Global issues and opportunities for optimized retinoblastoma care

Teleoncology: Novel Approaches for Improving Cancer Care in North America

Due to widespread healthcare workforce shortages, many patients living in remote and rural North America currently have reduced access to various medical specialists. These shortages, coupled with the aging North American population, highlight the need to transform contemporary healthcare delivery systems. The exchange of medical information via telecommunication technology, known as telemedicine, offers promising solutions to address the medical needs of an aging population and the increased demand for specialty medical services. This progressive movement has also improved access to quality health care by mitigating the current shortage of trained subspecialists. Minimizing the effects of these shortages is particularly urgent in the care of cancer patients, many of whom require regular follow-up and close monitoring. Cancer patients living in remote areas of North America have reduced access to specialized care and, thus, have unacceptably high mortality and morbidity rates. Teleoncology, or the use of telemedicine to provide oncology services remotely, has the ability to improve access to high-quality care and assist in alleviating the burden of some of the severe adverse events associated with cancer. In this review, the authors describe how recent advances in teleoncology can reduce healthcare disparities and improve future cancer care in North America.

Signaling pathways driving ocular malignancies and their targeting by bioactive phytochemicals

Ocular cancers represent a rare pathology. The American Cancer Society estimates that 3,360 cases of ocular cancer occur annually in the United States. The major types of cancers of the eye include ocular melanoma (also known as uveal melanoma), ocular lymphoma, retinoblastoma, and squamous cell carcinoma. While uveal melanoma is one of the primary intraocular cancers with the highest occurrence in adults, retinoblastoma remains the most common primary intraocular cancer in children, and squamous cell carcinoma presents as the most common conjunctival cancer. The pathophysiology of these diseases involves specific cell signaling pathways. Oncogene mutations, tumor suppressor mutations, chromosome deletions/translocations and altered proteins are all described as causal events in developing ocular cancer. Without proper identification and treatment of these cancers, vision loss, cancer spread, and even death can occur. The current treatments for these cancers involve enucleation, radiation, excision, laser treatment, cryotherapy, immunotherapy, and chemotherapy. These treatments present a significant burden to the patient that includes a possible loss of vision and a myriad of side effects. Therefore, alternatives to traditional therapy are urgently needed. Intercepting the signaling pathways for these cancers with the use of naturally occurring phytochemicals could be a way to relieve both cancer burden and perhaps even prevent cancer occurrence. This research aims to present a comprehensive review of the signaling pathways involved in various ocular cancers, discuss current therapeutic options, and examine the potential of bioactive phytocompounds in the prevention and targeted treatment of ocular neoplasms. The current limitations, challenges, pitfalls, and future research directions are also discussed.

Explainable AI for Retinoblastoma Diagnosis: Interpreting Deep Learning Models with LIME and SHAP

Retinoblastoma is a rare and aggressive form of childhood eye cancer that requires prompt diagnosis and treatment to prevent vision loss and even death. Deep learning models have shown promising results in detecting retinoblastoma from fundus images, but their decision-making process is often considered a "black box" that lacks transparency and interpretability. In this project, we explore the use of LIME and SHAP, two popular explainable AI techniques, to generate local and global explanations for a deep learning model based on InceptionV3 architecture trained on retinoblastoma and non-retinoblastoma fundus images. We collected and labeled a dataset of 400 retinoblastoma and 400 non-retinoblastoma images, split it into training, validation, and test sets, and trained the model using transfer learning from the pre-trained InceptionV3 model. We then applied LIME and SHAP to generate explanations for the model's predictions on the validation and test sets. Our results demonstrate that LIME and SHAP can effectively identify the regions and features in the input images that contribute the most to the model's predictions, providing valuable insights into the decision-making process of the deep learning model. In addition, the use of InceptionV3 architecture with spatial attention mechanism achieved high accuracy of 97% on the test set, indicating the potential of combining deep learning and explainable AI for improving retinoblastoma diagnosis and treatment.

