Large Single Center Research Articles

The Incidence of Gastrointestinal Stromal Tumors in Obese Patients-A Large Single Center Experience.

Background and Objectives: Gastrointestinal stromal tumors (GISTs) are rare mesenchymal neoplasms located mainly in the fundus (60–70%). The incidence of GIST is approximately 10 per million population per year in Europe, with a peak incidence at the age of 63. Recent studies suggest that morbidly obese patients have a higher incidence of GIST than the general population. The aim of this study was to analyze the incidence of GIST in patients undergoing laparoscopic sleeve gastrectomy (LSG) in our department. Materials and Methods: this paper present the retrospective study of prospectively collected data of 1564 patients who underwent LSG in a single large bariatric center from October 2013 to September 2021. After surgery, each sample of the resected stomach was sent for histopathological examination. For the analysis, we included patients diagnosed with GIST intraoperatively or postoperatively. Results: GISTs were found in five patients (0.31%). There were three men and two women. The mean age was 50.2 (range 32–63 ± 11.8) and the mean preoperative body mass index was 43.3 kg/m2 (40–49.4 ± 3.2). In four cases, GISTs were found in the fundus (80%), and in one in the pylorus (20%). None of the tumors were larger than 7 mm in diameter and all were diagnosed as a very low-risk category. No adjuvant treatment was required. All patients achieved good or satisfactory bariatric and metabolic results. Conclusions: The incidence of GIST in our study was estimated at 0.31%. All patients had a very low-risk GIST and no recurrence until follow-up. Recent literature suggests that the risk of GIST is higher in the obese population, and therefore surgeons should be aware of the risk of incidental GIST during LSG.

Is It Possible to Expand Oocyte Donors by Decreasing Number of Oocytes for Own Use? Insights From a Large Single-Center Study.

BackgroundCurrently, in China, only women undergoing in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) cycles can donate oocytes to others, but at least 15 oocytes must be kept for their own treatment. Thus, the aim of this study was to determine whether oocyte donation compromises the cumulative live birth rate (CLBR) of donors and whether it is possible to expand oocyte donors’ crowd.MethodsThis was a retrospective cohort study from August 2015 to July 2017 including a total of 2,144 patients, in which 830 IVF–embryo transfer (IVF-ET) patients were eligible for oocyte donation and 1,314 patients met all other oocyte donation criteria but had fewer oocytes retrieved (10–17 oocytes). All 830 patients were advised to donate approximately three to five oocytes to others and were eventually divided into two groups: the oocyte donation group (those who donated) and the control group (those who declined). The basic patient parameters and CLBR, as well as the number of supernumerary embryos after achieving live birth, were compared. These two factors were also compared in all patients (2,144) with oocyte ≥10.ResultsIn 830 IVF-ET patients who were eligible for oocyte donation, only the oocyte number was significantly different between two groups, and the donation group had more than the control group (25.49 ± 5.76 vs. 22.88 ± 5.11, respectively; p = 0.09). No significant differences were found between the two groups in other factors. The results indicate that the live birth rate in the donation group was higher than that in the control group (81.31% vs. 82.95%, p = 0.371), without significance. In addition, CLBR can still reach as high as 73% when the oocyte number for own use was 10. Supernumerary embryos also increased as the oocyte number increased in all patients (oocyte ≥10).ConclusionsCurrently, oocyte donation did not compromise CLBR, and oocyte donation can decrease the waste of embryos. In addition, in patients with 10 oocytes retrieved, the CLBR was still good (73%). Thus, it is possible to expand oocyte donors if the number of oocyte kept for own use was decreased from 15 to 10 after enough communication with patients.

Epstein-Barr Virus Prevalence at Diagnosis and Seroconversion during Follow-Up in Pediatric Inflammatory Bowel Disease.

