Management of patients with cardiac implantable electronic devices (CIED) undergoing radiotherapy: A consensus document from Associazione Italiana Aritmologia e Cardiostimolazione (AIAC), Associazione Italiana Radioterapia Oncologica (AIRO), Associazione Italiana Fisica Medica (AIFM)

Effect of simultaneous integrated boost concepts on photoneutron and distant out-of-field doses in VMAT for prostate cancer

BACKGROUND

A simultaneous integrated boost (SIB) may result in increased out-of-field (DOOF) and photoneutron (HPN) doses in volumetric modulated arc therapy (VMAT) for prostate cancer (PCA). This work therefore aimed to compare DOOF and HPN in flattened (FLAT) and flattening filter-free (FFF) 6‑MV and 10-MV VMAT treatment plans with and without SIB.

METHODS

Eight groups of 30 VMAT plans for PCA with 6 MV or 10 MV, with or without FF and with uniform (2 Gy) or SIB target dose (2.5/3.0 Gy) prescriptions (CONV, SIB), were generated. All 240 plans were delivered on a slab-phantom and compared with respect to measured DOOF and HPN in 61.8 cm distance from the isocenter. The 6‑ and 10-MV flattened VMAT plans with conventional fractionation (6- and 10-MV FLAT CONV) served as standard reference groups. Doses were analyzed as a function of delivered monitor units (MU) and weighted equivalent square field size Aeq. Pearson's correlation coefficients between the presented quantities were determined.

RESULTS

The SIB plans resulted in decreased HPN over an entire prostate RT treatment course (10-MV SIB vs. CONV -38.2%). Omission of the flattening filter yielded less HPN (10-MV CONV -17.2%; 10-MV SIB -22.5%). The SIB decreased DOOF likewise by 39% for all given scenarios, while the FFF mode reduced DOOF on average by 60%. A strong Pearson correlation was found between MU and HPN (r > 0.9) as well as DOOF (0.7 < r < 0.9).

CONCLUSION

For a complete treatment, SIB reduces both photoneutron and OOF doses to almost the same extent as FFF deliveries. It is recommended to apply moderately hypofractionated 6‑MV SIB FFF-VMAT when considering photoneutron or OOF doses.

Impact of Radiotherapy on Malfunctions and Battery Life of Cardiac Implantable Electronic Devices in Cancer Patients

PURPOSE

This study analyses a large number of cancer patients with CIEDs for device malfunction and premature battery depletion by device interrogation after each radiotherapy fraction and compares different guidelines in regard to patient safety.

METHODS

From 2007 to 2022, a cohort of 255 patients was analyzed for CIED malfunctions via immediate device interrogation after every RT fraction.

RESULTS

Out of 324 series of radiotherapy treatments, with a total number of 5742 CIED interrogations, nine device malfunctions (2.8%) occurred. Switching into back-up/safety mode and software errors occurred four times each. Once, automatic read-out could not be performed. The median prescribed cumulative dose at planning target volume (PTV) associated with CIED malfunction was 45.0 Gy (IQR 36.0-64.0 Gy), with a median dose per fraction of 2.31 Gy (IQR 2.0-3.0 Gy). The median maximum dose at the CIED at time of malfunction was 0.3 Gy (IQR 0.0-1.3 Gy). No correlation between CIED malfunction and maximum photon energy (p = 0.07), maximum dose at the CIED (p = 0.59) nor treatment localization (p = 0.41) could be detected. After excluding the nine malfunctions, premature battery depletion was only observed three times (1.2%). Depending on the national guidelines, 1-9 CIED malfunctions in this study would have been detected on the day of occurrence and in none of the cases would patient safety have been compromised.

CONCLUSION

Radiation-induced malfunctions of CIEDs and premature battery depletion are rare. If recommendations of national safety guidelines are followed, only a portion of the malfunctions would be detected directly after occurrence. Nevertheless, patient safety would not be compromised.

From organ at risk to target organ: Dosimetric comparison of myocardial stereotactic ablative body radiotherapy between helical tomotherapy and volumetric arc therapy for refractory ventricular tachycardia

Ventricular tachycardia (VT) is an important type of arrhythmia with a risk of sudden death. Although implanted cardiac defibrillation and radiofrequency ablation are used together with medical treatments for VT, the treatment options are limited in cases that do not respond to them. Stereotactic ablative body radiotherapy (SABR) applied to VT substrates in resistant cases is an emerging treatment with positive results. Such clinical results have increased the interest in this subject. However, the ideal treatment device and method have not yet been described for this therapy, which is generally applied at a single fraction using various devices and methods. Herein, treatment planning was conducted for a total of 8 patients (11 VT substrates) using the Varian TrueBeam EDGE and TomoTherapy Radixact devices at a single center, and the results were compared dosimetrically. The Wilcoxon-signed rank test was used for the statistical analysis, and mean values were expressed as medians and interquartile ranges (IQRs). In the volumetric modulated arc therapy (VMAT) and helical tomotherapy (HT) plans, the plan coverages and conformity indexes were similar; meanwhile, the homogeneity indexes were 0.10 (IQR = 0.05) and 0.07 (IQR = 0.05), respectively, and were significantly better in the HT plan (p = 0.02). The gradient indexes were 3.18 (IQR = 0.8) and 5.33 (IQR = 3.68) in the VMAT and HT plans, respectively, and were significantly better in the VMAT plan. For the organs at risk, similar doses were observed. The maximum doses for the stomach and esophagus and the mean doses for the left lung and both lungs were significantly lower in the VMAT plan. Similarly, the maximum and mean doses for the cardiac substructures and great vessels were significantly lower in the VMAT plan. More homogeneous plans were obtained in HT, while a faster dose reduction and lower critical organ dose were observed in VMAT. Reasonable myocardial SABR plans could be obtained with both techniques. The effects of the dosimetric differences on the clinical outcomes should be evaluated in prospective clinical studies.

Management of Patients with Cardiovascular Implantable Electronic Devices Undergoing Radiation Therapy: A National Survey of Canadian Multidisciplinary Radiation Oncology Professionals

Purpose

This study aimed to characterize contemporary management of Canadian patients with cardiovascular implantable electronic devices (CIEDs) undergoing radiation therapy (RT) in light of updated American Association of Physicists in Medicine guidelines.