Angiographic analysis of ophthalmic artery flow direction in children undergoing chemosurgery for retinoblastoma compared to age-matched controls

PURPOSE

Catheter-based intra-arterial chemotherapy (IAC) has revolutionized the treatment of retinoblastoma (RB). Variability in ophthalmic artery (OA) flow, either retrograde from external carotid artery branches, or anterograde from the internal carotid artery, necessitates multiple IAC techniques. We evaluated the direction of OA flow and identify OA flow reversal events over the course of IAC treatment as well in comparison to OA flow direction in non-RB children.

MATERIALS AND METHODS

We performed a retrospective analysis of OA flow direction in all RB patients treated with IAC, along with an age-matched control group who underwent cerebral angiography at our center from 2014 to 2020.

RESULTS

IAC was administered to a total of 18 eyes (15 patients). Initial anterograde OA flow was demonstrated in 66% (n  =  12) of eyes. Five OA reversal events were identified (3/5 anterograde-to-retrograde). All five events were in patients receiving multiagent chemotherapy. No correlation was found between OA flow reversal events and the initial IAC technique. A control group of 88 angiograms representing 82 eyes (41 patients) was utilized. The anterograde flow was observed in 76 eyes (86.4%). Our control group included 19 patients with sequential angiograms. One OA flow reversal event was identified.

CONCLUSION

OA flow direction is dynamic in IAC patients. Anterograde and retrograde OA directional switches do occur and may necessitate delivery technique variation. In our analysis, all OA flow reversal events were associated with multiagent chemotherapy regimens. Both anterograde and retrograde OA flow patterns were observed in our control cohort, suggesting bidirectional flow can occur in non-RB children.

Effect of Andrographis paniculata polysaccharide on human retinoblastoma Y79 cell proliferation and apoptosis

AIM

To explore the effect of the Andrographis paniculata (A. paniculata) polysaccharide on the proliferation and apoptosis of human retinoblastoma (RB) Y79 cells and its mechanism.

METHODS

The refined A. paniculata polysaccharide was obtained using techniques such as water extraction, ethanol precipitation, and decompression concentration. The inhibition effect of the A. paniculata polysaccharide on the proliferation of Y79 cells was detected by cell proliferation assay. Flow cytometry was used for the detection of cell apoptosis rate and cycle change. Real-time qunatitative polymerase chain reaction (RT qPCR)and Western blotting were used to detect the expression of cell apoptosis signal pathway-related factors (caspase-3, caspase-8, and caspase-9) and cell cycle signal pathway-related factors (CDK1 and cyclinB1) at the transcriptional and translational levels.

RESULTS

Infrared and ultraviolet spectrum scanning showed that the extracted drug was a polysaccharide with high purity. After being treated with different concentrations of A. paniculata polysaccharide for different periods of time, the Y79 cells showed different degrees of proliferation inhibition. Flow cytometric observations showed that the cell apoptosis rate and the proportion of cells blocked in the G2/M phase were significantly increased after A. paniculata polysaccharide treatment. Further analysis revealed that the mRNA and protein expression of caspase-3, caspase-8, and caspase-9 in the A. paniculata polysaccharide treatment groups increased significantly compared with that in the control groups, while the expression of CDK1 and cyclinB1 decreased significantly.

CONCLUSION

The A. paniculata polysaccharide could inhibit the proliferation and induce apoptosis of Y79 cells. Its possible mechanism is via the upregulation of caspase-3, caspase-8, and caspase-9 expression in the cell apoptotic signaling pathway and the downregulation of CDK1 and cyclinB1 expression in the cell cycle signaling pathway.

Assessment of Retinoblastoma Capacity in the Middle East, North Africa, and West Asia Region

PURPOSE

We aimed to evaluate the capacity to treat retinoblastoma in the Middle East, North Africa, and West Asia region.