Primary Epstein–Barr virus infection in pediatric patients with inflammatory bowel disease during immunomodulation with thiopurines has been associated with increased risk for malignancies or hemophagocytic lymphohistiocytosis. We determined Epstein–Barr virus (EBV) seroprevalence at inflammatory bowel disease (IBD) diagnosis and seroconversion during follow-up in a large single center cohort of children with IBD. EBV serology results and patient characteristics were retrospectively retrieved from the hospital documentation system. EBV seronegative patients at IBD diagnosis were prospectively retested. We report on IBD patients with symptomatic active EBV infection and a complicated disease course, and those diagnosed with malignancy with respect to EBV status and drug exposure. Of 402 patients, 194 (48%) had available EBV serology results at time of IBD diagnosis at a median of 12 years (IQR 9–14 years). Thereof, 102 (53%) were EBV-positive. Of 92 EBV-negative patients, 66 were retested and 17% showed a seroconversion at a mean follow-up time of 4.3 years (SD 3 years). Three children treated with azathioprine experienced acute clinically relevant EBV infection 2, 2.5, and 4 years after IBD diagnosis, two developed signs of hemophagocytic lymphohistiocytosis. Three cases of malignancy occurred in the cohort, though none seemed to be triggered by EBV. In conclusion, almost 50% of pediatric IBD patients were EBV-naïve following diagnosis and may be at increased risk to develop severe EBV infection during immunosuppressive therapy, potentially associated with complications such as hemophagocytic lymphohistiocytosis or malignancy.

Normal Life Expectancy for Polycythemia Vera Patients Is Possible

▪Introduction: Polycythemia vera (PV), a chronic myeloproliferative neoplasm, is characterized by shortened overall survival (OS) due to potentially fatal thrombosis, progression to myelofibrosis (MF), and acute leukemia. Treatment with aspirin, attentive phlebotomy (PHL) and cytoreductive agents can prevent thrombosis; but it is unknown whether available treatments can achieve a normal life-span for PV patients (pts). Our objective was to assess the extent by which PV alters OS of pts receiving available treatment at our center and in the community.Methods: We obtained demographics and survival data of adult PV pts from our Weill Cornell Medicine (WCM) Research Database Repository (PV-WCM) diagnosed from 1974-2020 as previously described (Abu-Zeinah et al. Leukemia 2021); and from the National Cancer Institute's Surveillance, Epidemiology and End Results (SEER) Program, 2001-2017. PV-WCM thrombosis and MF progression data were available. WCM institutional review board approval and SEER data use agreement were in place. OS of PV pts was estimated using Kaplan-Meier (KM) analysis. Propensity Score Matching was used to identify a subgroup of SEER pts (PV-SEER) with similar age, sex, and race demographics to PV-WCM for comparison of OS. Cox proportional hazards was used for multivariable analysis (MVA) of survival. Actuarial survival of the US population matched by age, sex, race, and year-of-birth was obtained from US Census. Observed OS was compared to actuarial OS using one-sided log-rank test.Results: We identified 470 PV-WCM and 16,492 PV pts from SEER. The median OS of the PV-WCM cohort and the SEER population was 26.6 and 12.8 years, respectively, but the groups differed by age and sex (Fig 1A). PV-WCM and matched PV-SEER, however, were well balanced by age, sex, and race (standardized mean difference <0.1). The median OS of PV-WCM was 10.8 years longer than PV-SEER (p<0.001, Fig 1B). MVA confirmed 65% lower mortality in the PV-WCM group relative to the PV-SEER population (p<0.001, Fig 1C). PV-SEER OS was shorter than actuarial OS of the US population (mortality HR 2.47, p<0.001), whereas PV-WCM OS was not significantly different than expected (mortality HR 1.15, p=0.136). Excess late mortality was observed in PV-WCM after 17 years, potentially due to increased incidence of MF progression, affecting almost 50% of PV pts after 25 years (Fig 1D).Discussion: These data point to the success of attentive management with aspirin, targeted PHL, and cytoreductive therapy at a specialty center in reducing the mortality of PV, owing in part, to ELN and NCCN treatment recommendations for preventing fatal thrombosis. Although excess thrombosis was not eliminated in PV-WCM pts, the incidence rate was low after the first two years (Fig 1D). In contrast, the incidence of MF progression increased, potentially contributing to excess late mortality. Current PV risk stratification and treatment recommendations neither predict nor aim to mitigate progression to MF, and do not satisfy the needs of younger, low-risk pts who are often symptomatic and harbor a lifetime threat of progression (Fig 1E). The recent Low-PV study showed that low-risk pts may also benefit from cytoreductive therapy with an agent such as interferon-alpha (rIFNα) over PHL alone (Barbui et al. Lancet Hematol 2021). PV-WCM pts treated with rIFNα (n=137), previously shown to have improved MF-free survival and OS (Abu-Zeinah et al. Leukemia 2021), had an OS similar to the matched US population (p=0.33, Fig 1F); whereas pts not treated with rIFNα had modestly shortened OS (HR 1.26, p=0.03). Because PV progression is among the leading causes of late morbidity and mortality, and available therapy can mitigate this, it may be time to reconsider and improve upon PV risk stratification and treatment.Conclusion: This large population-based and single center study shows that although PV survival remains shortened, normal life expectancy for PV pts is possible with available care. The discrepancy between survival in the community and at a specialized center highlights the need for greater community outreach, health equity, and education regarding treatment standards for PV. Hopefully, this study motivates development of new PV risk stratification and treatment recommendations that focus not only on hematologic control and thrombosis prevention, but also on preventing MF progression, improving OS, and restoring normal life expectancy. [Display omitted] DisclosuresAbu-Zeinah: PharmaEssentia: Membership on an entity's Board of Directors or advisory committees. Silver: Abbvie: Consultancy; PharamEssentia: Consultancy, Speakers Bureau. Scandura: CR&T (Foudation): Research Funding; European Leukemia net: Honoraria, Other: travel fees ; MPN-RF (Foundation): Research Funding; Constellation: Research Funding; Abbvie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. OffLabel Disclosure:Interferon-alpha is used off label in the treatment of polycythemia vera.

