The clinical outcomes of proton beam radiation therapy for retinoblastomas that were resistant to chemotherapy and focal treatment

Craniospinal irradiation and/or intraventricular radioimmunotherapy after high-dose chemotherapy and autologous stem cell rescue in patients with CNS retinoblastoma-Safety and outcomes

BACKGROUND

The prognosis for patients with central nervous system (CNS) retinoblastoma (RB) (trilateral or stage 4b metastatic RB) treated with high-dose chemotherapy and autologous stem cell transplant (HDC-ASCT) remains poor. The impact of irradiation when administered as part of upfront therapy post HDC-ASCT on treatment outcomes and survival is unknown.

METHODS

We performed a retrospective review of all patients with CNS RB (seven stage 4b, eight trilateral, one pineal lesion belonging to methylation group RB) who underwent induction chemotherapy with an intent to proceed to HDC-ASCT at two institutions.

RESULTS

Twelve of 16 patients (n = 75%) achieved an objective response to induction chemotherapy, while four patients had progressive/refractory disease; two patients responded to subsequent therapy and proceeded to ASCT, and two patients did not. Seven of 14 patients who underwent HDC-ASCT, received radiotherapy as part of upfront therapy post HDC-ASCT in the form of craniospinal irradiation (CSI) (n = 3), intraventricular radioimmunotherapy (n = 3), or both CSI and intraventricular radioimmunotherapy (n = 1). The Kaplan-Meier estimate of overall survival for these patients was 62.5% at 5 years; no patients developed second malignant neoplasms within the radiation fields. For the seven patients who did not receive radiotherapy, the overall survival was 28.6% at 5 years.

CONCLUSIONS

CSI (23.4 Gy) alone or in conjunction with intraventricular RIT may have clinical utility in eliminating persistent MRD post HDC-ASCT, contributing to improved disease-free survival in patients with CNS RB. This treatment strategy merits evaluation in a prospective, multicenter clinical trial for patients with CNS metastatic RB.

Feasibility of Proton Beam Therapy as a Rescue Therapy in Heavily Pre-Treated Retinoblastoma Eyes

Simple Summary

A variety of therapies are available for the treatment of retinoblastomas. Nevertheless, despite exhaustion of all therapeutic methods, refractory or recurrent courses of the disease occur. In eyes with a function worthy of preservation radiation therapy may become unavoidable. Proton beam therapy, compared to conventional photon-based radiotherapy, is a highly conformal form of radiation therapy with a high biological effectiveness with a simultaneously reduced probability of radiation-related side-effects and induction of secondary primary malignancies. The aim of our retrospective study was to evaluate the efficacy of proton beam therapy as rescue therapy in 15 heavily pretreated retinoblastoma eyes. In our retrospective series of a highly negatively selected patient population, we were able to preserve 60% of the eyes with a manageable side effect profile. A cataract, as the most common long-term complication, was evident in 44.4% of the preserved eyes. There was no in-field second tumor manifestation during follow-up, therefore the preliminary data of this study and series published by others suggest that the risk is significantly lower after proton beam therapy compared to conventional external beam radiation therapy using photons.

Abstract

Despite the increased risk of subsequent primary tumors (SPTs) external beam radiation (EBRT) may be the only therapeutic option to preserve a retinoblastoma eye. Due to their physical properties, proton beam therapy (PBT) offers the possibility to use the effectiveness of EBRT in tumor treatment and to decisively reduce the treatment-related morbidity. We report our experiences of PBT as rescue therapy in a retrospectively studied cohort of 15 advanced retinoblastoma eyes as final option for eye-preserving therapy. The average age at the initiation of PBT was 35 (14–97) months, mean follow-up was 22 (2–46) months. Prior to PBT, all eyes were treated with systemic chemotherapy and a mean number of 7.1 additional treatments. Indication for PBT was non-feasibility of intra-arterial chemotherapy (IAC) in 10 eyes, tumor recurrence after IAC in another 3 eyes and diffuse infiltrating retinoblastoma in 2 eyes. Six eyes (40%) were enucleated after a mean time interval of 4.8 (1–8) months. Cataract formation was the most common complication affecting 44.4% of the preserved eyes, yet 77.8% achieved a visual acuity of >20/200. Two of the 15 children treated developed metastatic disease during follow-up, resulting in a 13.3% metastasis rate. PBT is a useful treatment modality as a rescue therapy in retinoblastoma eyes with an eye-preserving rate of 60%. As patients are at lifetime risk of SPTs consistent monitoring is mandatory.

