Patient vulnerability in stereotactic arrhythmia radioablation (STAR): a preliminary ethical appraisal from the STOPSTORM.eu consortium

This preliminary ethical appraisal from the STOPSTORM.eu consortium is meant to raise critical points that clinicians administering stereotactic arrhythmia radioablation should consider to meet the highest standards in medical ethics and thus promote quality of life of patients recruited for radiotherapy treatments at a stage in which they experience a significant degree of vulnerability.

Dose escalation for stereotactic arrhythmia radioablation of recurrent ventricular tachyarrhythmia - a phase II clinical trial

BACKGROUND

Stereotactic arrhythmia radioablation (STAR) is delivered with a planning target volume (PTV) prescription dose of 25 Gy, mostly to the surrounding 75-85% isodose line. This means that the average and maximum dose received by the target is less than 35 Gy, which is the minimum threshold required to create a homogenous transmural fibrosis. Similar to catheter ablation, the primary objective of STAR should be transmural fibrosis to prevent heterogenous intracardiac conduction velocities and the occurrence of sustained ventricular arrhythmias (sVA) caused by reentry. We hypothesize that the current dose prescription used in STAR is inadequate for the long-term prevention of sVA and that a significant increase in dose is necessary to induce transmural scar formation.

OBJECTIVE

A single arm, multi-center, phase II, dose escalation prospective clinical trial employing the i3 + 3 design is being conducted to examine the safety of a radiation dose-escalation strategy aimed at inducing transmural scar formation. The ultimate objective of this trial is to decrease the likelihood of sVA recurrence in patients at risk.

METHODS

Patients with ischemic or non-ischemic cardiomyopathy and recurrent sVA, with an ICD and history of ≥ 1 catheter ablation for sVA will be included. This is a prospective, multicenter, one-arm, dose-escalation trial utilizing the i3 + 3 design, a modified 3 + 3 specifically created to overcome limitations in traditional dose-finding studies. A total of 15 patients will be recruited. The trial aims to escalate the ITV dose from 27.0 Gy to an ITV prescription dose-equivalent level of maximum 35.1 Gy by keeping the PTV prescription dose constant at 25 Gy while increasing the dose to the target (i.e. the VT substrate without PTV margin) by step-wise reduction of the prescribing isodose line (85% down to 65%). The primary outcome of this trial is safety measured by registered radiation associated adverse events (AE) up to 90 days after study intervention including radiation associated serious adverse events graded as at least 4 or 5 according to CTCAE v5, radiation pneumonitis or pericarditis requiring hospitalization and decrease in LVEF ≥ 10% as assessed by echocardiography or cardiac MRI at 90 days after STAR. The sample size was determined assuming an acceptable primary outcome event rate of 20%. Secondary outcomes include sVA burden at 6 months after STAR, time to first sVA recurrence, reduction in appropriate ICD therapies, the need for escalation of antiarrhythmic drugs, non-radiation associated safety and patient reported outcome measures such as SF-36 and EQ5D.

DISCUSSION

DEFT-STAR is an innovative prospective phase II trial that aims to evaluate the optimal radiation dose for STAR in patients with therapy-refractory sVA. The trial has obtained IRB approval and focuses on determining the safe and effective radiation dose to be employed in the STAR procedure.

TRIAL REGISTRATION

NCT05594368.

STereotactic Arrhythmia Radioablation (STAR): the Standardized Treatment and Outcome Platform for Stereotactic Therapy Of Re-entrant tachycardia by a Multidisciplinary consortium (STOPSTORM.eu) and review of current patterns of STAR practice in Europe