Methods and Materials

A 22-question web-based survey was distributed to members of the Canadian Association of Radiation Oncology, Canadian Organization of Medical Physicists, and Canadian Association of Medical Radiation Technologists from January to February 2020. Respondent demographics, knowledge, and management practices were elicited. Statistical comparisons by respondent demographics were performed using χ² and Fisher exact tests.

Results

In total, 155 surveys were completed by 54 radiation oncologists, 26 medical physicists, and 75 radiation therapists in academic (51%) and community (49%) practices across all provinces. The majority of respondents (77%) had managed >10 patients with CIEDs in their career. Most respondents (70%) reported using risk-stratified institutional management protocols. Respondents used manufacturer recommendations, rather than American Association of Physicists in Medicine or institutionally recommended dose limits, when the manufacturer limit was 0 Gy (44%), 0 to 2 Gy (45%), or >2 Gy (34%). The majority of respondents (86%) reported institutional policies to refer to a cardiologist for CIED evaluation both before and after completion of RT. Cumulative dose to CIED, pacing dependence, and neutron production were considered during risk stratification by 86%, 74%, and 50% of participants, respectively. Dose and energy thresholds for high-risk management were not known by 45% and 52% of respondents, with radiation oncologists and radiation therapists significantly less likely to report thresholds than medical physicists (P < .001). Although 59% of respondents felt comfortable managing patients with CIEDs, community respondents were less likely to feel comfortable than academic respondents (P = .037).

Conclusions

The management of Canadian patients with CIEDs undergoing RT is characterized by variability and uncertainty. National consensus guidelines may have a role in improving provider knowledge and confidence in caring for this growing population.

Neutron dose from a 6-MV X-ray beam in radiotherapy

Although a 6-MV X-ray beam is employed clinically as a non-neutron-producing beam, no studies have reported how few neutrons are produced from a 6-MV beam. This study aimed to theoretically deduce the neutron dose from a 6-MV beam using Monte Carlo simulations for the notification of safety and risk in radiotherapy. Nuclei from a nuclear database with neutron separation energies below 6 MeV were surveyed, suggesting that the certain content of ²H in the human body may result in some contribution. Thus, Monte Carlo calculation considering ²H in a phantom was performed. The calculation suggested that the distribution of the neutron dose from a 6-MV beam consisted of two components: one had neutrons from ²H concentrated within an irradiation field, and the other had those due to other elements such as ¹⁸³W spreading from a gantry head to a treatment room. Although uncertainty owing to the normalization factor of the Monte Carlo calculations was a factor of three, the neutron doses at distances of 0 and 50 cm from an irradiation field were calculated as 27 and 1.5 nSv/MU, respectively, under intensity-modulated radiotherapy (IMRT) or volumetric modulated arc therapy (VMAT). The calculations suggest that neutrons produced by a 6-MV beam are approximately 70 and 20 times safer than those by a 10-MV beam in the case of IMRT/VMAT and total body irradiation, respectively. Thus, this study theoretically reported the approximate number of neutrons delivered by a 6-MV beam for the first time.

Establishing quality indicators to comprehensively assess quality assurance and patient safety in radiotherapy and their relationship with an institution's background

BACKGROUND AND PURPOSE

Quality indicators (QIs) for radiotherapy have been proposed by several groups, but no study has been conducted to correlate the implementation of indicators specific to patient safety over the course of the clinical process with an institution's background. An initial large-scale survey was conducted to understand the implementation status of QIs established for quality assurance and patient safety in radiotherapy and the relationship between implementation status and an institutions' background.

MATERIALS AND METHOD

Overall, 68 QIs that were established by this research team after a pilot survey were used to assess structures and processes for quality assurance and patient safety. Data on the implementation of QIs and the institutions' backgrounds were obtained from designated cancer care hospitals in Japan.

RESULTS

Overall, 284 institutions (72 %) responded and had a median QI achievement rate of 60.8 %. QIs with low implementation rates, such as the implementation of an error reporting system and establishment of a quality assurance department, were identified. The QI achievement rate and scale of the institution were positively correlated, and the achievement rate of all QIs was significantly higher (p < 0.001) in institutions capable of advanced treatments, such as intensity-modulated radiotherapy, and those with a quality assurance department.

CONCLUSION

A large-scale survey on QIs revealed their implementation and relationship with a facility's background. QIs that require improvement were identified, and that these QIs might be effective in providing advanced medical care to many patients.

A systematic review and meta-analysis on oncological radiotherapy in patients with a cardiac implantable electronic device: Prevalence and predictors of device malfunction in 3121 patients

BACKGROUND

The number of patients with cardiac implantable electronic devices (CIEDs) undergoing radiotherapy (RT) for cancer treatment is growing. At present, prevalence and predictors of RT-induced CIEDs malfunctions are not defined.

METHODS

Systematic review and meta-analysis conducted following the PRISMA recommendations. PubMed, Scopus and Google Scholar were searched from inception to 31/01/2022 for studies reporting RT-induced malfunctions in CIEDs patients. Aim was to assess the prevalence of RT-induced CIEDs malfunctions and identify potential predictors.

RESULTS

Thirty-two out of 3962 records matched the inclusion criteria and were included in the meta-analysis. A total of 135 CIEDs malfunctions were detected among 3121 patients (6.6%, 95% confidence interval [CI]: 5.1%-8.4%). The pooled prevalence increased moving from pacemaker (PM) to implantable cardioverter defibrillator (ICD), and cardiac resynchronization therapy and defibrillator (CRT-D) groups (4.1%, 95% CI: 2.9-5.8; 8.2% 95% CI: 5.9-11.3; and 19.8%, 95% CI: 11.4-32.2 respectively). A higher risk ratio (RR) of malfunctions was found when neutron-producing energies were used as compared to non-neutron-producing energies (RR 9.98, 95% CI: 5.09-19.60) and in patients with ICD/CRT-D as compared to patients with PM/CRT-P (RR 2.07, 95% CI: 1.40-3.06). On the contrary, no association was found between maximal radiation dose at CIED >2 Gy and CIEDs malfunctions (RR 0.93; 95% CI: 0.31-2.76).

CONCLUSIONS

Radiotherapy related CIEDs malfunction had a prevalence ranging from 4% to 20%. The use of neutron-producing energies and more complex devices (ICD/CRT-D) were associated with higher risk of device malfunction, while the radiation dose at CIED did not significantly impact on the risk unless higher doses (>10 Gy) were used.