Clinical and magnetic resonance imaging features of 14 patients with trilateral retinoblastoma

Background

Our study aimed to comprehensively investigate the age of onset, magnetic resonance imaging (MRI) features, and prognosis of children with trilateral retinoblastoma (TRB).

Methods

We included 14 patients with TRB diagnosed or followed up in our hospital. The age of onset and MRI features of the intraocular tumor and intracranial lesions were evaluated. A follow-up study was also conducted.

Results

A total of 11 participants were diagnosed with concurrent TRB at the age of 11.1±7.4 months, and 3 participants had late-onset TRB at age 37±19.1 months. The incidence of TRB with unilateral eye involvement was 7.1% (1/14). The intraocular tumors showed intense enhancement in contrast-enhanced T1-weighted images (WI) and significant diffusion restriction in diffusion WI (DWI) with an apparent diffusion coefficient (ADC) of (0.619±0.22)×10^-3 mm²/s. The intracranial lesions showed similar DWI aspects with an ADC value of (0.680±0.206)×10^-3 mm²/s. Therapeutically, 8 participants had a period of intraocular tumor stabilization and significant intracranial lesion volume reduction after chemotherapy, and 6 participants had given up treatment. Only 2 participants who simultaneously received high-dose chemotherapy and autologous hematopoietic stem cell rescue were still alive with no recurrence at 24 and 54 months of follow-up. The 1-, 2-, and 3-year overall survival (OS) rates were 80%, 18.75%, and 12.5%, respectively.

Conclusions

Patients with unilateral or bilateral RB can develop TRB. The intraocular and intracranial tumors showed slightly different ADC values. High-dose chemotherapy, combined with stem cell rescue can significantly improve survival. A long term and scheduled follow-up before 60 months of age is necessary for screening later-onset TRB patients.

The role of external beam radiation therapy for retinoblastoma after failure of combined chemoreduction and focal consolidation therapy

Purpose: To study the role of external beam radiation therapy (EBRT) for the treatment of retinoblastoma eyes that were not cured by combined systemic chemotherapy and focal consolidation therapy.Methods and Materials: A retrospective case series of 28 eyes for 24 retinoblastoma patients treated by EBRT after the failure of tumor controlled by chemotherapy and focal therapy. The main outcome measures included: international intraocular retinoblastoma classification stage (IIRC) and Reese Ellsworth (RE) stage, tumor seeding, treatment modalities, eye salvage, and survival.Results: The median age at diagnosis was 11 months. There were 14 (58%) males and 20 (83%) bilateral cases. All eyes were treated initially by systemic chemotherapy (range; 6-8 cycles). The dose of radiation used for all eyes was 45 Gray (Gy).The mean follow-up was 75months, and the overall eye salvage rate after EBRT was 13 (46%) eyes: 67% (2/3) for IIRC group B, 71% (5/7) for group C, and 33% (6/18) for group D eyes. Vitreous seeds and tumor stage migration during management by chemotherapy were the most important significant predictive factors for tumor control (p = .001 and 0.033, respectively).Conclusion: Eyes with retinoblastoma that failed chemotherapy followed by focal therapy were controlled with EBRT. However, the presence of vitreous seeds, stage migration during the course of chemotherapy, as well as good vision in the other eye may not justify the known risks of EBRT.

Paediatric proton therapy

Proton beam therapy is a highly conformal form of radiation therapy, which currently represents an important therapeutic component in multidisciplinary management in paediatric oncology. The precise adjustability of protons results in a reduction of radiation-related long-term side-effects and secondary malignancy induction, which is of particular importance for the quality of life. Proton irradiation has been shown to offer significant advantages over conventional photon-based radiotherapy, although the biological effectiveness of both irradiation modalities is comparable. This review evaluates current data from clinical and dosimetric studies on the treatment of tumours of the central nervous system, soft tissue and bone sarcomas of the head and neck region, paraspinal or pelvic region, and retinoblastoma. To date, the clinical results of irradiating childhood tumours with high-precision proton therapy are promising both with regard to tumour cure and the reduction of adverse events. Modern proton therapy techniques such as pencil beam scanning and intensity modulation are increasingly established modern facilities. However, further investigations with larger patient cohorts and longer follow-up periods are required, in order to be able to have clear evidence on clinical benefits.

