need for external beam radiotherapy allow preservation of the eye in some cases, often with visual function.

Retinoblastoma—comparative analysis of external radiotherapy techniques, including an IMRT technique

PURPOSE

To compare the numerous external radiotherapy (RT) techniques for the treatment of retinoblastoma, as well as an intensity-modulated RT (IMRT) technique. The latter was elaborated to evaluate the potential dose reduction in the surrounding tissue, as well as the potential avoidance of subdosage in the ora serrata retinae.

METHODS AND MATERIALS

A 2-year-old patient with unilateral retinoblastoma underwent CT. With the aid of an ophthalmologist, the ocular structures were delimited, and 13 techniques described in published reports were reproduced on three-dimensional planning software and identified according to their authors. A technique with four noncoplanar fields using IMRT was also elaborated. These techniques were compared according to the dose to the ora serrata retinae, lens, orbit (volume that received a dose of >or=20 Gy), vitreous, optic nerve, lacrimal gland (volume that received a dose of >or=34 Gy), and cornea and according to their ease of reproducibility.

RESULTS

The techniques that attained the therapeutic dose to the ora serrata retinae were the IMRT technique and the techniques of Haye, Cassady, Cormack, and al-Beteri. The Cormack technique had the lowest volume that received a dose of >or=20 Gy in the orbit, followed by the IMRT technique. The IMRT technique also achieved the lowest volume that received a dose of >or=34 Gy (14%) in the lacrimal gland. The Abramson/McCormick/Blach, Cassady, Reese, and Schipper techniques were the easiest to reproduce and the Chin the most complex.

CONCLUSION

Retinoblastoma treatment with IMRT has an advantage over the other techniques, because it allows for the greatest reduction of dose to the orbit and lacrimal gland, while maintaining the therapeutic dose to the ora serrata retinae and vitreous.

[Retinoblastoma]

Retinoblastomas are the most frequent intraocular tumors in childhood. Untreated, the tumor is almost always fatal. Using a multidisciplinary approach combining the efforts of ophthalmologists, radiation oncologists, pediatric oncologists and geneticists a survival rate of more than 95% can be achieved. Molecular genetic research on the origin of retinoblastomas has substantially helped in our understanding of the origin of malignant tumors in general, as well as to the key role of the Rb-1 gene as a tumor suppressor.

Proton radiation therapy for retinoblastoma: Comparison of various intraocular tumor locations and beam arrangements

PURPOSE

To study the optimization of proton beam arrangements for various intraocular tumor locations; and to correlate isodose distributions with various target and nontarget structures.

METHODS AND MATERIALS

We considered posterior-central, nasal, and temporal tumor locations, with straight, intrarotated, or extrarotated eye positions. Doses of 46 cobalt grey equivalent (CGE) to gross tumor volume (GTV) and 40 CGE to clinical target volume (CTV) (2 CGE per fraction) were assumed. Using three-dimensional planning, we compared isodose distributions for lateral, anterolateral oblique, and anteromedial oblique beams and dose-volume histograms of CTVs, GTVs, lens, lacrimal gland, bony orbit, and soft tissues.

RESULTS

All beam arrangements fully covered GTVs and CTVs with optimal lens sparing. Only 15% of orbital bone received doses > or =20 CGE with a lateral beam, with 20-26 CGE delivered to two of three growth centers. The anterolateral oblique approach with an intrarotated eye resulted in additional reduction of bony volume and exposure of only one growth center. No appreciable dose was delivered to the contralateral eye, brain tissue, or pituitary gland.

CONCLUSIONS

Proton therapy achieved homogeneous target coverage with true lens sparing. Doses to orbit structures, including bony growth centers, were minimized with different beam arrangements and eye positions. Proton therapy could reduce the risks of second malignancy and cosmetic and functional sequelae.