The Use of Cardiac Stereotactic Radiation Therapy (SBRT) to Manage Ventricular Tachycardia: A Case Report, Review of the Literature and Technical Notes

BACKGROUND

among cardiac arrhythmias, ventricular tachycardia (VT) is one that can lead to cardiac death, although significant progress has been made in its treatment, including the use of implantable cardioverter-defibrillators (ICD) and radiofrequency catheter ablation. Nevertheless, long-term recurrence rates remain in about half of patients and drastically impact the patient's quality of life. Moreover, recurrent ICD shocks are painful and are associated with higher mortality and worsening of heart failure. Recently, more and more experiences are demonstrating potential efficacy in the use of stereotactic body radiotherapy (SBRT) (also called cardiac radio-ablation) to treat this condition. In this paper, we report our experience in the use of cardiac radio-ablation for the treatment of refractory ventricular tachycardia with a focus on the technique used, along with a review of the literature and technical notes.

CASE PRESENTATION

an 81-year-old male patient with a long history of non-ischemic dilated cardiomyopathy and mechanical mitral prosthesis underwent a biventricular cardioverter defibrillator implant after atrial ventricular node ablation. At the end of 2021, the number of tachycardias increased significantly to about 10 episodes per day. After failure of medical treatment and conventional RT catheter ablation, the patient was treated with SBRT for a total dose of 25 Gy in a single session at the site of the ectopic focus. No acute toxicity was recorded. After SBRT (follow-up 7 months) no other VT episodes were recorded.

CONCLUSION

SBRT appears to be safe and leads to a rapid reduction in arrhythmic storms as treatment for VT without acute toxicity, representing one of the most promising methods for treating VT storms.

The impact of particle radiotherapy on the functioning of cardiac implantable electronic devices: a systematic review of in vitro and in vivo studies according to PICO criteria

The number of oncological patients who may benefit from proton beam radiotherapy (PBT) or carbon ion radiotherapy (CIRT), overall referred to as particle radiotherapy (RT), is expected to strongly increase in the next future, as well as the number of cardiological patients requiring cardiac implantable electronic devices (CIEDs). The management of patients with a CIED requiring particle RT deserves peculiar attention compared to those undergoing conventional photon beam RT, mostly due to the potential generation of secondary neutrons by particle beams interactions. Current consensus documents recommend managing these patients as being at intermediate/high risk of RT-induced device malfunctioning regardless of the dose on the CIED and the beam delivery method used, despite the last one significantly affects secondary neutrons generation (very limited neutrons production with active scanning as opposed to the passive scattering technique). The key issues for the current review were expressed in four questions according to the Population, Intervention, Control, Outcome criteria. Three in vitro and five in vivo studies were included. Based on the available data, PBT and CIRT with active scanning have a limited potential to interfere with CIED that has only emerged from in vitro study so far, while a significant potential for neutron-related, not severe, CIED malfunctions (resets) was consistently reported in both clinical and in vitro studies with passive scattering.

Patients with Cardiac Implantable Electronic Device Undergoing Radiation Therapy: Insights from a Ten-Year Tertiary Center Experience

Background: The number of patients with cardiac implantable electronic devices (CIEDs) receiving radiotherapy (RT) is increasing. The management of CIED-carriers undergoing RT is challenging and requires a collaborative multidisciplinary approach. Aim: The aim of the study is to report the real-world, ten-year experience of a tertiary multidisciplinary teaching hospital. Methods: We conducted an observational, real-world, retrospective, single-center study, enrolling all CIED-carriers who underwent RT at the San Raffaele University Hospital, between June 2010 and December 2021. All devices were MRI-conditional. The devices were programmed to an asynchronous pacing mode for patients who had an intrinsic heart rate of less than 40 beats per minute. An inhibited pacing mode was used for all other patients. All tachyarrhythmia device functions were temporarily disabled. After each RT session, the CIED were reprogrammed to the original settings. Outcomes included adverse events and changes in the variables that indicate lead and device functions. Results: Between June 2010 and December 2021, 107 patients were enrolled, among which 63 (58.9%) were pacemaker carriers and 44 (41.1%) were ICD carriers. Patients were subjected to a mean of 16.4 (±10.7) RT sessions. The most represented tumors in our cohort were prostate cancer (12; 11%), breast cancer (10; 9%) and lung cancer (28; 26%). No statistically significant changes in device parameters were recorded before and after radiotherapy. Generator failures, power-on resets, changes in pacing threshold or sensing requiring system revision or programming changes, battery depletions, pacing inhibitions and inappropriate therapies did not occur in our cohort of patients during a ten-year time span period. Atrial arrhythmias were recorded during RT session in 14 patients (13.1%) and ventricular arrhythmias were observed at device interrogation in 10 patients (9.9%). Conclusions: Changes in device parameters and arrhythmia occurrence were infrequent, and none resulted in a clinically significant adverse event.

Stereotactic Radiotherapy Ablation and Atrial Fibrillation: Technical Issues and Clinical Expectations Derived From a Systematic Review

Aim

The purpose of this study is to collect available evidence on the feasibility and efficacy of stereotactic arrhythmia radio ablation (STAR), including both photon radiotherapy (XRT) and particle beam therapy (PBT), in the treatment of atrial fibrillation (AF), and to provide cardiologists and radiation oncologists with a practical overview on this topic.

Methods

Three hundred and thirty-five articles were identified up to November 2021 according to preferred reporting items for systematic reviews and meta-analyses criteria; preclinical and clinical studies were included without data restrictions or language limitations. Selected works were analyzed for comparing target selection, treatment plan details, and the accelerator employed, addressing workup modalities, acute and long-term side-effects, and efficacy, defined either by the presence of scar or by the absence of AF recurrence.

Results

Twenty-one works published between 2010 and 2021 were included. Seventeen studies concerned XRT, three PBT, and one involved both. Nine studies (1 in silico and 8 in vivo; doses ranging from 15 to 40 Gy) comprised a total of 59 animals, 12 (8 in silico, 4 in vivo; doses ranging from 16 to 50 Gy) focused on humans, with 9 patients undergoing STAR: average follow-up duration was 5 and 6 months, respectively. Data analysis supported efficacy of the treatment in the preclinical setting, whereas in the context of clinical studies the main favorable finding consisted in the detection of electrical scar in 4/4 patients undergoing specific evaluation; the minimum dose for efficacy was 25 Gy in both humans and animals. No acute complication was recorded; severe side-effects related to the long-term were observed only for very high STAR doses in 2 animals. Significant variability was evidenced among studies in the definition of target volume and doses, and in the management of respiratory and cardiac target motion.

