A high-risk retinoblastoma subtype with stemness features, dedifferentiated cone states and neuronal/ganglion cell gene expression

Retinoblastoma is the most frequent intraocular malignancy in children, originating from a maturing cone precursor in the developing retina. Little is known on the molecular basis underlying the biological and clinical behavior of this cancer. Here, using multi-omics data, we demonstrate the existence of two retinoblastoma subtypes. Subtype 1, of earlier onset, includes most of the heritable forms. It harbors few genetic alterations other than the initiating RB1 inactivation and corresponds to differentiated tumors expressing mature cone markers. By contrast, subtype 2 tumors harbor frequent recurrent genetic alterations including MYCN-amplification. They express markers of less differentiated cone together with neuronal/ganglion cell markers with marked inter- and intra-tumor heterogeneity. The cone dedifferentiation in subtype 2 is associated with stemness features including low immune and interferon response, E2F and MYC/MYCN activation and a higher propensity for metastasis. The recognition of these two subtypes, one maintaining a cone-differentiated state, and the other, more aggressive, associated with cone dedifferentiation and expression of neuronal markers, opens up important biological and clinical perspectives for retinoblastomas.

Retinoblastoma for Pediatric Ophthalmologists

Retinoblastoma can present in 1 or both eyes and is the most common intraocular malignancy in childhood. It is typically initiated by biallelic mutation of the RB1 tumor suppressor gene, leading to malignant transformation of primitive retinal cells. The most common presentation is leukocoria, followed by strabismus. Heritable retinoblastoma accounts for 45% of all cases, with 80% being bilateral. Treatment and prognosis of retinoblastoma is dictated by the disease stage at initial presentation. The 8th Edition American Joint Committee on Cancer (AJCC) TNMH (tumor, node, metastasis, heritable trait) staging system defines evidence-based clinical and pathological staging for overall prognosis for eye(s) and child. Multiple treatment options are available in 2018 for retinoblastoma management with a multidisciplinary team, including pediatric ocular oncology, medical oncology, radiation oncology, genetics, nursing, and social work. Survival exceeds 95% when disease is diagnosed early and treated in centers specializing in retinoblastoma. However, survival rates are less than 50% with extraocular tumor dissemination. We summarize the epidemiology, genetics, prenatal screening, diagnosis, classification, investigations, and current therapeutic options in the management of retinoblastoma.

Histopathologic grading of anaplasia in retinoblastoma

PURPOSE

To determine whether the degree of tumor anaplasia has prognostic value by evaluating its correlation with high-risk histopathologic features and clinical outcomes in a series of retinoblastoma patients.

DESIGN

Retrospective clinicopathologic study.

METHODS

The clinical and pathologic findings in 266 patients who underwent primary enucleation for retinoblastoma were reviewed. The histologic degree of anaplasia was graded as retinocytoma, mild, moderate, or severe as defined by increasing cellular pleomorphism, number of mitoses, nuclear size, and nuclear hyperchromatism. Nuclear morphometric characteristics were measured. The clinical and pathologic data of 125 patients were compared using Kaplan-Meier estimates of survival. Fisher exact test and multivariate regression were used to analyze the association between anaplasia grade and high-risk histologic features.

RESULTS

Increasing grade of anaplasia was associated with decreased overall survival (P = .003) and increased risk of metastasis (P = .0007). Histopathologic features that were associated with anaplasia included optic nerve invasion (P < .0001), choroidal invasion (P < .0001), and anterior segment invasion (P = .04). Multivariate analysis considering high-risk histopathology and anaplasia grading as predictors of distant metastasis and death showed that high-risk histopathology was statistically significant as an independent predictor (P = .01 for metastasis, P = .03 for death) but anaplasia was not (P = .63 for metastasis, P = .30 for death). In the absence of high-risk features, however, severe anaplasia identified an additional risk for metastasis (P = .0004) and death (P = .01).

CONCLUSION

Grading of anaplasia may be a useful adjunct to standard histopathologic criteria in identifying retinoblastoma patients who do not have high-risk histologic features but still have an increased risk of metastasis and may need adjuvant therapy.

