Recommendations for Post-Operative Radiotherapy after complete resection of Thymoma - a French DELPHI consensus initiative

BACKGROUND

Thymomas are rare intrathoracic malignancies that can relapse after surgery. Whether or not Post-Operative Radiotherapy (PORT) should be delivered after surgery remains a major issue. RADIORYTHMIC is an ongoing, multicenter, randomized phase 3 trial addressing this question in patients with completely R0 resected Masaoka-Koga stage IIb/III thymoma. Experts in the field met to develop recommendations for PORT.

METHODS

A scientific committee from the RYTHMIC network identified key issues regarding the modalities of PORT in completely resected thymoma. A DELPHI-method was used to question 24 national experts, with 115 questions regarding: 1/ Imaging techniques, 2/ Clinical Target Volume (CTV) and margins, 3/ Dose constraints to Organs At Risk, 4/ Dose and fractionation, 5/ Follow-up and records. Consensus was defined when opinions reached ≥ 80% agreement.

RESULTS

We established the following recommendations: pre-operative contrast-enhanced CT-scan is recommended (94% agreement); optimization of radiation delivery includes either a 4D-CT based planning (82% agreement), a breath-holding inspiration breath-hold-based planning, or daily control CT-imaging (81% agreement); imaging fusion based on cardiovascular structures of pre-operative and planning CT-scan is recommended (82% agreement); right coronary and left anterior descending coronary arteries should be delineated as cardiac substructures (88% agreement); rotational RCMI/VMAT is recommended (88% agreement); total dose is 50Gy (81% agreement) with 1.8-2Gy per fraction (94% agreement); cardiac evaluation, and follow-up for patients with history of cardiovascular disease is recommended (88% agreement) with EKG and evaluation of LVEF at 5 years and 10 years.

CONCLUSION

This is the first consensus for PORT in thymoma. Implementation will help to harmonize practices.

Peptide radionuclide radiation therapy with Lutathera in multirecurrent nonanaplastic meningiomas: antitumoral activity study by growth rate analysis

PURPOSE

Several retrospective studies and meta-analyses of Peptide Radionuclide Radiation Therapy in meningiomas suggest six-month progression-free survival improvement for WHO grade 1 and 2 meningiomas. In the present study, we aimed to evaluate the impact of such treatment on three-dimensional volume growth rate (3DVGR) in nonanaplastic meningiomas.

METHODS

The authors performed a retrospective study including eight patients treated with Lutathera®. Millimetric 3D T1-weighted with gadolinium enhancement magnetic resonance imaging sequences were requested for volume measurement. Then, tumor growth rate was classified following a previously described 3DVGR classification (Graillon et al.).

RESULTS

Patients harbored seven WHO grade 2 meningiomas and one aggressive WHO grade 1. All patients, except one, underwent four treatment cycles. 3DVGR significantly decreased at 3, 6, and 12 months after treatment initiation analyzing each lesion separately. Mean and median 3DVGR from all patients were respectively at 29.5% and 44.5%/6 months before treatment initiation, then at 16.5% and 25%/6 months at three months post-treatment initiation, 9.5% and 4.5%/6 months after 6 months, as well as 9.5% and 10.5%/6 months after 12 months. At 3, 6, and 12 months after treatment initiation, 4/8, 6/7, and 5/6 patients were class 2 (stabilization or severe 3DVGR slowdown), respectively. No patient was class 1 at 6 and 12 months, suggesting a lack of drug response.

CONCLUSION

In nonanaplastic meningiomas, Lutathera®'s antitumoral activity appeared delayed and more likely observed at six months, while no major response was observed under treatment. Moreover, its antitumoral activity persisted for 12-18 months following treatment initiation.

Radiotherapy management of paediatric cancers with synchronous metastasis

Cancer in childhood represent 1% of all the new diagnosed cancers. About 30% of children with cancer receive radiation therapy, representing about 600 to 700 patients per year in France. As a consequence, paediatric cancers with synchronous metastasis is a very rare situation in oncology, with usually poor standard of care. However, considerable efforts are made by paediatric oncology scientific societies to offer trials or treatment consensus despite these rare situations. The article proposes to synthesize the radiotherapy management of both primary tumour and synchronous metastasis in the most "common" childhood or adolescent cancers.

The organization of care in pediatric radiotherapy across SIOP Europe affiliated centers: A multicenter survey in the framework of the 'Joint Action on Rare Cancers' project

BACKGROUND/PURPOSE

To reduce inequalities among SIOPE-affiliated countries, standard and optional levels to deliver 'Good Clinical Practice' compliant treatment in pediatric radiation oncology have been published. The aim of this project was to map the availability of pediatric radiotherapy resources across SIOPE-affiliated radiotherapy departments.

MATERIALS/METHODS

An online survey with 34 questions was distributed to 246 radiotherapy departments across 35 SIOPE-affiliated countries. In addition to demographic data, 15 general items related to the organization of the radiotherapy process, and 10 radiotherapy-specific items were defined. For each of the 25 items, sum scores were calculated per center and country. Mann-Whitney U tests were used to analyze associations.

RESULTS

Between March-June 2019, 121 departments (49 %) out of 31 countries (89 %) completed the survey. At center level, involvement of core disciplines in tumor boards (28 %), and integration of dedicated pediatric radiation therapy technologists (24 %) are limited, while rare & complex brachytherapy procedures are performed in many centers (23 %). For general and radiotherapy-specific items respectively, a relevant variation of sum scores was observed across countries (Δgeneral: ≤10 points; ΔRT_specific: ≤5 points) and among centers within a country (Δgeneral: ≤9 points; ΔRT_specific: ≤6 points). Sum scores for general and radiotherapy-specific items were higher in countries with a high-income (p < 0.01) and higher health development index (p < 0.01). A larger annual number of irradiated pediatric patients was associated with higher sum scores for general items (p < 0.01).

CONCLUSION

This survey demonstrates the disparities in organization of pediatric radiotherapy departments between SIOPE-affiliated countries and centers within the same country. Investment is needed to reduce inequalities in pediatric radiotherapy care.

Radio-chemotherapy feasibility for biopsy-only unresectable IDH wild-type glioblastomas (BO-GBM)

Background

"Biopsy-only" glioblastoma (BO-GBM) is a heterogeneous, understudied group of patients associated with a poor outcome. Our objective was to explore the pattern of care and prognosis associated with BO-GBM in our center.

Methods

Patients with IDH wild-type BO-GBM included in a prospective regional cohort initiated in 2014 and closed in 2017 were retrospectively reviewed for patient characteristics, MRI findings, treatment allocation, and delivery.

Results

Of 535 patients included in the cohort, 137 patients were included in the present analysis. The median age was 66 years old and the median KPS was 70. Forty-six patients (33.6%) were referred to radiotherapy and chemotherapy (RT-TMZ) regimen, 75 (54.7%), considered unfitted for RT, received chemotherapy upfront (CT) and 16 (11.7%) were referred to palliative care (PC). Regarding the first group, 91% of patients completed the RT-TMZ. In the CT group, 11 of 75 patients (14.7%) underwent radiotherapy after chemotherapy upfront. Median overall survival was 12.3 months (95% CI, 15.30-24.16), 5.7 months (95% CI, 6.22-9.20), and 1.9 months (95% CI, 1.43-5.08) in RT-TMZ, CT, and PC groups, respectively. In multivariate analyses, progression-free survival was impacted by baseline KPS (P < .001) and MGMT status (P = .004). Overall survival was impacted by baseline KPS (P < .001) and age (P = .030).

Conclusion

BO-GBM constitute a large and heterogeneous population in which one-third of patients is amenable to the standard of care, with survival outcome close to one of the patients who underwent surgery. Reliable criteria are needed to help select patients for adequate treatment while new strategies are warranted for BO-GBM unfit for RT.

