Treatment of Retinoblastoma: What Is the Latest and What Is the Future

The management of retinoblastoma, the most common intraocular malignancy in children, has changed drastically over the last decade. Landmark developments in local drug delivery, namely, safer techniques for intravitreal chemotherapy injection and ophthalmic artery chemosurgery, have resulted in eye globe salvages that were not previously attainable using systemic chemotherapy or external beam irradiation. Novel drugs, oncolytic viruses, and immunotherapy are promising approaches in the treatment of intraocular retinoblastoma. Importantly, emerging studies of the pattern of tumor dissemination and local drug delivery may provide the first steps toward new treatments for metastatic disease. Here, we review recent advances in retinoblastoma treatment, especially with regard to local drug delivery, that have enabled successful conservative management of intraocular retinoblastoma. We also review emerging data from preclinical and clinical studies on innovative approaches that promise to lead to further improvement in outcomes, namely, the mechanisms and potential uses of new and repurposed drugs and non-chemotherapy treatments, and discuss future directions for therapeutic development.

Neonatal Retinoblastoma

Retinoblastoma is the most common ocular malignancy of childhood. With an estimated 300 cases annually in the United States, retinoblastoma is nevertheless considered a rare tumor. Although retinoblastoma primarily affects younger children, diagnosis during the neonatal age range is less common. However, an understanding of patients at risk is critical for appropriate screening. Early detection and treatment by a multidisciplinary specialty team maximizes the chance for survival and ocular/vision salvage while minimizing treatment-related toxicity. Testing for alterations in the RB1 gene has become standard practice, and informs screening and genetic counseling recommendations for patients and their families.

Interventional neuro-oncology

Interventional neuro-oncology encompasses an array of image-guided therapies-intra-arterial chemotherapy, regional drug delivery, chemoembolization, tumor ablation-along with techniques to improve therapy delivery such as physical or chemical blood-brain barrier disruption and percutaneous catheter placement. Endovascular and percutaneous image-guided approaches to the treatment of the brain, eye, and other head and neck tumors will be discussed.

Risk Factors for Acute Choroidal Ischemia after Intra-arterial Melphalan for Retinoblastoma: The Role of the Catheterization Approach

PURPOSE

To identify risk factors for acute choroidal ischemia (ACI) after intra-arterial chemotherapy (IAC) for retinoblastoma.

DESIGN

Retrospective cohort study.

PARTICIPANTS

Two hundred twenty patients (248 eyes) treated with IAC in Lausanne between November 2008 and September 2019 (665 procedures). All patients were evaluated on a monthly basis with fundus photography and fluorescein angiography before and after each IAC injection.

METHODS

Acute choroidal ischemia, defined as any new choroidal ischemia clinically diagnosed within 35 days after an IAC injection, were noted. Eyes with choroidal complications diagnosed later than 35 days after the last IAC injection (n = 7) or those for which the status of the choroid was not assessable (n = 35) were excluded. Specific procedure parameters and treatment regimens were compared between the group of eyes with and without ACI.

MAIN OUTCOME MEASURES

Procedure-related risk factors for ACI after IAC injection and visual acuity assessment in the group of eyes with ACI.

RESULTS

Acute choroidal ischemia developed in 35 of 206 included eyes after a mean of 2 injections. No differences were found between the two study groups regarding age at first IAC injection, disease grouping at diagnosis, previously administered treatments, number of IAC injections, drug dose, mean injection time, injection method (pulsatile vs. continuous), or concomitant intravitreal melphalan use. Treatment regimen (melphalan vs. combined melphalan plus topotecan; P < 0.05), catheterization route (internal carotid artery vs. external carotid or posterior communicating artery; P < 0.001), and catheterization type (occlusive into the ophthalmic artery [OA] vs. nonocclusive; P < 0.001) were included in multivariate analysis, and occlusive catheterization was identified as an independent risk factor for ACI (P < 0.001). In the subgroup undergoing an occlusive procedure, placement of the catheter tip into the OA distal third versus medial and proximal thirds (P = 0.04) and a mean catheter diameter-to-OA lumen ratio of 0.6 or more (P < 0.001) were correlated significantly with ACI. Complete vision loss was noted in 27% of the eyes with ACI that were old enough for visual assessment (n = 9/33), whereas 33% maintained a useful vision ranging between 0.1 and 0.8 (n = 11/33).

CONCLUSIONS

Catheterization of the OA should be attempted from an ostial position or an external carotid approach to minimize the risk of potentially vision-threatening choroidal complications.

Superselective intra-arterial chemotherapy treatment for retinoblastoma: clinical experience from a tertiary referral centre

OBJECTIVE

To evaluate the treatment outcomes of an alternative retrograde superselective ophthalmic artery catheterization (intra-arterial chemotherapy [IAC]), while treating retinoblastoma patients.

METHODS

A retrospective review of IAC for 21 treatment-naïve eyes (21 patients, primary group) and 10 eyes of previously treated 9 patients (secondary group). Statistical analysis was performed using Number Cruncher Statistical System 2007, Kaplan-Meier survival analysis, and Fisher's exact test.