METHODS

A Web-based assessment that investigated retinoblastoma-related pediatric oncology and ophthalmology infrastructure and associated capacity at member institutions of the Pediatric Oncology East and Mediterranean group was distributed. Data were analyzed in terms of availability, location, and confidence of use for each resource needed for the management of retinoblastoma. Resources were categorized by diagnostics, focal therapy, chemotherapy, advanced treatment, and supportive care. Responding institutions were further divided into an asset-based tiered system.

RESULTS

In total, responses from 23 institutions were obtained. Fifteen institutions reported the availability of an ophthalmologist, 12 of which held primary off-site appointments. All institutions reported the availability of a pediatric oncologist and systemic chemotherapy A significant portion of available resources was located off site. Green laser was available on site at seven institutions, diode laser at six institutions, cryotherapy at 12 institutions, and brachytherapy at nine institutions. There existed marked disparity between the availability of some specific ophthalmic resources and oncologic resources.

CONCLUSION

The assessment revealed common themes related to the treatment of retinoblastoma in low- and- middle-income countries, including decentralization of care, limited resources, and lack of multidisciplinary care. Resource disparities warrant targeted intervention in the Middle East, North Africa, and West Asia region to advance the management of retinoblastoma in the region.

A 20-year audit of retinoblastoma treatment outcomes

Objectives

To evaluate the long-term treatment outcomes in intraocular retinoblastoma (RB) including the associated factors for eventual treatment with external beam radiotherapy (EBRT) and enucleation as well as to analyse the risk factors for metastasis and death in extraocular RB.

Methods

Retrospective analysis of 390 eyes from 256 (89.8%) intraocular RB and 29 (10.2%) extraocular RB cases diagnosed and treated between October 1998 and May 2018 at one of the largest tertiary care centers in Turkey.

Results

Of 351 intraocular RB eyes, 53.3% had group D/E disease at presentation. 75 (21.4%) of 351 eyes underwent primary enucleation. Of the remaining 276 eyes undergoing eye-conserving treatments, 201 (72.8%) were salvaged. Most of these eyes were treated using intravenous chemotherapy and/or focal treatments [transpupillary thermotherapy (TTT) and cryotherapy] initially. EBRT was eventually required in 48 (17.4%) eyes and secondary enucleation in 75 (27.2%) eyes. At mean follow-ups of 76.7 and 39.7 months for intraocular and extraocular RB cohorts, respectively, 180 (46.2%) eyes underwent primary/secondary enucleation and exenteration. Overall, 13 cases developed metastasis and 9 died. Two patients with trilateral RB also expired. Multivariable risk factors for enucleation were the presence of vitreous seeds (p < 0.001), absence of EBRT administration (p = 0.033), 5–9 TTT applications compared with no TTT (p = 0.031), and each 1 mm increase in tumour base diameter (p < 0.001). Univariate factors predictive of metastasis were the presence of extraocular RB detected by imaging methods (p < 0.001) and extrascleral/optic nerve cut end involvement at histopathological examination (p < 0.001).

Conclusions

In our series, 72.8% of the intraocular RB eyes undergoing eye-conserving treatments were saved. The globe salvage rate for all intraocular and extraocular RB eyes was 53.8% and the overall survival rate was 96.1%.

Ophthalmic Artery Chemosurgery: A Nursing Perspective

Retinoblastoma (RB) is the most common primary cancer to affect the eyes in children with approximately 350 cases/year in the United States and 8000 worldwide. Today, sadly, 50% of children with RB worldwide die from their disease. In our experience, utilization of ophthalmic artery chemosurgery (OAC) has transformed the treatment plan for patients; with over 1500 procedures performed, our survival rate exceeds 98%. It is now our standard first-line therapy for RB. OAC is a surgical outpatient procedure which delivers concentrated doses of chemotherapy directly to the tumor without the toxicities of systemic chemotherapy. Our team approach and nursing management of these patients are the focus of this article. Nursing navigation and collaboration after OAC is vital and requires a combined effort by the nurses along with physicians, interventional radiologists, and the patient's families to ensure appropriate follow-up is established. Proper patient education throughout the process is crucial as is open and available communication for parents of patients with the nursing staff. The success in our treatment of this disease can be much accredited to the multidisciplinary team approach, with nursing playing an integral part in the support and management of these patients.