The EU Horizon 2020 Framework-funded Standardized Treatment and Outcome Platform for Stereotactic Therapy Of Re-entrant tachycardia by a Multidisciplinary (STOPSTORM) consortium has been established as a large research network for investigating STereotactic Arrhythmia Radioablation (STAR) for ventricular tachycardia (VT). The aim is to provide a pooled treatment database to evaluate patterns of practice and outcomes of STAR and finally to harmonize STAR within Europe. The consortium comprises 31 clinical and research institutions. The project is divided into nine work packages (WPs): (i) observational cohort; (ii) standardization and harmonization of target delineation; (iii) harmonized prospective cohort; (iv) quality assurance (QA); (v) analysis and evaluation; (vi, ix) ethics and regulations; and (vii, viii) project coordination and dissemination. To provide a review of current clinical STAR practice in Europe, a comprehensive questionnaire was performed at project start. The STOPSTORM Institutions' experience in VT catheter ablation (83% ≥ 20 ann.) and stereotactic body radiotherapy (59% > 200 ann.) was adequate, and 84 STAR treatments were performed until project launch, while 8/22 centres already recruited VT patients in national clinical trials. The majority currently base their target definition on mapping during VT (96%) and/or pace mapping (75%), reduced voltage areas (63%), or late ventricular potentials (75%) during sinus rhythm. The majority currently apply a single-fraction dose of 25 Gy while planning techniques and dose prescription methods vary greatly. The current clinical STAR practice in the STOPSTORM consortium highlights potential areas of optimization and harmonization for substrate mapping, target delineation, motion management, dosimetry, and QA, which will be addressed in the various WPs.

Splenomegaly in patients with primary or secondary myelofibrosis who are candidates for allogeneic hematopoietic cell transplantation: a Position Paper on behalf of the Chronic Malignancies Working Party of the EBMT

Splenomegaly is a hallmark of myelofibrosis, a debilitating haematological malignancy for which the only curative option is allogeneic haematopoietic cell transplantation (HCT). Considerable splenic enlargement might be associated with a higher risk of delayed engraftment and graft failure, increased non-relapse mortality, and worse overall survival after HCT as compared with patients without significantly enlarged splenomegaly. Currently, there are no standardised guidelines to assist transplantation physicians in deciding optimal management of splenomegaly before HCT. Therefore, the aim of this Position Paper is to offer a shared position statement on this issue. An international group of haematologists, transplantation physicians, gastroenterologists, surgeons, radiotherapists, and radiologists with experience in the treatment of myelofibrosis contributed to this Position Paper. The key issues addressed by this group included the assessment, prevalence, and clinical significance of splenomegaly, and the need for a therapeutic intervention before HCT for the control of splenomegaly. Specific scenarios, including splanchnic vein thrombosis and COVID-19, are also discussed. All patients with myelofibrosis must have their spleen size assessed before allogeneic HCT. Myelofibrosis patients with splenomegaly measuring 5 cm and larger, particularly when exceeding 15 cm below the left costal margin, or with splenomegaly-related symptoms, could benefit from treatment with the aim of reducing the spleen size before HCT. In the absence of, or loss of, response, patients with increasing spleen size should be evaluated for second-line options, depending on availability, patient fitness, and centre experience. Splanchnic vein thrombosis is not an absolute contraindication for HCT, but a multidisciplinary approach is warranted. Finally, prevention and treatment of COVID-19 should adhere to standard recommendations for immunocompromised patients.

Survey results of the STOPSTORM consortium about stereotactic arrhythmia radioablation in Europe

Funding Acknowledgements

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): Horizon 2020 research and innovation programme

Background/Introduction

In patients with structural heart disease (SHD), ventricular tachycardia (VT) plays a decisive role in sudden cardiac death. VT patients are often treated with antiarrhythmic medication and catheter ablation. For refractory VTs, STereotactic Arrhythmia Radioablation (STAR) delivered to the underlying VT substrate has recently been introduced and showed promising results for otherwise untreatable patients. [1]

Purpose

The purpose of the STOPSTORM consortium is to harmonize and optimize STAR across Europe. It consists of 31 members including 24 electrophysiology and 22 radiation oncology departments performing or participating in STAR throughout eight European countries. To obtain initial overview of organization, equipment, procedures, experiences, and quality levels for STAR, a detailed survey was circulated among STOPSTORM members.

Methods

The survey included questions for electrophysiology (18 questions), radiation oncology (24 questions) and medical physics (23 questions). The survey was the first step for accreditation of the centres and therefore mandatory for all consortium members.

