Remote ischemic preconditioning versus sham-control for prevention of anastomotic leakage after resection for rectal cancer (RIPAL trial): a pilot randomized controlled, triple-blinded monocenter trial.

PURPOSE: Remote ischemic preconditioning (RIPC) reportedly reduces ischemia‒reperfusion injury (IRI) in various organ systems. In addition to tension and technical factors, ischemia is a common cause of anastomotic leakage (AL) after rectal resection. The aim of this pilot study was to investigate the potentially protective effect of RIPC on anastomotic healing and to determine the effect size to facilitate the development of a subsequent confirmatory trial. MATERIALS AND METHODS: Fifty-four patients with rectal cancer (RC) who underwent anterior resection were enrolled in this prospectively registered (DRKS0001894) pilot randomized controlled triple-blinded monocenter trial at the Department of Surgery, University Medicine Mannheim, Mannheim, Germany, between 10/12/2019 and 19/06/2022. The primary endpoint was AL within 30 days after surgery. The secondary endpoints were perioperative morbidity and mortality, reintervention, hospital stay, readmission and biomarkers of ischemia‒reperfusion injury (vascular endothelial growth factor, VEGF) and cell death (high mobility group box 1 protein, HMGB1). RIPC was induced through three 10-min cycles of alternating ischemia and reperfusion to the upper extremity. RESULTS: Of the 207 patients assessed, 153 were excluded, leaving 54 patients to be randomized to the RIPC or the sham-RIPC arm (27 each per arm). The mean age was 61 years, and the majority of patients were male (37:17 (68.5:31.5%)). Most of the patients underwent surgery after neoadjuvant therapy (29/54 (53.7%)) for adenocarcinoma (52/54 (96.3%)). The primary endpoint, AL, occurred almost equally frequently in both arms (RIPC arm: 4/25 (16%), sham arm: 4/26 (15.4%), p = 1.000). The secondary outcomes were comparable except for a greater rate of reintervention in the sham arm (9 (6-12) vs. 3 (1-5), p = 0.034). The median duration of endoscopic vacuum therapy was shorter in the RIPC arm (10.5 (10-11) vs. 38 (24-39) days, p = 0.083), although the difference was not statistically significant. CONCLUSION: A clinically relevant protective effect of RIPC on anastomotic healing after rectal resection cannot be assumed on the basis of these data.

Flow Cytometric Characterization of Hematopoietic Stem and Progenitor Cell Subpopulations in Autologous Peripheral Blood Stem Cell Preparations after Cryopreservation.

Introduction: Autologous stem cell transplantation is a successful routine procedure with only a small number of non-engraftment cases, although the time to hematopoietic recovery may vary considerably across patients. While CD34 has been the decisive marker for enumerating hematopoietic stem and progenitor cells (HSPCs) for more than 30 years, the impact of CD34-positive cellular subpopulations in autologous HSPC grafts on hematopoietic reconstitution remains unclear. Methods: The two-color ISHAGE protocol represents the current gold standard for CD34+ cell enumeration but includes only the number of viable CD45+/CD34+ cells relative to the body weight of the recipient. We adapted a multicolor flow cytometry marker panel for advanced characterization of CD34 subpopulations in retained samples of autologous peripheral blood stem cell products (n = 49), which had been cryostored for a wide range from 4 to 15 years. The flow cytometric analysis included CD10, CD34, CD38, CD45, CD45RA, CD133, and viability staining with 7AAD. The findings were correlated with clinical engraftment data, including reconstitution of leukocytes, neutrophils, and platelets after transplantation (TPL). Results: We demonstrated that the identification of autologous HSPC subpopulations by flow cytometry after cryopreservation is feasible. Regarding the distribution of HSPC subpopulations, a markedly different pattern was observed in comparison to previously published data obtained using fresh autologous material. Our data revealed the largest ratio of lympho-myeloid progenitors (LMPPs) after freezing and thawing, followed by multipotent progenitors and erythroid-myeloid progenitors. A high ratio of LMPPs, representing an immature stage of differentiation, correlated significantly with early neutrophilic granulocyte and leukocyte engraftment (p = 0.025 and p = 0.003). Conversely, a large ratio of differentiated cells correlated with late engraftment of neutrophilic granulocytes (p = 0.024). Overall, successful engraftment was documented for all patients. Conclusion: We established an advanced flow cytometry panel to assess the differentiation ability of cryostored autologous peripheral blood stem cell grafts and correlated it with timely hematopoietic reconstitution. This approach represents a novel and comprehensive way to identify hematopoietic stem and progenitor subpopulations. It is a feasible way to indicate the engraftment capacity of stem cell products.

