Role of PET/CT in Staging and Evaluation of Treatment Response After 3 Cycles of Chemotherapy in Locally Advanced Retinoblastoma: A Prospective Study

Management of Extraocular Retinoblastoma: ICMR Consensus Guidelines

Retinoblastoma (RB) is the most common intraocular malignancy of childhood. Advanced stage presentation of RB is common in low middle-income countries (LMICs) due to lack of awareness, social taboos associated with enucleation, seeking alternative conservative treatment options, and poor accessibility to health care. Over the last few decades, there have been significant advancements in the management of extraocular RB (EORB) which have improved outcomes and helped in minimizing treatment-related toxicities. The incorporation of multimodality approaches including chemotherapy, surgery, and radiotherapy (RT) has shown promising results; however, prognosis remains poor especially in LMICs. In this article, authors have discussed the ICMR consensus guidelines on the management of EORB, including metastatic RB.

Baseline and Post-NACT Imaging in Retinoblastoma With Optic Nerve Involvement: Can MRI Predict Prognosis?

PURPOSE

To describe a staging system for optic nerve invasion using magnetic resonance imaging (MRI) and report any correlation with survival outcome.

METHODS

This was a ambispective study. Twenty-one patients with retinoblastoma who had optic nerve involvement on MRI were staged at baseline based on contrast enhancement and/or thickening and length of involvement. Response to neoadjuvant chemotherapy (NACT) was noted according to proposed response evaluation criteria and results were correlated with survival outcome.

RESULTS

Baseline MRI staging was able to predict event-free survival (EFS) (P = .0015) using the log-rank test for trends. Patients with optic nerve enhancement alone showed 100% survival prognosis. Optic nerve thickening cases with complete or partial response to NACT showed better EFS (P > .90) than those with stable disease according to response evaluation criteria.

CONCLUSIONS

The modified staging system for optic nerve invasion used in the current study significantly predicted EFS. The study also showed that response to NACT may be affected by baseline staging. The authors recommend that cases with optic nerve enhancement only, irrespective of the length of involvement (stage 0), may be treated with upfront enucleation. Cases with optic nerve thickening may be staged to evaluate the correlation with survival outcome in a larger cohort in future studies. [J Pediatr Ophthalmol Strabismus. 2024;61(2):98-105.].

Depleted hexokinase1 and lack of AMPKα activation favor OXPHOS-dependent energetics in retinoblastoma tumors

Lack of retinoblastoma (Rb) protein causes aggressive intraocular retinal tumors in children. Recently, Rb tumors have been shown to have a distinctly altered metabolic phenotype, such as reduced expression of glycolytic pathway proteins alongside altered pyruvate and fatty acid levels. In this study, we demonstrate that loss of hexokinase 1(HK1) in tumor cells rewires their metabolism allowing enhanced oxidative phosphorylation-dependent energy production. We show that rescuing HK1 or retinoblastoma protein 1 (RB1) in these Rb cells reduced cancer hallmarks such as proliferation, invasion, and spheroid formation and increased their sensitivity to chemotherapy drugs. Induction of HK1 was accompanied by a metabolic shift of the cells to glycolysis and a reduction in mitochondrial mass. Cytoplasmic HK1 bound Liver Kinase B1 and phosphorylated AMP-activated kinase-α (AMPKα Thr172), thereby reducing mitochondria-dependent energy production. We validated these findings in tumor samples from Rb patients compared to age-matched healthy retinae. HK1 or RB1 expression in Rb-/- cells led to a reduction in their respiratory capacity and glycolytic proton flux. HK1 overexpression reduced tumor burden in an intraocular tumor xenograft model. AMPKα activation by AICAR also enhanced the tumoricidal effects of the chemotherapeutic drug topotecan in vivo. Therefore, enhancing HK1 or AMPKα activity can reprogram cancer metabolism and sensitize Rb tumors to lower doses of existing treatments, a potential therapeutic modality for Rb.

An Interesting Case of Post-enucleation Retinoblastoma Presenting With Distant Liver and Skeletal Metastases Detected on 18F-Fluorodeoxyglucose Positron Emission Tomography-Computed Tomography

Retinoblastomas are the most common primary ocular malignancies in the pediatric population. They are known to undergo metastasis to distant sites like the bone marrow, lymph nodes, and skeleton, but liver metastasis is rare. 18F-fluorodeoxyglucose positron emission tomography-computed tomography is an interesting imaging technique that allows for staging for disease metastasis and plays a crucial role in treatment planning and prognostication of retinoblastoma patients with suspected distant metastasis. The case report highlights this very fact by demonstrating the case of a one-year-old boy with retinoblastoma that had metastasized to the skull bones and even the liver.