Continuing challenges in the management of retinoblastoma with chemotherapy

The management of retinoblastoma has gradually changed over the past 10 years. Over 95% of children with retinoblastoma in the United States are cured with modern techniques. The challenge remains, however, in maintaining the eye and vision. There is a trend away from enucleation and external beam radiotherapy toward focal conservative treatments involving primary chemoreduction in conjunction with thermotherapy and cryotherapy. This is related to earlier detection of the disease, recognition of more effective chemotherapeutic agents, more focused local treatment modalities, and, most importantly, knowledge of the long-term risks of external beam radiotherapy. Enucleation is still preferable for retinoblastoma that fills most of the eye, especially when the disease is unilateral or when there is concern for tumor invasion into the optic nerve, choroid, or orbit. The orbital integrated implant is placed after enucleation and provides acceptable prosthesis motility and appearance. External beam radiotherapy is still vital for treating advanced retinoblastoma, especially when there is diffuse vitreous or subretinal seeding after failure of other methods and preservation of vision is a priority. The most important recent advance in the management of retinoblastoma is the use of intravenous chemotherapy for tumor reduction, a technique of neoadjuvant chemotherapy termed "chemoreduction." This is followed by tumor consolidation with focal measures such as thermotherapy, cryotherapy, and plaque radiotherapy. This strategy provides reduced tumor volume and often permits consolidation with methods other than radiotherapy. It appears that vision can be preserved in some cases with these methods, avoiding some of the local complications like radiation cataract or macular edema that have been found with radiotherapy techniques. External beam radiotherapy and enucleation can now be avoided in most cases of Reese-Ellsworth groups I (minimal disease) through IV (moderate disease) retinoblastoma. The most advanced stage of retinoblastoma, Reese-Ellsworth group V, continues to provide the greatest difficulty for management, and external beam radiotherapy and enucleation are often employed in addition to chemoreduction to save the child's life. A collaborative prospective study in North America is currently under way to further study the benefits and risks of chemoreduction for minimal, moderate, and advanced retinoblastoma.

T1 Gd-enhanced compared with CISS sequences in retinoblastoma: superiority of T1 sequences in evaluation of tumour extension

BACKGROUND

As adequate therapy for retinoblastoma in young children depends on infiltration of extra-retinal structures, diagnostic modalities play an essential role.

METHODS

In this widely extended study, 80 children with retinoblastoma were studied with MRI (standard fat-suppressed Gd-enhanced T1, T2 thin-slice sequences (additionally with small loop surface coil), constructive interference in steady state (CISS) sequence covering the orbita). The images were analysed by two blinded neuroradiologists. Histology was used as the gold standard.

RESULTS

MRI assumed infiltration of extra-retinal structures in 13 of 80 patients of which ten were confirmed by histology. Affected extra-retinal structures were: optic nerve (five, of which two were on CISS and three on T1 with higher image resolution using the surface coil), scleral infiltration (five, of which four on CISS and T1) and ciliary body infiltration (one on CISS and T1). Another 61 enucleated patients did not have any extra-retinal infiltration in histology. The CISS sequence with multiplanar reconstruction was mainly helpful in revealing exact three-dimensional tumour extension with excellent clinical acceptance and pre-surgical planning but T1 fat-suppressed Gd-enhanced images were superior in revealing exact tumour extension.

CONCLUSION

CISS sequences allow to produce excellent anatomical images and to perform multiplanar reconstruction to better demonstrate tumour extension. However, T1-weighted sequences after contrast application are more sensitive (60 versus 40%) in detecting infiltration of the optic nerve but equal in detecting scleral infiltration.

Causes of chemoreduction failure in retinoblastoma and analysis of associated factors leading to eventual treatment with external beam radiotherapy and enucleation

PURPOSE

To evaluate the causes of chemoreduction failure in retinoblastoma and to analyze the associated factors for eventual treatment with external beam radiotherapy and enucleation.

DESIGN

Prospective noncomparative case series.

PARTICIPANTS

Seventy-one patients with 105 eyes with intraocular retinoblastoma that underwent chemoreduction therapy between October 1998 and January 2003.

INTERVENTION

A 6-treatment cycle of chemoreduction therapy with vincristine, etoposide, and carboplatin was administered at monthly intervals. Unresponsive disease was defined as persistence of retinal tumors, vitreous seeds, or subretinal seeds after the second treatment cycle, with no appreciable sign of regression. Eyes with unresponsive disease were enucleated after the second treatment. Eyes that responded to chemoreduction therapy received focal treatment, including indirect laser photocoagulation, transpupillary thermotherapy, cryotherapy, and ruthenium 106 episcleral plaque radiotherapy after the second chemoreduction treatment, if necessary, to achieve complete tumor regression. Recurrence was defined as the regrowth of retinal tumors, vitreous or subretinal seeds after an initial favorable response, and regression. Recurrent retinal tumor, vitreous seeds, or subretinal seeds were treated with focal treatments and 2 to 3 additional chemoreduction treatments. When these methods failed or were not applicable, external beam radiotherapy and/or enucleation was administered.