High-risk retinoblastoma based on international classification of retinoblastoma: analysis of 519 enucleated eyes

PURPOSE

To determine the correlation between the International Classification of Retinoblastoma (ICRB) and histopathologic high-risk retinoblastoma.

DESIGN

Retrospective study.

PARTICIPANTS

A total of 519 patients.

INTERVENTION

Primary enucleation.

MAIN OUTCOME MEASURES

High-risk retinoblastoma, metastasis, and death.

RESULTS

Of 519 primarily enucleated eyes, 87 (17%) were classified as group D and 432 (83%) were classified as group E on the basis of the ICRB. High-risk retinoblastoma was identified in 23% (117/519) of enucleated eyes, including 17% (15/87) group D and 24% (102/432) group E eyes. High-risk histopathologic features of retinoblastoma included anterior chamber involvement (5/15 [33%] group D eyes, 31/102 [30%] group E eyes), isolated massive posterior uveal invasion ≥ 3 mm (7/15 [47%] group D eyes, 22/102 [22%] group E eyes), isolated post-laminar optic nerve invasion (2/15 [13%] group D eyes, 46/102 [45%] group E eyes), and any combination of posterior uveal invasion and optic nerve involvement (7/15 [47%] group D eyes, 37/102 [36%] group E eyes). On logistic regression analysis, massive posterior uveal invasion ≥ 3 mm was more common in group D eyes (P = 0.0442), and post-laminar optic nerve invasion was more common in group E eyes (P = 0.0390). Of 117 patients with high-risk retinoblastoma, systemic adjuvant chemotherapy was administered in 83 patients (71%). Systemic metastasis developed in 0% (0/15) of those with high-risk group D retinoblastoma and 10% (10/102) of those with high-risk group E retinoblastoma over a mean follow-up period of 78 months (median, 62 months; range, 1-419 months). There was no metastasis in any patient (n = 402) classified with non-high-risk retinoblastoma. Of the 10 patients who developed metastasis, 4 had received prior adjuvant chemotherapy and 6 had no prior adjuvant chemotherapy. There was no metastasis in high-risk patients treated with vincristine sulphate, etoposide phosphate, and carboplatin (VEC). Death from metastasis occurred in 4% of high-risk patients (5/117).

CONCLUSIONS

On the basis of the ICRB, 17% of group D and 24% of group E eyes are at increased risk for metastatic disease. In this study, 8% of patients developed metastasis. There was no metastasis in any patient classified with non-high-risk retinoblastoma.

FINANCIAL DISCLOSURE(S)

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

Delay in the diagnosis of retinoblastoma in China

PURPOSE

Retinoblastoma is the most frequent primary intraocular tumour and is rapidly gaining importance in Asia. As the survival is markedly dependent on early diagnosis and as information on that is not available from East Asia, we assessed the time interval between symptoms detection and therapy of children treated in the Beijing TongRen Eye Hospital.

METHODS

The retrospective study consisted of all patients who were treated in the study period from January 1987 to November 2006 in the Beijing TongRen Hospital and for whom the data on delay in diagnosis, age, clinical appearance and histological tumour features were available.

RESULTS

The inclusion criteria were met by 572 patients (326 boys) with a mean age of 2.6 ± 1.8. Mean interval between first detection of symptoms and clinical diagnosis and therapy was 4.1 ± 5.9 months (range: 3-36 months). A diagnostic delay of 2 months or >6 months was found for 337 (59%) children and 98 (17%) children, respectively. Diagnostic delay was significantly (p < 0.001) the longest in the 2- to 4-year-old group (5.5 ± 7.4 months). It decreased from the study period 1987-1991 to the period 2002-2006 (p < 0.001). It was significantly associated with the clinical appearance (p = 0.001) and histological finding (p = 0.008).

CONCLUSIONS

Delay in the diagnosis of retinoblastoma depended on the age of the children, study period, and clinical and histological stage. Because the prognosis is markedly influenced by tumour stage, further improvements in the alertness of parents, family doctors and paediatricians and in the medical infrastructure in China may be addressed.

What are the hallmarks of cancer?