PET/CT and PET/MRI in ophthalmic oncology (Review)

Orbital and ocular anatomy is quite complex, consisting of several tissues, which can give rise to both benign and malignant tumors, while several primary neoplasms can metastasize to the orbital and ocular space. Early detection, accurate staging and re-staging, efficient monitoring of treatment response, non-invasive differentiation between benign and malignant lesions, and accurate planning of external radiation treatment, are of utmost importance for the optimal and individualized management of ophthalmic oncology patients. Addressing these challenges requires the employment of several diagnostic imaging techniques, such as high-definition digital fundus photography, ultrasound imaging, optical coherence tomography, optical coherence tomography (OCT)-angiography, computed tomography (CT) and magnetic resonance imaging (MRI). In recent years, technological advances have enabled the development of hybrid positron emission tomography (PET)/CT and PET/MRI systems, setting new standards in cancer diagnosis and treatment. The capability of simultaneously targeting several cancer-related biochemical procedures using positron emitting-radiopharmaceuticals, while morphologically characterizing lesions by CT or MRI, together with the intrinsic quantitative capabilities of PET-imaging, provide incremental diagnostic information, enabling accurate, highly efficient and personalized treatment strategies. Aim of the current review is to discuss the current applications of hybrid PET/CT and PET/MRI imaging in the management of patients presenting with the most commonly encountered orbital and ocular tumors.

Downregulation of CKS1B restrains the proliferation, migration, invasion and angiogenesis of retinoblastoma cells through the MEK/ERK signaling pathway

Retinoblastoma (RB) is a common neoplasm that is exhibited in individuals globally. Increasing evidence demonstrated that cyclin‑dependent kinase regulatory subunit 1B (CKS1B) may be involved in the pathogenesis of various tumor types, including multiple myeloma and breast cancer. In the present study, the hypothesis that CKS1B downregulation would effectively inhibit the proliferation, invasion and angiogenesis of RB cells through the mitogen‑activated protein kinase kinase (MEK)/extracellular signal‑regulated kinase (ERK) signaling pathway was examined. Initial investigation of the expression profile of CKS1B in RB and adjacent retina tissues was performed using reverse transcription‑quantitative polymerase chain reaction and western blot analysis. A total of three RB cell lines, SO‑RB50, Y79 and HXO‑RB44, were examined for selection of the cell line with the highest expression of CKS1B, and human normal retinal vascular endothelial cells (ACBRI‑181) were also evaluated. CKS1B short hairpin RNA (shRNA) sequences (shRNA CKS1B‑1, shRNA CKS1B‑2 and shRNA CKS1B‑3) and negative control shRNA sequences were constructed and transfected into cells at the third generation to evaluate the role of shCKS1B and the MEK/ERK signaling pathway in RB. Furthermore, the effect of shCKS1B on cell proliferation, migration, invasion, apoptosis and angiogenesis was investigated. CKS1B was determined to be highly expressed in RB tissue, compared with adjacent retina tissue. SO‑RB50 and HXO‑RB44 cells treated with shRNA CKS1B‑1 and shRNA CKS1B‑2 were selected for the present experiments. Activation of the MEK/ERK signaling pathway increases the expression of MEK, ERK, B‑cell lymphoma 2, proliferating cell nuclear antigen, cyclin D1, vascular endothelia growth factor and basic fibroblast growth factor, enhances cell proliferation, migration, invasion and lumen formation, and decreases apoptosis. Following silencing CKS1B, the aforementioned conditions were reversed. The key observations of the present study demonstrated that shCKS1B can inhibit the proliferation, invasion and angiogenesis of RB cells by suppressing the MEK/ERK signaling pathway. Thus, CKS1B represents a potential research target in the development of therapeutics for RB.

