The Effect of Ophthalmic Artery Chemosurgery on Immune Function in Retinoblastoma Patients: A Single Institution Retrospective Analysis

Ophthalmic Artery Chemosurgery for Retinoblastoma Babies Less than 3 Months Old or under 6-kg Weight

OBJECTIVE

To determine the feasibility, safety, and efficacy of ophthalmic artery chemosurgery (OAC) for very young children who have unilateral and bilateral retinoblastoma.

DESIGN

Retrospective, consecutive review of all children with retinoblastoma (unilateral and bilateral) treated with OAC in the first 3 months of life or, if weighing <6 kg, treated at the Memorial Sloan Kettering Cancer Center.

PARTICIPANTS

All children with retinoblastoma (unilateral or bilateral) treated with OAC (17 patients) in the first 3 months of life or weighing <6 kg.

METHODS

Ophthalmic artery chemosurgery delivered by microcatheter inserted in the femoral artery and through the internal carotid artery. Combinations of melphalan, carboplatin, and topotecan were delivered in 60 sessions via the ophthalmic artery in 17 patients.

MAIN OUTCOME MEASURES

Ocular salvage, serial electroretinograms, patient survival, second cancers, fever/neutropenia, transfusion of any blood product, groin bleeding or femoral artery occlusion, and anesthetic complications.

RESULTS

Seventeen retinoblastoma patients under the age of 3 months or weighing <6 kg were successfully canulated and treated a total of 60 times (11 bilateral patients and 6 unilateral patients) with combinations of Melphalan, Carboplatin, and Topotecan. All patients are alive; the mean follow-up 4 years. No patient developed metastatic disease, second cancer, or trilateral retinoblastoma and all eyes were salvaged. There were no cases of chemotherapy induced fever/neutropenia or need for transfusion of any blood product. Electroretinogram was not impaired by treatment, significant improvement in 30Hz function was seen (P = 0.02; mean before 61 μV, after 71 μV, SEM: 5.25 vs. 5.82).

CONCLUSIONS

Very young children (<3 months old and <6 kg weight) with unilateral or bilateral retinoblastoma can be safely and effectively treated with OAC (intra-arterial chemotherapy) without significant complications even though the majority had advanced intraocular disease (Reese-Ellsworth Vb or International Classification of Retinoblastoma "D" and "E"). This includes treating both eyes in the same session and as young as 5 weeks and weighing 3.6 kg. This eliminates the need for systemic chemotherapy, which is well known to be toxic to the youngest children.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

What have we learned about intraarterial chemotherapy (Ophthalmic Artery Chemosurgery) for retinoblastoma in the past 18 years? The third A. Linn Murphree Lecture

Intraarterial chemotherapy (Ophthalmic Artery Chemosurgery/OAC) for retinoblastoma has transformed management of retinoblastoma worldwide since Pierre Gobin MD and I introduced it in 2006. Case reports, institutional series, meta-analyses, and randomized trials have validated its effectiveness and safety. It allows more eyes to be saved (at Memorial Sloan Kettering Cancer Center (MSKCC) as a result, we have gone from removing 96% of retinoblastoma eyes that presented with leukocoria (comparable to modern day International Classification "D" and "E" eyes) to saving 95% of these eyes with primary OAC management allows the majority of advanced intraocular eyes to be salvaged (both "D" and "E" eyes) prior to the chemoreduction era to saving 95% of these eyes with primary OAC management. OAC attains cures faster than intravenous protocols, has fewer systemic side effects, and is overall cheaper than intravenous approaches (because of the absence of side effects which are the main driver of cost in pediatric oncology). Unlike systemic chemotherapy no ports are needed (and no removal of ports for life threatening infections), it does not alter the immune system (so children can be immunized), it does not affect patient growth (and children who had received systemic chemotherapy catch up in growth during OAC), it does not affect hearing (which systemic Carboplatin does-especially in children <6 months of age), it eliminates the second cancers caused by radiation and systemic chemotherapy and does not compromise survival with all series showing patient survival >98%.

Spotlight on Targeted Chemotherapy in Retinoblastoma: Safety, Efficacy, and Patient Outcomes

As the most common primary intraocular malignancy of childhood, retinoblastoma (RB) has had a complex journey in its management, following a course from enucleation as the first life-saving treatment to numerous globe-salvaging therapies during the last century. Currently, this potentially lethal disease has achieved high survival rates owing to multidisciplinary management and the introduction of neoadjuvant and multimodal chemotherapy. Therefore, the goal of treatment is shifting toward conserving the globe and vision as much as possible. Up until recently, many advanced cases of RB were enucleated primarily; however, targeted chemotherapy via the ophthalmic artery and management of intraocular seeding by local administration of chemotherapeutic agents have revolutionized the globe-conserving therapies. The added benefit of avoiding systemic complications of cytotoxic drugs resulted in these methods gaining popularity, and they are becoming a main part of care in many referral centers. Initially, there were some safety concerns regarding these approaches; however, increasing experience has shown that these modalities are relatively safe procedures and many complications can be averted by changing the choice of the drug and using some prophylactic measures. It is hoped that, in the near future, with advances in early diagnosis and patient-targeted molecular therapies, as well as gene-editing techniques, the patient's vision can be saved even in advanced RB.

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.

Efficacy, Toxicity, and Pharmacokinetics of Intra-Arterial Chemotherapy Versus Intravenous Chemotherapy for Retinoblastoma in Animal Models and Patients

Purpose

Through controlled comparative rabbit experiments and parallel patient studies, our purpose was to understand mechanisms underlying differences in efficacy and toxicity between intra-arterial chemotherapy (IAC) and intravenous chemotherapy (IVC).