The seminal article by Douglas Hanahan and Robert Weinberg on the hallmarks of cancer is 10 years old this year and its contribution to how we see cancer has been substantial. But, in embracing this view, have we lost sight of what makes cancer cancer?

Chemoreduction for group E retinoblastoma: comparison of chemoreduction alone versus chemoreduction plus low-dose external radiotherapy in 76 eyes

PURPOSE

To evaluate chemoreduction (CRD) for group E retinoblastoma.

DESIGN

Retrospective, comparative case series.

PARTICIPANTS

Seventy-six eyes of 56 patients with group E retinoblastoma were treated with CRD alone or CRD plus low-dose prophylactic external beam radiotherapy (CRD+P-EBR). The CRD included vincristine, etoposide, and carboplatin (6 cycles). The P-EBR was given routinely 2 months after completion of CRD at a suggested dose of 2600 cGy. Therapeutic EBR (T-EBR) was only given at the time of extensive tumor recurrence at a suggested dose of 3800 cGy.

METHODS

Retrospective chart review.

MAIN OUTCOME MEASURES

Globe salvage.

RESULTS

Of the 76 eyes, 64 received CRD alone and 12 received CRD+P-EBR. At the 2-year follow-up, globe salvage was achieved in 29 (53%) of 55 eyes in the CRD group and in 10 (91%) of 11 eyes in the CRD+P-EBR group. At 5 years, globe salvage was achieved in 20 (48%) of 42 eyes in the CRD group and in 4 (80%) of 5 eyes in the CRD+P-EBR group (P=0.347). Of the 64 eyes in the CRD group, 16 (25%) were salvaged with CRD alone and 13 (20%) with CRD+T-EBR, whereas 22 (34%) were enucleated after CRD alone and 13 (20%) were enucleated after CRD+T-EBR. Of the 12 eyes in the CRD+P-EBR group, 10 (83%) were salvaged with CRD+P-EBR, whereas 2 (17%) were enucleated and none required T-EBR. The median dose for T-EBR was 3800 cGy, and that for P-EBR was 2600 cGy. Eyes treated with CRD+P-EBR showed significantly less recurrence, leading to less chance of enucleation or therapeutic radiotherapy than that for CRD alone (P<0.001). Visual acuity was 20/100 or better or fix and follow in 9 (32%) of 28 salvaged eyes in the CRD group and in 4 (40%) of 10 in the CRD+P-EBR group. At 5 years, there were no patients in either group with metastasis of pinealoblastoma or who had died. In one patient in the CRD group, a second cancer developed.

CONCLUSIONS

Group E retinoblastoma managed with CRD+P-EBR showed significantly less need for enucleation or therapeutic radiotherapy than eyes treated with CRD alone. These findings merit further study and consideration.

A proposal for an international retinoblastoma staging system

BACKGROUND

Although intra-retinal tumor has long been staged presurgically according to the Reese-Ellsworth (R-E) system, retinoblastoma differs from other pediatric neoplasms in never having had a widely accepted classification system that encompasses the entire spectrum of the disease. Comparisons among studies that consider disease extension, risk factors for extra-ocular relapse, and response to therapy require a universally accepted staging system for extra-ocular disease.

PROCEDURE

A committee of retinoblastoma experts from large centers worldwide has developed a consensus classification that can encompass all retinoblastoma cases and is presented herein. Patients are classified according to extent of disease and the presence of overt extra-ocular extension. In addition, a proposal for substaging considering histopathological features of enucleated specimens is presented to further discriminate between Stage I and II patients.

RESULTS

The following is a summary of the classification system developed-Stage 0: Patients treated conservatively (subject to presurgical ophthalmologic classifications); Stage I: Eye enucleated, completely resected histologically; Stage II: Eye enucleated, microscopic residual tumor; Stage III: Regional extension [(a) overt orbital disease, (b) preauricular or cervical lymph node extension]; Stage IV: Metastatic disease [(a) hematogenous metastasis: (1) single lesion, (2) multiple lesions; (b) CNS extension: (1) prechiasmatic lesion, (2) CNS mass, (3) leptomeningeal disease]. A proposal is also presented for substaging of enucleated Stages I and II eyes.