Conclusion

STAR is an innovative non-invasive procedure already applied for experimental treatment of ventricular arrhythmias. Particular attention must be paid to safety, rather than efficacy of STAR, given the benign nature of AF. Uncertainties persist, mainly regarding the definition of the treatment plan and the role of the target motion. In this setting, more information about the toxicity profile of this new approach is compulsory before applying STAR to AF in clinical practice.

Safety verification of carbon-ion radiotherapy for patients with cardiac implantable electronic devices (CIEDs)

According to guidelines, carbon-ion beam therapy is considered to carry a high safety risk for patients with cardiac implantable electronic devices (CIEDs), although the actual impacts remain unclear. In this study, we investigated the safety of carbon-ion beam therapy in patients with CIEDs. Patients with CIEDs who underwent carbon-ion therapy at Gunma University Heavy Ion Medical Center between June 2010 and December 2019 were identified and investigated for abnormalities in the operation of their CIEDs, such as oversensing and resetting during irradiation, and abnormalities in operation after treatment. In addition, the risk of irradiation from carbon-ion beam therapy was evaluated by model simulations. Twenty patients (22 sites) with CIEDs were identified, 19 with pacemakers and one with an implantable cardioverter-defibrillator (ICD). Treatments were completed without any problems, except for one case in which the treatment was discontinued because of worsening of the primary disease. Monte Carlo simulation indicated that the carbon beam irradiation produced neutrons at a constant and high level in the irradiation field. Nevertheless, with the distances between the CIEDs and the irradiation fields in the analyzed cases, the quantity of neutrons at the CIEDs was lower than that within the irradiation. Although carbon-ion beam therapy can be safely administered to patients with CIEDs, it is advisable to perform the therapy with sufficient preparation and backup devices because of the risks involved.

[ESC guidelines 2021 on cardiac pacing and cardiac resynchronization therapy : What's new?]

The new European Society of Cardiology (ESC) guidelines on cardiac pacing and cardiac resynchronization therapy were presented together with the new ESC heart failure guidelines at the ESC congress in September. The new document includes detailed sections on patient evaluation and clinical assessment, implantation, minimizing complications and patient follow-up. The guidelines have been updated and expanded particularly on the approach to reflex syncope, the indications after transcatheter aortic valve implantation (TAVI) and the perioperative management. The indications for cardiac resynchronization therapy (CRT) are now in line with the simultaneously published ESC heart failure guidelines. New physiological forms of stimulation and leadless pacing are now included in the guidelines.

Radiotherapy for patient with cardiac implantable electronic device, consensus from French radiation oncology society

Radiotherapy in patients with cardiac implantable electronic device such as pacemakers or defibrillators, is a clinical situation that is becoming increasingly common. There is a risk of interaction between the magnetic field induced by accelerators and the cardiac implantable electronic device, but also a risk of device dysfunction due to direct and/or indirect irradiation if the cardiac implantable electronic device is in the field of treatment. The risk can be dose-dependent, but it is most often independent of the total dose and occurs randomly in case of neutron production (stochastic effect). The presence of this type of device is therefore described as a contraindication for radiotherapy by the French national agency for the safety of medicines and health products (Agence nationale de sécurité du médicament et des produits de santé, ANSM). Nevertheless, since radiotherapy is often possible, it is advisable to respect the recommendations of good practice, in particular the eligibility criteria, the monitoring modalities before, during and after irradiation according to the type of treatment, the dose and the characteristics of the cardiac implantable electronic device. It is sometimes necessary to discuss repositioning the device and/or modifying the treatment plan to minimize the risk of cardiac implantable electronic device dysfunction. We present the update of the recommendations of the French society of oncological radiotherapy on in patients with cardiac implantable electronic device.

Management of IMRT in a gastric cancer patient with pacemaker: A case report and review of the literature

Due to the prolongation of a lifetime, more cancer patients with cardiac implantable electronic devices are treated by radiotherapy. However, radiation may cause permanent or temporary malfunctions on these devices, and new-generation devices are more sensitive to radiation. Besides, radiotherapy techniques and image guidance methods that may cause different interactions with the functions of the devices have been changed significantly recently. Here, we reported our clinical experience in a patient with a pacemaker who underwent radiotherapy with intensity-modulated radiation therapy (IMRT) due to gastric cancer and reviewed the literature.

Particle therapy using protons or carbon ions for cancer patients with cardiac implantable electronic devices (CIED): a retrospective multi-institutional study

PURPOSE

To evaluate the outcomes of particle therapy in cancer patients with cardiac implantable electronic devices (CIEDs).

MATERIALS AND METHODS

From April 2001 to March 2013, 19,585 patients were treated with proton beam therapy (PBT) or carbon ion therapy (CIT) at 8 institutions. Of these, 69 patients (0.4%, PBT 46, CIT 22, and PBT + CIT 1) with CIEDs (64 pacemakers, 4 implantable cardioverter defibrillators, and 1 with a cardiac resynchronization therapy defibrillator) were retrospectively reviewed. All the patients with CIEDs in this study were treated with the passive scattering type of particle beam therapy.

RESULTS

Six (13%) of the 47 PBT patients, and none of the 23 CIT patients experienced CIED malfunctions (p = 0.105). Electrical resets (7) and over-sensing (3) occurred transiently in 6 patients. The distance between the edge of the irradiation field and the CIED was not associated with the incidence of malfunctions in 20 patients with lung cancer. A larger field size had a higher event rate but the test to evaluate trends as not statistically significant (p = 0.196).

CONCLUSION

Differences in the frequency of occurrence of device malfunctions for patients treated with PBT and patients treated with CIT did not reach statistical significance. The present study can be regarded as a benchmark study about the incidence of malfunctioning of CIED in passive scattering particle beam therapy and can be used as a reference for active scanning particle beam therapy.

