Comparison of retinoblastoma reduction for chemotherapy vs external beam radiotherapy

Surgical Outcomes in Radiation-induced Cataracts After External-beam Radiotherapy in Retinoblastoma

Objectives:

To investigate visual outcomes, surgical complications and tumor recurrence among children with retinoblastoma undergoing phacoemulsification and posterior chamber intraocular lens (PCIOL) implantation for radiation-induced cataract secondary to external beam radiotherapy.

Materials and Methods:

The medical records of all patients treated by phacoemulsification and PCIOL implantation for radiation-induced cataract after external beam radiotherapy for retinoblastoma at a single institution between 1980 and 2014 were reviewed retrospectively. The study included 6 eyes of 6 children (4 girls, 2 boys).

Results:

Four patients had bilateral and two patients had unilateral retinoblastoma. The median age at diagnosis of retinoblastoma was 28.3 months (range, 12-96 months). All patients received chemoreduction (OPEC protocol) and external beam radiotherapy with or without local ophthalmic therapies and developed radiation-induced cataracts. The median interval from retinoblastoma diagnosis to cataract surgery was 96.3 months (range, 73-122 months). Time interval between surgery and last retinoblastoma treatment was 67.2 months. Postoperative complications included iridocyclitis in 2 eyes and posterior capsule opacification in all eyes. The mean follow-up after surgery was 105.8 months (range, 59-120 months). Final visual acuity was better in all eyes than preoperative visual acuities.

Conclusion:

Phacoemulsification and PCIOL implantation is an effective method of managing radiation-induced cataracts in eyes with previously treated retinoblastoma. However, visual acuity was limited by the presence of primary macular tumor.

Management of retinoblastoma: opportunities and challenges

Nano-delivery systems have significantly evolved over the last decade for the treatment of cancer by enabling site-specific delivery and improved bioavailability. The widely investigated nanoparticle systems are biodegradable polyesters, dendrimers, liposomes, mesoporous silica and gold nanoparticles. These particles when conjugated with different targeting motifs enhance the therapeutic efficiency of the drug molecules and biocompatibility. However, the application of such systems towards the treatment of retinoblastoma (RB), a rapidly spreading childhood eye cancer, still remains in its infancy. Nanoparticle-based systems that have been investigated for RB therapy have displayed improved drug delivery to the most restricted posterior segment of the eyes and have increased intra-vitreal half-life of the chemotherapy agents highlighting its potential in treatment of this form of cancer. This review focuses on the challenges involved in the treatment of RB and highlights the attempts made to develop nano-dimensional systems for the treatment of RB.

Effects of metformin on retinoblastoma growth in vitro and in vivo

Recent studies suggest that the anti-diabetic drug metformin may reduce the risk of cancer and have anti-proliferative effects for some but not all cancers. In this study, we examined the effects of metformin on human retinoblastoma cell proliferation in vitro and in vivo. Two different human retinoblastoma cell lines (Y79, WERI) were treated with metformin in vitro and xenografts of Y79 cells were established in nu/nu immune-deficient mice and used to assess the effects of pharmacological levels of metformin in vivo. Metformin inhibited proliferation of the retinoblastoma cells in vitro. Similar to other studies, high concentrations of metformin (mM) blocked the cell cycle in G0‑G1, indicated by a strong decrease of G1 cyclins, especially cyclin D, cyclin-dependent kinases (4 and 6), and flow cytometry assessment of the cell cycle. This was associated with activation of AMPK, inhibition of the mTOR pathways and autophagy marker LC3B. However, metformin failed to suppress growth of xenografted tumors of Y79 human retinoblastoma cells in nu/nu mice, even when treated with a maximally tolerated dose level achieved in human patients. In conclusion, suprapharmacological levels (mM) of metformin, well above those tolerated in vivo, inhibited the proliferation of retinoblastoma cells in vitro. However, physiological levels of metformin, such as seen in the clinical setting, did not affect the growth of retinoblastoma cells in vitro or in vivo. This suggests that the potential beneficial effects of metformin seen in epidemiological studies may be limited to specific tumor types or be related to indirect effects/mechanisms not observed under acute laboratory conditions.