Results

All centres participating in STOPSTORM completed the survey. 16 centres performed a total of 84 STAR treatments until May 2021 and 11 centres already participate in clinical trials for STAR.

Annual number of VT ablations in SHD: less than 20 (17%), 20-50 (50%), 50-100 (21%), more than 100 (12%) and epicardial: less than 20 (71%), 20-50 (17%), n/s (12%). An overview of the availability of a clinical program for catheter ablation of ventricular arrhythmia with certification of the respective national cardiology society and the practice of general quality audits for ablation is given in figure 1. Participation in multicentre clinical trials in cardiology/EP were indicated by 19 departments (79%).

Target volume definition is based on invasive electroanatomical mapping during VT (96%), pace mapping (75%), reduced voltage areas (63%) and/or late ventricular potentials (75%). Half of the centres includes the clinical VT substrate, while the other half includes the whole arrhythmogenic substrate. Non-invasive surface ECG mapping has so far found little application: used clinically (13%), research purposes (8%) and evaluation (4%).

Stereotactic Body Radiotherapy experience (> 10 years: 82%, > 200 p.a.: 59%) is high. In all but one clinic, a dose of 25 Gy in a single fraction is applied. The prescription method, planning technique and inhomogeneity in the target volume, however, varies greatly. All departments perform patient-specific plan verifications for STAR, but with various evaluation criteria.

Conclusion

Experience in STAR within the STOPSTORM consortium is adequate, while the survey shows areas of harmonization and optimization need for substrate mapping, target delineation, dosimetry and quality assurance which will be addressed in the STOPSTORM project work-packages.

Current Status and Perspectives of Irradiation-Based Conditioning Regimens for Patients with Acute Leukemia Undergoing Hematopoietic Stem Cell Transplantation

Acute myeloid leukemia and acute lymphoblastic leukemia are the most common indications for allogeneic hematopoietic stem cell transplantation. Total body irradiation (TBI) is an important part of conditioning regimens. TBI-based regimens offer advantages in sanctuary sites but are associated with significant risks of early and late side effects, including pulmonary toxicity, growth retardation, and second malignancy. TBI is also associated with technical problems, such as dose heterogeneity. With evolving techniques in radiation oncology, it is possible to focus the dose to the entire skeleton while sparing the rest of the body. This technique is called total marrow irradiation (TMI). TMI is able to deliver the same or higher doses to bone marrow while reducing toxicity. With the success of TMI, we are moving toward ultra-personalized conditioning. We review the clinical role of the irradiation-based regimens currently in clinical use, emphasizing on their strengths and limitations. Novel technologies with targeted irradiation accompanied by the modern imaging techniques and increased knowledge of the disease process can help us achieve our goal of maximum response with minimum toxicity.

Effect of Therapeutic Ionizing Radiation on Implantable Electronic Devices: Systematic Review and Practical Guidance

Cardiac implantable electronic devices (CIEDs) have been in use for over 50 years and their therapeutic value is undisputable. With the rapidly aging population, it is estimated that the number of CIEDs will grow dramatically over the next 2 decades. Given these predictions, the topic of management of concomitant conditions associated with older age becomes more relevant than ever. In particular, the number of patients with an implanted CIED diagnosed with cancer is expected to rise by about 70%, from 14 million in 2012 to 22 million within the next 2 decades. Treatment of most of these tumors and tumor metastases requires radiation therapy. However, the necessary high doses of radiation can potentially interact with the function, longevity, and integrity of the CIEDs and/or cause harm to the patient. The impact of an absence of clear therapeutic guidelines for oncology patients with CIEDs who should undergo radiation therapy is vast; and due to the fear of possible complications related to device failure, many of these patients may not be treated adequately to their needs, which can strongly affect their prognosis. This article summarizes the available data on the management of patients with CIEDs undergoing radiotherapy. It systematically presents possible causes and consequences of direct and scattered radiation on CIEDs, highlights possible complications that may occur during this kind of treatment, and provides practical guidance for this challenging real life clinical setting.