Study of feasible and safe condition for total body irradiation using cardiac implantable electronic devices

Cardiac implantable electronic devices (CIEDs) were believed to have a tolerance dose and that direct irradiation has to be avoided. Thus, no clinical guidelines have mentioned the feasibility of total body irradiation (TBI) with a CIED directly. The purpose of this work was to study a feasible and safe condition for TBI using a CIED. Eighteen CIEDs were directly irradiated by a 6-MV X-ray beam, where a non-neutron producible beam was employed for the removal of any neutron contribution to CIED malfunction. Irradiation up to 10 Gy in accumulated dose was conducted with a 100-cGy/min dose rate, followed by up to 20 Gy at 200 cGy/min. An irradiation test of whether inappropriate ventricular shock therapy was triggered or not was also performed by using a 6-MV beam of 5, 10, 20 and 40 cGy/min to two CIEDs. No malfunction was observed during irradiation up to 20 Gy at 100 and 200 cGy/min without activation of shock therapy. These results were compared with typical TBI, suggesting that a CIED in TBI will not encounter malfunction because the prescribed dose and the dose rate required for TBI are much safer than those used in this experiment. Several inappropriate shock therapies were, however, observed even at 10 cGy/min if activated. The present result suggested that TBI was feasible and safe if a non-neutron producible beam was employed at low dose-rate without activation of shock therapy, where it was not inconsistent with clinical and non-clinical data in the literature. The feasibility of TBI while using a CIED was discussed for the first time.

A Review and Analysis of Managing Commonly Seen Implanted Devices for Patients Undergoing Radiation Therapy

Purpose

This review article aims to consolidate information regarding existing and emerging implanted devices used in patients undergoing radiation therapy and to categorize levels of attention needed for each device, including which devices require monitoring throughout treatment.

Methods and Materials

Based on the collective information from scholar searches, manufacturers' technical reports, and institutional experiences in the past years, commonly present devices in patients with cancer are compiled. This work summarizes cardiac pacemaker, implanted cardiac defibrillator, hepatic pump, intrathecal pain pump, neurostimulator, shunt, loop recorder, and mediport. Three different classifications of implanted devices can be made based on the potential effect of radiation: life-dependent, nonlife-dependent but with adverse effects if overdosed, and devices without electronic circuits. Implanted devices that contain electronic circuits that would be life-dependent or have adverse effects if overdosed, include cardiac pacemakers, implanted cardiac defibrillators, programmable hepatic pumps, pain pumps, neurostimulators, and loop recorders.

Results

Dose exposure to these devices need to be calculated or measured in vivo, especially for cardiac implanted devices, and they should be minimized to assure continued healthy functioning. Treatment planning techniques should be chosen to reduce entry, exit and internal scatter dose. Lower energy photon beams should be used to decrease potential neutron contamination. Implanted devices without electronic circuits are less of a concern. If a patient is life-dependent on the implanted device, it is not recommended to treat the patient with proton therapy.

Conclusions

This study reviewed the management of patients with commonly seen implanted devices and summarized a workflow for identifying and planning when a patient has implanted devices. Classifications of implanted devices could help clinicians make proper decisions in regard to patients with specific implanted devices. Lastly, the management of such devices in the era of the pandemic is also discussed in this review article.

Implantable cardiac pacemaker failure by cumulative dose effects of flattening filter free beams

Cumulative dose effects, which are one of the main causes of errors that occur when an implantable cardiac pacemaker (ICP) is irradiated with ionizing radiation, induce permanent failure in ICPs. Although flattening filter free (FFF) beams, which are often used in stereotactic radiotherapy, are known to have different characteristics from conventional (with flattening filter [WFF]) beams, the cumulative dose effects on ICPs with FFF beams have been under-investigated. This study investigates ICP failure induced by cumulative dose effects of FFF beams. When the ICP placed in the center of the irradiation field was irradiated with 10 MV-FFF at 24 Gy/min, the cumulative dose at which failure occurred was evaluated on the basis of the failure criteria associated with high cumulative dose as described in the American Association of Physicists in Medicine Task Group 203. The ICP failures such as a mild battery depletion at a cumulative dose of 10 Gy, pacing-output voltage change >25% at a cumulative dose of 122 Gy, and the loss of telemetry capability at cumulative dose 134 Gy were induced by cumulative dose effects. The cumulative doses by which the cumulative dose effects of FFF beams induced ICP failure were not very different from those reported in previous studies with WFF beams. Therefore, radiotherapy with FFF beams (and WFF beams) for patients with ICP requires appropriate management for minimizing the cumulative dose effects.

Linac-based STereotactic Arrhythmia Radioablation (STAR) for ventricular tachycardia: a treatment planning study

OBJECT

To analyze geometrical approaches, prescription modalities, and delivery efficiency for linear accelerator (Linac)-based STereotactic Arrhythmia Radioablation (STAR) for ventricular tachycardia.

METHODS

The anatomy and planning target volume (PTV) of the first Italian STAR patient were used. To assess geometrical approaches, 3 plans prescribed to 75% isodose-line, differing for number, length of arcs, and couch rotations, were generated and compared (Plans#1-3). Volumetric-arc with 6-MV flattening-filter-free (FFF) was employed. To evaluate prescription modality and delivery, the best geometrical plan was compared with other plans prescribed on 70%, 65%, and 60% isodose-line and with another one using 10MV-FFF beams (Plans#4-7).

RESULTS

For Plans#1-3, PTV coverage, mean cardiac dose, monitor units (MUs), and beam-delivery-time (BDT) were 96-98.5%, 4.9-5.2 Gy, 7047-7790, and 5-6 min, respectively. Plans#4-7 were similar in terms of mean cardiac dose, MUs and BDT to Plans#1-3, except in maximum dose and lower time for 10MV-FFF plan.

CONCLUSION

Linac-based STAR is safe and efficient in terms of BDT and MUs. To ensure high dose to PTV, different dose prescription modalities should be evaluated. The 10FFF approach was the faster but not suitable in patient with cardiac implantable electronic devices.

Safety of lung stereotactic ablative radiotherapy for the functioning of cardiac implantable electronic devices

BACKGROUND AND PURPOSE

The prevalence of patients with a cardiac implantable device (CIED) developing cancer and requiring a course of radiotherapy (RT) is increasing remarkably. Previously published reports agree that standard and conventionally fractionated RT is usually safe for CIEDs, but no "in-vivo" reports are available on the potential effects of thoracic stereotactic ablative radiotherapy (SABR) regimens to CIEDs functioning. The purpose of our study is therefore to evaluate the effects of SABR on CIEDs (pacemakers [PM] or implantable cardiac defibrillators [ICD]) in a cohort of patients affected by primary or metastatic lung lesions.

MATERIALS AND METHODS

We retrospectively collected all CIED-bearing patients undergoing SABR between 2007 and 2019 at our Institution. All CIEDs were interrogated before and after the SABR course to check for any malfunction. Prescription dose, beam energy and maximum dose (Dmax) to CIEDs were retrieved for each patient. Electrical records of the CIEDs were reviewed by the medical records.