[The potential of complementary music interventions in patients with head and neck cancer]. / Das Potenzial komplementärer Musikinterventionen bei Patienten mit malignen Kopf-Hals-Tumoren.

PURPOSE: The established treatment regimen for patients suffering from cancer in the head and neck region often leads to physical and mental health problems and therefore can significantly reduce the quality of life (QoL) in these patients. The available data indicate that additional complementary treatments, such as music interventions, may improve patients' QoL and compliance and reduce symptoms during therapy. METHODS: Anonymous data collection using a self-designed questionnaire was conducted in patients suffering from cancer in the head and neck area in our outpatient department. The questionnaire particularly asked the patients about their need and interest in music interventions during therapy. RESULTS: In total, 138 patients were consecutively enrolled in the study. The mean age was 64.9 years, including 68.1% men and 31.9% women. Only 11.5% listened to music regularly during their therapy at the time of data collection, yet 52.2% stated that they would be interested in music interventions. Patients especially conceived the relaxing and encouraging effects from listening to music. Most patients would prefer group therapies (56%) or listening to their own music (36.6%). CONCLUSION: Our data suggest that there is a need for music interventions in patients suffering from cancer in the head and neck, as they anticipate they would experience positive effects, including reduced somatic and non-somatic symptoms and improved QoL. The lack of homogenous data emphasizes the need for further trials in the field of complementary music interventions to establish science-based concepts in the future.

Bladder cancer in patients with neurogenic bladder disorder: a comparative study of different etiologies.

PURPOSE: The objective of this study was to conduct a comparative study of different etiologies of neurogenic bladder disorders (NBDs) in patients with bladder cancer (BC) regarding patient- and tumor-related parameters and their oncological outcome. METHODS: Out of 98 patients with bladder tumors and neurogenic disease, 23 patients with BC and NBDs from Jan 1, 2010, to Dec 31, 2020, were included. The different etiologies of NBDs were merged in three groups based on the level of the nervous system (NS)-lesion: (i) central (n = 6), (ii) spinal cord (n = 10), and (iii) peripheral lesions (n = 7). RESULTS: Patients with lesions at the spinal cord level were younger at the time of BC diagnosis compared to patients with central or peripheral NS lesions (54 vs. 68 vs. 78 years, p = 0.0219). However, the latency to malignant transformation was more than twice as long (33 vs. 15 years, p = 0.0108). Most tumors were muscle-invasive or locally advanced BCs (62%) and presented lymph node metastases (55%), resulting in a poor mean overall survival of 30.9 ± 3.6 months. No significant differences regarding histopathology, tumor stage, and oncological outcome could be observed between the groups. CONCLUSION: Patients with NBDs have a poor prognosis regardless of their etiology or the level of NS lesion. Patients with spinal cord lesions, including congenital NBDs, appear to develop BC at a young age, but compared to other etiologies latency from NBD to BC is longer.

[Time management in operating rooms-a cross-sectional study to evaluate estimated and objective durations of otorhinolaryngologic surgical procedures]. / Zeitmanagement im OP ­ eine Querschnittstudie zur Bewertung der subjektiven und objektiven Dauer chirurgischer Prozeduren im HNO-Bereich.

BACKGROUND: Accurate planning of operating times in surgical clinics is essential. Moreover, high-capacity utilization of operating rooms (ORs) is necessary for economic efficiency. OBJECTIVE: Most planning of operating times is performed by surgeons. Herein, surgeons' estimated times and the objective times for performing surgical procedures were compared to detect sources of error. MATERIALS AND METHODS: In a retrospective analysis, the durations of 1809 operations using general anesthesia (22 types of surgery) by 31 surgeons (12 specialists and 19 residents) were compared. Comparisons were analyzed by Mann-Whitney U­tests. RESULTS: The comparison of objective times of surgical action showed significant differences between specialists and residents in 6 of 15 types of surgeries. The post-processing times estimated by specialists deviated from the objective times in 2 out of 22 surgery types, while the post-processing times estimated by residents deviated in 7 of 15 types. Specialists misjudged the incision-to-suture times in 7 of 22 surgery types, and residents misjudged these times in 3 of 15 types. The preparation times estimated by specialists deviated from the objective times in 16 of 22 types of surgeries and in 7 of 15 types estimated by residents. CONCLUSION: A surgeon's routine must be carefully considered in order to estimate operating times. Specialists generally underestimated preparation and post-processing times and overestimated incision-to-suture times, whereas residents underestimated all three. Preparation and post-processing times must be considered in planning and, ideally, determined together with anesthesiologists and surgical assistants.