The clinically used photosensitizer Verteporfin (VP) inhibits YAP-TEAD and human retinoblastoma cell growth in vitro without light activation

Verteporfin (VP), a benzoporphyrin derivative, is clinically used in photodynamic therapy for neovascular macular degeneration. Recent studies indicate that VP may inhibit growth of hepatoma cells without photoactivation through inhibition of YAP-TEAD complex. In this study, we examined the effects of VP without light activation on human retinoblastoma cell lines. Verteporfin but not vehicle control inhibited the growth, proliferation and viability of human retinoblastoma cell lines (Y79 and WERI) in a dose-dependent manner and was associated with downregulation of YAP-TEAD associated downstream proto-oncogenes such as c-myc, Axl, and surviving. In addition VP affected signals involved in cell migration and angiogenesis such as CTGF, cyr61, and VEGF-A but was not associated with significant effect on the mTOR/autophagy pathway. Of interest the pluripotency marker Oct4 were downregulated by Verteporfin treatment. Our results indicate that the clinically used photosensitizer VP is a potent inhibitor of cell growth in retinoblastoma cells, disrupting YAP-TEAD signaling and pluripotential marker OCT4. This study highlights for the first time the role of the YAP-TEAD pathway in Retinoblastoma and suggests that VP may be a useful adjuvant therapeutic tool in treating Rb patients.

Colorimetric and longitudinal analysis of leukocoria in recreational photographs of children with retinoblastoma

Retinoblastoma is the most common primary intraocular tumor in children. The first sign that is often reported by parents is the appearance of recurrent leukocoria (i.e., "white eye") in recreational photographs. A quantitative definition or scale of leukocoria--as it appears during recreational photography--has not been established, and the amount of clinical information contained in a leukocoric image (collected by a parent) remains unknown. Moreover, the hypothesis that photographic leukocoria can be a sign of early stage retinoblastoma has not been tested for even a single patient. This study used commercially available software (Adobe Photoshop®) and standard color space conversion algorithms (operable in Microsoft Excel®) to quantify leukocoria in actual "baby pictures" of 9 children with retinoblastoma (that were collected by parents during recreational activities i.e., in nonclinical settings). One particular patient with bilateral retinoblastoma ("Patient Zero") was photographed >7, 000 times by his parents (who are authors of this study) over three years: from birth, through diagnosis, treatment, and remission. This large set of photographs allowed us to determine the longitudinal and lateral frequency of leukocoria throughout the patient's life. This study establishes: (i) that leukocoria can emerge at a low frequency in early-stage retinoblastoma and increase in frequency during disease progression, but decrease upon disease regression, (ii) that Hue, Saturation and Value (i.e., HSV color space) are suitable metrics for quantifying the intensity of retinoblastoma-linked leukocoria; (iii) that different sets of intraocular retinoblastoma tumors can produce distinct leukocoric reflections; and (iv) the Saturation-Value plane of HSV color space represents a convenient scale for quantifying and classifying pupillary reflections as they appear during recreational photography.

The treatment of retinoblastoma with four-drug regimen including cisplatin, etoposide, vincristine, and cyclophosphamide

Over an 11-year period, 59 patients (83 eyes) were treated with four-drug chemotherapy (cisplatin, etoposide, cyclophosphamide, and vincristine) at Hacettepe University, Departments of Ophthalmology and Pediatric Oncology. We evaluated the clinical features, treatment modalities, and outcome of these patients with a median follow-up of 55 months (range 9-130 months). Enucleation was performed as a first-line treatment for 30 eyes due to iris neovascularization and neovascular glaucoma, tumor in the anterior chamber regardless of the tumor stage, and for the patients with the Reese-Ellsworth (RE) group Vb. Chemotherapy was given regardless of tumor stages according to the RE groups in all 59 patients (83 eyes). Fifty-three eyes were treated with chemoreduction (CRD) and focal treatment. The rates of globe preservation were 87% for bilateral tumors and 35% for unilateral tumors in the CRD group. The 5-year overall (OS) and enucleation-free survival (EnFS) was 86.9% and 40%, respectively, for the whole group. At 3rd year, ocular survival rate for the eyes with vitreal or subretinal seeding was 58% and without seeding was 66% (P = .78). Seeding or subretinal collection may not indicate poor prognosis under intensive chemotherapy. The intensive four-drug chemotherapy protocol might have satisfactory results in the retinoblastoma (RBL) patients.