Invasive Aspergillosis in Allogeneic Hematopoietic Stem Cell Transplantation Recipients: A Large Cohort Single-Center Study

Background. Invasive aspergillosis (IA) is dominant among invasive fungal infections after allogeneic hematopoietic stem cell transplantation (allo-HSCT). The emergence of new immunosuppressive drugs, the expanding use of antifungal agents with activity against Aspergillus spp. on the one hand, and the improvement of the diagnostics and therapy on the other hand affect epidemiology of IA.Methods. We analyzed 663 patients who underwent allo-HSCT from 2016 to 2020 years in CIC 725. During the observation period, 43 patients with proven and probable IA were included into analysis. According to EORTC/MSG 2019 criteria, 2 proven and 41 probable cases were diagnosed in adults with hematological malignances and non-malignant hematological diseases during 1 year after allo-HSCT. We characterized the IA after allo-HSCT and conducted the comparative analysis of patients and transplant characteristics who developed IA after allo-HSCT and did not. The median follow up time was 13,9 months.Results. Cumulative incidence of IA during 1-year period after allo-HSCT was 8%. Among all cases of IA most common underlying diagnoses were acute leukemia - 32% and lymphomas - 30%. The main sites of infection were lungs 93%, sinuses - 2%, disseminated lesions - 5%. The IA was diagnosed by bronchoalveolar (BAL) or sinuses liquid culture in 54% cases, and the etiology were Aspergillus fumigatus - 8 (42%), Aspergillus niger - 5 (26%), Aspergillus flavus - 2 (11%), Aspergillus terreus - 1 (5%), Aspergillus spp. - 3 (16%). The median day of IA onset was day +59 (range, 2 to 282) after allo-HSCT. First line therapy of IA was predominantly with voriconazole (vori) monotherapy - 35 (81%), combination based on vori - 5 (12%). Salvage combination therapy were prescribed in two patients: vori + echinocandins (echino) and L amph B + echino. Overall survival at 12 weeks in patients with IA was 76%. Comparative analysis showed that in patients with IA statistically significant more frequent were patients with AML, HL, NHL, Ph(-) MPNs, second or more allo-HSCT, CMV-reactivation, aGVHD, aGVHD grade 3-4, severe chGVHD (Table 1). To identify the risk factors including primary antifungal prophylaxis planning to conduct the multivariate subgroup analysis. Patients with IA had lower level of lymphocytes on day +60 (p=0.006) and 100 (p=0.009) compared to patients without IA (pic.1).Conclusions. Incidence of IA after allo-HSCT was 8% with the median day +59. The main site of infection was lungs, etiology - Aspergillus fumigatus. Overall survival at 12 weeks in patients with IA was 76%. In the era of primary and secondary prophylaxis we identified risk groups for developing IA after allo-HSCT among the previously undescribed, worthy of further study: subsequent allo-HSCT, underlying disease: HL, NHL, Ph (-) MPNs. [Display omitted] DisclosuresKlimko: Gilead Sciences, MSD, Pfizer Pharmaceuticals, and Astellas Pharma: Speakers Bureau; Gilead Science, MSD, Pfizer: Membership on an entity's Board of Directors or advisory committees. Kulagin: Pfizer: Speakers Bureau; Johnson & Johnson: Speakers Bureau; Roche: Speakers Bureau; Sanofi: Speakers Bureau; Generium: Speakers Bureau; Biocad: Research Funding; Apellis: Research Funding; Alexion: Research Funding; X4 Pharmaceuticals: Research Funding; Novartis: Speakers Bureau.