RESULTS

Thirty-four consecutive patients (24 with a PM and 10 with an ICD), who underwent 38 separate SABR courses, were included in the study. Eight patients (24%) were PM-dependent. Prescription dose of SABR ranged 26-60 Gy in 1-8 fractions, with a photon energy ranging 6-to-10 MV (76.3% and 23.7%, respectively) and a median Dmax to CIEDs of 0.17 Gy (range 0.04-1.97 Gy). Electrical parameters were stable in post-treatment device programming visits and no transient or persistent alteration of the CIED function was recorded in any patient. No inappropriate interventions were recorded in the 10 ICD-bearing patients during the treatment fractions.

CONCLUSIONS

Thoracic SABR proved to be safe for CIEDs when the dose is kept <2 Gy and the beam energy is ≤10 MV, irrespective of the pacing-dependency and of the CIED type.

Linac-based STereotactic Arrhythmia Radioablation (STAR) of ventricular tachycardia: Case report and literature review

Linac-based STereotactic Arrhythmia Radioablation (STAR) is a safety and effective approach for selected patients with ventricular arrhythmias.

JASTRO/JCS Guidelines for radiotherapy in patients with cardiac implantable electronic devices

This publication is an English version of the Japanese Society for Radiation Oncology (JASTRO) and The Japanese Circulation Society official guidelines for patients with cardiac implantable electronic devices (CIEDs). Several radiotherapy-associated malfunctions have been reported for CIEDs such as pacemakers and implantable cardioverter-defibrillators. Accordingly, guidelines for radiotherapy in patients with CIEDs have been issued by other countries and societies. In August 2010, JASTRO published the ‘Radiotherapy Guidelines for Patients with Pacemakers and Implantable Defibrillators’ (hereafter referred to as the former guidelines). Given new findings in this decade, a multidisciplinary working group of radiation oncologists, medical physicists, radiation therapists and cardiologists jointly reviewed and revised the former guidelines.

Safe application of extensive radiotherapy to a cardiac resynchronization device

Patients with cardiac implantable electronic devices undergoing radiotherapy (RT) are prone to the risk of device failure. Guidelines and manufacturer's instructions are lacking practical recommendations for cumulative radiation doses to pacemakers or implantable cardioverter defibrillators. The present case demonstrates the effect of RT of a Merkel cell carcinoma near the location of a cardiac resynchronization therapy pacemaker. Despite guideline recommendations, surgical relocation or de novo implantation of the device on the contralateral side was avoided to prevent the dissemination of tumour cells, inflammation, and wound healing complications. A total dose of 47.25 Gy applied in very close proximity to the cardiac resynchronization therapy pacemaker was carried out safely without jeopardizing the patient and any device malfunction during and after treatment within >1.5 years of follow‐up period. The present case demonstrates that high‐dose RT near to a cardiac resynchronization therapy device can be carried out safely. Special precautions during RT as well as close device follow‐up interrogations are mandatory. Large‐scale studies are needed for the true frequency of adverse events.

Radiotherapy-induced malfunctions of cardiac implantable electronic devices in cancer patients

The number of patients with cardiac implantable electronic devices (CIEDs) requiring radiation therapy (RT) for cancer treatment is increasing. The purpose of this study is to estimate the prevalence, possible predictors, and clinical impact of RT-related CIEDs malfunctions. We retrospectively reviewed the medical records of all pacemaker (PM)/implantable cardioverter-defibrillator (ICD) patients who underwent RT in the last 14 years. One hundred and twenty-seven patients who underwent 150 separate RT courses were analysed (99 with a PM and 27 with an ICD). Of note, 21/127 (16.6%) patients were PM-dependent. Neutron-producing RT was used in 37/139 (26.6%) courses, whereas non-neutron-producing RT was used in 102/139 (73.4%) courses. The cumulative dose (Dmax) delivered to the CIED exceeded 5 Gy only in 2/132 (1.5%) cases. Device malfunctions were observed in 3/150 (2%) RT courses, but none was life-threatening or led to a major clinical event and all were resolved by CIED reprogramming. In all cases, the Dmax delivered to the CIED was < 2 Gy. Two malfunctions occurred in the 37 patients treated with neutron-producing RT (5.4%), and 1 malfunction occurred in the 102 patients treated with non-neutron-producing RT (1%) (p = 0.17). Device relocation from the RT field was performed in 2/127 (1.6%) patients. RT in patients with CIED is substantially safe if performed in an appropriately organized environment, with uncommon CIEDs malfunctions and no major clinical events. Neutron-producing energies, rather than Dmax, seem to increase the risk of malfunctions. Device interrogation on a regular basis is advised to promptly manage CIED malfunctions.

STRA-MI-VT (STereotactic RadioAblation by Multimodal Imaging for Ventricular Tachycardia): rationale and design of an Italian experimental prospective study

Background

Ventricular tachycardia (VT) is a life-threatening condition, which usually implies the need of an implantable cardioverter defibrillator in combination with antiarrhythmic drugs and catheter ablation. Stereotactic body radiotherapy (SBRT) represents a common form of therapy in oncology, which has emerged as a well-tolerated and promising alternative option for the treatment of refractory VT in patients with structural heart disease.

Objective

In the STRA-MI-VT trial, we will investigate as primary endpoints safety and efficacy of SBRT for the treatment of recurrent VT in patients not eligible for catheter ablation. Secondary aim will be to evaluate SBRT effects on global mortality, changes in heart function, and in the quality of life during follow-up.

Methods

This is a spontaneous, prospective, experimental (phase Ib/II), open-label study (NCT04066517); 15 patients with structural heart disease and intractable VT will be enrolled within a 2-year period. Advanced multimodal cardiac imaging preceding chest CT-simulation will serve to elaborate the treatment plan on different linear accelerators with target and organs-at-risk definition. SBRT will consist in a single radioablation session of 25 Gy. Follow-up will last up to 12 months.

Conclusions

We test the hypothesis that SBRT reduces the VT burden in a safe and effective way, leading to an improvement in quality of life and survival. If the results will be favorable, radioablation will turn into a potential alternative option for selected patients with an indication to VT ablation, based on the opportunity to treat ventricular arrhythmogenic substrates in a convenient and less-invasive manner.