CONCLUSIONS

The proposed staging system is the product of an international effort to adopt a uniform staging system for patients with retinoblastoma to cover the whole spectrum of the disease.

The International Classification of Retinoblastoma predicts chemoreduction success

PURPOSE

To evaluate the reliability of the International Classification of Retinoblastoma (ICRB) for predicting treatment success with chemoreduction (CRD).

DESIGN

Noncomparative interventional case series.

PARTICIPANTS

Two hundred forty-nine consecutive eyes.

METHODS

All eyes were treated with CRD and were classified according to the ICRB: group A included those eyes with retinoblastoma </=3 mm; group B included those eyes with retinoblastoma >3 mm, macular location, or minor subretinal fluid; group C included those eyes with retinoblastoma with localized seeds; group D included those eyes with retinoblastoma with diffuse seeds; group E included those eyes with massive retinoblastoma necessitating enucleation. The CRD regimen included vincristine, etoposide, and carboplatin for 6 cycles plus local consolidation with thermotherapy or cryotherapy.

MAIN OUTCOME MEASURE

Chemoreduction success, defined as avoidance of external beam radiotherapy or enucleation.

RESULTS

Of the 249 eyes, 23 (9%) were in group A, 96 (39%) were in group B, 21 (8%) were in group C, and 109 (44%) were in group D. In this series, group E eyes were managed with enucleation. Treatment success was achieved in 100% of group A, 93% of group B, 90% of group C, and 47% of group D eyes.

CONCLUSIONS

The ICRB can be of assistance in predicting CRD success for retinoblastoma. Additional treatment methods are necessary to salvage more group D eyes.

Intraocular retinoblastoma: the case for a new group classification

This article argues the case for the creation of a new group classification of intraocular retinoblastoma. The current Reese-Ellsworth group classification has not been updated since it was published 35 years ago. The proposed classification is based on the natural history of intraocular retinoblastoma and on the risk of loss of the eye following primary therapy.

Management of advanced retinoblastoma

This review provides an update on the current management of advanced retinoblastoma.

Outcome following initial external beam radiotherapy in patients with Reese-Ellsworth group Vb retinoblastoma

OBJECTIVE

To describe patient and ocular outcomes following initial treatment with external beam radiotherapy (EBT) in eyes with Reese-Ellsworth group Vb retinoblastoma.

METHODS

Retrospective case series (from January 1, 1979, to February 28, 2002). The Kaplan-Meier method was used to analyze survival (ocular and patient) and incidence (second cancer) data.

RESULTS

Two hundred forty-three patients with 1 or more Reese-Ellsworth group Vb eyes were identified. Of 284 group Vb eyes, 63 (22.2%) initially received EBT, vs 172 (60.6%) that were initially enucleated. Of the 63 radiated group Vb eyes, 31 (49.2%) had no further tumor growth, 26 (41.3%) developed a recurrence, and 8 (12.7%) developed a new tumor. Of the 63 radiated group Vb eyes, 33 (52.4%) developed ocular complications. The ocular survival rate of radiated group Vb eyes was 81.4% at 1 year and 53.4% at 10 years. Twenty-eight radiated group Vb eyes survived to the last follow-up with visual acuity information. Thirteen patients developed second cancers, 11 in the field of radiation. The probability of developing a second cancer following initial EBT for group Vb disease in patients with bilateral disease was 29.7% by 10 years after diagnosis. Survival from second cancers in patients with bilateral disease initially receiving EBT for group Vb disease was 93.6% at 5 years and 52.6% at 18(1/4) years. No patient with unilateral disease developed a second cancer. Deaths due to metastatic retinoblastoma were uncommon.

CONCLUSIONS

To our knowledge, this is the first study focusing exclusively on group Vb eyes treated initially with EBT, most of which were salvaged with vision. Outcome data provided herein are clinically relevant when choosing treatment options for advanced intraocular retinoblastoma.

Chemoreduction for retinoblastoma. Analysis of tumor control and risks for recurrence in 457 tumors

PURPOSE

To evaluate retinoblastoma control following chemoreduction.