Whole Body Positron Emission Tomography/Computed Tomography (PET/CT) in the Evaluation of Ophthalmic Tumors

The clinical value of whole body positron emission tomography/computed tomography (PET/CT) as an imaging tool in diagnosis of ophthalmic tumors was investigated. The retrospective observational case series were performed on the patients with suspected ophthalmic tumors who underwent whole body PET/CT. The golden standard of diagnosis was the final pathological diagnosis or the results of long-term follow-up for patients without surgery/biopsy. PET/CT findings were compared with the golden standard. The sensitivity, specificity, accuracy and positive likelihood ratio of PET/CT in the detection of ophthalmic tumors were calculated. The clinical application of PET/CT in different types of ophthalmic tumors was evaluated. The results showed that 30 patients (18 males and 12 females) with a mean age of 43.0 years (range 4-63 years) were collected. The mean sizes of orbital tumors and intraocular tumors were 26.8 mm×17.8 mm and 11.2 mm×6.1 mm, respectively. The overall sensitivity, specificity, accuracy and positive likelihood ratio of whole body PET/CT in ophthalmic tumors were 76.5%, 71.4%, 75.0% and 2.67, and were 62.5%, 100% and 70.0% in intraocular tumors, and those were 100%, 60.0% and 84.6% in orbital tumors, respectively. PET/CT findings were applied to help make appropriate treatment options in 27 out of 30 patients (90.0%), and 12 (40.0%) patients changed the treatment strategy. False negative results in 4 cases and false positive results in 2 cases were observed in this series. It was suggested that PET/CT was an effective imaging modality in detecting, diagnosing and developing therapeutic schedule for patients with ophthalmic tumors. It was more sensitive and accurate for detecting orbital tumors than for detecting intraocular tumors.

Role of Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in Various Orbital Malignancies

Orbital swelling comprises wide spectrum of pseudotumors, benign and malignant tumor. Malignant tumor may be primary or secondary tumor, and they constitute about 36% of orbital tumors in adult. Fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) scan is extensively used in hematological malignancies and in solid tumors for staging, treatment response, and restaging. Recently, the use of FDG-PET/CT in orbital malignancies has gained importance. The aim of this pictorial essay is to illustrate few important orbital malignancies detected in F-18 FDG-PET/CT and discuss its role in assessing the primary lesion and associated systemic finding.

Three presentations of CNS disease in patients with intraocular retinoblastoma at a tertiary medical center in the United States

BACKGROUND

Patients with intraocular retinoblastoma who present with central nervous (CNS) disease at diagnosis is very rare in developed countries.

METHODS

Herein, we report a review of patients with intraocular retinoblastoma diagnosed with concurrent CNS disease in the United States between January 2011 and June 2013.

RESULTS

Three patients were identified in this review. The first case is a 2-year old male who presented with unilateral Group E retinoblastoma, optic nerve infiltration to the orbital apex, and a suprasellar mass. The second case is a 5-month old female with bilateral retinoblastoma, who had no optic nerve invasion, but demonstrated a temporal lobe lesion that was biopsy-proven to be metastatic retinoblastoma. The third case is a 10-month old girl with bilateral retinoblastoma who presented with a sellar mass and no evidence of optic nerve invasion in the enucleated Group E eye.

CONCLUSIONS

Although rare in developed countries, patients with intraocular retinoblastoma can present with a spectrum of CNS findings at the time of diagnosis. Magnetic resonance imaging of the brain and orbits is a critical component of the staging evaluation.

Orbital tumours and tumour-like lesions: exploring the armamentarium of multiparametric imaging

Although the orbit is a small anatomical space, the wide range of structures present within it are often the site of origin of various tumours and tumour-like conditions, both in adults and children. Cross-sectional imaging is mandatory for the detection, characterization, and mapping of these lesions. This review focuses on multiparametric imaging of orbital tumours. Each tumour is reviewed in relation to its clinical presentation, compartmental location, imaging characteristics, and its histological features. We herein describe orbital tumours as lesions of the globe (retinoblastoma, uveal melanoma), optic nerve sheath complex (meningioma, optic nerve glioma), conal-intraconal compartment (hemangioma), extraconal compartment (dermoid/epidermoid, lacrimal gland tumours, lymphoma, rhabdomysarcoma), and bone and sinus compartment (fibrous dysplasia). Lesions without any typical compartmental localization and those with multi-compartment involvement (veno-lymphatic malformation, plexiform neurofibroma, idiopathic orbital pseudotumour, IgG4 related disease, metastases) are also reviewed. We discuss the role of advanced imaging techniques, such as MR diffusion-weighted imaging (DWI), diffusion tensor imaging, fluoro-2-deoxy-D-glucose positron emission tomography CT (FDG-PET CT), and positron emission tomography MRI (MRI PET) as problem-solving tools in the evaluation of those orbital masses that present with non-specific morphologic imaging findings. Main messages/Teaching points • A compartment-based approach is essential for the diagnosis of orbital tumours. • CT and MRI play a key role in the work-up of orbital tumours. • DWI, PET CT, and MRI PET are complementary tools to solve diagnostic dilemmas. • Awareness of salient imaging pearls and diagnostic pitfalls avoids interpretation errors.