A randomized in vitro evaluation of transient and permanent cardiac implantable electronic device malfunctions following direct exposure up to 10 Gy

BACKGROUND AND PURPOSE

High-dose 6‑MV radiotherapy may cause cardiac implantable electronic devices (CIEDs) to malfunction. To assess CIED malfunctions resulting from direct exposure up to 10 Gy, 100 pacemakers (PMs) and 40 implantable cardioverter-defibrillators (ICDs) were evaluated.

MATERIALS AND METHODS

CIEDs underwent baseline interrogation. In ICDs, antitachycardia therapies were disabled via the programmer while the detection windows were left enabled. A computed tomography (CT) scan was performed to build the corresponding treatment plan. CIEDs were "blinded" and randomized to receive single doses of either 2, 5, or, 10 Gy via a 6-MV linear accelerator (linac) in a water phantom. Twenty-two wireless telemetry-enabled CIEDs underwent a real-time session, and their function was recorded by the video camera in the bunker. The CIEDs were interrogated after exposure and once monthly for 6 months.

RESULTS

During exposure, regardless of dose, 90.9% of the CIEDs recorded electromagnetic interference, with 6 ICDs (27.3%) reporting pacing inhibition and inappropriate arrhythmia detections. After exposure, a backup reset was observed in 1 PM (0.7% overall, 1% among PMs), while 7 PMs (5% overall, 7% among PMs) reported battery issues (overall immediate malfunction rate was 5.7%). During follow-up, 4 PMs (2.9% overall; 4% among PMs) and 1 ICD (0.7% overall; 2.5% among ICDs) reported abnormal battery depletion, and 1 PM (0.7% overall; 1% among PMs) reported a backup reset (overall late malfunction rate was 4.3%).

CONCLUSION

Apart from transient electromagnetic interference, last-generation CIEDs withstood direct 6‑MV exposure up to 10 Gy. Permanent battery or software errors occurred immediately or later only in less recent CIEDs.

The effect of stereotactic body radiotherapy (SBRT) using flattening filter-free beams on cardiac implantable electronic devices (CIEDs) in clinical situations

PURPOSE

This study focused on determining risks from stereotactic radiotherapy using flattening filter-free (FFF) beams for patients with cardiac implantable electronic device (CIEDs). Two strategies were employed: a) a retrospective analysis of patients with CIEDs who underwent stereotactic radiosurgery (SRS)/SBRT at the Peter MacCallum Cancer Centre between 2014 and 2018 and b) an experimental study on the impact of FFF beams on CIEDs.

METHODS

A retrospective review was performed. Subsequently, a phantom study was performed using 30 fully functional explanted CIEDs from two different manufacturers. Irradiation was carried out in a slab phantom with 6-MV and 10-MV FFF beams. First, a repetition-rate test (RRT) with a range of beam pulse frequencies was conducted. Then, multifraction SBRT (48 Gy/4 Fx) and single-fraction SBRT (28 Gy/1 Fx) treatment plans were used for lung tumors delivered to the phantom.

RESULTS

Between 2014 and 2018, 13 cases were treated with an FFF beam (6 MV, 1400 MU/min or 10 MV, 2400 MU/min), and 15 cases were treated with a flattening filter (FF) beam (6 MV, 600 MU/min). All the devices were positioned outside the treatment field at a distance of more than 5 cm, except for one case, and no failures were reported due to SBRT/SRS. In the phantom rep-rate tests, inappropriate sensing occurred, starting at a rep-rate of 1200 MU/min. Cardiac implantable electronic device anomalies during and after delivering VMAT-SBRT with a 10-MV FFF beam were observed.

CONCLUSIONS

The study showed that caution should be paid to managing CIED patients when they undergo SBRT using FFF beams, as it is recommended by AAPM TG-203. Correspondingly, it was found that for FFF beams although there is small risk from dose-rate effects, delivering high dose of radiation with beam energy greater than 6 MV and high-dose rate to CIEDs positioned in close vicinity of the PTV may present issues.

Effect of X-ray dose rates higher than 8 Gy/min on the functioning of cardiac implantable electronic devices

Direct irradiation may cause malfunctioning of cardiac implantable electronic devices (CIEDs). Therefore, a treatment plan that does not involve direct irradiation of CIEDs should be formulated. However, CIEDs may be directly exposed to radiation because of the sudden intrafractional movement of the patient. The probability of CIED malfunction reportedly depends on the dose rate; however, reports are only limited to dose rates ≤8 Gy/min. The purpose of this study was to investigate the effect of X-ray dose rates >8 Gy/min on CIED function. Four CIEDs were placed at the center of the radiation field and irradiated using 6 MV X-ray with flattening filter free (6 MV FFF) and 10 MV X-ray with flattening filter free (10 MV FFF). The dose rate was 4-14 Gy/min for the 6 MV FFF and 4-24 Gy/min for 10 MV FFF beams. CIED operation was evaluated with an electrocardiogram during each irradiation. Three CIEDs malfunctioned in the 6 MV FFF condition, and all four CIEDs malfunctioned in the 10 MV FFF condition, when the dose rate was >8 Gy/min. Pacing inhibition was the malfunction observed in all four CIEDs. Malfunction occurred simultaneously along with irradiation and simultaneously returned to normal function on stopping the irradiation. An X-ray dose rate >8 Gy/min caused a temporary malfunction due to interference. Therefore, clinicians should be aware of the risk of malfunction and manage patient movement when an X-ray dose rate >8 Gy/min is used for patients with CIEDs.

Stereotactic Ablative radiation therapy (SABR) for cardiac arrhythmia: A new therapeutic option?

AIM

Stereotactic ablative radiation therapy (SABR) is used in non-oncologic indications, recently even for cardiac arrhythmias. Thus, aim of this analysis is to review preclinical, early clinical evidences and future direction of the latter new treatment approach.

METHOD

A collection of available data regarding SABR and cardiac arrhythmias was made, by Pubmed research and 2 independent researchers, including preclinical and clinical data. A review of ongoing trials was conducted on ClinicalTrials.gov.

RESULTS

Preclinical research conducted in animal models showed that a safe and effective noninvasive treatment approach for cardiac arrhythmias could be represented by SABR with a median time of response around 2-3 months. The treatment dose plays a crucial role: the atrioventricular node would seem more radiosensitive than the other cardiac electric zones. Clinical data, such as published case series, case reports and early prospective studies, have already suggested the feasibility, efficacy and safety of SABR (25 Gy in one session) for refractory ventricular arrhythmias.