Compression Bioreactor-Based Mechanical Loading Induces Mobilization of Human Bone Marrow-Derived Mesenchymal Stromal Cells into Collagen Scaffolds In Vitro.

Articular cartilage (AC) is an avascular tissue composed of scattered chondrocytes embedded in a dense extracellular matrix, in which nourishment takes place via the synovial fluid at the surface. AC has a limited intrinsic healing capacity, and thus mainly surgical techniques have been used to relieve pain and improve function. Approaches to promote regeneration remain challenging. The microfracture (MF) approach targets the bone marrow (BM) as a source of factors and progenitor cells to heal chondral defects in situ by opening small holes in the subchondral bone. However, the original function of AC is not obtained yet. We hypothesize that mechanical stimulation can mobilize mesenchymal stromal cells (MSCs) from BM reservoirs upon MF of the subchondral bone. Thus, the aim of this study was to compare the counts of mobilized human BM-MSCs (hBM-MSCs) in alginate-laminin (alginate-Ln) or collagen-I (col-I) scaffolds upon intermittent mechanical loading. The mechanical set up within an established bioreactor consisted of 10% strain, 0.3 Hz, breaks of 10 s every 180 cycles for 24 h. Contrary to previous findings using porcine MSCs, no significant cell count was found for hBM-MSCs into alginate-Ln scaffolds upon mechanical stimulation (8 ± 5 viable cells/mm3 for loaded and 4 ± 2 viable cells/mm3 for unloaded alginate-Ln scaffolds). However, intermittent mechanical stimulation induced the mobilization of hBM-MSCs into col-I scaffolds 10-fold compared to the unloaded col-I controls (245 ± 42 viable cells/mm3 vs. 22 ± 6 viable cells/mm3, respectively; p-value < 0.0001). Cells that mobilized into the scaffolds by mechanical loading did not show morphological changes. This study confirmed that hBM-MSCs can be mobilized in vitro from a reservoir toward col-I but not alginate-Ln scaffolds upon intermittent mechanical loading, against gravity.

iNO Therapy in Patients with Congenital Diaphragmatic Hernia - Discrepancy between Widespread Use and Therapeutic Effects.

BACKGROUND: Despite recent studies failing to prove beneficial effects of iNO therapy in patients with CDH, its use is still widespread. The aim of this work was to analyze iNO use in a retrospective cohort focusing on outcome parameters. Patients 378 CDH patients born and treated in Mannheim University Medical Center, Department for Neonatology, between 2010 and 2017 constituted our cohort. Therapy was based on the standardized protocol of the CDH EURO Consortium. METHOD: General data (sex, birth weight, gestational age etc.) and therapy-related data (duration of iNO application, OI after 60 mins, need for ECMO support etc.) were collected from clinical reports and then conducted using SAS for both mono- and multivariate analyses. RESULTS: Out of 378 newborns with CDH, 265 received iNO (70.1%), of whom 82 (30.9%) showed a significant OI reduction of ≥5 pts after 60 mins (=responders), median OI improved by 1.85 pts overall. Among initial responders iNO, application reduced the need for ECMO support (p=0.0054), increased the time to ECMO initiation (p=0.005) and reduced mortality (p=0.0396). DISCUSSION: A group of 43 patients considerably benefited from iNO and thererfore as they did not need ECMO support. Even though iNO therapy has failed to prove significant beneficial effects for non-responders, the application is still to be considered an essential treatment method in the transitional period of CDH patients. CONCLUSIONS: A more critical approach towards iNO application in nonresponders should be promoted. Further extensive multicenter studies on treatment alternatives for CDH-PAH are desirable.

[Single-center retrospective analysis of extracorporal photopheresis in clinical practice : Peripheral venous compared to central venous access]. / Unizentrische, retrospektive Analyse der praktischen Durchführung der extrakorporalen Photopherese : Periphervenöser und zentralvenöser Zugang im Vergleich.