Expanding global access to radiotherapy

Radiotherapy is a critical and inseparable component of comprehensive cancer treatment and care. For many of the most common cancers in low-income and middle-income countries, radiotherapy is essential for effective treatment. In high-income countries, radiotherapy is used in more than half of all cases of cancer to cure localised disease, palliate symptoms, and control disease in incurable cancers. Yet, in planning and building treatment capacity for cancer, radiotherapy is frequently the last resource to be considered. Consequently, worldwide access to radiotherapy is unacceptably low. We present a new body of evidence that quantifies the worldwide coverage of radiotherapy services by country. We show the shortfall in access to radiotherapy by country and globally for 2015-35 based on current and projected need, and show substantial health and economic benefits to investing in radiotherapy. The cost of scaling up radiotherapy in the nominal model in 2015-35 is US$26·6 billion in low-income countries, $62·6 billion in lower-middle-income countries, and $94·8 billion in upper-middle-income countries, which amounts to $184·0 billion across all low-income and middle-income countries. In the efficiency model the costs were lower: $14·1 billion in low-income, $33·3 billion in lower-middle-income, and $49·4 billion in upper-middle-income countries-a total of $96·8 billion. Scale-up of radiotherapy capacity in 2015-35 from current levels could lead to saving of 26·9 million life-years in low-income and middle-income countries over the lifetime of the patients who received treatment. The economic benefits of investment in radiotherapy are very substantial. Using the nominal cost model could produce a net benefit of $278·1 billion in 2015-35 ($265·2 million in low-income countries, $38·5 billion in lower-middle-income countries, and $239·3 billion in upper-middle-income countries). Investment in the efficiency model would produce in the same period an even greater total benefit of $365·4 billion ($12·8 billion in low-income countries, $67·7 billion in lower-middle-income countries, and $284·7 billion in upper-middle-income countries). The returns, by the human-capital approach, are projected to be less with the nominal cost model, amounting to $16·9 billion in 2015-35 (-$14·9 billion in low-income countries; -$18·7 billion in lower-middle-income countries, and $50·5 billion in upper-middle-income countries). The returns with the efficiency model were projected to be greater, however, amounting to $104·2 billion (-$2·4 billion in low-income countries, $10·7 billion in lower-middle-income countries, and $95·9 billion in upper-middle-income countries). Our results provide compelling evidence that investment in radiotherapy not only enables treatment of large numbers of cancer cases to save lives, but also brings positive economic benefits.

Retinoblastoma. Fifty years of progress. The LXXI Edward Jackson Memorial Lecture

PURPOSE

To review the progress made in understanding the genetic basis, molecular pathology, and treatment of retinoblastoma since the previous Jackson lecture on the topic was published 50 years ago.

DESIGN

Perspective based on personal experience and the literature.

METHODS

The literature regarding retinoblastoma was reviewed since 1963. Advances in understanding the biology and treatment of retinoblastoma provided context through the author's clinical, pathologic, and research experiences.

RESULTS

Retinoblastoma was first identified in the 1500s and defined as a unique clinicopathologic entity in 1809. Until the mid-1900s, knowledge advanced sporadically, with technological developments of ophthalmoscopy and light microscopy, and with the introduction of surgical enucleation, chemotherapy, and radiation therapy. During the last 50 years, research and treatment have progressed at an unprecedented rate owing to innovations in molecular biology and the development of targeted therapies. During this time period, the retinoblastoma gene was discovered; techniques for genetic testing for retinoblastoma were developed; and plaque brachytherapy, chemoreduction, intra-arterial chemotherapy, and intraocular injections of chemotherapeutic agents were successfully introduced.

