Spectrum of RB1 mutations identified in 403 retinoblastoma patients.

BACKGROUND: Retinoblastoma (RB) is a malignant, childhood tumour of the developing retina that occurs with an estimated frequency of 1 in 20 000. Identification of oncogenic mutations in the RB1 gene aids in the clinical management of families with a heritable predisposition to RB. Here we present the spectrum of genetic and epigenetic changes identified in 194 tumours and 209 blood samples, from 403 unrelated RB patients. METHODS: Mutation screening was carried out across all 27 RB1 exons and their associated splice sites. Small coding sequence changes were detected using fluorescent conformation analysis followed by sequencing. Large exonic deletions were detected by quantitative fluorescent PCR. Methylation specific PCR of the RB1 promoter was performed to detect epigenetic alterations. Polymorphism analysis was used to determine loss of heterozygosity in tumour samples. RESULTS: 95% of the expected mutations were identified in the tumour samples, with 16 samples exhibiting only one mutation, while two samples had no detectable RB1 mutation. 96% of bilateral/familial RB blood samples and 9.5% of unilateral sporadic blood samples, yielded mutations. 111 were novel mutations. CONCLUSIONS: The full range of screening techniques is required to achieve a high screening sensitivity in RB patients.

Efficacy and complications of super-selective intra-ophthalmic artery melphalan for the treatment of refractory retinoblastoma.

PURPOSE: To report the efficacy of super-selective intra-ophthalmic artery melphalan (IAM) for the treatment of refractory retinoblastoma and any associated complications of this treatment. DESIGN: A prospective case series. PARTICIPANTS: Eyes with retinoblastoma that had been treated with systemic chemotherapy or local therapy and had a relapse of their condition. METHODS: All patients receiving IAM between May 2009 and September 2010 were included in the study. Intra-ophthalmic artery melphalan was offered to patients who had failed to respond adequately to systemic chemotherapy and local treatment where appropriate or because of a new recurrence of retinoblastoma that could not be treated with local therapies. None of the patients were excluded because of central nervous system abnormalities. Patients received 2 treatments of IAM given 4 weeks apart. All patients received an orthoptic assessment 3 weeks after each treatment and an examination under anesthesia (EUA). A third treatment was given if an unsatisfactory response was observed on EUA after 2 treatments. MAIN OUTCOME MEASURES: The response of the retinoblastoma tumor(s) and any associated local side effects from the treatment. RESULTS: A total of 15 eyes in 14 patients were treated with IAM during the study period. The mean age at the time of IAM was 31.5 months (median 17.3, range 11.2-150.7 months), and the mean follow-up was 8.7 months (3-16.3 months). Tumor control was achieved in 12 eyes (80%), and 12 eyes (80%) had local side effects that included third cranial nerve palsy in 6 (40%), orbital edema in 3 (20%), permanent retinal detachment in 1 (7%), and vitreous hemorrhage in 4 (27%). Seven eyes (47%) developed significant retinal pigment epithelium changes. CONCLUSIONS: Intra-ophthalmic artery melphalan is an effective treatment for retinoblastoma, achieving a high level of remission in refractory tumors. It can be associated with significant local side effects that can result in loss of vision and possible amblyogenesis. Clinicians and parents need to consider the benefits and potential local side effects before embarking on treatment.

Retinoblastoma treated with primary chemotherapy alone: the significance of tumour size, location, and age.

AIMS: To evaluate how tumour size, retinal location, and patient age affect the outcome of retinoblastoma foci treated with chemotherapy. METHODS: Retrospective review of retinoblastoma foci treated with primary chemotherapy alone. Individual tumours were coded with regard to their largest basal diameter, location within the eye (macula, macula to equator, equator to ora serrata), and patient's age at diagnosis. Successfully treated tumours required no further intervention while those requiring additional treatment were coded as failures. RESULTS: 56 (72%) tumours responded successfully to chemotherapy alone while 22 (28%) required additional therapy. 26 of 31 macular tumours (84%) and 30 of 47 extramacular tumours (64%) responded to chemotherapy (p <0.060). Relative to size, 46 of 60 tumours (77%) greater than 2 mm in basal diameter were successfully treated with chemotherapy, while only 10 of 18 tumours (56%) less than or equal to 2 mm responded (p <0.088). Among the eight tumour foci diagnosed in children less than 2 months of age, five (63%) failed to respond to chemotherapy alone (p <0.032). CONCLUSION: Retinoblastoma is more likely to respond to primary chemotherapy if it is located in the macula and if the patient is older than 2 months of age. Tumours measuring less than 2 mm in diameter may be less responsive to this treatment.

Visual outcomes following intraophthalmic artery melphalan for patients with refractory retinoblastoma and age appropriate vision.

BACKGROUND/AIMS: To determine the frequency and cause of visual loss following intra-arterial melphalan (IAM) in patients with retinoblastoma with age appropriate vision. METHODS: Assessment of patients with refractory retinoblastoma that had undergone systemic chemotherapy, with or without local treatment, and were subsequently treated with IAM. Eyes of patients with a healthy foveola were assessed. The main outcome measures included visual, macular (including Pattern Visual Evoked Potentials and Fundus Fluorescein Angiography) and retinal functions (Electroretinograms). RESULTS: Five of twelve eyes (42%) demonstrated severe visual loss following IAM at last follow-up (median 21 months). This was due to either retinal detachment (1 eye, 20%) or choroidal ischaemia involving the foveola (4 eyes, 80%). All 3 eyes that had technical difficulties or vasospasm during catheterisation suffered visual loss. 8 out of 10 eyes that had a non-age adjusted dose of melphalan suffered visual loss. Electroretinograms post-IAM deteriorated in 4 of 8 eyes (50%) and Pattern Visual Evoked Potentials deteriorated in 3 (37%), though only one of these 3 showed concomitant visual acuity loss. CONCLUSIONS: Structural and vascular damage to the foveola limited visual acuity. Complications associated with catheterisation and high doses of melphalan may be contributory factors to visual morbidity. Although visual loss is described, no patient developed metastases and most retained good vision.

Comparative genomic hybridization of 49 primary retinoblastoma tumors identifies chromosomal regions associated with histopathology, progression, and patient outcome.

Forty-nine primary retinoblastoma (Rb) tumors were analyzed by the use of comparative genomic hybridization (CGH), and clinical/histological correlations were performed. Adverse histological factors were present in 13 patients. Chromosomal imbalance was a frequent phenomenon, seen in 96% of the tumors. Gain of 6p represented the most frequent event (69% of the tumors), whereas +1q was observed in 57%, confirming that these abnormalities are key secondary events in retinoblastoma tumor progression. Loss of 13q and 16 was significantly associated with tumors displaying adverse histo-prognostic factors, whereas -16q was significantly associated with tumors without adverse features. In three patients who developed an extra-ocular relapse, the tumors showed -13q and 2/3 had -5q, suggesting that these abnormalities may be associated with metastasis. Children >or= 36 months of age at enucleation tended to have more CGH abnormalities per tumor than children < 12 months (median numbers 11 vs. 3). In addition, +1q, +13q, -16, and -16q were more frequent in children with an older age at enucleation. Identical CGH changes were found in both tumors from one patient with bilateral tumors, suggesting a common origin. It is possible that tumors displaying loss of 13q and 5q indicate those patients who may suffer an adverse outcome and who would require alternative or more intensive therapy. CGH analysis on larger cohorts and in prospective clinical trials will be invaluable in determining whether a genetic classification of retinoblastoma represents a reliable measure of prognosis.