Outcomes of Proton Beam Radiation Therapy for Retinoblastoma With Vitreous Seeds

Vitreous seeds are the most challenging aspect in the management of retinoblastoma. We report the outcomes of treatment with proton beam radiation therapy (PBRT) for retinoblastoma with vitreous seeds in naive or previously treated eyes. In this retrospective case series, we analyzed data of 4 retinoblastoma patients with vitreous seeds who received PBRT at the Proton Therapy Center, National Cancer Center in Korea between June 2007 and August 2017. All 4 eyes treated by PBRT were classified as group D according to the International Classification of Retinoblastoma (ICRB) criteria, and the vitreous seeds, as class 3 (clouds). The tumor and vitreous seeds regressed in 2 eyes, and globe salvage was achieved in these 2 eyes (50%). The post-PBRT ophthalmologic follow-up time of these 2 preserved eyes was 12 and 50 months, respectively. Visual acuity measurements of the successfully treated patients were 20/40 and 20/600. No radiation-associated malignancies were noted. In conclusion, PBRT successfully treated vitreous seeds classified as clouds in half of the cases, and successfully treated patients who retained useful vision. Therefore, PBRT might be a viable treatment option for vitreous seeds in patients with retinoblastoma.

Effects on Periocular Tissues after Proton Beam Radiation Therapy for Intraocular Tumors

BACKGROUND

To present our experience on orbital and periorbital tissue changes after proton beam radiation therapy (PBRT) in patients with intraocular tumors, apart from treatment outcomes and disease control.

METHODS

Medical records of 6 patients with intraocular tumors who had been treated with PBRT and referred to oculoplasty clinics of two medical centers (Seoul National University Hospital and Seoul Metropolitan Government-Seoul National University Boramae Medical Center) from October 2007 to September 2014 were retrospectively reviewed. The types of adverse effects associated with PBRT, their management, and progression were analyzed. In anophthalmic patients who eventually underwent enucleation after PBRT due to disease progression, orbital volume (OV) was assessed from magnetic resonance (MR) images using the Pinnacle3 program.

RESULTS

Among the six patients with PBRT history, three had uveal melanoma, and three children had retinoblastoma. Two eyes were treated with PBRT only, while the other four eyes ultimately underwent enucleation. Two eyes with PBRT only suffered from radiation dermatitis and intractable epiphora due to canaliculitis or punctal obstruction. All four anophthalmic patients showed severe enophthalmic features with periorbital hollowness. OV analysis showed that the difference between both orbits was less than 0.1 cm before enucleation, but increased to more than 2 cm³ after enucleation.

CONCLUSION

PBRT for intraocular tumors can induce various orbital and periorbital tissue changes. More specifically, when enucleation is performed after PBRT due to disease progression, significant enophthalmos and OV decrease can develop and can cause poor facial cosmesis as treatment sequelae.

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.

Monte Carlo study for designing a dedicated "D"-shaped collimator used in the external beam radiotherapy of retinoblastoma patients

PURPOSE

Retinoblastoma is the most common intraocular malignancy in the early childhood. Patients treated with external beam radiotherapy respond very well to the treatment. However, owing to the genotype of children suffering hereditary retinoblastoma, the risk of secondary radio-induced malignancies is high. The University Hospital of Essen has successfully treated these patients on a daily basis during nearly 30 years using a dedicated "D"-shaped collimator. The use of this collimator that delivers a highly conformed small radiation field, gives very good results in the control of the primary tumor as well as in preserving visual function, while it avoids the devastating side effects of deformation of midface bones. The purpose of the present paper is to propose a modified version of the "D"-shaped collimator that reduces even further the irradiation field with the scope to reduce as well the risk of radio-induced secondary malignancies. Concurrently, the new dedicated "D"-shaped collimator must be easier to build and at the same time produces dose distributions that only differ on the field size with respect to the dose distributions obtained by the current collimator in use. The scope of the former requirement is to facilitate the employment of the authors' irradiation technique both at the authors' and at other hospitals. The fulfillment of the latter allows the authors to continue using the clinical experience gained in more than 30 years.