MAIN OUTCOME MEASURES

The use of external beam radiotherapy and enucleation for chemoreduction failure, which was defined as unresponsive or recurrent disease.

RESULTS

The mean follow-up was 25.7 months (range: 6-49). Ten of 105 eyes (9.5%) with unresponsive disease were enucleated after the second treatment. Of the remaining 95 eyes, 42 (44.2%) developed recurrence after chemoreduction. Recurrent disease failing to be treated successfully by other methods was treated with external beam radiotherapy in 26 of 95 eyes (27.4%) and enucleation in 22 of 95 eyes (23.2%). External beam radiotherapy was successful in preventing enucleation in 20 of 26 eyes (76.9%). Overall, the globe salvage rate was 69.5%, ranging from 36.1% for Reese-Ellsworth group V disease to 87.0% for groups I to IV disease. Histopathologically, 29 of 31 enucleated eyes (93.5%) had poorly differentiated or moderately differentiated retinoblastoma. Using multivariate logistic regression analysis, factors predictive of eventual treatment with external beam radiotherapy were female gender (P = 0.010), presence of subretinal seeds (P = 0.023), and a greater number of chemoreduction treatments (P = 0.027). By multivariate analysis, the factors associated with the need for eventual treatment with enucleation were recurrence of retinal tumors (P = 0.004), presence of vitreous seeds (P = 0.008), greater tumor thickness (P = 0.015), presence of subretinal fluid (P = 0.040), and older patient age (P = 0.042).

CONCLUSIONS

Chemoreduction failure in this article was defined as unresponsive or, more commonly, recurrent retinoblastoma. Older patient age, greater tumor thickness, presence of vitreous seeds and subretinal fluid at baseline, and retinal tumor recurrence after chemoreduction were factors associated with the need for enucleation.

Retinoblastoma in Victoria, 1976-2000: changing management trends and outcomes

PURPOSE

To describe changes in the management of retinoblastoma in Victoria and to review the effect of newer, conservative treatments on preservation of eyes, visual outcome and mortality by comparing a similar group of patients treated over successive time intervals.

METHODS

A retrospective analysis of all cases of retinoblastoma diagnosed and treated in Victoria between 1956 and 2000 was conducted. Historical data on 77 cases previously published by O'Day et al. was used for the period 1956-1976 (series 1). Data on 88 cases recorded in the Royal Children's Hospital (Melbourne) Retinoblastoma Database was used for the period 1976-2000. The latter group was subdivided into those treated between 1976 and 1989 (series 2), prior to the advent of modern eye saving treatments, and those treated subsequent to their introduction from 1990 to 2000 (series 3).

RESULTS

In unilateral retinoblastoma, final enucleation rates for 1956-1976 (series 1) and 1976-1989 (series 2) were almost identical, being 98% and 97% of affected eyes, respectively (P = 1.00). Despite the newer treatments used after 1990 (series 3), 88% of affected eyes were still enucleated, representing a statistically similar outcome to series 2 (P = 0.33). In bilateral retinoblastoma, primary enucleation of the more involved eye was similar for series 1 (84%) and 2 (80%) but series 3 (41%) was substantially less than series 2 (P = 0.04) following the increased use of conservative treatments. In series 3, 59% of more involved eyes were treated conservatively compared with 16% (P = 0.007) and 20% (P = 0.04) for series 1 and 2, respectively. Despite attempts at eye salvage, the failure rate was higher in series 3 (29%) yielding a final enucleation rate of 70%, which represented a modest downward trend in the numbers of eyes finally enucleated; 84% (series 1), 73% (series 2) and 70% (series 3) (test for trend, P = 0.33). Bilateral enucleation rates were significantly lower, from 36% and 30% in series 1 and 2, respectively, to 7% in series 3 (test for trend, P = 0.02). As a consequence, more eyes were preserved over time, being 20/50 (40%) in series 1, 15/30 (50%) in series 2 and 21/34 (62%) in series 3. Comparison of visual outcome was hampered by incomplete data in series 1 but it appeared series 2 and 3 achieved better visual acuities with 67% and 62% of preserved eyes in bilateral cases measuring equal to or better than 6/12. Mortality rates in all series were low, being 7.8% in series 1, 4.5% in series 2 and nil in series 3.