[Characteristics of radiotherapy for adolescents and young adults]

Radiotherapy for adolescents and young adults is complex in several aspects. The population is very heterogeneous and has characteristics derived from both paediatric and adult populations both in terms of pathology (anatomical pathology, response to treatment) and the patient's physical, biological and psychological characteristics. This article reviews the characteristics to be taken into account in adolescent and young adult patients radiotherapy and more particularly in some of the most common diseases.

Respective Roles of Surgery, Chemotherapy, and Radiation Therapy for Recurrent Pediatric and Adolescent Ependymoma: A National Multicentric Study

PURPOSE

Half of the children and adolescents treated for intracranial ependymoma experience recurrences that are not managed in a standardized manner. This study aimed to retrospectively evaluate recurrence treatments.

METHODS AND MATERIALS

We assessed overall survival (OS) and progression-free survival (PFS) after a first relapse in a population of patients from the Pediatric Ependymoma Photons Protons and Imaging study (PEPPI study) who were treated with surgery and radiation therapy in French Society of Childhood Cancer reference centers between 2000 and 2013. Data were analyzed using the Cox model as well as a landmark analysis at 4 months that accounted for the guarantee-time bias.

RESULTS

The median follow-up of the whole population of 202 patients was 105.1 months, with a 10-year OS of 68.2% and PFS of 45.5%. Among the 100 relapse cases, 68.0% were local relapses, 20.0% were metastatic, and 12.0% were combined (local and metastatic). Relapses were treated by surgery (n = 79) and/or reirradiation (n = 52) and/or chemotherapy (n = 22). The median follow-up after relapse was 77.8 months. The OS and PFS at 5 years were 43.1% and 16.2%, respectively. After surgery or radiation therapy of the first relapse, OS and PFS were more favorable, whereas treatments that included chemotherapy with or without focal treatment were associated with worse OS and PFS. In the multivariate analysis, stereotactic hypofractionated reirradiation after surgery was associated with a significantly better outcome (OS, P = .030; PFS, P = .008) and chemotherapy with a worse outcome (OS, P = .028; PFS, P = .033).

CONCLUSIONS

This analysis of relapse treatments within the PEPPI study determined that irrespective of whether the relapse was localized or metastatic, treatments that included surgery and/or reirradiation had better outcomes.

Optic Nerve Sheath Meningiomas: Solving Diagnostic Challenges with 68Ga-DOTATOC PET/CT

⁶⁸Ga-DOTATOC PET could be a noninvasive, highly sensitive, and specific technique for the challenging diagnosis of optic nerve sheath meningioma (ONSM). Our objective was to report the use and results of ⁶⁸Ga-DOTATOC PET in suspected ONSM. Twelve subjects who underwent ⁶⁸Ga-DOTATOC PET for suspected ONSM in our department were retrospectively included. Standardised clinical and radiological data were collected. The PET examination results were classified as positive or negative, and lesion standardised uptake values (SUV_max) were recorded. ⁶⁸Ga-DOTATOC PET confirmed positive uptake in six cases (SUV_max > 5), leading to ONSM diagnoses followed by radiation therapy in patients with vision loss. Six ⁶⁸Ga-DOTATOC PET scans were considered negative (SUV_max < 5); these comprised one case of neurosarcoidosis, one cavernous malformation, and four uncertain diagnoses, leading to further investigation. ⁶⁸Ga-DOTATOC PET was helpful in tumour volume delineation before radiation therapy, leading to a decrease in dose exposure. Noninvasive ⁶⁸Ga-DOTATOC PET should be performed before treating nonhistologically proven meningiomas with radiotherapy or stereotactic radiosurgery, particularly in cases of uncertain diagnosis with MRI, which characterises most ONSM cases. PET SUV_max thresholds to distinguish meningioma from nonspecific uptake in other lesions need to be adapted to ONSM. ⁶⁸Ga-DOTATOC PET improves the intraorbital lesion diagnostic approach and therefore impacts therapeutic management.

Radiotherapy quality assurance in paediatric clinical trials: first report from six QUARTET-affiliated trials

BACKGROUND AND PURPOSE

SIOP Europe's QUARTET project launched in 2016; aiming to improve access to high-quality radiotherapy for children and adolescents treated within clinical trials across Europe. The aim of this report is to present the profile of institutions participating in six QUARTET-affiliated trials and a description of the initial individual case review (ICR) outcomes.

METHODS

This is a two-part analysis. Firstly, using facility questionnaires, beam output audit certificates, and advanced technique credentialing records to create a profile of approved institutions, and secondly, collating trial records for ICRs submitted prior to 31/10/2022. Trials included are: SIOPEN HR-NBL1, SIOPEN-LINES, SIOPEN- VERITAS, SIOP-BTG HRMB, EpSSG-FaR-RMS, and SIOPEN HR-NBL2.

RESULTS

By 31/10/2022, a total of 103 institutions had commenced QUARTET site approval procedures to participate in QUARTET-affiliated trials; 66 sites across 20 countries were approved. These participating institutions were often paediatric referral sites with intensity modulated radiotherapy or proton beam therapy, designated paediatric radiation oncologists, and paediatric adapted facilities and imaging protocols available. In total, 263 patient plans were submitted for ICR, 254 ICRs from 15 countries were completed. ICRs had a rejection rate of 39.8%, taking an average of 1.4 submissions until approval was achieved. Target delineation was the most frequent reason for rejection.

CONCLUSION

The QUARTET facility questionnaire is a valuable tool for mapping resources, personnel, and technology available to children and adolescents receiving radiotherapy. Prospective ICR is essential for paediatric oncology clinical trials and should be prioritised to reduce protocol violations.

Innovative treatments for meningiomas

Multi-recurrent high-grade meningiomas remain an unmet medical need in neuro-oncology when iterative surgeries and radiation therapy sessions fail to control tumor growth. Nevertheless, the last 10years have been marked by multiple advances in the comprehension of meningioma tumorigenesis via the discovery of new driver mutations, the identification of activated intracellular signaling pathways, and DNA methylation analyses, providing multiple potential therapeutic targets. Today, Anti-VEGF and mTOR inhibitors are the most used and probably the most active drugs in aggressive meningiomas. Peptide radioactive radiation therapy aims to target SSTR2A receptors, which are strongly expressed in meningiomas, but have an insufficient effect in most aggressive meningiomas, requiring the development of new techniques to increase the dose applied to the tumor. Based on the multiple potential intracellular targets, multiple targeted therapy clinical trials targeting Pi3K-Akt-mTOR and MAP kinase pathways as well as cell cycle and particularly, cyclin D4-6 are ongoing. Recently discovered driver mutations, SMO, Akt, and PI3KCA, offer new targets but are mostly observed in benign meningiomas, limiting their clinical relevance mainly to rare aggressive skull base meningiomas. Therefore, NF2 mutation remains the most frequent mutation and main challenging target in high-grade meningioma. Recently, inhibitors of focal adhesion kinase (FAK), which is involved in tumor cell adhesion, were tested in a phase 2 clinical trial with interesting but insufficient activity. The Hippo pathway was demonstrated to interact with NF2/Merlin and could be a promising target in NF2-mutated meningiomas with ongoing multiple preclinical studies and a phase 1 clinical trial. Recent advances in immune landscape comprehension led to the proposal of the use of immunotherapy in meningiomas. Except in rare cases of MSH2/6 mutation or high tumor mass burden, the activity of PD-1 inhibitors remains limited; however, its combination with various radiation therapy modalities is particularly promising. On the whole, therapeutic management of high-grade meningiomas is still challenging even with multiple promising therapeutic targets and innovations.