DESIGN

Interventional case series.

METHODS

Prospective.

SETTING

Single center trial.

PATIENT POPULATION

457 retinoblastomas in 193 eyes of 125 patients. Nonrandomized, noncomparative study.

INTERVENTION

All patients received intravenous vincristine, etoposide, and carboplatin,. The tumors were managed with chemoreduction alone (group W) or chemoreduction combined with thermotherapy (group X), cryotherapy (group Y), or both thermotherapy and cryotherapy (group Z).

MAIN OUTCOME MEASURE

Tumor recurrence in each treatment group.

RESULTS

Of 457 retinoblastomas, 63 (14%) were in group W, 256 (56%) in group X, 127 (28%) in group Y, and 11 (2%) in group Z. The tumor was located in the macula in 33 (52%) of group W, 109 (43%) of group X, 3 (2%) of group Y, and 9 (1%) of group Z. The mean tumor thickness at initial examination was 7 mm for group W, 4 mm for group X, 2 mm for group Y, and 3 mm for group Z. Using Kaplan-Meier estimates, recurrence of the individual retinoblastoma at 7 years was found in 45% of group W and 18% for combined groups X, Y, and Z. Risk factors predictive of tumor recurrence by multivariate analysis included macular tumor location for all groups and additionally female gender for group W and increasing tumor thickness for groups X, Y, and Z.

CONCLUSIONS

Chemoreduction alone or combined with cryotherapy or thermotherapy is effective for treatment of retinoblastoma, but tumor recurrence rate is highest for those located in the macula and those with greater thickness.

Practical Approach to Management of Retinoblastoma

OBJECTIVE

To present a simplified approach to management of retinoblastoma using basic clinical features.

DESIGN

In a prospective, nonrandomized, single-center clinical trial, 158 eyes of 103 patients with retinoblastoma were managed with 6 cycles of chemoreduction (vincristine sulfate, etoposide, and carboplatin). The eyes were classified according to the Reese-Ellsworth classification and were also grouped on the basis of clinical features as follows: group 1, tumor only; group 2, tumor plus subretinal fluid; group 3, tumor plus focal seeds (3a, focal subretinal seeds; 3b, focal vitreous seeds); group 4, tumor plus diffuse seeds (4a, diffuse subretinal seeds; 4b, diffuse vitreous seeds); and group 5, neovascular glaucoma or invasive retinoblastoma.

MAIN OUTCOME MEASURE

Treatment success (avoidance of enucleation and external beam radiotherapy).

RESULTS

According to the Reese-Ellsworth classification, chemoreduction was successful in 100% of group Ia, 100% of group Ib, 86% of group IIa, 100% of group IIb, 91% of group IIIa, 100% of group IIIb, 50% of group IVa, 77% of group IVb, 50% of group Va, and 27% of group Vb. There was erratic correlation of the Reese-Ellsworth classification with treatment success. In contrast, the simplified grouping system displayed a smooth, nonerratic correlation for treatment success, with 100% success for group 1, 91% for group 2, 59% for group 3, and 12% for group 4 (group 5 always managed by primary enucleation). When all 6 subcategory groups were analyzed, there was consistent correlation for treatment success of 100% for group 1, 91% for group 2, 68% for group 3a, 54% for group 3b, 17% for group 4a, and 11% for group 4b.

CONCLUSION

This practical approach to retinoblastoma using basic clinical features is predictive of treatment success for eyes in which modern conservative therapy for retinoblastoma is used.