CONCLUSIONS

Following the introduction of new conservative treatments, there has been an increase in preservation of eyes and improved visual outcome, and a dramatic decrease in numbers of bilateral enucleations without adversely affecting survival.

Globe conserving treatment of the only eye in bilateral retinoblastoma

AIMS

To quantify the rates of eye preservation and patient survival, local tumour relapse and recurrence, and development of new tumours in the remaining eye of children with bilateral retinoblastoma with one eye already enucleated. Also, in the same children, to describe the types of primary and secondary treatment procedures, and to define the anatomical outcome.

METHODS

This is a retrospective observational case series report. The study participants consisted of 107 patients with bilateral retinoblastoma with one eye enucleated within 1 month of baseline examination and had their remaining eye treated conservatively. The main outcome measure were: primary treatment failures, new tumours, enucleation of the only eye, death, remission, and anatomical outcomes (retinal detachment, vitreous haemorrhage, and cataract).

RESULTS

The median age at diagnosis was 8.4 (range 0.2-44, SD 10.1) months with a median ophthalmic follow up of 44.3 (8.1-114, SD 10.1) months. In 22 of the 107 patients (21%) the treated eye was in Reese Ellsworth groups I or II and in the remaining 85 (79%) in groups III-V at diagnosis. The primary treatment was cryotherapy in 14% (15/107) of eyes, radioactive plaque brachytherapy in 3.7% (4/107), and chemotherapy in 10% (11/107). It was lens sparing radiotherapy in 37% (40/107), whole eye radiotherapy in 29% (31/107), combined radiotherapy and chemotherapy in 2.8% (3/107), chemothermotherapy in 0.9% (1/107), and combined focal therapy in 1.8% (2/107). The primary treatment failed to achieve local tumour control during the follow up period in 37% (40/107) of eyes. In 17 eyes failure was due to inadequate control of the presenting tumour, in 16 to development of a new tumour, and in eight eyes to a combination of both. 35 (88%) of the 40 failures were managed by secondary conservative treatment and the remaining five were treated by enucleation of the only eye. There were eight (7.4%) deaths and the 3 year survival rate was 93% (100/108). Anatomical results included vitreous haemorrhage in four cases, tractional retinal detachment also in four cases, and 24 children required cataract surgery.

CONCLUSIONS

Aggressive conservative treatment achieved a good rate of globe salvage without impairing survival.

Retinoblastoma: review of 30 years' experience with external beam radiotherapy

A review of the experience at the Peter MacCallum Cancer Centre (Peter Mac), Melbourne, Australia in treating retinoblastoma with external beam radiotherapy was conducted. Outcomes of particular interest were tumour control, vision preservation and treatment late effects. The review was restricted to patients that had intact eyes treated at Peter Mac from 1965 until 1997 with at least 2 years of follow up. Histories were reviewed regarding patient and tumour characteristics and treatment details. Thirty-five patients were identified in whom 47 eyes were treated. Of the tumours, 47% were Reese-Ellsworth stage IV or V and the majority of others were at high risk for vision loss because of tumour location. The radiation treatment technique became increasingly sophisticated during the study period. Radiation dose and fraction size have similarly evolved but most patients received 30-50 Gy. Since 1989, a highly accurate contact lens immobilization technique has been used to deliver 40 Gy in 20 fractions. Thirteen eyes required additional local therapy. Of the treated eyes, 34 (72%) remain intact and 74% of these have useful vision. One patient died from retinoblastoma and three from second malignant neoplasms. With modern radiotherapy, late toxicities other than growth arrest and non-progressive cataract did not occur during the study period. Tumour control was high and a very acceptable rate of organ and vision preservation was achieved in a relatively high-risk population. Modern radiotherapy continues to develop in an attempt to improve treatment accuracy and minimize late radiation toxicity.

Treatment of intraocular retinoblastoma with vincristine and carboplatin

PURPOSE

To evaluate the efficacy of chemoreduction using vincristine and carboplatin in preventing or delaying external-beam radiotherapy (EBRT) or enucleation in patients with intraocular retinoblastoma.