METHODS

The Monte Carlo code PENELOPE was used to study the effect that the different structural elements of the dedicated "D"-shaped collimator have on the absorbed dose distribution. To perform this study, the radiation transport through a Varian Clinac 2100 C/D operating at 6 MV was simulated in order to tally phase-space files which were then used as radiation sources to simulate the considered collimators and the subsequent dose distributions. With the knowledge gained in that study, a new, simpler, "D"-shaped collimator is proposed.

RESULTS

The proposed collimator delivers a dose distribution which is 2.4 cm wide along the inferior-superior direction of the eyeball. This width is 0.3 cm narrower than that of the dose distribution obtained with the collimator currently in clinical use. The other relevant characteristics of the dose distribution obtained with the new collimator, namely, depth doses at clinically relevant positions, penumbrae width, and shape of the lateral profiles, are statistically compatible with the results obtained for the collimator currently in use.

CONCLUSIONS

The smaller field size delivered by the proposed collimator still fully covers the planning target volume with at least 95% of the maximum dose at a depth of 2 cm and provides a safety margin of 0.2 cm, so ensuring an adequate treatment while reducing the irradiated volume.

Impact of socioeconomic disparities on cause-specific survival of retinoblastoma

Retinoblastoma (RB) is a rare disease of infancy and early childhood. This study investigated the effects of socioeconomic factors on the cause-specific survival of RB. Data from patients diagnosed with RB between 1973 and 2009 were obtained from the Surveillance, Epidemiology and End Results (SEER) database. The study included 1,456 patients with a the mean follow-up time (SD) of 128.75 (113.74) months and a mean age (SD) of 1.4 (2.6) years. This study analyzed socioeconomic, staging and treatment factors available in the SEER database for RB. Kaplan-Meier analysis was used to analyze time-to-failure data. The two-sample Kolmogorov-Smirnov test was used for univariate analysis and the Cox proportional hazards model was used for multivariate analysis. The area under the receiver operating characteristic (ROC) curve was computed for predictors. SEER stage was the most significant predictive pretreatment factor. The identified socioeconomic barriers included ethnicity and rural-urban residence status that led to a 3% decrease in RB cause-specific survival. Thus, eliminating barriers to treatment is crucial for reducing the outcome disparities.

Effect of fractionated irradiation on the expression of multidrug resistance genes in the CNE1 human nasopharyngeal carcinoma cell line

Nasopharyngeal carcinoma (NPC) often develops drug resistance following radiotherapy. The molecular basis of radiotherapy-related multidrug resistance (MDR) remains unclear. In the present study, we investigated the effect of fractionated irradiation on the expression of the MDR-1 gene and the MDR-associated protein P-glycoprotein (P-gp) in CNE1 human NPC cells. CNE1 cells were treated with fractionated X-rays. Drug resistance was determined by MTT assay. The expression levels of MDR-1 and P-gp were analyzed by RT-PCR and western blot analysis, respectively. Differential expression was analyzed by gene chips. The results revealed that low levels of mRNA expression of MDR1 were present in non-irradiated CNE1 cells. Compared with the control, the expression of MDR1 mRNA was gradually increased following fractionated irradiation. On day 21, the expression of MDR1 mRNA was increased 1.59- and 2.19-fold, compared with the control, by treatment with 10 and 20 Gy, respectively. We observed decreased MDR1 expression following treatment with 10 and 20 Gy irradiation on days 28 and 35, compared with day 21. On days 21, 28 and 35, expression was increased 1.37-, 1.40- and 1.15-fold by treatment with 20 Gy compared with 10 Gy. Expression of MDR1 was significantly upregulated by treatment with 50 Gy irradiation compared with the control on days 78 and 106. P-gp expression was consistent with that of MDR1 mRNA expression. The sensitivity of CNE1 cells to cisplatin was reduced following irradiation compared with the control. A total of 26 genes were significantly upregulated and 8 genes were significantly downregulated compared with the control. Results of the present study have shown that MDR1 and P-gp are upregulated in CNE1 cells following irradiation. Multiple genes were involved in the mechanism of radiation-induced drug resistance.