BACKGROUND: Extracorporal photopheresis (ECP) was shown to be effective without severe side effects in the treatment of cutaneous T cell lymphoma (CTCL) and graft versus host disease (GvHD). However, only few studies investigated the practical aspects of ECP. METHODS: Treatment protocols of 2038 ECP procedures in 52 patients (CTCL, n = 29; GvHD, n = 15; other, n = 8) were evaluated. The patients were treated with the UVAR® XTS™ ECP system (Therakos, Inc. Johnson & Johnson, Raritan, NJ, USA) between 2001 and 2010. All patients started with a peripheral venous access. During the course of treatment 7 patients were treated via a port and 4 via a central venous catheter. RESULTS: In all, 1765 (86.6%) treatments were performed with a peripheral venous access; 239 (11.7%) ECPs were done via a port and 34 (1.7%) via a central venous catheter. The peripheral venous access showed a higher flow rate and longer photoactivation time. ECPs via port lead to higher UV-irradiated volumes, longer treatment times and higher differences in systolic blood pressure. The following side effects were observed: being unwell (n = 13), hypo- (n = 13) and hypertension (n = 7), vertigo (n = 4), headache (n = 4), shortness of breath (n = 4), fever (n = 3) and metallic taste (n = 3). Technical complications such as problems with venous access (9.6%) occurred in 385 (18.9%) treatments. CONCLUSIONS: Peripheral venous access should be preferred for ECP treatments.

Small bowel protection in IMRT for rectal cancer : A dosimetric study on supine vs. prone position.

BACKGROUND: This treatment planning study analyzes dose coverage and dose to organs at risk (OAR) in intensity-modulated radiotherapy (IMRT) of rectal cancer and compares prone vs. supine positioning as well as the effect of dose optimization for the small bowel (SB) by additional dose constraints in the inverse planning process. PATIENTS AND METHODS: Based on the CT datasets of ten male patients in both prone and supine position, a total of four different IMRT plans were created for each patient. OAR were defined as the SB, bladder, and femoral heads. In half of the plans, two additional SB cost functions were used in the inverse planning process. RESULTS: There was a statistically significant dose reduction for the SB in prone position of up to 41% in the high and intermediate dose region, compared with the supine position. Furthermore, the femoral heads showed a significant dose reduction in prone position in the low dose region. Regarding the additional active SB constraints, the dose in the high dose region of the SB was significantly reduced by up to 14% with the additional cost functions. There were no significant differences in the dose distribution of the planning target volume (PTV) and the bladder. CONCLUSION: Prone positioning can significantly reduce dose to the SB in IMRT for rectal cancer and therefore should not only be used in 3D conformal radiotherapy but also in IMRT of rectal cancer. Further protection of the SB can be achieved by additional dose constraints in inverse planning without jeopardizing the homogeneity of the PTV.

Analysis of Burnout Prevalence among German Physicians Working in a Palliative Care Setting: A Survey of the AIO Quality of Life Working Group.

INTRODUCTION: Palliative care physicians (Pcps) face special challenges caring for terminally ill patients. We conducted this study to evaluate the burnout (bo) prevalence among pcps and sought to identify risk as well as protective factors as a basis for the development of preventive measures. METHODS: Participants (Pcs) were invited via e-mail to complete an online survey between May and June 2022. Besides the Oldenburg Burnout Inventory assessing the bo dimensions of exhaustion (exh) and disengagement (dis), sociodemographic data were collected. RESULTS: The study found that 58% (cut-off mean value [M] ≥2.18) or more specifically, 38% (cut-off M ≥2.5) of the pcs showed increased scores in the exh subscale as a key dimension of bo. All dimensions were correlated with the level of medical and palliative care training, with higher scores for physicians in training. Furthermore, pcs without preventive measures like employee appraisals at work were more likely to be considered exhausted, disengaged, or burned out. The discrepancy between high exh and low dis scores shows that the polled pcps, despite feeling exh, nevertheless considered their work meaningful. CONCLUSION: Bo prevalence among pcps exceeds that of the general population and other specialties, whereas inexperienced pcps might be at high risk of shifting from exh to bo and could therefore benefit from tailored support. Further preventive measures including individual and organizational aspects are necessary to prevent bo and promote health among medical staff, thereby preserving quality of patient care. Elementary preventive measures such as employee appraisals can have a protective effect against bo.

Long-Term Evaluation of the Shape of the Reconstructed Diaphragm in Patients with Left-Sided Congenital Diaphragmatic Hernia Using Serial Chest Radiographs and Correlation to Further Complications.