Stereotactic body radiation therapy (SBRT) as salvage treatment for early stage lung cancer with interstitial lung disease (ILD): An observational and exploratory case series of non-asian patients

Interstitial lung disease (ILD) can coexist with early-stage lung cancer (LC) and may compromise surgery and worsen patients' outcomes. Stereotactic body radiation therapy (SBRT) is the gold standard treatment for medically inoperable early-stage lung cancer, but radiation therapy is contra-indicated for patients with ILD because of the higher risk of severe radiation-induced pneumonitis. SBRT may spare healthy lung tissue, but data are scarce in this rare population. Our exploratory case series aimed to retrospectively identify patients treated with SBRT in this setting: 19 patients were diagnosed with early-stage LC-ILD over the past 6 years and 9 received SBRT. Most of them were smokers with a median age of 71, 4 had no pathological documentation. After SBRT, 5 patients had grade I-II respiratory adverse events (AEs), but none had treatment-related grade III-IV respiratory AEs. Two patients died within 6 months of SBRT, and for both, death was related to metastatic relapse. In this case series, the radiological evolution of ILD before radiotherapy and the evolution of the radiotherapy scar on CT-Scan were also explored with different evolutionary models. This exploratory study shows available data that could be studied in a larger retrospective cohort to identify risk factors for SBRT in the LC-ILD population. The use of dosimetric data as a risk factor for SBRT should be done with cautiousness due to heterogeneous and complex dose delivery and different fractionation schedule.

Locomotion performance for oscillatory swimming in free mode

Oscillatory swimming of a fishlike body, whose motion is essentially promoted by the flapping tail, has been studied almost exclusively in axial mode under an incoming uniform stream or, more recently, self-propelled under a virtual body resistance. Obviously, both approaches do not consider the unavoidable recoil motions of the real body which have to be necessarily accounted for in a design procedure for technological means. Actually, once combined with the prescribed kinematics of the tail, the recoil motions lead to a remarkable improvement on the resulting swimming performance. An inviscid impulse model, linear in both potential and vortical contributions, is a proper tool to obtain a deeper comprehension of the physical events with respect to more elaborated flow interaction models. In fact, at a first look, the numerical results seem to be quite entangled, since their trends in terms of the main flapping parameters are not easy to be identified and a fair interpretation is obtained by means of the model capability to separate the effects of added mass and vortex shedding. Specifically, a prevailing dependence of the potential contribution on the heave amplitude and of the vortical contribution on the pitch amplitude is instrumental to unravel their combined action. A further aid for a proper interpretation of the data is provided by accounting separately for a geometrical component of the recoil which is expected to follow from the annihilation of any spurious rigid motion in case no fluid interactions occur. The above detailed decomposition of the recoil motions shows, through the numerical results, how the single components are going to influence the main flapping parameters and the locomotion performance as a guide for the design of biomimetic swimmers.

Stereotactic radiosurgery for post operative brain metastasic surgical cavities: a single institution experience

BACKGROUND

The standard therapy for brain metastasis was surgery combined with whole brain radiotherapy (WBRT). The latter is however, associated with important neurocognitive toxicity. To reduce this toxicity, postoperative stereotactic radiosurgery (SRS) is a promising technique. We assessed the efficacy and the tolerance to postoperative Gamma Knife radiosurgery (GK) on the tumor bed after resection of brain metastases.

METHODS

Between February 2011 and December 2016, following macroscopic complete surgical resection, 64 patients and 65 surgical cavities were treated by GK in our institution. The indication for adjuvant radiosurgery was a multidisciplinary decision. The main assessment criteria considered in this study were local control, intracranial metastasis-free survival (ICMFS), overall survival and toxicity.

RESULTS

Median follow-up: 11.1 months. Median time between surgery and radiosurgery: 35 days. Median dose was 20 Gy prescribed to the 50% isodose line, for a median treated volume of 5.6 cc. Four patients (7%) suffered from local recurrence. Local recurrence-free, intracranial recurrence-free and overall survival at 1 year were 97.5%, 57.6% and 62.4% respectively. In total, 23 patients (41%) suffered from intracranial recurrence outside the tumor bed. In univariate analysis: concomitant GK treatment of multiple lesions and the tumor bed was associated with a decrease in ICMFS (HR = 1.16 [1.005-1.34] p = 0.04). In multivariate analysis: a non-lung primary tumor was significantly associated with a decrease in ICMFS (HR = 8.04 [1.82-35.4] p = 0.006). An increase in performance status (PS) and in the initial number of cerebral metastases significantly reduced overall survival (HR = 5.4 [1.11-26.3] p = 0.037, HR = 2.7 [1.004-7.36] p = 0.049, respectively) and One radiation necrosis histologically proven.

CONCLUSION

Our study confirmed that postoperative GK after resection of cerebral metastases is an efficient and well-tolerated technique, to treat volumes of all sizes (0.8 to 40 cc). Iterative SRS or salvage WBRT can be performed in cases of intracranial relapse, postponing WBRT with its potential side effects.

QUARTET: A SIOP Europe project for quality and excellence in radiotherapy and imaging for children and adolescents with cancer

The European Society for Paediatric Oncology (SIOPE) Radiation Oncology Working Group presents the QUARTET Project: a centralised quality assurance programme designed to standardise care and improve the quality of radiotherapy and imaging for international clinical trials recruiting children and adolescents with cancer throughout Europe. QUARTET combines the paediatric radiation oncology expertise of SIOPE with the infrastructure and experience of the European Organisation for Research and Treatment of Cancer to deliver radiotherapy quality assurance programmes for large, prospective, international clinical trials. QUARTET-affiliated trials include children and adolescents with brain tumours, neuroblastoma, sarcomas including rhabdomyosarcoma, and renal tumours including Wilms' tumour. With nine prospective clinical trials and two retrospective studies within the active portfolio in March 2022, QUARTET will collect one of the largest repositories of paediatric radiotherapy and imaging data, support the clinical assessment of radiotherapy, and evaluate the role and benefit of radiotherapy quality assurance for this cohort of patients within the context of clinical trials.

Beta-blockers disrupt mitochondrial bioenergetics and increase radiotherapy efficacy independently of beta-adrenergic receptors in medulloblastoma

Background

Medulloblastoma is the most frequent brain malignancy of childhood. The current multimodal treatment comes at the expense of serious and often long-lasting side effects. Drug repurposing is a strategy to fast-track anti-cancer therapy with low toxicity. Here, we showed the ability of β-blockers to potentiate radiotherapy in medulloblastoma with bad prognosis.

Methods

Medulloblastoma cell lines, patient-derived xenograft cells, 3D spheroids and an innovative cerebellar organotypic model were used to identify synergistic interactions between β-blockers and ionising radiations. Gene expression profiles of β-adrenergic receptors were analysed in medulloblastoma samples from 240 patients. Signaling pathways were explored by RT-qPCR, RNA interference, western blotting and RNA sequencing. Medulloblastoma cell bioenergetics were evaluated by measuring the oxygen consumption rate, the extracellular acidification rate and superoxide production.

Findings

Low concentrations of β-blockers significantly potentiated clinically relevant radiation protocols. Although patient biopsies showed detectable expression of β-adrenergic receptors, the ability of the repurposed drugs to potentiate ionising radiations did not result from the inhibition of the canonical signaling pathway. We highlighted that the efficacy of the combinatorial treatment relied on a metabolic catastrophe that deprives medulloblastoma cells of their adaptive bioenergetics capacities. This led to an overproduction of superoxide radicals and ultimately to an increase in ionising radiations-mediated DNA damages.

Interpretation

These data provide the evidence of the efficacy of β-blockers as potentiators of radiotherapy in medulloblastoma, which may help improve the treatment and quality of life of children with high-risk brain tumours.