‘Application of Prognostic Scoring in Systemic Mastocytosis Patients within a UK Centre of Excellence: Guys and St Thomas’ NHS Foundation Trust.‘

‘Application of Prognostic Scoring in Systemic Mastocytosis Patients within a UK Centre of Excellence: Guys and St Thomas’ NHS Foundation Trust.‘

SP5.2.3 Comparison of Open Abdomen Management Techniques in a cohort of patients with Encapsulating Peritoneal Sclerosis – A large single centre retrospective review

Abstract Aims Encapsulating peritoneal sclerosis (EPS) is a rare phenomenon characterised by encasement and obstruction of the bowel by thickened peritoneum. In our centre, EPS laparotomies are typically managed with open abdomen (OA) and planned relook at 24-48 hours. The aim of the study was to compare ABTHERATM open abdomen negative pressure wound therapy (NPWT) with packing (betadine-soaked gauze) as temporary abdominal closure (TAC) techniques in OA management. Methods We performed retrospective analysis of a contemporaneously maintained database of all patients who underwent surgery for EPS between 2010-2020. A variety of variables were included with the primary endpoint being time to definitive fascial closure. Patient demographics, surgical complications, subsequent method of closure (including mesh usage) and outcomes were recorded. Results 99/122 patients underwent open abdomen management. 43/99 were managed with NPWT and 56/99 were managed with packing. The NPWT group had significantly higher fascial closure rates without need for subsequent bridged (mesh) closure when compared to the packed abdomen [62.8% vs 12.5%, (p &amp;lt; 0.001, c2 test)]. In the NPWT group, there were also fewer failed closures [4.7% vs 19.6%, (p = 0.03, c2 test)] along with shorter time to definitive closure and reduced theatre episodes. No incidence of intestinal fistulation was associated with NPWT. Conclusion This study provides definitive guidance as to the benefit of ABTHERATM open abdomen NPWT for fascial closure following open abdominal management. ABTHERATM open abdomen NPWT provides significant advantages over traditional methods of TAC and may provide benefit in OA management in other patient groups (sepsis and trauma) as well.

Ependymomas: surgeon case volume and patient outcomes

Abstract Aims Ependymomas (tumours arising from ependymal cells) are rare in the adult population and therefore there is limited class 1 evidence on the treatment and management of these patients. We present our experience from a large single center. We address whether management should be undertaken by sub-specialised surgeons with high volume experience. Method Retrospective comparative study. Results High volume surgeons operated on larger volume (16.14 mm3, 8.31mm3, p=0.10) and more complex tumours (multi-centric cases p=0.10). We find a non-significant improvement in complication rate (p=0.77), extent of gross total resection (70.8% against 65.7%) and a positive change in performance status for high volume surgeons (p=0.84). Length of hospital stay is significantly prolonged when complications occur (14.2 and 48.4 days, p&amp;lt;0.05). Conclusion Surgeons who have higher case load of ependymomas operate on more complex tumours. In addition, our results indicate there is a technical advantage of high volume surgeons compared to low volume surgeons, which translates into improved clinical outcomes for patients. We show that this has a significant impact on length of hospital stay, as well as the associated economical implications. For rare tumours such as ependymomas, super-specialisation and referral to surgeons with higher case volume will likely improve patient outcomes. We call for a multi-centre, prospective studies to combine data in demonstrating statistical significance (power calculation for complication rate, N=150, p=0.05).