PATIENTS AND METHODS

Twenty-five patients (43 eyes) with newly diagnosed intraocular retinoblastoma received primary treatment with eight courses of vincristine and carboplatin. Focal treatments were delayed until documentation of disease progression. Outcome measures for each eye were length of time to disease progression, avoidance or delay of EBRT, and globe survival. Event-free survival was defined as the length of time to EBRT or enucleation.

RESULTS

Disease in all eyes responded to chemotherapy and progressed in only two patients before completion of the eight courses of therapy. Disease in all but four eyes progressed and required focal treatments. Event-free survival estimates at 2 years were 59.2% +/- 12.0% for Reese-Ellsworth group I, II, and III eyes and 26.3% +/- 9.2% for group IV and V eyes. Nineteen eyes (44.2%) required EBRT and 13 eyes (30.2%) were enucleated. The ocular salvage rate was 83.3% for Reese-Ellsworth group I to III eyes and 52.6% for group IV and V eyes. For those patients receiving EBRT, the median time from enrollment to EBRT was 9.5 months (median age at EBRT, 21 months).

CONCLUSION

In combination with appropriate early intensive focal treatments, chemoreduction with vincristine and carboplatin, without etoposide, may be an alternative treatment for patients with early-stage intraocular retinoblastoma, although additional studies are needed. Patients with advanced intraocular disease require more aggressive treatments.

High resolution magnetic resonance imaging of retinoblastoma

BACKGROUND/AIMS

Diagnosis of retinoblastoma is mainly based on indirect ophthalmoscopy, but additional imaging techniques are indispensable for the staging of the disease. A new high resolution magnetic resonance imaging (MRI) technique for the examination of the eye was evaluated. A new surface coil with a diameter of 5 cm allows a field of view of 60 mm with an in-plane resolution of 0.8 mm. We compared preoperative MRI scans with the histology after enucleation in 21 cases of retinoblastoma. Parameters studied were appearance of retinoblastoma, choroidal and scleral infiltration, extraocular extension, optic nerve infiltration, and vitreous seeding.

RESULTS

All retinoblastomas could be visualised as hypointense to vitreous on T2 weighted images and slightly hyperintense to vitreous on plain T1 weighted images with a moderate enhancement after contrast application. Histology revealed seven cases with infiltration of the optic disc or optic nerve. Preoperative MRI scans depict juxtapapillary tumour masses, but it was impossible to differentiate between a juxtapapillary retinoblastoma, a prelaminar infiltration of the optic disc, or a just postlaminar optic nerve infiltration. In five of 14 cases with a proved tumour infiltration of the choroid, MRI scans showed an inhomogeneous contrast enhancement of the choroid in enhanced T1 weighted sequences beneath the retinoblastoma. Whether this sign is specific for a choroidal infiltration or is just an artefact remains unclear. High resolution MRI scans did not allow the exclusion of this form of intraocular tumour extension. All nine cases with proved vitreous seeding were not detected by MRI scans. None of these cases showed scleral infiltration or orbital tumour extension. Therefore, it is not possible to judge the rank of this technique in detecting orbital tumour growth.

CONCLUSION

The new MRI technique is of limited value in visualisation of prelaminar or postlaminar infiltration of the optic nerve. Advanced choroidal infiltration might be visualised by contrast enhanced T1 weighted MRI scans, but the available spatial resolution did not allow the exclusion this critical form of tumour growth by MRI scans. Nevertheless, high resolution MRI with the new surface coil has superior contrast and spatial resolution compared to computed tomograph (CT) or other available imaging techniques. MRI cannot replace CT in detecting tumour calcification but with increasing experience with this new technique it should be possible to renounce CT scans in the majority of cases of retinoblastoma.

Proton radiotherapy for paediatric tumours: potential areas for clinical research

Radiotherapy plays an important role in the management of children with cancer. The aim is to achieve local tumour control while minimizing long-term effects. In the treatment of tumours of the central nervous system (CNS) the most important long-term effects are neuropsychological. Elsewhere orthopaedic long-term effects may compromise function or be cosmetically harmful. Proton therapy has the potential for homogeneous irradiation of the target volume while reducing the magnitude and/or extent of the low dose area outside the target volume. This may be clinically relevant for long-term effects in children. Proton radiotherapy has an established role in the treatment of children with chordomas and chondrosarcomas of the base of skull. Planning studies have demonstrated the potential for improving the therapeutic ratio for radiotherapy for tumours of the central nervous system by achieving a uniform dose within the target volume while minimizing the severity of neuropsychological sequelae. Clinical experience of proton radiotherapy for children remains limited with potential areas for clinical research.