CONCLUSIONS

Nearly all patients with retinoblastoma in developed countries can now be cured of their primary cancer--a remarkable achievement for a childhood cancer that once was uniformly fatal. Much of this success is owed to deciphering the role of the Rb gene, and the benefits of targeted therapies, such as chemoreduction with consolidation as well as intra-arterial and intravitreal chemotherapies. Going forward, the main challenge will be ensuring that access to care is available for all children, particularly those in developing countries.

Causes, outcome and prevention of abandonment in retinoblastoma in India

BACKGROUND

The high-cure rates of 90% in retinoblastoma are not replicated in developing countries due to late presentation and poor compliance to treatment. The present study takes a closer look at causes of abandonment of therapy and effectiveness of counselling in reducing abandonment.

PROCEDURE

A retrospective study of children with retinoblastoma registered at our centre from March 2008 through August 2011.

RESULTS

Fifty (49.50%) of 101 children registered for treatment abandoned therapy. Abandonment rates were significantly higher in rural as compared to urban children (P = 0.02). There was no significant difference in rate of abandonment between stages or laterality of disease and other socio-demographic factors. Telephone calls were more effective than letters in tracing patients (31.2% vs. 2.4%). Major reasons cited behind abandonment were financial problems (30%) and unwillingness to enucleate (20%). Of the 12 children who returned and were retreated 6 (50%) died of progressive disease. Nineteen (73%) of those who did not return died at home. Abandonment rates steadily declined from 71.42% in 2008 to 16.66% in 2011 (P = 0.01) due to effective pre-abandonment counselling by a support team under the National Retinoblastoma Registry of India from 2009.

CONCLUSIONS

Abandonment rates for children with retinoblastoma continue to be unacceptably high. Rural background, financial constraints and hesitancy to enucleate were important causes behind abandonment. Outcome of patients who abandoned treatment was uniformly dismal. Inclusion of support team and intensified initial counselling helped in improving compliance.

Cytokine-induced killer cells co-cultured with complete tumor antigen-loaded dendritic cells, have enhanced selective cytotoxicity on carboplatin-resistant retinoblastoma cells

Retinoblastoma (RB) is a challenging disease that affects mostly young children. Chemical therapy has been shown to have limitations during clinical practice, principally because of the ability of RB to become resistant to the treatment. Nevertheless, chemotherapy is still the main treatment for RB, and immunotherapy has become a promising treatment for most solid tumors with fewer side effects than traditional therapies. In this study, we explored the antitumor effects of cytokine-induced killer (CIK) cells co-cultured with dendritic cells (DCs) pulsed with complete tumor antigens (DC-Ag). Cytotoxicity and specificity were evaluated on an RB cell line (RB-Y79), on a human normal retina cell line (hTERT-RPE1) and a carboplatin-resistant RB cell line. Our results showed that CIK differentiation and cytotoxicity were enhanced by co-culturing CIKs with DC-Ag. Moreover, the co-culture improved the CIK proliferation rate by increasing IL-6 and decreasing IL-10 levels in the culture medium. Furthermore, the use of DC-Ag-CIK cells had little effect on normal retinal cells but high cytotoxicity on RB cells even on carboplatin-resistant retinoblastoma cells. This is the first study showing that DC cells pulsed with the complete tumor antigen improve proliferation, differentiation and cytotoxic activity of CIKs specific not only for RB but also for the chemotherapy-resistant form of the malady. Thus highly efficient immunotherapy based on DC-Ag-CIK cells may be a potential effective and safe mean of treating RB especially to patients where traditional chemical therapy has failed.