Long-term morphological appearance of transcatheter valves left in the ascending aorta after valve dislocation during transcatheter aortic valve implantation

Abstract Background Transcatheter valve embolization and migration (TVEM) is a potential complication of transcatheter aortic valve implantation (TAVI) (1). Registries suggest low incidence but clinical relevance due to increased acute and mid-term mortality with the majority embolizing in the aorta. However, there is little data on potential late complications such as leaflet and stent thrombosis or aortic wall alterations by migrated valves. Purpose The aim of our study was to analyze the incidence and clinical characteristics of TVEM in a large single center cohort of TAVI patients and to examine dislocated valves by ECG-gated computed tomography (CT). Methods and results Between July 2009 and May 2020, 40 TVEM occurred in 3387 TAVI procedures performed in our center (1.18%). TVEM was defined according to Valve Academic Research Consortium-2 (VARC-2) criteria (3). Majority of TVEM were left in the ascending aorta (31 ascending, 3 arch, 1 descending aorta). 90% of TVEM occurred with a self-expanding valve (SEV), with no difference between older and newer valve generations, 10% with a ballon-expandable valve. Analyzing a TAVI sample cohort (n=200), horizontal aorta (p&amp;lt;0.001, OR 11.7, 95% CI: [3.9:34.8]), defined as aortic angulation &amp;gt;48°(4), as well as the use of SEV (p&amp;lt;0.001, OR 12.8, 95% CI: [3.1:53.9]) were identified as a predisposing risk factor for TVEM. OR in SEV was severely increased when isolating the analysis for patients with horizontal aorta only (p=0.003, OR 23.75, 95% CI: [2.8:129]). No other predisposing risk factors were identified in this cohort. Out of 35 patients still alive, 6 patients were willing to participate in our imaging sub-study. CT exams were performed on average 47 months after TAVI (IQR 50 months [25%Q: 16.8, 75%Q: 72.8]). We detected no leaflet or stent thrombosis, yet CT identified pin protrusions in the aorta in 3 out of 6 patients. Conclusions TVEM is a rare complication of TAVI. TVEM was significantly associated to the use of self-expanding valves and the presence of horizontal aorta. CT did detect pin protrusions in several cases which could bear the possible risk of perforation but showed no signs of long-term damage. Funding Acknowledgement Type of funding sources: None. Representative CT images after TVEM

S1092 Long Term Outcomes of TIPS for Patients With Refractory Variceal Bleeding and Ascites: “A Real World Experience” From a Single Large Center

S1092 Long Term Outcomes of TIPS for Patients With Refractory Variceal Bleeding and Ascites: “A Real World Experience” From a Single Large Center

S1087 Outcomes of Management of Hemorrhoids in Patients With Cirrhosis: A National Analysis

Introduction: Hemorrhoids are seen more commonly in cirrhotic patients (40-44%) as compared to the non-cirrhotic population. Limited data is available on outcomes of management options for hemorrhoids in patients with cirrhosis and the data available is limited to a few case reports, most of which were done outside the United States. We aimed to investigate the hospital related outcomes of different therapies implied for patients with cirrhosis and concomitant hemorrhoids. Methods: We used ICD-9 codes to identify adult patients with cirrhosis and hemorrhoids in the national inpatient sample database through 2010 to 2014. Similarly, we used ICD-9 procedural codes to select patients who underwent injection sclerotherapy (IS), band ligation (BL) and hemorrhoidectomy during these years. Our outcomes of interest included inpatient mortality, length of stay (LOS), and total hospitalization charges. Results: Out of 391,073 adult patients with hemorrhoids, we found 14,069 (3.6%) with compensated cirrhosis (CC) and 16,133 (4.13%) patients with decompensated cirrhosis (DC). Patients in the cirrhosis group were younger and mostly males as compared to the non-cirrhosis group. Among cirrhosis patients, majority of the patients underwent BL (3.51% in CC & 3.98% in DC) followed by hemorrhoidectomy (2.03% in CC & 1.87% in DC). 0.11% of those with CC underwent IS and 0.74% of those with DC. Patients in the DC group had a higher incidence of inpatient mortality (13.68% for IS, 8% for BL, and 5.1% for hemorrhoidectomy), LOS (11.2 days for IS, 9.6 days for BL, and 11.8 days for hemorrhoidectomy) and total hospital charges ($40,521.96 for IS, $25,254.33 for BL, and $29,716.33 for hemorrhoidectomy) as compared to CC. Among different therapies, IS had a higher mortality and increased hospitalization cost but comparable LOS to hemorrhoidectomy especially in the DC group (Table 1). Conclusion: A small percentage of patient with cirrhosis (CC or DC) underwent interventions for hemorrhoids. Among those who underwent interventions, worse outcomes including healthcare utilization, mortality, and LOS are seen in patients with DC. This is the first national report to our knowledge on outcomes of hemorrhoids management in cirrhotics. However, the findings are limited due to the inherent limitation of the database and should be interpreted with caution and should be followed by large single center studies.Table 1.: Outcomes of Treatments for Hemorrhoids in Patients with Cirrhosis (*) Numbers are rounded off to 10 to protect patient privacy.