Orbital growth retardation in retinoblastoma survivors: work in progress

BACKGROUND

Orbital growth retardation, after enucleation and/or external beam radiation for retinoblastoma (RB), is a serious late effect. We measured orbital volumes of RB survivors treated at Hadassah University Hospital, Jerusalem, between 1980-1998.

PROCEDURE

Forty-five orbits of 28 children with RB (17 bilateral, 11 unilateral) were examined. Thirty-six orbits were irradiated, 19 enucleated, and 10 both enucleated and irradiated. The orbital volumes were calculated from a three-dimensional orbital CT reconstruction. The orbits of RB survivors were compared to age-matched controls.

RESULTS

The mean age at diagnosis was 13 months, mean follow-up time was 56 months. The mean volume of RB orbits (14.4 cc) was statistically significantly smaller than control orbits (17.8 cc). There was no difference between the mean volume of orbits treated with enucleation, irradiation or both. The orbital volume of children treated before the age of 12 months was statistically significantly smaller than those treated later. There was no difference between mean volume of fellow orbits in unilateral RB and controls. The mean orbital asymmetry index in control children (2.6%) was statistically significantly smaller than in RB survivors (14%).

CONCLUSIONS

There was a significant orbital growth retardation after enucleation and/or irradiation for RB. There was no difference between mean orbital volumes after enucleation, radiation or both. Orbital growth retardation was most prominent in children treated in the first year of life. Although small in number, our study suggests that deferring enucleation and/or irradiation until after the age of 12 months may reduce long-term complications.

Echography of retinoblastoma: histopathologic correlation and serial evaluation after globe-conserving radiotherapy or chemotherapy

PURPOSE

To assess the sensitivity of echography in detecting retinoblastoma, compare tumor features observed by echography with histopathology data, and assess the usefulness of echography in serially following retinoblastoma tumors after globe-conserving treatments.

METHODS

The medical and echography records of all patients treated for retinoblastoma at the Bascom Palmer Eye Institute between 1991 and 1997 were reviewed. All eyes underwent pretreatment echographic evaluation, and eyes treated with external beam radiotherapy, brachytherapy, or chemotherapy underwent serial follow-up echography.

RESULTS

Sixty-nine eyes of 48 patients were identified. Echography demonstrated evidence of retinoblastoma in 69 of 69 (100%) eyes and calcification in 63 (91.3%) eyes. Histopathology was superior to echography in detecting optic nerve invasion, extraocular extension, and presence of calcification.

CONCLUSION

Echography is a useful adjunct to indirect ophthalmoscopy in establishing the diagnosis of retinoblastoma. While not as specific as histopathology, echographic evaluation before and after treatment of retinoblastoma permits monitoring of treatment response and may aid in detecting recurrent tumor growth or failure to respond to treatment.