Retinoblastoma cells are inhibited by aminoimidazole carboxamide ribonucleotide (AICAR) partially through activation of AMP-dependent kinase

5-Aminoimidazole-4-carboxamide-1-beta-4-ribofuranoside (AICAR), an analog of AMP, is widely used as an activator of AMP-kinase (AMPK), a protein that regulates the responses of the cell to energy change. We studied the effects of AICAR on the growth of retinoblastoma cell lines (Y79, WERI, and RB143). AICAR inhibited Rb cell growth, induced apoptosis and S-phase cell cycle arrest, and led to activation of AMPK. These effects were abolished by treatment with dypiridamole, an inhibitor that blocks entrance of AICAR into cells. Treatment with the adenosine kinase inhibitor 5-iodotubericidin to inhibit the conversion of AICAR to ZMP (the direct activator of AMPK) reversed most of the growth-inhibiting effects of AICAR, indicating that some of the antiproliferative effects of AICAR are mediated through AMPK activation. In addition, AICAR treatment was associated with inhibition of the mammalian target of rapamycin pathway, decreased phosphorylation of ribosomal protein-S6 and 4E-BP1, down-regulation of cyclins A and E, and decreased expression of p21. Our results indicate that AICAR-induced activation of AMPK inhibits retinoblastoma cell growth. This is one of the first descriptions of a nonchemotherapeutic drug with low toxicity that may be effective in treating Rb patients.

Outcomes of cataract surgery following radiation treatment for retinoblastoma

PURPOSE

To report the outcomes after cataract extraction in eyes previously treated for retinoblastoma.

METHODS

We reviewed the medical records of consecutive patients treated with cataract extraction at our institution for radiation-induced cataract following retinoblastoma treatment between 1992 and 2007.

RESULTS

Twelve eyes of 11 patients were included. The median age at diagnosis of retinoblastoma was 7.4 months. The median quiescent interval before cataract surgery was 34.6 months (range, 17-240 months). All patients underwent limbal-based extracapsular cataract extraction with scleral-tunnel wound construction. Anterior vitrectomy and posterior capsulotomy were performed in 7 eyes; an intraocular lens was placed in 10 eyes. A laser capsulotomy was subsequently performed in 5 eyes. No postoperative complications occurred. One patient underwent a pars plana vitrectomy for vitreous hemorrhage and proliferative retinopathy 5 years after cataract extraction. The median follow-up after surgery was 6.0 years (range, 1.1-12.3 years). Final visual acuity was between 20/20 and 20/60 in 6 eyes, between 20/70 and 20/200 in 2 eyes, and worse than 20/200 in 4 eyes. No intraocular tumor recurrences or metastases occurred. Two patients developed secondary rhabdomyosarcomas; 1 patient succumbed to the disease.

CONCLUSIONS

Limbal-based cataract extraction in our series was not associated with tumor recurrence or metastasis. The optimal quiescent interval is not known; however, no tumor recurrences occurred in our series when a minimum 17-month quiescent period was achieved. Visual improvement was noted in every patient, although several patients only experienced modest gains.

Prognostic factors and treatment outcomes of retinoblastoma in pediatric patients: a single-institution study

PURPOSE

Since 1997, our institute has used neoadjuvant chemotherapy for intraocular retinoblastoma. However, some of the patients showed signs of recurrence months to years later. We therefore attempted to determine the prognostic factors of treatment outcomes and survival in our patients.

METHODS

We reviewed 90 patients treated from 1997 to 2006. The following information was recorded: demographic and ophthalmological data, clinical classification, histopathological data, and treatment methods and outcomes.