Funding

This study was funded by institutional grants and charities.

Guide for paediatric radiotherapy procedures

A third of children with cancer receive radiotherapy as part of their initial treatment, which represents 800 paediatric irradiations per year in France carried out in 15 specialized centres approved on the recommendations of the French national cancer institute in decreasing order of frequency, the types of cancer that require irradiation are: brain tumours, neuroblastomas, Ewing's sarcomas, Hodgkin's lymphomas, soft tissue sarcomas including rhabdomyosarcomas, and nephroblastomas. The treatment guidelines follow the recommendations of the French society for childhood cancers (SFCE) or the French and European prospective protocols. The therapeutic indications, the technical and/and ballistic choices of complex cases are frequently discussed during bimonthly paediatric radiotherapy technical web-conferences. All cancers combined, overall survival being 80%, long-term toxicity logically becomes an important concern, making the preparation of treatments complex. The irradiation methods include all the techniques currently available: 3D conformational irradiation, intensity modulation radiation therapy, irradiation under normal or hypofractionated stereotaxic conditions, brachytherapy and proton therapy. We present the update of the recommendations of the French society for radiation oncology on the indications, the technical methods of realization and the organisation and the specificities of paediatric radiation oncology.

SIOP PNET5 MB Trial: History and Concept of a Molecularly Stratified Clinical Trial of Risk-Adapted Therapies for Standard-Risk Medulloblastoma

BACKGROUND

SIOP PNET5 MB was initiated in 2014 as the first European trial using clinical, histological, and molecular parameters to stratify treatments for children and adolescents with standard-risk medulloblastoma.

METHODS

Stratification by upfront assessment of molecular parameters requires the timely submission of adequate tumour tissue. In the standard-risk phase-III cohort, defined by the absence of high-risk criteria (M0, R0), pathological (non-LCA), and molecular biomarkers (MYCN amplification in SHH-MB or MYC amplification), a randomized intensification by carboplatin concomitant with radiotherapy is investigated. In the LR stratum for localized WNT-activated medulloblastoma and age <16 years, a reduction of craniospinal radiotherapy dose to 18 Gy and a reduced maintenance chemotherapy are investigated. Two additional strata (WNT-HR, SHH-TP53) were implemented during the trial.

RESULTS

SIOP PNET5 MB is actively recruiting. The availability of adequate tumour tissue for upfront real-time biological assessments to assess inclusion criteria has proven feasible.

CONCLUSION

SIOP PNET5 MB has demonstrated that implementation of biological parameters for stratification is feasible in a prospective multicentre setting, and may improve risk-adapted treatment. Comprehensive research studies may allow assessment of additional parameters, e.g., novel medulloblastoma subtypes, and identification and validation of biomarkers for the further refinement of risk-adapted treatment in the future.

P04.08 Biopsy-only glioblastoma (BO-GBM) as a heterogeneous group of patients

BACKGROUND

“Biopsy-only” glioblastoma is associated with a heterogeneous functional and survival outcome. BO-GBM patients is an understudied group of patients associated to a poor outcome, which has been reported to represent 21% of histologically confirmed GBM in the US National Cancer Data Base. Pattern of care included radiotherapy-temozolomide (RT-TMZ) standard regimen completed in 15% of patients, any other form of oncologic treatment in 60%, and supportive care alone in 25% of patients. Our objective was to explore pattern of care and prognosis associated to BO-GBM in our center.

MATERIAL AND METHODS

Patients with BO-GBM included in a prospective regional glioma SIRIC cohort initiated in 2014 and closed in 2017 were retrospectively reviewed for patients characteristics, MRI finding, treatment allocation and delivery. PFS and OS were analyzed.

RESULTS

Of 535 patients included in the cohort, 86 patients were referred &gt; 3 months post-surgery and were excluded from this analysis while 449 patients were included at initial surgery, of which 158 patients (35%) underwent biopsy only. Of 158 patients, 18 patients were excluded for missing data leaving 139 patients for the present analysis. Fifty-four (39%) were referred to RT-TMZ (50 patients completed concomitant treatment), 68 (49%) considered unfitted for RT received chemotherapy upfront (CT-UF) (of which 4 were subsequently referred to RT), 17 (12%) were referred to palliative care only (PC). Groups differed at baseline for age (mean 60, 68, and 69 years, for RT-TMZ, CT-UF, and PC respectively); for KPS (70, 60, and 50 for RT-TMZ, CT-UF, and PC respectively); for mean tumor surface measured on gadolinium-enhanced T1-weighted (793, 1420, 1412 mm2 for RT-TMZ, CT-UF, PC); for tumor extension (bilateral in 6.4% and 29.3% for RT-TMZ and CT-UF respectively); for mean steroid intake (45, 60, 100 mg daily respectively). Median OS was 14 months (95% CI, 9.65–18.71), 8 months (95% CI, 4.62–7.67), and 2 months (95% CI, 0.67–3.33) for RT-TMZ, CT-UF, and PC respectively.

CONCLUSION

Inoperable GBM constitute a large and heterogeneous population in which one third of patients are amenable to standard of care, with survival outcome close to the one of patients who underwent surgery. Patients considered unfit for RT-TMZ at diagnosis fail to be referred subsequently to RT after CT and exhibit a poor survival outcome. Thus, reliable criteria are needed to help selecting patients for adequate treatment while new strategies are warranted for BO-GBM unfit for RT.

Prognostic relevance of clinical and molecular risk factors in children with high-risk medulloblastoma treated in the phase II trial PNET HR+5

BACKGROUND

High-risk medulloblastoma is defined by the presence of metastatic disease and/or incomplete resection and/or unfavorable histopathology and/or tumors with MYC amplification. We aimed to assess the 3-year progression-free survival (PFS) and define the molecular characteristics associated with PFS in patients aged 5-19 years with newly diagnosed high-risk medulloblastoma treated according to the phase II trial PNET HR+5.

METHODS

All children received postoperative induction chemotherapy (etoposide and carboplatin), followed by 2 high-dose thiotepa courses (600 mg/m2) with hematological stem cell support. At the latest 45 days after the last stem cell rescue, patients received risk-adapted craniospinal radiation therapy. Maintenance treatment with temozolomide was planned to start between 1-3 months after the end of radiotherapy. The primary endpoint was PFS. Outcome and safety analyses were per protocol (all patients who received at least one dose of induction chemotherapy).

RESULTS

Fifty-one patients (median age, 8 y; range, 5-19) were enrolled. The median follow-up was 7.1 years (range: 3.4-9.0). The 3 and 5-year PFS with their 95% confidence intervals (95% CI) were 78% (65-88) and 76% (63-86), and the 3 and 5-year OS were 84% (72-92) and 76% (63-86), respectively. Medulloblastoma subtype was a statistically significant prognostic factor (P-value = 0.039) with large-cell/anaplastic being of worse prognosis, as well as a molecular subgroup (P-value = 0.012) with sonic hedgehog (SHH) and group 3 being of worse prognosis than wingless (WNT) and group 4. Therapy was well tolerated.

CONCLUSIONS

This treatment based on high-dose chemotherapy and conventional radiotherapy resulted in a high survival rate in children with newly diagnosed high-risk medulloblastoma.

Metronomic Maintenance With Weekly Vinblastine After Induction With Bevacizumab-Irinotecan in Children With Low-grade Glioma Prevents Early Relapse

BACKGROUND

Pediatric low-grade glioma (pLGG) represents the most common brain tumor in childhood. Previous studies have reported that a therapeutic strategy on the basis of the association of bevacizumab alone (B) or in combination with irinotecan (BI) could produce rapid tumor response and clinical improvement in children with pLGG. Nevertheless, a majority of patients relapses shortly (median, 5 mo) after stopping B or BI treatment. We proposed metronomic maintenance with weekly vinblastine added after a 6 months induction of B/BI to prevent early relapse.