CONCLUSION

Considering the ongoing trials of SABR and new technological improvements in radiotherapy (e.g. hybrid magnetic resonance) and in arrhythmias noninvasive mapping systems, the future analyses will improve the reliability of those preliminary results.

Interaction between CIEDs and modern radiotherapy techniques: Flattening filter free-VMAT, dose-rate effects, scatter radiation, and neutron-generating energies

BACKGROUND AND PURPOSE

Providing evidence for radiotherapy (RT)-induced effects on cardiac implantable electric devices (CIEDs) with focus on flattening filter free-volumetric modulated arc therapy (FFF-VMAT) at 6 and 10 MV as well as 3D-conformal radiotherapy (3D-CRT) at 18 MV.

MATERIALS AND METHODS

68 CIEDs (64 implantable cardioverter-defibrillators (ICDs) and 4 cardiac pacemakers (PMs)) were located on the left chest position on a slab phantom and irradiated under telemetrical surveillance either directly, or distant to 3D-CRT or FFF-VMAT, dose-rate 2500 cGy/min, and target dose of 150 Gy. Devices were placed within, close by (2.5 cm and 5 cm), and distant (35 cm) to the radiation field. Scatter radiation (SR) and photon neutrons (PN) were recorded. CIEDs were investigated in following groups: 1a) 18 MV 3D-CRT - 4 ICDs/4 PMs out of radiation field, 1b) 18 MV open field - 4 ICDs/4 PMs within radiation field, 2) 6 MV FFF-VMAT, 15 ICDs in 35 cm distance to VMAT, 3) 10 MV-FFF VMAT, 15 ICDs in 35 cm distance to VMAT, 4) 6 MV FFF-VMAT, 15 ICDs in 2.5 cm distance to VMAT, 5) 10 MV FFF-VMAT, 15 ICDs in 2.5 cm distance to VMAT.

RESULTS

No incidents occurred at 6 MV FFF. 10 MV FFF-VMAT and 18 MV 3D-CRT resulted in data loss, reset, and erroneous sensing with inhibition of pacing (leading to inadequate defibrillation) in 8/34 ICDs and 2/4 PMs which were not located within radiation. Direct radiation triggered instantaneous defibrillation in 3/4 ICDs.

CONCLUSIONS

6 MV FFF-VMAT is safe even at high dose-rates of 2500 cGy/min, regardless whether CIEDs are located close (2.5 cm) or distant (35 cm) to the radiation beam. CIEDs should never be placed within radiation and energy should always be limited to 6 MV. At 6 MV, VMAT at high dose-rates can be used to treat tumors, which are located close to CIEDs.

PAIDEIA: pacemaker and implanted cardioverter defibrillator management in radiation therapy-a survey by the Young Group of the Italian Association of Radiotherapy and Clinical Oncology (AIRO)

INTRODUCTION

The management of patients bearing a cardiac implantable electronic device and needing a radiotherapy treatment is an important clinical scenario. The aim of this survey was to evaluate the level of awareness within the Italian Radiation Oncologist community on this topic.

MATERIALS AND METHODS

A survey was promoted by the Young Group of Italian Association of Radiotherapy and Clinical Oncology (AIRO) with a questionnaire made up of 22 questions allowing for multiple answers, which was administered, both online and on paper version. It was addressed to Radiation Oncologists, AIRO members, participating in the National Congress held in 2015.

RESULTS

A total of 113 questionnaires were collected back and analyzed (survey online: 50 respondents; paper version: 63). The answers showed a good level of awareness on the issue, but with a nonhomogeneous adherence to the different published guidelines (GL). There is a general low rate of referral for a preliminary cardiological evaluation in patients bearing PM/ICDs, in line with some published surveys; nevertheless, a focused attention to certain specific treatment factors and patient-centered point of view emerged.

CONCLUSIONS

A generally good awareness of this topic was shown but homogeneous application of GL was not observed, possibly due to the multiplicity of available GL. A prospective data collection could help to better clarify the shadows on this topics.

Management of radiotherapy patients with implanted cardiac pacemakers and defibrillators: A Report of the AAPM TG-203†

Managing radiotherapy patients with implanted cardiac devices (implantable cardiac pacemakers and implantable cardioverter-defibrillators) has been a great practical and procedural challenge in radiation oncology practice. Since the publication of the AAPM TG-34 in 1994, large bodies of literature and case reports have been published about different kinds of radiation effects on modern technology implantable cardiac devices and patient management before, during, and after radiotherapy. This task group report provides the framework that analyzes the potential failure modes of these devices and lays out the methodology for patient management in a comprehensive and concise way, in every step of the entire radiotherapy process.

Inevitable high-dose irradiation to lead of implantable cardioverter defibrillator in small cell lung cancer: a case report

BACKGROUND

Radiotherapy has been shown to cause malfunction of implantable cardioverter-defibrillators, and there are few studies of implantable cardioverter-defibrillators and radiotherapy. We report an unusual case of small cell lung cancer in a patient with an implantable cardioverter-defibrillator in whom direct irradiation to the electrode and lead could not be avoided.

CASE PRESENTATION

We report a case of radiotherapy in a 72-year-old Korean man with a limited stage of small cell lung cancer who had undergone insertion of an implantable cardioverter-defibrillator because of ventricular fibrillation. The radiation dose was 60 Gy in 30 fractions to the thorax. The mean dose and maximum dose estimated at the body of the implantable cardioverter-defibrillator were 0.89 Gy and 2.23 Gy, respectively. The mean and maximum doses of the lead and electrode were 17.12 Gy and 55.72 Gy in the lead and 1.81 Gy and 7.10 Gy in the electrode, respectively, because part of the lead and electrode was inevitably in the irradiated fields. The function of the patient's implantable cardioverter-defibrillator was checked daily, and no change in implantable cardioverter-defibrillator function was observed for the duration of radiotherapy. The patient was tolerated the treatment well without severe complications. Computed tomography performed at 4 weeks after radiotherapy showed a good response with regression of the tumor. The patient was alive with complete remission of the tumor and without any implantable cardioverter-defibrillator dysfunction more than 36 months after the end of treatment.

CONCLUSIONS

This case demonstrates that radiotherapy may be a safe and effective treatment modality through careful monitoring of implantable cardioverter-defibrillators in patients with lung cancer who have implantable cardioverter-defibrillators.