Methods

In rabbits, ocular tissue drug levels were measured following IAC and IVC. Retinal toxicity was assessed using electroretinography, fluorescein angiography, optical coherence tomography (OCT) and OCT angiography. Efficacy to eradicate retinoblastoma orthotopic xenografts was compared. In IAC and IVC patients, we measured blood carboplatin pharmacokinetics and compared efficacy and toxicity.

Results

In rabbits receiving IAC, maximum carboplatin levels were 134 times greater in retina (P = 0.01) and 411 times greater in vitreous (P < 0.001), and total carboplatin (area under the curve) was 123 times greater in retina (P = 0.005) and 131 times greater in vitreous (P = 0.02) compared with IVC. Melphalan levels were 12 times greater (P = 0.003) in retina and 26 times greater in vitreous (P < 0.001) for IAC. Blood levels were not different. IAC melphalan (but not IV melphalan or IV carboplatin, etoposide, and vincristine) caused widespread apoptosis in retinoblastoma xenografts but no functional retinal toxicity or cytopenias. In patients, blood levels following IVC were greater (P < 0.001) but, when adjusted for treatment dose, were not statistically different. Per treatment cycle in patients, IVC caused higher rates of anemia (0.32 ± 0.29 vs. 0.01 ± 0.04; P = 0.0086), thrombocytopenia (0.5 ± 0.42 vs. 0.0 ± 0.0; P = 0.0042), and neutropenia (0.58 ± 0.3 vs. 0.31 ± 0.25; P = 0.032) but lower treatment success rates (P = 0.0017).

Conclusions

The greater efficacy and lower systemic toxicity with IAC appear to be attributable to the greater ocular-to-systemic drug concentration ratio compared with IVC.

Translational Relevance

Provides an overarching hypothesis for a mechanism of efficacy/toxicity to guide future drug development.

Rabbit Model of Intra-Arterial Chemotherapy Toxicity Demonstrates Retinopathy and Vasculopathy Related to Drug and Dose, Not Procedure or Approach

Purpose

To use our intra-arterial chemotherapy (IAC) rabbit model to assess the impact of IAC procedure, drug, dose, and choice of technique on ocular structure and function, to study the nature and etiology of IAC toxicity, and to compare to observations in patients.

Methods

Rabbits received IAC melphalan (0.4-0.8 mg/kg), carboplatin (25–50 mg), or saline, either by direct ophthalmic artery cannulation, or with a technique emulating nonocclusion. Ocular structure/function were assessed with examination, electroretinography (ERG), fundus photography, fluorescein angiography, optical coherence tomography (OCT), and OCT angiography, prior to and 5 to 6 weeks after IAC. Blood counts were obtained weekly. We reviewed our last 50 IAC treatments in patients for evidence of ocular or systemic complications.

Results

No toxicity was seen in the saline control group. With standard (0.4 mg/kg) melphalan, no vascular/microvascular abnormalities were seen with either technique. However, severe microvascular pruning and arteriolar occlusions were seen occasionally at 0.8 mg/kg doses. ERG reductions were dose-dependent. Histology showed melphalan dose-dependent degeneration in all retinal layers, restricted geographically to areas of greatest vascular density. Carboplatin caused massive edema of ocular/periocular structures. IAC patients experienced occasional periocular swelling/rash, and only rarely experienced retinopathy or vascular events/hemorrhage in eyes treated multiple times with triple (melphalan/carboplatin/topotecan) therapy. Transient neutropenia occurred after 46% of IAC procedures, generally after triple therapy.

Conclusions

IAC toxicity appears to be related to the specific drug being used and is dose-dependent, rather than related to the IAC procedure itself or the specific technique selected. These rabbit findings are corroborated by our clinical findings in patients.

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.

Growth patterns of survivors of retinoblastoma treated with ophthalmic artery chemosurgery

Although studies from pediatric cancers (largely acute lymphoblastic leukemia) have shown that patients undergoing systemic chemotherapy may experience decreased growth velocity during the treatment phase, no such data exist for retinoblastoma patients treated with systemic chemotherapy or ophthalmic artery chemosurgery (OAC). The purpose of this study is to report growth patterns of our retinoblastoma (Rb) population who were treated with OAC in a retrospective, single center (Memorial Sloan Kettering Cancer Center) review of 341 patients treated between 2006 and 2016. Children who only received OAC were classified as naive; those who were treated initially with systemic chemotherapy and subsequently presented to our center for OAC were termed secondary; and a small group of patients who received single-agent systemic chemotherapy prior to OAC were labeled bridge. For all patients, height and weight were recorded at monthly intervals during OAC (short-term) and then annually during a follow-up period (long-term) up to 3 years after treatment. Excluded from this study were children who received external radiation therapy and those with genetic syndromes, which are independently associated with growth derangements. During OAC, there was no significant difference in growth velocity between the naïve and secondary groups. In either group, number of treatments also did not affect growth rate. Three years after the end of OAC, naïve patients were in the 68th percentile by height (95% CI 61.30, 74.63) compared to secondary patients in the 61st percentile (95% CI 51.1, 71.47). Both groups were in the same weight percentiles during the first two years of follow-up but at the three-year follow-up period, naïve patients were in the 63rd percentile (95% CI 57.4, 69.4) and secondary patients were in the 60th percentile (95% CI 50.4, 69.7). OAC for retinoblastoma does not appear to impact short-term growth velocity, weight gain during the treatment period or after three years.