Feasibility of reducing the irradiation dose in regions of active neurogenesis for prophylactic cranial irradiation in patients with small-cell lung cancer

Prophylactic cranial irradiation (PCI) is performed on patients with limited or extensive small-cell lung cancer to reduce incidence of brain metastases and prolong survival. PCI may induce neurocognitive impairment. Decreasing irradiation of neural stem cells (NSC) might reduce PCI-induced toxicity. We tested the feasibility of reducing irradiation doses to neural stem cell (NSC) regions while maintaining prescribed doses to the planned target volume (PTV). Irradiation plans utilizing intensity-modulated radiotherapy (IMRT), helical TomoTherapy, and RapidArc for 10 consecutive lung cancer patients were evaluated. The dose distribution, dose-volume histograms, and dose homogeneity indexes were analyzed. Planned and actual dose distributions were compared by dosimetric analysis. Both helical tomotherapy and LINAC-based IMRT reduced the radiation dose to the NSC regions by approximately 45% while maintaining the full dose to the rest of brain. Measured dose distributions matched the planned dose distributions.Protecting the regions of active neurogenesis is technically feasible. Whether reducing the dose by 35% to 45% is sufficient to reduce treatment toxicity, however, can only be addressed in a randomized study. Further reducing the dose within the NSC region might also significantly decrease the dosage to the PTV.

Effects of X-ray irradiation on methylation levels of p16, MGMT and APC genes in sporadic colorectal carcinoma and corresponding normal colonic mucosa

BACKGROUND

Colorectal cancer, one of the most aggressive cancers, occurs with a high incidence world-wide. Cancer development and progression is dictated by a series of alterations in a number genes, e.g., tumor suppressor genes, DNA repair genes, oncogenes and others. DNA methylation is an epigenetic modification that is profoundly altered in most cancers. Radiation is a well-known genotoxic agent and human carcinogen that gives rise to a variety of long-term effects. The inheritance of genomic instability suggests the possible involvement of epigenetic mechanisms, such as changes in methylation of the cytosine residues located within CpG dinucleotides. In the current study we evaluated the effect of X-ray irradiation on methylation levels of p16, MGMT and APC genes in colorectal cancers and normal colonic mucosa.

MATERIAL/METHODS

Fresh tissue samples were obtained from 28 patients (ages 26 to 81 years) with primary colorectal adenocarcinoma and corresponding normal tissues. We used methylation-specific polymerase chain reaction (MSP) for analysis of the methylation status of p16, MGMT, APC1A and APC1B genes.

RESULTS

Methylation of p16, MGMT, APC1A and APC1B was detected in 42%, 67%, 42% and 20% of tumors before X-ray irradiation and in 63%, 56%, 25% and 31% after radiotherapy, respectively. In corresponding normal colonic mucosa, methylation of p16, MGMT and APC1A was detected in 17%, 25% and 8% before and in 19%, 31% and 6% after irradiation, respectively.

CONCLUSIONS

Differences between groups, although noticeable, did not reach the level of statistical significance.

[Prospective analysis of criteria for interpreting measurements of thyroglobulin serum concentration during conditions of endogenous TSH stimulation in serum of patients with differentiated thyroid carcinoma]

The aim of this study was the assessment of diagnostic value of thyroglobulin serum measurement in patients with DTC during endogenous TSH stimulation. Thyroglobulin was measured by immunofluorometric method (Delfia-Wallac) in patients after combined surgery and I131 ablation. Predictive values for two threshold levels 10 and 30 ng/ml were compared. At 5 years follow up it has been demonstrated, that Tg values higher than 10 ng/ml were the true signals of DTC relapse only in 46% patients. Tg values higher than 30 ng/ml were associated with disease progression in 65% of patients. Thus, we accept Tg concentration of 30 ng/ml measured during endogenous TSH stimulation as a good cut-off limit for the detection of DTC progression. Reduction of this threshold up to 10 ng/ml is associated with the increased risk of false positive results.