PATIENTS AND METHODS

Monocentric retrospective analysis of a patient with pLGG treated with B or BI for 6 months followed by a 12-month maintenance with weekly vinblastine (6 mg/m²) from October 2012 to September 2019 in a single institution.

RESULTS

In total, 18 patients (7 males and 11 females) were identified. Because of progression during the B or BI induction 2/18 children were excluded. In total, 16 patients were analyzed with a median age of 10 years (range, 4 to 16 y). A total of 13 patients received BI and 3 patients received B alone. The mean duration of induction was 6.2 months (range, 2 to 12 mo). After induction 5/16 patients had a partial radiologic response, 11/16 patients had stable disease. All patients started maintenance (median duration, 12 mo; range, 3 to 12 mo). With a median follow-up of 3.9 years after the end of B or BI (range, 11 mo to 7.2 y), 15/16 patients were alive and 9/16 patients were progression-free. Seven of 16 children progressed with a median time to progression of 23 months (ranges, 5 to 39 mo). Three of 16 (18%) children progressed during vinblastine maintenance and 4/16 (25%) patients after the end of maintenance. After the total duration of treatment, clinical improvement was noted in 4 patients, 9 patients had stable symptoms, and only 3 patients progressed. One and 2-year event-free survival were, respectively, 81.2% and 56.2%. Two-year overall survival was 93.7%.

CONCLUSIONS

We report here, the potential benefit and the improvement of progression-free survival by adding metronomic maintenance with weekly vinblastine after initial induction with B or BI in children with low-grade glioma.

Stereotactic Body Radiotherapy for Frail Patients with Primary Renal Cell Carcinoma: Preliminary Results after 4 Years of Experience

Simple Summary

Surgical therapy is currently the standard of care for the treatment of primary renal cell carcinoma (RCC). Alternative strategies such as stereotactic body radiotherapy (SBRT) have emerged as potentially curative treatment approaches. In this study, we show a promising short-term local control effect of SBRT in the management of primary RCC. The treatment was well tolerated with no high-grade side effects. The main advantages are the outpatient management without anesthesia and the non-invasive approach. Thus, SBRT appears to be a promising alternative to surgery, or ablative therapy, to treat primary RCC in patients with poor physical health. Future studies are needed to definitively assess the place of SBRT in the RCC treatment portfolio.

Abstract

Introduction: The aim of this study was to report the oncological outcomes and toxicity of stereotactic body radiotherapy (SBRT) to treat primary renal cell carcinoma (RCC) in frail patients unfit for surgery or standard alternative ablative therapies. Methods: We retrospectively enrolled 23 patients who had SBRT for primary, biopsy-proven RCC at our tertiary center between October 2016 and March 2020. Treatment-related toxicities were defined using CTCAE, version 4.0. The primary outcome was local control which was defined using the Response Evaluation Criteria in Solid Tumors. Results: The median age, Charlson score and tumor size were 81 (IQR 79–85) years, 7 (IQR 5–8) and 40 (IQR 28–48) mm, respectively. The most used dose fractionation schedule was 35 Gy (78.3%) in five or seven fractions. The median duration of follow-up for all living patients was 22 (IQR 10–39) months. Local recurrence-free survival, event-free survival, cancer-specific survival and overall survival were 96 (22/23), 74 (18/23), 96 (22/23) and 83% (19/23), respectively. There were no grade 3–4 side effects. No patients required dialysis during the study period. No treatment-related deaths or late complications were reported. Conclusion: SBRT appears to be a promising alternative to surgery or ablative therapy to treat primary RCC in frail patients.

Association of inoperable glioblastoma with a heterogeneous functional and survival outcome

e14036

Background: “Biopsy only” GBM patients is an understudied group of patients associated to a poor outcome, which has been reported to represent 21% of histologically confirmed GBM in the US National Cancer Data Base. Pattern of care included radiotherapy-temozolomide (RT-TMZ) standard regimen completed in 15% of patients, any other form of oncologic treatment in 60%, and supportive care alone in 25% of patients (Kole, Cancer 2016). Our objective was to explore heterogeneity of inoperable GBM patients group, both for patients characteristics, pattern of care planned and completed, functional and survival outcome. Methods: Patients with inoperable GBM included in a prospective regional glioma cohort initiated in 2014 were retrospectively reviewed for patients characteristics, MRI finding, treatment allocation and delivery. Functional independency analyzed as a cumulative time of KPS≥70, PFS and OS were analyzed. Results: Of 535 patients referred to our center, 449 patients were included at initial surgery, of which 158 patients (35%) underwent biopsy only. 18 patients were excluded for missing data leaving 139 patients for the present analysis. 54 (39%) were referred to RT-TMZ (50 patients completed concomitant treatment), 68 (49%) considered unfitted for RT received chemotherapy upfront (CT-UF) (of which 3 were subsequently referred to RT), 17 (12%) referred to palliative care only (PC). Groups differed at baseline for age (mean 60, 68, 69y for RT-TMZ, CT-UF, PC respectively); for KPS (70, 60, 50 for RT-TMZ, CT-UF, PC respectively); for mean tumor surface (793, 1420, 1412 cm2 for RT-TMZ, CT-UF, PC); for tumor extension (bilateral in 6.4% and 29.3% for RT-CT and CT-UF respectively); for steroid intake (45, 60, 100 mg daily respectively). Median OS was 14 months (95% CI, 9.65-18.71), 8 months (95% CI, 4.62-7.67), 2 months (95% CI, 0.67-3.33) for RT-TMZ, CT-UF, PC respectively. Of importance, mean duration of functional independence was of 8.3 months, 2.1 months, and 0.1 month for RT-TMZ, CT-UF, and PC respectively; 33/139 (24%) of the patients experienced functional independency for more than 40% of their life time. Conclusions: Inoperable GBM constitute a large and heterogeneous population in which more than 1/3 of the patients are amenable to standard of care, with survival outcome similar to the one of patients who underwent surgery. Patients considered unfit for RT-CT at diagnosis fail to be referred subsequently to RT after CT and exhibit a poor survival outcome that deserve new effective treatments. Cumulative duration of functional independence is limited and should be considered as part of treatment evaluation.

Brain tumors: Medulloblastoma, ATRT, ependymoma

Children with medulloblastoma, atypical teratoid rhabdoid tumor (ATRT), and ependymoma are treated with a multidisciplinary approach including surgery, radiotherapy, and chemotherapy. Lower doses of craniospinal irradiation and tumor bed boost together with chemotherapy are the current standard of care for average-risk medulloblastoma in the Children's Oncology Group (COG). The International Society of Pediatric Oncology (SIOP) is examining the role of hyperfractionated craniospinal irradiation and chemotherapy in high-risk patients. The recent stratification of medulloblastoma into specific molecular risk groups has prompted both COG and SIOP to reexamine the role of these modalities in these different risk groups to maximize cure rates and minimize long-term complications. Proton therapy has shown lower rates of neurocognitive and endocrine complications compared with photons. Ependymomas are treated with maximal surgical resection and adjuvant radiation therapy. The role of chemotherapy in ependymoma is currently being studied in both COG and SIOP. Likewise, for ATRT the role of different high-dose chemotherapy regimens together with local radiation therapy in infants, or craniospinal radiation in older children, is the current focus of research.

Radical radiotherapy for paediatric solid tumour metastases: An overview of current European protocols and outcomes of a SIOPE multicenter survey

PURPOSE/OBJECTIVE

About 20% of children with solid tumours (ST) present with distant metastases (DM). Evidence regarding the use of radical radiotherapy of these DM is sparse and open for personal interpretation. The aim of this survey was to review European protocols and to map current practice regarding the irradiation of DM across SIOPE-affiliated countries.