"Retinoblastoma survival disparity": The expanding horizon in developing countries

The patients' survival for the most common intraocular tumor in children, retinoblastoma, has a wide spectrum among the world countries. This study was conducted to provide an overview of the retinoblastoma survival disparity worldwide by discussing the trends of patients' survival, as well as recent advances in the management of retinoblastoma. The design of this study was literature review and commentary. Selected articles from PubMed (except one) including both developing and developed countries regarding the patients' survival in retinoblastoma were considered and reviewed critically. An analysis of 47 articles was performed. In conclusion, in spite of an obvious contrast of retinoblastoma survival disparity in the world, the expanding horizons in developing countries are promising and continuing on all fronts and results are hope-inspiring.

Strategies to manage retinoblastoma in developing countries

Survival of retinoblastoma is >90% in developed countries but there are significant differences with developing countries in stage at presentation, available treatment options, family compliance, and survival. In low-income countries (LICs), children present with advanced disease, and the reasons are socioeconomic and cultural. In middle-income countries (MICs), survival rates are better (>70%), but there is a high prevalence of microscopically disseminated extraocular disease. Programs for eye preservation have been developed, but toxicity-related mortality is higher. Although effective treatment of microscopically extraocular disease improved the outcome, worldwide survival will be increased only by earlier diagnosis and better treatment adherence.

Pre-Enucleation Chemotherapy for Eyes Severely Affected by Retinoblastoma Masks Risk of Tumor Extension and Increases Death From Metastasis

Purpose

Initial response of intraocular retinoblastoma to chemotherapy has encouraged primary chemotherapy instead of primary enucleation for eyes with clinical features suggesting high risk of extraocular extension or metastasis. Upfront enucleation of such high-risk eyes allows pathologic evaluation of extraocular extension, key to management with appropriate surveillance and adjuvant therapy. Does chemotherapy before enucleation mask histologic features of extraocular extension, potentially endangering the child's life by subsequent undertreatment?

Methods

We performed retrospective analysis of 100 eyes with advanced retinoblastoma enucleated with, or without, primary chemotherapy, in Beijing Tongren Hospital, retrospectively, from October 31, 2008. The extent of retinoblastoma invasion into optic nerve, uvea, and anterior chamber on histopathology was staged by pTNM classification. The treatment groups were compared for pathologic stage (Cochran-Armitage trend test) and disease-specific mortality (competing risks methods).

Results

Children who received chemotherapy before enucleation had lower pTNM stage than primarily enucleated children (P = .01). Five patients who received pre-enucleation chemotherapy died as a result of extension into brain or metastasis. No patients who had primary enucleation died. For children with group E eyes, disease-specific survival (DSS) was lower with pre-enucleation chemotherapy (n = 45) than with primary enucleation (n = 37; P = .01). Enucleation longer than 3 months after diagnosis was also associated with lower DSS (P < .001).

Conclusion

Chemotherapy before enucleation of group E eyes with advanced retinoblastoma downstaged pathologic evidence of extraocular extension, and increased the risk of metastatic death from reduced surveillance and inappropriate management of high-risk disease, if enucleation was performed longer than 3 months after diagnosis.

Retinoblastoma CSF metastasis cured by multimodality chemotherapy without radiation

OBJECTIVE

Cerebrospinal fluid (CSF) metastasis is the most difficult type of retinoblastoma metastasis to cure, even with bone marrow transplant. Most metastatic retinoblastoma cells express P-glycoprotein causing multidrug resistance (MDR). P-glycoprotein-rich blood vessels form blood-brain and blood-eye barriers, inhibit drug entry into central nervous system (CNS) and eyes. High-dose craniospinal radiation is too morbid for treatment of young children. To cure CSF metastasis without radiation, we designed an intensive multimodality chemotherapy regimen.

METHOD

After left eye enucleation, a 4-month-old boy with bilateral International Intraocular Retinoblastoma Classification Group E eyes and CSF metastasis was treated with 7-cycle high-dose carboplatin and etoposide, standard-dose vincristine, and high-dose/short-infusion cyclosporine to inhibit P-glycoprotein. Intraventricular drugs, non-substrate of P-glycoprotein (cytarabine), or less susceptible to MDR (topotecan), contributed to treatment of the metastasis. On achieving complete response, he was consolidated with supralethal-dosage carboplatin, etoposide, and cyclophosphamide, and his bone marrow rescued with autologous cord blood stem cells.