Chemotherapy for retinoblastoma: a current topic

Retinoblastoma is the most common primary intraocular tumour in children, with an incidence of 1 in 15,000 live births. Treatment strategies for retinoblastoma have gradually evolved over the past few decades. There has been a trend away from enucleation (removal of the eye) and external beam radiation therapy toward focal 'conservative' treatments. Every effort has been made to save the child's life with preservation of eye and sight, if possible. Primary enucleation continues to be the commonly used method of treatment for retinoblastoma. It is employed in situations where eyes contain large tumours, long standing retinal detachments, neovascular glaucoma and suspicion of optic nerve invasion or extrascleral extension. Most of these eyes either have or are expected to have no useful vision. Radiation therapy continues to be an effective treatment option for retinoblastoma. However, external beam radiotherapy has unfortunately been associated with secondary non-ocular cancers in the field of radiation (primarily in children carrying the RB-1 germline mutation). Ophthalmic plaque brachytherapy has a more focal and shielded radiation field, and may carry less risk. Unfortunately, its applicability is limited to small to medium-sized retinoblastomas in accessible locations. Cryotherapy and transpupillary thermotherapy (TTT) have been used to provide control of selected small tumours. TTT is an advanced laser system adapted to the indirect ophthalmoscope which provides flexible nonsurgical treatment for small retinoblastomas. Recent research in the treatment of retinoblastoma has concentrated on methods of combining chemotherapy with other local treatment modalities (TTT, radiotherapy, cryotherapy). This approach combines the principle of chemotherapeutic debulking in paediatric oncology with conservative focal therapies in ophthalmology. Termed chemoreduction, intravenous or subconjunctival chemotherapy is used to debulk the initial tumour volume and allow for local treatment with TTT, cryotherapy and plaque radiotherapy. Cyclosporin has been added to the chemotherapy regimen in several centres. Other clinical settings where chemotherapy is considered are situations where the histopathology suggests a high risk for metastatic disease and where there is extraocular extension. There is no consensus that chemotherapy is needed when choroidal invasion is observed on histopathology. However, in patients where the retinoblastoma is noted beyond the cut end of the optic nerve or if there is disruption of the sclera with microscopic invasion of the orbital tissue, treatment has been helpful. Systemic and intrathecal chemotherapy with local and cranial radiotherapy has improved the survival of these patients. Most recently, the use of new chemotherapy modalities with haematopoietic stem cell rescue or local radiotherapy has increased the survival of patients with distant metastasis. Nevertheless, the prognosis of patients with central nervous system involvement is still poor.

Recent developments in the management of retinoblastoma

The management of retinoblastoma has gradually changed over the past few decades. There is a trend away from enucleation and external beam radiotherapy toward focal conservative treatments. This is primarily because of earlier detection of the disease and more focused treatment modalities. Enucleation is still employed for retinoblastoma that fills most of the eye, especially when there is a concern for tumor invasion into the optic nerve or choroid. After enucleation, an integrated orbital implant, provides improved motility and appearance of the prosthesis. External beam radiotherapy continues to be an important method of treating less advanced retinoblastoma, especially when there is diffuse vitreous or subretinal seeding. Plaque radiotherapy is useful for controlling small- to medium-sized retinoblastomas, even those with focal vitreous seeds. Tumors that recur after failure of other methods are often suitable for plaque treatment. When plaque radiotherapy is employed in a child receiving chemotherapy, eventual radiation retinopathy can occur. Cryotherapy and photocoagulation provide excellent control of selected small tumors. Advanced laser delivery systems, particularly those that have been adapted to the indirect ophthalmoscope, have facilitated the visualization for treatment of tumors. Thermotherapy is the newest focal method for retinoblastoma. When combined with chemotherapy, thermotherapy provides satisfactory tumor control, leaving the child with a reasonably small scar, thus preserving more vision. Chemoreduction, using intravenous or subconjunctival routes, is often employed to reduce initial tumor volume and thus allow for focal treatment to eradicate the residual smaller tumor. Many children with advanced retinoblastoma can be spared external beam radiotherapy and enucleation mostly as a result of chemoreduction and focal methods. Chemoreduction combined with cryotherapy, thermotherapy, and plaque radiotherapy plays an important role in the current management of many children with retinoblastoma.

Choroidal hemangiomas: visual and anatomic results of treatment by photocoagulation or radiation therapy

PURPOSE

Choroidal hemangioma is a benign hamartoma that causes accumulation of subretinal fluid and resultant visual loss. Although photocoagulation can result in resolution of subretinal fluid, some have found that recurrence is common and final visual acuity often is poor. The purpose of this study is to evaluate the visual and anatomic results of radiation therapy and photocoagulation in treating patients with visual loss from choroidal hemangiomas.

METHODS

A retrospective review was performed of patients with circumscribed choroidal hemangiomas (CCH) or diffuse choroidal hemangiomas (DCH) treated for visual loss caused by accumulation of subretinal fluid. Of 23 patients with CCH, 13 were treated by photocoagulation, 8 by plaque brachytherapy, and 2 by lens-sparing external beam radiation therapy (LSRT). All five patients with DCH were treated by LSRT.