MATERIALS/METHODS

Radiotherapy guidelines for metastatic sites (bone, brain, distant lymph nodes, lung and liver) in eight European protocols for rhabdomyosarcoma, non-rhabdomyosarcoma soft-tissue sarcoma, Ewing sarcoma, neuroblastoma and renal tumours were reviewed. SIOPE centres irradiating ≥50 children annually were invited to participate in an online survey.

RESULTS

Radiotherapy to at least one metastatic site was recommended in all protocols, except for high-risk neuroblastoma. Per protocol, dose prescription varied per site, and information on delineation and treatment planning/delivery was generally missing. Between July and September 2019, 20/27 centres completed the survey. Around 14% of patients were deemed to have DM from ST at diagnosis, of which half were treated with curative intent. A clear cut-off for a maximum number of DM was not used in half of the centres. Regardless of the tumour type and site, conventional radiotherapy regimens were most commonly used to treat DM. When stereotactic radiotherapy was used, a wide range of fractionation regimens were applied.

CONCLUSION

Current radiotherapy guidelines for DM do not allow a consistent approach in a multicentre setting. Prospective (randomised) trials are needed to define the role of radical irradiation of DM from paediatric ST.

Radio-induced esophageal motility disorders: An unrecognized diagnosis

PURPOSE

Esophageal motility disorders (EMD) after cervical or thoracic radiation therapy (RT) may represent a late impairment and appear under-diagnosed. This study aimed to assess the prevalence of EMD, diagnosed by high-resolution esophageal manometry (HREM) after cervical or thoracic RT. In this retrospective, single-centre study, all patients whom received cervical or thoracic RT and underwent HREM were eligible.

MATERIAL AND METHODS

Oncologic data were collected: site of neoplasia, type of cancer, oncologic management (surgery and chemotherapy). EMD were classified according to the new Chicago Classification.

RESULTS

Twenty patients (14 females), of mean age 62.33±11.14 years were included. Breast cancer was the most represented indication for RT (40%). Other cancers were lung tumor, head and neck tumors and Hogdkin's lymphoma. Dysphagia was the most frequent symptom justifying HREM (70%). Patients received a mean of 51±19.27 Gy, 70% of them (14/20) had radiation therapy concomitantly with chemotherapy. The delay between last radiation therapy session and HERM was 10.68±12.42 years. Twelve (60%) patients had an abnormal pattern at on HERM. Among them, 3 patients (15%) presented with a major motility disorder. The most frequent motility disorder was ineffective esophageal motility in 8 (40%) patients, 1 (5%) patient presented with type II achalasia.

CONCLUSION

EMD should be suspected in patients with a history of cervical or thoracic RT in case of upper GI symptoms with normal endoscopy. In these particular patients, a manometric diagnosis that can explain their symptoms is of particular importance to limit anxiety linked to unexplained troubles.

Early Toxicities After High Dose Rate Proton Therapy in Cancer Treatments

Background

The conventional dose rate of radiation therapy is 0.01–0.05 Gy per second. According to preclinical studies, an increased dose rate may offer similar anti-tumoral effect while dramatically improving normal tissue protection. This study aims at evaluating the early toxicities for patients irradiated with high dose rate pulsed proton therapy (PT).

Materials and Methods

A single institution retrospective chart review was performed for patients treated with high dose rate (10 Gy per second) pulsed proton therapy, from September 2016 to April 2020. This included both benign and malignant tumors with ≥3 months follow-up, evaluated for acute (≤2 months) and subacute (>2 months) toxicity after the completion of PT.

Results

There were 127 patients identified, with a median follow up of 14.8 months (3–42.9 months). The median age was 55 years (1.6–89). The cohort most commonly consisted of benign disease (55.1%), cranial targets (95.1%), and were treated with surgery prior to PT (56.7%). There was a median total PT dose of 56 Gy (30–74 Gy), dose per fraction of 2 Gy (1–3 Gy), and CTV size of 47.6 ml (5.6–2,106.1 ml). Maximum acute grade ≥2 toxicity were observed in 49 (38.6%) patients, of which 8 (6.3%) experienced grade 3 toxicity. No acute grade 4 or 5 toxicity was observed. Maximum subacute grade 2, 3, and 4 toxicity were discovered in 25 (19.7%), 12 (9.4%), and 1 (0.8%) patient(s), respectively.

Conclusion

In this cohort, utilizing high dose rate proton therapy (10 Gy per second) did not result in a major decrease in acute and subacute toxicity. Longer follow-up and comparative studies with conventional dose rate are required to evaluate whether this approach offers a toxicity benefit.

Testicular transposition in children before scrotal external radiotherapy

Testicular transposition (TT) before scrotal external radiotherapy (RT) is poorly reported in children with cancer, with only rare case reports published. TT surgical techniques, dosimetric parameters, and testicular functions are retrospectively reported in 12 children, median age 12.8 years, after scrotal RT for sarcomas. TT has low morbidity and allows a dramatic RT dose decrease in the healthy testicle. Endocrine functions seem preserved while more follow-up is needed to assess fertility. Though a rare situation, TT should be discussed in children and young adult cases when a scrotal high-dose RT is needed.

Exclusive Hyperfractionated Radiation Therapy and Reduced Boost Volume for Standard-Risk Medulloblastoma: Pooled Analysis of the 2 French Multicentric Studies MSFOP98 and MSFOP 2007 and Correlation With Molecular Subgroups

PURPOSE

Medulloblastoma has recently been characterized as a heterogeneous disease with 4 distinct molecular subgroups: wingless (WNT), sonic hedgehog (SHH), group 3, and group 4, with a new definition of risk stratification. We report progression-free survival, overall survival, and long-term cognitive effects in children with standard-risk medulloblastoma exclusively treated with hyperfractionated radiation therapy (HFRT), reduced boost volume, and online quality control, and we explore the prognostic value of biological characteristics in this chemotherapy-naïve population.

METHODS AND MATERIALS

Patients with standard-risk medulloblastoma were enrolled in 2 successive prospective multicentric studies, MSFOP 98 and MSFOP 2007, and received exclusive HFRT (36 Gy, 1 Gy/fraction twice daily) to the craniospinal axis followed by a boost at 68 Gy restricted to the tumor bed (1.5 cm margin), with online quality assurance before treatment. Patients with MYC or MYCN amplification were not excluded at the time of the study. We report progression-free survival and overall survival in the global population, and according to molecular subgroups as per World Health Organization 2016 molecular classification, and we present cognitive evaluations based on the Wechsler scale.

RESULTS

Data from 114 patients included in the MSFOP 98 trial from December 1998 to October 2001 (n = 48) and in the MSFOP 2007 from October 2008 to July 2013 (n = 66) were analyzed. With a median follow-up of 16.2 (range, 6.4-19.6) years for the MSFOP 98 cohort and 6.5 (1.6-9.6) years for the MSFOP 2007 cohort, 5-year overall survival and progression-free survival in the global population were 84% (74%-89%) and 74% (65%-81%), respectively. Molecular classification was determined for 91 patients (WNT [n = 19], SHH [n = 12], and non-WNT/non-SHH [n = 60]-including group 3 [n = 9], group 4 [n = 29], and not specified [n = 22]). Our results showed more favorable outcome for the WNT-activated subgroup and a worse prognosis for SHH-activated patients. Three patients had isolated extra-central nervous system relapse. The slope of neurocognitive decline in the global population was shallower than that observed in patients with a normofractionated regimen combined with chemotherapy.