Background: Defining risk factors for long-term comorbidities in patients after neonatal repair of congenital diaphragmatic hernia (CDH) is an important cornerstone of the implementation of targeted longitudinal follow-up programs. Methods: This study systematically assessed serial chest radiographs of 89 patients with left-sided CDH throughout a mean follow-up of 8.2 years. These geometrical variables for the left and right side were recorded: diaphragmatic angle (LDA, RDA), diaphragmatic diameter (LDD, RDD), diaphragmatic height (LDH, RDH), diaphragmatic curvature index (LDCI, RDCI), lower lung diameter (LLLD, RLLD) and thoracic area (LTA, RTA). Results: It was demonstrated that the shape of the diaphragm in patients with large defects systematically differs from that of patients with small defects. Characteristically, patients with large defects present with a smaller LDCI (5.1 vs. 8.4, p < 0.001) at 6 months of age, which increases over time (11.4 vs. 7.0 at the age of 15.5 years, p = 0.727), representing a flattening of the patch and the attached rudimentary diaphragm as the child grows. Conclusions: Multiple variables during early follow-up were significantly associated with comorbidities such as recurrence, scoliotic curves of the spine and a reduced thoracic area. Some geometrical variables may serve as surrogate parameters for disease severity, which is associated with long-term comorbidities.

Analysis of end-of-life treatment and physician perceptions at a university hospital in Germany.

PURPOSE: Providing state-of-the-art palliative care is crucial in all areas of in- and outpatient settings. Studies on the implementation of palliative care standards for dying patients are rare. METHODS: N = 141 physicians from all internal departments were polled anonymously about the treatment of dying patients using a self-designed questionnaire. Furthermore, we evaluated the terminal care of n = 278 patients who died in internal medicine departments at University Hospital Mannheim between January and June, 2019 based on clinical data of the last 48 h of life. We defined mandatory criteria for good palliative practice both regarding treatment according to patients' records and answers in physicians' survey. RESULTS: Fifty-six physicians (40%) reported uncertainties in the treatment of dying patients (p < 0.05). Physicians caring for dying patients regularly stated to use sedatives more frequently and to administer less infusions (p < 0.05, respectively). In multivariate analysis, medical specialization was identified as an independent factor for good palliative practice (p < 0.05). Physicians working with cancer patients regularly were seven times more likely to use good palliative practice (p < 0.05) than physicians who did not. Cancer patients received good palliative practice more often than patients dying from non-malignant diseases (p < 0.05). CONCLUSION: Guideline-based palliative care for dying patients was found to be implemented more likely and consistent within the oncology department. These results point to a potential lack of training of fellows in non-oncological departments in terms of good end-of-life care.

Robot-assisted esophagectomy may improve perioperative outcome in patients with esophageal cancer - a single-center experience.

Background: Although the introduction of minimally invasive surgical techniques has improved surgical outcomes in recent decades, esophagectomy for esophageal cancer is still associated with severe complications and a high mortality rate. Robot-assisted surgery is already established in certain fields and robot-assisted esophagectomy may be a possible alternative to the standard minimally invasive esophagectomy. The goal of this study was to investigate whether robot assistance in esophagectomy can improve patient outcome while maintaining good oncological control. Material and methods: Data of all patients who underwent minimally invasive esophagectomy between January 2018 and November 2021 at University Hospital Mannheim was collected retrospectively. Patients were divided into two cohorts according to operative technique (standard minimally invasive (MIE) vs. robot-assisted esophagectomy (RAMIE), and their outcomes compared. In a separate analysis, patients were propensity score matched according to age, gender and histological diagnosis, leading to 20 matching pairs. Results: 95 patients were included in this study. Of those, 71 patients underwent robot-assisted esophagectomy and 24 patients underwent standard minimally invasive esophagectomy. Robot-assisted esophagectomy showed a lower incidence of general postoperative complications (52.1% vs. 79.2%, p=0.0198), surgical complications (42.3% vs. 75.0%, p=0.0055), a lower rate of anastomotic leakage (21.1% vs. 50.0%, p=0.0067), a lower Comprehensive Complication Index (median of 20.9 vs. 38.6, p=0.0065) as well as a shorter duration of hospital stay (median of 15 vs. 26 days, p=0.0012) and stay in the intensive care unit (median of 4 vs. 7 days, p=0.028) than standard minimally invasive surgery. After additionally matching RAMIE and MIE patients according to age, gender and diagnosis, we found significant improvement in the RAMIE group compared to the MIE group regarding the Comprehensive Complication Index (median of 20.9 vs. 38.6, p=0.0276), anastomotic leakage (20% vs. 55%, p=0.0484) and severe toxicity during neoadjuvant treatment (0 patients vs. 9 patients, p=0.005). Conclusion: Robot-assisted surgery can significantly improve outcomes for patients with esophageal cancer. It may lead to a shorter hospital stay as well as lower rates of complications, including anastomotic leakage.