RESULTS

Enucleation was avoided in two of 57 eyes in the unilateral group. Sixteen of 54 eyes in the bilateral group were salvaged by systemic chemotherapy with local treatment. There was no difference in histopathological findings between the two groups. Nine of 57 patients in the unilateral group demonstrated poor outcomes, compared with four of 27 in the bilateral group. Significant poor prognostic factors for survival were optic nerve head invasion, orbital involvement, abnormal results on bone marrow aspiration, lumbar puncture, bone scan, and group E or F classification.

CONCLUSIONS

The 15% mortality rate in our patients is slightly higher than that reported in developed countries. Delayed diagnosis and treatment is the main cause of avoidable deaths. Improving education of both clinicians and parents would increase survival rates in this potentially fatal disease.

Basic fibroblast growth factor impact on retinoblastoma progression and survival

PURPOSE

Chemotherapy resistance is a problem in the treatment of advanced retinoblastoma (RB). Since basic fibroblast growth factor (bFGF) is a survival factor for neural precursor cells, bFGF was evaluated as a growth and chemoresistance factor in RB.

METHODS

bFGF expression was analyzed in the LH-betaTag transgenic mouse model of RB and human RB cell lines by immunofluorescence, RT-PCR, and Western blot. Proliferation and apoptosis (TUNEL) assays were performed.

RESULTS

bFGF levels significantly increased during tumorigenesis in transgenic RB, as a function of tumor status (P = 0.005). PCR and confocal microscopy confirmed that the human cell lines and primary tumors expressed bFGF. bFGF was localized to vascular and tumor cells and rarely to glial cells. Exogenous 18-kDa bFGF induced proliferation in two RB cell lines (WERI and Y79). Western blot analysis demonstrated 34-, 22-, and 18-kDa isoforms in transgenic RB and both cell lines. In TUNEL assays, chemoresistance to carboplatin-induced apoptosis was observed in the Y79 line, which expressed a higher ratio of high (34 kDa)- to low-molecular-weight bFGF isoforms, compared with the WERI line. Similar to other bFGF tumor studies, exogenous low-molecular-weight (18 kDa) bFGF (1 ng) significantly enhanced carboplatin-induced apoptosis in the more chemosensitive WERI, but not the chemoresistant Y79 line.

CONCLUSIONS

RB tumors produce significant amounts of bFGF, and the differential production and response to isoforms of bFGF may have implications for invasive tumor growth and chemoresistance.

Clinical and epidemiological characteristics of retinoblastoma: correlation with prognosis in a Turkish pediatric oncology center

Advanced intraocular tumors and metastatic disease in retinoblastoma patients still occur frequently in developing countries. The aim of this retrospective study was to describe the clinical and epidemiological characteristics of patients with retinoblastoma and the effects of these features on disease prognosis in the authors' pediatric oncology unit as a developing country profile to define the problem. A retrospective chart review of 91 patients who presented to the unit between May 1996 and December 2003 was conducted in this study. Patients with unilateral disease presented at a median age of 24 months and those with bilateral disease at a median age of 9.5 months (p < .01). Most of the eyes with retinoblastoma (68.6%) had Reese-Ellsworth stage V disease. Metastatic disease was diagnosed in 19 (20.9%) patients. Cases with metastatic disease presented at a median age of 24 months and those without metastatic disease at a median age of 12.5 months (p < .05). In 31 patients (34.1%) there was a delay in diagnosis. The enucleation ratio in eyes with advanced intraocular stage was significantly higher than in eyes with early intraocular stage (57.9 vs. 3.8%) (p < .001). In patients with metastatic disease, tumor recurrence was more frequent than in the nonmetastatic patients (36.8 vs. 4.2%) (p < .01). Seven children (7.7%) died due to central nervous system (CNS) metastasis (p < .01). Advanced intraocular disease and distant metastases occur more frequently in Turkish children with retinoblastoma than in children in developed countries, causing a higher rate of enucleation and mortality. Late referral might account for the delayed diagnosis.