CONCLUSIONS

HFRT led to a 5-year survival rate similar to other treatments combined with chemotherapy, with a reduced treatment duration of only 6 weeks. We confirm the MSFOP 98 results and the prognostic value of molecular status in patients with medulloblastoma, even in the absence of chemotherapy. Intelligence quotient was more preserved in children with medulloblastoma who received exclusive HFRT and reduced local boost, and intelligence quotient decline was delayed compared with patients receiving standard regimen. HFRT may be appropriate for patients who do not consent to or are not eligible for prospective clinical trials; for patients from developing countries for whom aplasia or ileus may be difficult to manage in a context of high cost/effectiveness constraints; and for whom shortened duration of RT may be easier to implement.

A rapid review of evidence and recommendations from the SIOPE radiation oncology working group to help mitigate for reduced paediatric radiotherapy capacity during the COVID-19 pandemic or other crises

OBJECTIVE

To derive evidence-based recommendations for the optimal utilisation of resources during unexpected shortage of radiotherapy capacity.

METHODS AND MATERIALS

We have undertaken a rapid review of published literature on the role of radiotherapy in the multimodality treatment of paediatric cancers governing the European practise of paediatric radiotherapy. The derived data has been discussed with expert paediatric radiation oncologists to derive a hierarchy of recommendations.

RESULTS

The general recommendations to mitigate the potential detriment of an unexpected shortage of radiotherapy facilities include: (1) maintain current standards of care as long as possible (2) refer to another specialist paediatric radiotherapy department with similar level of expertise (3) prioritise use of existing radiotherapy resources to treat patients with tumours where radiotherapy has the most effect on clinical outcome (4) use chemotherapy to defer the start of radiotherapy where timing of radiotherapy is not expected to be detrimental (5) active surveillance for low-grade tumours if appropriate and (6) consider iso-effective hypofractionated radiotherapy regimens only for selected patients with predicted poor prognosis. The effectiveness of radiotherapy and recommendations for prioritisation of its use for common and challenging paediatric tumours are discussed.

CONCLUSION

This review provides evidence-based treatment recommendations during unexpected shortage of paediatric radiotherapy facilities. It has wider applications for the optimal utilisation of facilities, to improve clinical outcome in low- and middle-income countries, where limited resources continue to be a challenge.

Feasibility of Dose Escalation in Patients With Intracranial Pediatric Ependymoma

Background and purpose: Pediatric ependymoma carries a dismal prognosis, mainly owing to local relapse within RT fields. The current prospective European approach is to increase the radiation dose with a sequential hypofractionated stereotactic boost. In this study, we assessed the possibility of using a simultaneous integrated boost (SIB), comparing VMAT vs. IMPT dose delivery.

Material and methods: The cohort included 101 patients. The dose to planning target volume (PTV59.4) was 59.4/1.8 Gy, and the dose to SIB volume (PTV67.6) was 67.6/2.05 Gy. Gross tumor volume (GTV) was defined as the tumor bed plus residual tumor, clinical target volume (CTV59.4) was GTV + 5 mm, and PTV59.4 was CTV59.4 + 3 mm. PTV67.6 was GTV+ 3 mm. After treatment plan optimization, quality indices and doses to target volume and organs at risk (OARs) were extracted and compared with the standard radiation doses that were actually delivered (median = 59.4 Gy [50.4 59.4]).

Results: In most cases, the proton treatment resulted in higher quality indices (p < 0.001). Compared with the doses that were initially delivered, mean, and maximum doses to some OARs were no higher with SIB VMAT, and significantly lower with protons (p < 0.001). In the case of posterior fossa tumor, there was a lower dose to the brainstem with protons, in terms of V59 Gy, mean, and near-maximum (D2%) doses.

Conclusion: Dose escalation with intensity-modulated proton or photon SIB is feasible in some patients. This approach could be considered for children with unresectable residue or post-operative FLAIR abnormalities, particularly if they have supratentorial tumors. It should not be considered for infratentorial tumors encasing the brainstem or extending to the medulla.

Recommendations for the organisation of care in paediatric radiation oncology across Europe: a SIOPE-ESTRO-PROS-CCI-Europe collaborative project in the framework of the JARC

Disparities in survival and long-term side-effects from paediatric cancer are observed across European Society for Paediatric Oncology (SIOPE)-affiliated countries. The Joint Action on Rare Cancers (JARC) is a project supported by the European Union and member states aiming to formulate recommendations on rare cancers, including paediatric malignancies, to reduce inequalities and to improve health outcomes. Most paediatric cancers are treated by a combination of systemic agents, surgery and/or radiotherapy. Radiotherapy for children is becoming increasingly complex because of the growing availability of new modalities and techniques and the evolution in molecular biology. These added challenges have the potential to enhance disparities in survival and side-effects between countries, but also among centres in the same country. To tackle radiotherapy-related inequalities, representatives of SIOPE, European SocieTy for Radiotherapy and Oncology, Paediatric Radiation Oncology Society and Childhood Cancer International-Europe defined 'standard' and 'optional' levels to deliver Good Clinical Practice-compliant treatment in paediatric radiation oncology with a focus on patient-related care, education and training. In addition, more than 250 paediatric radiotherapy centres across the SIOPE-affiliated countries have been mapped. For a better understanding of resources in paediatric radiotherapy, JARC representatives are working on an online survey for paediatric radiation oncologists of each centre in SIOPE-affiliated countries. The outcome of this survey will give an insight into the strengths and weaknesses of paediatric radiotherapy across SIOPE-affiliated countries and can be relevant for European Reference Networks in terms of collaboration pathways and referrals in paediatric radiotherapy.

Leptomeningeal Gliomatosis: A Single Institution Study of 31 Patients

BACKGROUND/AIM

Secondary leptomeningeal gliomatosis (LG) is a rare and severe progression pattern of glioma. Our objective was to evaluate the characteristics and outcome of patients with LG.

PATIENTS AND METHODS

We retrospectively reviewed 31 patients diagnosed with secondary LG. At the time of LG diagnosis, the median age of patients was 45 years. The histological grade was IV in 20 patients and II to III in 11 patients. As a first-line of therapy for LG, 22 patients received an oncological treatment: i) BCNU-temozolomide (TMZ) (n=15), ii) other type of chemotherapy (n=7), and iii) no treatment (supportive care) (n=9).

RESULTS

Following LG diagnosis, the median progression-free survival (PFS) and overall survival (OS) were 1.8 months [95% confidence interval (CI)=0.9-2.7] and 2.1 months (95%CI=1.3-3), respectively. The univariate analyses showed an improved OS with age of less than 45 years (p<0.001), a prolonged interval from the initial glioma diagnosis (IGD) to LG diagnosis (p=0.003), BCNU-TMZ as the preferred first-line treatment for LG out of the three options (p=0.008), and Karnofsky performance status (KPS) ≥70 (p=0.012). Prolonged interval from IGD to LG diagnosis (HR=5.839) and BCNU-TMZ as the chosen first-line treatment for LG (HR=6.635) remained significant in the multivariate analyses as well. Among the 22 treated patients, the median OS was significantly higher (p=0.008) with the BCNU-TMZ treatment (5.7 months; 95%CI=4.2-7.1), compared to other types of treatment offered (2 months; 95%CI=1.1-2.9).

CONCLUSION

The time interval from the IGD to the LG diagnosis is a potential prognostic factor for LG. BCNU-TMZ may be a therapeutic option in the present setting.

A new methodology to derive 3D kinetic parametric FDG PET images based on a mathematical approach integrating an error model of measurement

Background

In FDG-PET, SUV images are hampered by large potential biases. Our aim was to develop an alternative method (ParaPET) to generate 3D kinetic parametric FDG-PET images easy to perform in clinical oncology.