Immunohistochemical localization of human pineal tissue antigens in normal retina and retinoblastomas

The normal human retina and retinoblastomas were examined immunohistochemically to assess the localization of pineal antigens in the retina and the oncogenesis and differentiation of retinoblastoma. In the present study, 41 eyes excised from children (aged 4 months to 7 years, all unilateral occurrence) diagnosed to have retinoblastoma and 4 eyes with normal retinas, were used. Retinoblastomas were histopathologically classified into well-differentiated, moderately-differentiated, and poorly-differentiated types. The antibodies used were 9 monoclonal antibodies to human pineal antigens and 6 antibodies to neural tissues. In the normal retina, staining patterns characteristic of retinal cell layers were observed with PP1, PP3, PP5, PP6, PI1, and PI2 antibodies. In retinoblastomas, PP5 antibody, which reacts with horizontal cells and ganglion cells, and PP6 antibody, which reacts with part of the bipolar cells in the inner nuclear layer, showed intense staining in well-differentiated retinoblastomas, but the intensity of staining and the positivity decreased with the degree of dedifferentiation. Antigens recognized by PP3 and PP4 antibodies were positive in all retinoblanstomas. Reactions to GFAP antibody and antibodies that recognize Müller cells were negative. Retinoblanstomas may express markers of not only photoreceptor cells but also other retinal nuclear cells. These results suggest that the retinoblastoma might be developed from visual stem cells, which are common progenitor cells of photoreceptor cells, intermediate neurons, and ganglion cells.

The development of young children with retinoblastoma

OBJECTIVES

To assess the health and development of children with retinoblastoma (RB), or cancer of the retina, and to determine if they are at greater risk for developmental delays than normal children. Specific aims were to determine if type of RB (unilateral vs bilateral), family history, and number of treatment types affected mental and motor development.

DESIGN

Descriptive study based on medical record review and pediatric, psychological, and visual evaluations.

SETTING

Major referral center for patients with RB and early intervention program in a voluntary urban hospital.

SUBJECTS AND METHODS

Fifty-four children younger than 41 months with RB who attend an ophthalmology oncology clinic were recruited for study. Measures included demographic variables such as social class and race/ethnicity, and medical factors such as age at diagnosis (<18 months vs >18 months), type of RB (unilateral or bilateral), family history of RB, and number and types of treatments. All children received a pediatric examination that assessed physical growth and health; a behavioral test of visual acuity using Teller acuity cards; and the Bayley Scales of Infant Development II, a standardized test of mental and motor development. Children found to have delays were referred to intervention services to treat their specific areas of weakness.

RESULTS

Three quarters of the children had had 1 eye enucleated; 51 of 54 had normal vision in at least 1 eye, and the other 3 had partial vision in 1 eye. Except for the RB, 46 children were largely normal in growth and health, and 8 had medical diagnoses that were unrelated to RB or its treatment. The average mental and motor development scores were in the normal range (91.4 +/- 16.3, and 91.1 +/- 13.4) and not significantly lower than the normal population. Twenty-six children were referred for early intervention services, and 21 of 26 were referred for services to improve their visuomotor coordination. Demographic variables were not associated with medical variables or outcome. Children with bilateral RB, in which both eyes are affected, performed significantly less well in motor development, received many more types of treatments, and were more likely to be referred for visuomotor therapy than children with unilateral RB.

CONCLUSIONS

Children with RB generally function normally in terms of physical health and mental and motor development. However, they are more likely to show delays in visuomotor integration. Early developmental evaluations may improve the visuomotor development of children with visual impairment due to RB.

Retinoblastomas in Ibadan Nigeria: II--Clinicopathologic features

Retinoblastomas are primary malignant intraocular neoplasms of childhood displaying photoreceptor differentiation. The present study reviews clinicopathological features of these neoplasms in Ibadan, Nigeria. Clinical, surgical pathology, and histological material of 44 histologically verified cases of retinoblastoma indexed in the Cancer Registry, University of Ibadan were analyzed. Retinoblastomas accounted for 1.1% of all malignant neoplasms and were equally frequent in male and female children. The mean age of our patients at the time of diagnosis was 32.3 months, which exceeds a corresponding age of 16-21.5 months recorded among Caucasian children. Leukocoria was the most common clinical manifestation. Eighteen percent of our patients had bilateral neoplasms. These patients were significantly younger than those with unilateral retinoblastomas. Flexner-Wintersteiner rosettes occurred in 61% and optic nerve involvement in 78% of the cases and the sites of predilection were regional lymph nodes, scalp, jaw, brain, skull, long bones, and gum.