RESULTS

Total fluoroscopy time ranged from 3 to 12 minutes. Globe salvage was 71.4% (15/21 eyes) and 80% (8/10 eyes) in the primary and secondary groups, respectively. Globe salvage rates were recorded as 100%, 100%, 70%, and 0% for group B, C, D, and E patients, respectively.

CONCLUSIONS

Retrograde IAC is effective in tumour control with shorter fluoroscopy time and acceptable complication rates both for naïve and treated patients. Furthermore, controlling retinoblastoma in advanced group D eyes was efficacious.

Intra-arterial chemotherapy in retinoblastoma - A paradigm change

Intra-arterial chemotherapy (IAC), also known as superselective ophthalmic artery chemotherapy or chemosurgery, is currently widely accepted as one of the primary treatment modalities for intraocular retinoblastoma worldwide. Following the introduction of the technique in 1998, IAC has evolved over the past decades to be safer and more effective. Accumulated evidence shows that IAC is more effective in providing eye salvage in group D and E retinoblastoma as compared to conventional systemic intravenous chemotherapy (IVC). In contrast to IVC, IAC has the added benefits of reduced overall treatment duration and minimal systemic toxicity. This review provides a comprehensive update on the history, technique, indications, contraindications, and outcome of IAC. We have also identified the strengths, weaknesses, opportunities and threats (SWOT analysis) of the technique in this review.

Conservative management of retinoblastoma: Challenging orthodoxy without compromising the state of metastatic grace. "Alive, with good vision and no comorbidity"

Retinoblastoma is lethal by metastasis if left untreated, so the primary goal of therapy is to preserve life, with ocular survival, visual preservation and quality of life as secondary aims. Historically, enucleation was the first successful therapeutic approach to decrease mortality, followed over 100 years ago by the first eye salvage attempts with radiotherapy. This led to the empiric delineation of a window for conservative management subject to a "state of metastatic grace" never to be violated. Over the last two decades, conservative management of retinoblastoma witnessed an impressive acceleration of improvements, culminating in two major paradigm shifts in therapeutic strategy. Firstly, the introduction of systemic chemotherapy and focal treatments in the late 1990s enabled radiotherapy to be progressively abandoned. Around 10 years later, the advent of chemotherapy in situ, with the capitalization of new routes of targeted drug delivery, namely intra-arterial, intravitreal and now intracameral injections, allowed significant increase in eye preservation rate, definitive eradication of radiotherapy and reduction of systemic chemotherapy. Here we intend to review the relevant knowledge susceptible to improve the conservative management of retinoblastoma in compliance with the "state of metastatic grace", with particular attention to (i) reviewing how new imaging modalities impact the frontiers of conservative management, (ii) dissecting retinoblastoma genesis, growth patterns, and intraocular routes of tumor propagation, (iii) assessing major therapeutic changes and trends, (iv) proposing a classification of relapsing retinoblastoma, (v) examining treatable/preventable disease-related or treatment-induced complications, and (vi) appraising new therapeutic targets and concepts, as well as liquid biopsy potentiality.

The American Society of Retina Specialists 2016 Founders Award Lecture

Purpose:

To review the current state of the art of retinal tumors with respect to clinical features, imaging, and management.

Methods:

Review of published literature and personal experience from an ocular oncology service.

Results:

There are several tumors that arise from the sensory retina including those of glial origin (astrocytic hamartoma, acquired astrocytoma, and solitary circumscribed retinal astrocytic proliferation), neural origin (retinoblastoma), and vascular origin (hemangioblastoma, cavernous hemangioma, racemose hemangioma, and vasoproliferative tumor). Most retinal tumors are benign with the exception of retinoblastoma and retinal metastasis. Some retinal tumors are associated with systemic oculoneurocutaneous syndromes such as tuberous sclerosis complex (TSC), 13q deletion syndrome, Von Hippel–Lindau disease, and systemic cavernous and racemose hemangioma syndromes with ocular, cutaneous, neurologic, and other findings. Regarding management, recent data indicate that retinal astrocytic hamartoma and retinal achromic patch are key to the diagnosis of TSC and imply greater risk for brain and kidney tumors. Some children with TSC respond to mammalian target of rapamycin inhibitors, controlling brain, kidney, and eye tumors. Children with retinoblastoma are all screened genetically, and systemic evaluation is provided for detection of metastasis and secondary-related tumors. Newer chemotherapy regimens by intravenous or intra-arterial routes have revolutionized retinoblastoma control. Retinal vascular tumors are uncommon but can have serious systemic implications. Therefore, imaging of the brain for related cerebellar hemangioblastoma, midbrain racemose hemangioma, or multifocal cavernomas is performed. Genetic testing for each disease can be revealing.

Conclusions:

Retinal tumors are often benign, can be recognized by clinical and imaging features, and can be associated with important systemic syndromes.