Systemic carboplatin for retinoblastoma: change in tumour size over time

BACKGROUND/AIM

Chemotherapy for intraocular retinoblastoma is used to shrink individual retinal tumours to a size amenable to focal treatments. Quantitative data regarding retinal tumour response following treatment with primary systemic carboplatin are reported.

METHODS

Changes in area and largest basal diameter of tumours that were exposed to carboplatin, had no concomitant focal treatment, and had digital funduscopic photography performed before and after treatment, were measured. Response was evaluated.

RESULTS

36 tumours were measured following one treatment: 34/36 (94.4%) responded, with a 37.1% mean decrease in area (median = 37.0%; range 4.0%-76.7%). Mean reduction in basal diameter was 21.3% (med = 21.0%; -7.9%-52.5%). 20 tumours were treated with a second cycle: 15/20 (75.0%) responded. Mean decrease in area was 17.8% (med = 15.3%; -7.0%-49.7%). The mean cumulative decrease in area after two treatments was 55.1% (med = 56.2%; 33.0%-74.5%). Mean cumulative reduction in basal diameter was 33.6% (med = 33.6%; 10.9%-53.2%). 12 tumours were treated with a third cycle: 3/12 (25.0%) responded, 8/12 were stable, and one progressed. Mean decrease in area was 5.4% (med = 7.2%; -17.7%-20.6%). Cumulative decrease in area after three treatments was 58.1% (med = 57.3%; 34.8%-77.2%). Mean cumulative reduction in basal diameter was 38.8% (med = 38.2%; 19.1%-54.1%).

CONCLUSIONS

Carboplatin caused measurable shrinkage of retinoblastoma tumours. Response was greatest following the initial treatment and decreased with subsequent treatments.

Pars Plana Lensectomy and Intraocular Lens Implantation in Pediatric Radiation-Induced Cataracts in Retinoblastoma

OBJECTIVE

To investigate visual outcomes, surgical complications, and tumor recurrence among children with retinoblastoma (RB) undergoing pars plana lensectomy, vitrectomy, and simultaneous intraocular lens insertion for radiation-related cataract secondary to external beam radiotherapy (EBRT).

DESIGN

Retrospective, noncomparative, consecutive case series.

METHODS

The medical records for all patients treated with pars plana lensectomy, vitrectomy, and posterior chamber intraocular lens implantation for radiation-induced cataract after EBRT for RB at a single institution between January 1, 1990, and December 31, 2000, were reviewed.

PARTICIPANTS

The study included 16 eyes of 12 children with Reese-Ellsworth stage V RB.

MAIN OUTCOME MEASURES

Visual acuity, surgical and postoperative complications, postoperative refraction, and tumor recurrence.

RESULTS

The median age at diagnosis of RB was 6 months (range, 1-49 months). All patients received EBRT as primary treatment and experienced radiation-induced cataracts. The median interval from RB diagnosis to cataract surgery was 42 months (range, 28-95 months). Preoperative mean visual acuity was 20/400, with 12 of 16 eyes (75%) having macular tumor involvement. All patients underwent pars plana lensectomy, vitrectomy, and posterior chamber intraocular lens insertion. Vitreous samples were evaluated by cytopathologic examination, and no viable tumor cells were identified in any of the vitreous specimens. Postoperative complications included transient cystoid macular edema in 5 eyes (31%) and iridocyclitis in 3 eyes (19%). The mean follow-up after cataract surgery was 66 months (range, 30-94 months). Final visual acuity was 20/40 or better in 11 of 16 eyes (69%). No late intraocular recurrence, orbital tumors, or metastatic disease was noted in this study.

CONCLUSIONS

Pars plana lensectomy, vitrectomy, and simultaneous intraocular lens implantation is an effective means of managing EBRT-induced cataracts in eyes with previously treated RB. There was no evidence of active tumor in eyes undergoing surgery at least 28 months after the diagnosis and commencement of therapy for RB, and no late intraocular, orbital, or metastatic tumors were detected. Visual acuity was limited by the presence of primary macular tumor pathologic features in a subset of patients, but final vision better than 20/400 may be achieved in these eyes.