External beam radiotherapy in retinoblastoma: tumor control and comparison of 2 techniques

OBJECTIVE

To investigate eye conservation, local control, and complication rates among children with retinoblastoma treated with 2 different external beam radiotherapy (EBR) techniques.

METHODS

Fifty-eight eyes in 42 patients received EBR as the primary treatment modality for retinoblastoma (median follow-up, 37 months). The EBR technique was relative lens-sparing (RLS) in 26 eyes and modified lateral beam (MLB) in 32 eyes. Both groups were comparable in Reese-Ellsworth retinoblastoma classification. If necessary, patients received focal salvage therapy.

RESULTS

At 24 months, eye conservation rates were 88.5% and 89.1% among eyes treated with RLS and MLB, respectively (P = .40); tumor control rates without salvage therapy were 84.6% and 53.3% (P = .02), respectively. Among eyes with Reese-Ellsworth stage IV and V disease, eye conservation rates were 88%+/-8% and 83%+/-9% at 36 months in the RLS and MLB groups, respectively, and local tumor control rates were 81%+/-10% and 51%+/-12%. Percentages of eyes without cataract at 36 months were 83.1% and 63.0%, respectively (P = .40). Among patients observed for at least 18 months, midfacial hypoplasia developed in 38.5% and 29.4%, respectively (P = .70).

CONCLUSIONS

The EBR technique was associated with high eye conservation and local control rates. Salvage therapy was performed significantly less frequently in the RLS group compared with the MLB group, and complication rates in both groups were similar.

The outcome of chemoreduction treatment in patients with Reese-Ellsworth group V retinoblastoma

OBJECTIVE

To determine the outcome of chemoreduction treatment in patients with Reese-Ellsworth group V retinoblastoma.

METHODS

Prospective analysis of 27 eyes in 22 patients with group V retinoblastoma treated with either 2- or 6-cycle chemoreduction and focal treatment methods (argon laser photocoagulation, transpupillary thermotherapy, cryotherapy, and plaque radiotherapy). The need for external beam irradiation and the eventual globe salvage rate were assessed. Median follow-up was 28 months.

RESULTS

There were 16 eyes in the 2-cycle chemoreduction treatment group and 11 eyes in the 6-cycle chemoreduction treatment group. No significant difference was noted between the 2 groups with respect to baseline patient and eye findings. After chemoreduction treatment, external beam irradiation was necessary in 12 (75%) of 16 eyes in the 2-cycle chemoreduction treatment group and in 4 (36%) of 11 eyes in the 6-cycle chemoreduction treatment group. There was no statistical difference between the 2- and 6-cycle chemoreduction treatment groups with respect to necessity for external beam irradiation (logistic regression analysis). All 4 eyes in the 2-cycle chemoreduction treatment group and 3 of 12 eyes in the 2-cycle chemoreduction treatment and irradiation group were eventually enucleated, the globe salvage rates being 0% and 75%, respectively. Two of 7 eyes in the 6-cycle chemoreduction treatment group and 1 of 4 eyes in the 6-cycle chemoreduction treatment and irradiation group were enucleated, the globe salvage rates being 71% and 75%, respectively. Except for the 2-cycle chemoreduction treatment group, in which the globe salvage rate was significantly lower (P = .03), there was no difference among the other 3 groups (2-cycle chemoreduction treatment and irradiation, 6-cycle chemoreduction treatment, and 6-cycle chemoreduction treatment and irradiation) with respect to globe salvage (logistic regression analysis).

CONCLUSIONS

Local tumor control of group V retinoblastoma is possible with 6-cycle chemoreduction and focal therapy when external beam irradiation is not used. A larger sample size is necessary to determine how often external beam irradiation can be avoided.

[Unilateral retinoblastomas with late bilateralization. Three case reports]

Three cases of unilateral retinoblastoma with late bilateralization are presented in this study. The rare occurrence of this event underlines the need for prolonged follow-up in the fellow-eye, even in the absence of familial retinoblastoma. In these three cases, the first affected eye was enucleated after a diagnosis made at three months, sixteen months and three years of age. New tumors appeared in the second eye when the children were sixteen years old in one case and five years old in two cases.

[Structural features of retinoblastoma]

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.