Small Bowel Obstruction After Neonatal Repair of Congenital Diaphragmatic Hernia-Incidence and Risk-Factors Identified in a Large Longitudinal Cohort-Study.

Objective: In patients with a congenital diaphragmatic hernia (CDH), postoperative small bowel obstruction (SBO) is a life-threatening event. Literature reports an incidence of SBO of 20% and an association with patch repair and ECMO treatment. Adhesions develop due to peritoneal damage and underly various biochemical and cellular processes. This longitudinal cohort study is aimed at identifying the incidence of SBO and the risk factors of surgical, pre-, and postoperative treatment. Methods: We evaluated all consecutive CDH survivors born between January 2009 and December 2017 participating in our prospective long-term follow-up program with a standardized protocol. Results: A total of 337 patients were included, with a median follow-up of 4 years. SBO with various underlying causes was observed in 38 patients (11.3%) and significantly more often after open surgery (OS). The majority of SBOs required surgical intervention (92%). Adhesive SBO (ASBO) was detected as the leading cause in 17 of 28 patients, in whom surgical reports were available. Duration of chest tube insertion [odds ratio (OR) 1.22; 95% CI 1.01-1.46, p = 0.04] was identified as an independent predictor for ASBO in multivariate analysis. Beyond the cut-off value of 16 days, the incidence of serous effusion and chylothorax was higher in patients with ASBO (ASBO/non-SBO: 2/10 vs. 3/139 serous effusion, p = 0.04; 2/10 vs. 13/139 chylothorax, p = 0.27). Type of diaphragmatic reconstruction, abdominal wall closure, or ECMO treatment showed no significant association with ASBO. A protective effect of one or more re-operations has been detected (RR 0.16; 95% CI 0.02-1.17; p = 0.049). Conclusion: Thoracoscopic CDH repair significantly lowers the risk of SBO; however, not every patient is suitable for this approach. GoreTex®-patches do not seem to affect the development of ASBO, while median laparotomy might be more favorable than a subcostal incision. Neonates produce more proinflammatory cytokines and have a reduced anti-inflammatory capacity, which may contribute to the higher incidence of ASBO in patients with a longer duration of chest tube insertion, serous effusion, chylothorax, and to the protective effect of re-operations. In the future, novel therapeutic strategies based on a better understanding of the biochemical and cellular processes involved in the pathophysiology of adhesion formation might contribute to a reduction of peritoneal adhesions and their associated morbidity and mortality.

Effectivity and applicability of the German DEGRO/DGK-guideline for radiotherapy in CIED-bearing patients.

BACKGROUND AND PURPOSE: No evidence has been presented until now whether recommendations given in recently issued guidelines concerning CIED-bearing patients significantly decrease RT-related complications. MATERIALS AND METHODS: 160 RT-cases were prospectively treated with 3D-CRT, IMRT, SBRT using exclusively 6 MV photons (n = 146) and electrons (n = 14) according to the 2015 issued German DEGRO/DGK-guideline for CIED-bearing patients and compared to 40 RT-cases (3D-CRT, 10-23 MV photons (n = 39) and electrons (n = 1)) of CIED-bearing patients which were treated in concordance to the 1994 issued AAPM-guideline. RESULTS: With AAPM-recommendations, complications occurred in 7/39 (17.95%) photon-RT cases, one patient experienced inadequate defibrillation therapy. For all patients treated with photon energies between 6 and 23 MV, a relative risk for CIED failure if treated with > 6 MV was calculated to be 9.03 (95% CI 5.24-15.55). After implementation of the DEGRO/DGK guideline, no complications were noted in 147 cases treated with photons, even though CIED-doses were as high as 5.37 Gy. In 13 cases treated with electrons, one PM lost patient-related data in a patient receiving antiproliferative RT to mammary glands. CONCLUSIONS: Implementation of the German DEGRO/DGK-guideline effectively prevented radiation-associated CIED failures in patients treated with photons. Limitation of photon energy to 6 MV, suspension of defibrillation therapy in ICDs, surveillance of patients according to risk stratification and avoidance of direct irradiation of CIEDs should become standard of care.

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.