Methods

The key points of our method are the use of a new error model of PET measurement extracted from a late dynamic PET acquisition of 15 min, centered over the lesion and an image-derived input function (IDIF). The 15-min acquisition is reconstructed to obtain five images of FDG mean activity concentration and images of its variance to model errors of PET measurement. Our approach is carried out on each voxel to derive 3D kinetic parameter images. ParaPET was evaluated and compared to Patlak analysis as a reference. Hunter and Barbolosi methods (Barbolosi-Bl: with blood samples or Barbolosi-Im: with IDIF) were also investigated and compared to Patlak. Our evaluation was carried on K_i index, the net influx rate and its maximum value in the lesion (K_i,max).

Results

This parameter was obtained from 41 non-small cell lung cancer lesions associated with 4 to 5 blood samples per patient, required for the Patlak analysis. Compare to Patlak, the median relative difference and associated range (median; [min;max]) in K_i,max estimates were not statistically significant (Wilcoxon test) for ParaPET (− 3.0%; [− 31.9%; 47.3%]; p = 0.08) but statistically significant for Barbolosi-Bl (− 8.0%; [− 30.8%; 53.7%]; p = 0.001), Barbolosi-Im (− 7.9%; [− 38.4%; 30.6%]; p = 0.007) or Hunter (32.8%; [− 14.6%; 132.2%]; p < 10^− 5). In the Bland-Altman plots, the ratios between the four methods and Patlak are not dependent of the K_i magnitude, except for Hunter. The 95% limits of agreement are comparable for ParaPET (34.7%), Barbolosi-Bl (30.1%) and Barbolosi-Im (30.8%), lower to Hunter (81.1%). In the 25 lesions imaged before and during the radio-chemotherapy, the decrease in the FDG uptake (ΔSUV_max or ΔK_i,max) is statistically more important (p < 0.02, Wilcoxon one-tailed test) when estimated from the K_i images than from the SUV images (additional median variation of − 2.3% [− 52.6%; + 19.1%] for ΔK_i,max compared to ΔSUV_max).

Conclusion

None of the four methodologies is yet ready to replace the Patlak approach, and further improvements are still required. Nevertheless, ParaPET remains a promising approach, offering a non-invasive alternative to methods based on multiple blood samples and only requiring a late PET acquisition. It allows deriving K_i values, highly correlated and presenting the lowest relative bias with Patlak estimates, in comparison to the other methods we evaluated. Moreover, ParaPET gives access to quantitative information at the pixel level, which needs to be evaluated in the perspective of radiomic and tumour response.

Trial registration

NCT 02821936; May 2016.

Negative Survival Impact of High Radiation Doses to Neural Stem Cells Niches in an IDH-Wild-Type Glioblastoma Population

Aims: Assess the impact of radiation doses to neural stem cell (NSC) niches in patients with IDH-wild-type glioblastoma.

Materials and Methods: Fifty patients were included in the study. NSC niches [SubVentricular Zone (SVZ) and Sub Granular Zone (SGZ)] were contoured by fusing CT scans and pre-therapy MRI, Tumor location defined ipsilateral and contralateral SVZ and SGZ. Prognostic significance of clinical, biological and dosimetric parameters were examined. We generated a Recursive Partitioning Analysis (RPA) model with independent prognostic classes.

Results: Median follow-up: 23.8 months. Event free and overall survival (OS): 10 and 19.1 months. Incomplete surgery, PTV (planning target volume), ipsilateral SVZ or NSC niche mean dose > 57.4 Gy, contralateral NSC niche mean dose > 35 Gy and bilateral NSC niche mean dose > 44 Gy were significantly correlated with reduced OS. Only EGFR amplification was an independent prognostic factor (p = 0.019) for OS. RPA generated independent risk groups: 1 (low risk): [ipsilateral NSC mean dose (INMD) < 58.01 Gy and methylated MGMT promoter], 2: (INMD < 58.01 Gy and unmethylated MGMT promoter and contralateral SVZ mean dose < 18.6 Gy; p = 0.43), 3: (INMD < 58.01 Gy and unmethylated MGMT promoter and contralateral SVZ mean dose > 18.6 Gy; p = 0.002) and 4: (very high risk) (INMD > 58.01 Gy; p < 0.001).

Conclusion: High radiation doses to ipsilateral NSC and contralateral SVZ could have a negative impact on overall survival in IDH-wild-type glioblastoma population.

Dosimetric comparison of five different techniques for craniospinal irradiation across 15 European centers: analysis on behalf of the SIOP-E-BTG (radiotherapy working group). Acta Oncol 2018;57:1240-1249. [PMID: 29698060 DOI: 10.1080/0284186x.2018.1465588]

PURPOSE

Conventional techniques (3D-CRT) for craniospinal irradiation (CSI) are still widely used. Modern techniques (IMRT, VMAT, TomoTherapy^®, proton pencil beam scanning [PBS]) are applied in a limited number of centers. For a 14-year-old patient, we aimed to compare dose distributions of five CSI techniques applied across Europe and generated according to the participating institute protocols, therefore representing daily practice.

MATERIAL AND METHODS

A multicenter (n = 15) dosimetric analysis of five different techniques for CSI (3D-CRT, IMRT, VMAT, TomoTherapy^®, PBS; 3 centers per technique) was performed using the same patient data, set of delineations and dose prescription (36.0/1.8 Gy). Different treatment plans were optimized based on the same planning target volume margin. All participating institutes returned their best treatment plan applicable in clinic.

RESULTS

The modern radiotherapy techniques investigated resulted in superior conformity/homogeneity-indices (CI/HI), particularly in the spinal part of the target (CI: 3D-CRT:0.3 vs. modern:0.6; HI: 3D-CRT:0.2 vs. modern:0.1), and demonstrated a decreased dose to the thyroid, heart, esophagus and pancreas. Dose reductions of >10.0 Gy were observed with PBS compared to modern photon techniques for parotid glands, thyroid and pancreas. Following this technique, a wide range in dosimetry among centers using the same technique was observed (e.g., thyroid mean dose: VMAT: 5.6-24.6 Gy; PBS: 0.3-10.1 Gy).

CONCLUSIONS

The investigated modern radiotherapy techniques demonstrate superior dosimetric results compared to 3D-CRT. The lowest mean dose for organs at risk is obtained with proton therapy. However, for a large number of organs ranges in mean doses were wide and overlapping between techniques making it difficult to recommend one radiotherapy technique over another.

SIOPE - Brain tumor group consensus guideline on craniospinal target volume delineation for high-precision radiotherapy

OBJECTIVE

To develop a consensus guideline for craniospinal target volume (TV) delineation in children and young adults participating in SIOPE studies in the era of high-precision radiotherapy.

METHODS AND MATERIALS

During four consensus meetings (Cambridge, Essen, Liverpool, and Marseille), conventional field-based TV has been translated into image-guided high-precision craniospinal TV by a group of expert paediatric radiation oncologists and enhanced by MRI images of liquor distribution.

RESULTS

The CTV_cranial should include the whole brain, cribriform plate, most inferior part of the temporal lobes, and the pituitary fossa. If the full length of both optic nerves is not included, the dose received by different volumes of optic nerve should be recorded to correlate with future patterns of relapse (no consensus). The CTV_cranial should be modified to include the dural cuffs of cranial nerves as they pass through the skull base foramina. Attempts to spare the cochlea by excluding CSF within the internal auditory canal should be avoided. The CTV_spinal should include the entire subarachnoid space, including nerve roots laterally. The lower limit of the spinal CTV is at the lower limit of the thecal sac, best visible on MRI scan. There is no need to include sacral root canals in the spinal CTV.

CONCLUSION

This consensus guideline has the potential to improve consistency of craniospinal TV delineation in an era of high-precision radiotherapy. This proposal will be incorporated in the RTQA guidelines of future SIOPE-BTG trials using CSI.