RESULTS

Following 1-cycle systemic chemotherapy and 2-dose intraventricular chemotherapy, the CSF metastasis cleared. The right eye tumor regressed completely. The patient remains in remission 8.3 years after diagnosis and 7.8 years post-transplant.

CONCLUSION

Intensive multimodality chemotherapy can cure CSF metastasis in retinoblastoma without incurring extreme morbidity from craniospinal radiation.

Retinoblastoma: the challenges of management in Ibadan, Nigeria

BACKGROUND

Retinoblastoma is a common highly malignant tumor of the eye. Late presentation leads to poor survival rate in many developing countries.

OBJECTIVE

To identify problems associated with management of retinoblastoma.

METHODS

A retrospective review of cases of retinoblastoma at the University College Hospital, Ibadan, between January 1992 and December 2007.

RESULTS

A total of 32 eyes of 26 patients were studied. Sixteen were males and 10 were females. Minimum age at presentation was 4 months and maximum age was 60 months (mean 30.69+/-14.2 mo). Over 90% presented after 1 month of onset. Reasons for late diagnosis included late presentation for unknown reasons, missed diagnosis, and mismanagement in a previous hospital. Eleven of 26 patients defaulted to avoid removal of the eye, and treatment was only completed in 5 patients. Problems included financial constraint regarding investigations and procurement of drugs, as well as availability of the chemotherapy.

CONCLUSIONS

Retinoblastoma is a problematic malignancy of childhood associated with management problems often related to difficulty with patients accepting removal of the affected eye and financial constraint for treatment.

Cancer mortality in long-term survivors of retinoblastoma

This study examined long-term cause-specific mortality among 998 Dutch retinoblastoma survivors, diagnosed from 1862 to 2005, according to follow-up time, treatment and heredity. After a median follow-up of 30.8 years, only cause-specific mortality for second malignancies among hereditary retinoblastoma survivors was statistically significantly increased with 12.8-fold. Risk of death from second malignancies among non-hereditary survivors was not increased. Mortality rates of second malignancy among hereditary patients were non-significantly elevated with 1.6-fold for treated with radiotherapy, compared to those treated otherwise. Standardised mortality ratios (SMRs) for second malignancy among hereditary patients increased during the first three decades after retinoblastoma diagnosis. Whereas these risks decreased after three decades, the absolute excess risk (AER) increased significantly, up to 23.2 excess cases per 1000 patients/year after five decades of follow-up. Fifty years after retinoblastoma diagnosis the cumulative mortality from any second malignancy was 17.3% for hereditary patients. Very long-term follow-up of retinoblastoma patients revealed an emerging excess risk of mortality in hereditary retinoblastoma survivors. This implies that lifelong follow-up is needed, whereas at the same time, patients and their physicians must be alerted to the increased second malignancy risks.

Insights from mouse models into human retinoblastoma

Novel murine models of retinoblastoma based on Rb gene deletion in concert with inactivation of Rb family members have recently been developed. These new Rb knockout models of retinoblastoma provide excellent tools for pre-clinical studies and for the exploration of the genetics of tumorigenesis driven by RB inactivation. This review focuses on the developmental consequences of Rb deletion in the retina and the genetic interactions between Rb and the two other members of the pocket protein family, p107 (Rbl1) and p130 (Rbl2). There is increasing appreciation that homozygous RB mutations are insufficient for human retinoblastoma. Identifying and understanding secondary gene alterations that cooperate with RB inactivation in tumorigenesis may be facilitated by mouse models. Recent investigation of the p53 pathway in retinoblastoma, and evidence of spatial topology to early murine retinoblastoma are also discussed in this review.