Rare case of trilateral retinoblastoma with spinal canal drop metastasis detected with fluorine-18 fluorodeoxyglucose positronemission tomography/computed tomography imaging

Trilateral retinoblastoma (TRb) is a rare syndrome associating hereditary bilateral or unilateral retinoblastoma (Rb) with an intracranial neuroblastic tumor. The latter arises in the midline, most often in the pineal gland, less frequently in the suprasellar or parasellar region. The outcome is usually fatal because of secondary spinal dissemination. We report 10-year-old boy presented with a right eye proptosis and leukocoria, and the magnetic resonance imaging (MRI) showed right orbital mass lesion infiltrating optic nerve and diagnosis of retinoblastoma was made. He was referred for fluorodeoxyglucose-positron emission tomography/computed tomography (FDG PET/CT) to find out the extent of the disease. PET/CT showed abnormal FDG-uptake within right orbital mass lesion, suprasellar enhancing lesion and drop metastasis in the cervical spinal canal level. He was diagnosed as a case of TRb with spinal canal drop metastasis. He underwent chemotherapy and craniospinal irradiation.

[(18)F]-fluorodeoxyglucose positron emission tomography and computed tomography in response evaluation of oncolytic adenovirus treatments of patients with advanced cancer

Computed tomography (CT) is the most commonly used radiological response evaluation method in contemporary oncology. However, it may not be optimally suitable for assessment of oncolytic virus treatments because of paradoxical inflammatory tumor swellings, which result from virus treatments, particularly when viruses are armed with immunostimulatory molecules. Here we investigated the prognostic utility of CT and [(18)F]-fluorodeoxyglucose (FDG) positron emission tomography (PET) in oncolytic virus treatments. We also investigated possible appearance of false-positive FDG signals in FDG-PET imaging of humans and hamsters treated with oncolytic adenoviruses. First, immunocompetent Syrian hamsters were treated with intratumoral adenovirus injections, tumor growth was followed up, and [(18)F]-FDG-uptake was quantitated with small animal PET/CT. Second, we describe a retrospective patient series, essentially 17 individual case reports, of advanced cancer patients treated with oncolytic adenoviruses in the context of an Advanced Therapy Access Program (ATAP) who underwent radiological response evaluation with both contrast-enhanced CT and FDG-PET. Third, we collected a retrospective case series of radiological response and survival data of 182 patients treated with oncolytic adenoviruses in ATAP to evaluate the prognostic reliability of CT and FDG-PET. Overall, responses in CT and FDG-PET correlated well with each other and were equally reliable as prognostic markers for long survival after oncolytic adenovirus treatment. Interestingly, we observed that new FDG-avid lymph nodes appearing in FDG-PET after virus treatments may represent inflammatory responses and therefore should not be interpreted as treatment failure in the absence of other signs or verification of disease progression. We also observed indications that FDG-PET might be more sensitive in detection of responses than tumor size.

Value of positron emission tomography/computed tomography in diagnosis and staging of primary ocular and orbital tumors

Accurate and reliable staging methods are crucial for optimal care of patients with ocular and orbital malignancies. Positron emission tomography/computed tomography (PET/CT) has recently emerged as a staging tool in the field of ophthalmic oncology. For detecting primary ocular or orbital lesions, PET/CT does not seem to provide an advantage over clinical ophthalmologic examination or conventional imaging studies such as CT or magnetic resonance imaging of the orbit. However, PET/CT may detect distant metastatic lesions that conventional imaging studies miss. For orbital and ocular adnexal lymphoma, use of PET/CT has been proven to be feasible and is now accepted both as a standard part of the initial staging work-up and for the assessment of response to therapy. For other ophthalmic tumors, PET/CT seems most appropriate for advanced metastatic tumors of the orbit, eyelid, and eye, for which the detection of distant metastasis with 1 comprehensive study may be preferable to performing multiple CT scans with contrast.