RESULTS

Of patients with CCH treated by brachytherapy, six (75%) of eight had visual acuity of 6/12 or better at 1 year and 8 (100%) of 8 had no subretinal fluid. Of patients with CCH treated by photocoagulation, 5 (38%) of 13 had visual acuity of 6/12 or better at 1 year and 6 (46%) of 13 had no subretinal fluid. Of patients with CCH treated by LSRT, none of two had visual acuity of 6/12 or better at 1 year and one of two had no subretinal fluid. Of the five patients with DCH treated by LSRT, all had complete resolution of subretinal fluid. Two had marked visual improvement and in the other three, vision was stabilized.

CONCLUSIONS

Plaque brachytherapy is an effective alternative to photocoagulation for treatment of subretinal fluid caused by CCH. Lens-sparing external beam radiation therapy is effective treatment in patients with DCH.

Radiation therapy for retinoblastoma: a retrospective review of 120 patients

PURPOSE

To characterize the patient population and treatment outcomes in patients with Retinoblastoma (RB) referred for External Beam Orbital Radiotherapy (EBORT) to King Faisal Specialist Hospital & Research Centre (KFSH&RC), Riyadh, Saudi Arabia from 1976 to 1993.

METHODS AND MATERIALS

A retrospective study of 120 patients with RB affecting a total of 192 eyes. Patients were divided into three groups. Group A are 60 patients (64 eyes) treated with EBORT to the intact eye to preserve vision. Reese-Ellsworth (RE) Staging was: 1: 12%; 2: 10%; 3: 12%; 4: 23%; and 5: 43%. Twenty-eight patients (47%) also received Vincristine, Adriamycin, and Cyclophosphamide chemotherapy (C/T). Mean follow-up, per patient, was 48.5 months. Standard treatment until 1992 was 45 Gy in 12 fractions of 3.75 Gy, three times weekly over 18 days. Assuming the alpha/beta ratio for early effects and tumor control at 10, Tk = 21 days, Tpot = 5 days, then the Biological Equivalent Dose (BED) was 62 Gy10 for early effects, and 101 Gy3 for late effects. Group B are 28 patients (28 eyes) treated for curative intent with EBORT to the orbit for locally advanced disease, usually after enucleation (24 eyes). Nineteen patients (83%) also had C/T. Mean follow-up was 22.6 months. Group C are 37 patients with advanced disease treated with radiotherapy for palliation. Seventeen (46%) also received C/T. Mean follow-up was 11.7 months.

RESULTS

Group A-following EBORT useful vision was retained in RE Stage 1 to 5: 7 of 7, 6 of 6, 4 of 8, 10 of 15, and 7 of 28 eyes, respectively. There was no significant difference between patients who received adjuvant chemotherapy and those who did not. Complications included cataract (27%), retinopathy (25%), vitreous hemorrhage (19%), and orbital deformities (11%). In Group B the local control rate was 71%. In Group C, 10 (27%) of the 37 patients were alive at last contact, and 27 (73%) were either terminal or dead of disease. None of Group A or B patients had positive CSF cytology, bone scan, or bone marrow examination. In Group C 19% had positive CSF cytology, and bone marrow, and 14% had a positive bone scan.

CONCLUSIONS

1) EBORT preserved useful vision in a significant proportion of patients even in eyes with advanced RE Stage RB, but longer follow-up is likely to reveal an even higher complication rate with this regime. 2) High dose per fraction probably contributed to the increased complications. 3) Chemotherapy did not demonstrate any effect on retaining vision in this study. 4) For disease that is confined to within the eye clinically and radiologically, invasive procedures for CSF cytology, bone marrow examination, and bone scan do not seem warranted. 5) The optimum technique, fractionation, and dosage for RB is still not well defined.

External beam radiotherapy for retinoblastoma: I. Whole eye technique

A retrospective analysis has been performed of the results of external beam radiotherapy for retinoblastoma using a whole eye technique. Local tumour control has been assessed in a consecutive series of 175 eyes in 142 children all of whom received external beam radiotherapy as the primary treatment for retinoblastoma. Follow up ranged from 2 to 17 years (median 9 years). Tumour control rates have been analysed with respect to the Reese Ellsworth classification and the series includes eyes in groups I to V. Focal salvage therapy was given for persistent, recurrent, or new tumours after radiotherapy. Following whole eye radiotherapy alone, the overall ocular cure rate was 57%, though with salvage therapy 80% of eyes could be preserved.