Pediatric stereo-electroencephalography: effects of robot assistance and other variables on seizure outcome and complications.

The safety of stereo-electroencephalography (SEEG) has been investigated; however, most studies have not differentiated pediatric and adult populations, which have different anatomy and physiology. The purpose of this study was to assess SEEG safety in the pediatric setting, focusing on surgical complications and the identification of patient and surgical risk factors, if any. The authors also aimed to determine whether robot assistance in SEEG was associated with a change in practice, surgical parameters, and clinical outcomes. The authors retrospectively studied all SEEG cases performed in their department from December 2014 to March 2020. They analyzed both demographic and surgical variables and noted the types of surgery-related complications and their management. They also studied the clinical outcomes of a subset of the patients in relation to robot-assisted and non-robot-assisted SEEG. Sixty-three children had undergone 64 SEEG procedures. Girls were on average 3 years younger than the boys (mean age 11.1 vs 14.1 years, p < 0.01). The overall complication rate was 6.3%, and the complication rate for patients with left-sided electrodes was higher than that for patients with right-sided electrodes (11.1% vs 3.3%), although the difference between the two groups was not statistically significant. The duration of recording was positively correlated to the number of implanted electrodes (r = 0.296, p < 0.05). Robot assistance was associated with a higher number of implanted electrodes (mean 12.6 vs 7.6 electrodes, p < 0.0001). Robot-assisted implantations were more accurate, with a mean error of 1.51 mm at the target compared to 2.98 mm in nonrobot implantations (p < 0.001). Clinical outcomes were assessed in the first 32 patients treated (16 in the nonrobot group and 16 in the robot group), 23 of whom proceeded to further resective surgery. The children who had undergone robot-assisted SEEG had better eventual seizure control following subsequent epilepsy surgery. Of the children who had undergone resective epilepsy surgery, 42% (5/12) in the nonrobot group and 82% (9/11) in the robot group obtained an Engel class IA outcome at 1 year (χ2 = 3.885, p = 0.049). Based on Kaplan-Meier survival analysis, the robot group had a higher seizure-free rate than the nonrobot group at 30 months postoperation (7/11 vs 2/12, p = 0.063). Two complications, whose causes were attributed to the implantation and head-bandaging steps, required surgical intervention. All complications were either transient or reversible. This is the largest single-center, exclusively pediatric SEEG series that includes robot assistance so far. SEEG complications are uncommon and usually transient or treatable. Robot assistance enabled implantation of more electrodes and improved epilepsy surgery outcomes, as compared to those in the non-robot-assisted cases.

Reappraisal of Limited Duration Tourniquet in Total Knee Arthroplasty: A Double-Blinded RCT.

The majority of arthroplasty surgeons use a full duration of tourniquet while doing total knee arthroplasty. Recent literature suggests clinical dilemma about superior function with limited duration use of a tourniquet. The purpose of this study is to evaluate the time-dependent effects and clinical outcome of tourniquet in patients undergoing total knee arthroplasty (TKA) and to assess the incidence of adverse vascular events of the limb in TKA. This study is the first of its kind to evaluate all the serious vascular events prospectively. Sixty participants who underwent TKA in the duration of 1.5years at a large single tertiary care centre were recruited and randomly allocated in two groups: Full duration tourniquet (n = 30) and tourniquet only during cementation (n = 30). All patients underwent preoperative and postoperative arterial and venous Doppler to evaluate the presence of thrombosis. The operative duration, blood loss, and clinical outcome (visual analogue scale, active knee range of motion, Knee Society score, and duration of stay) were recorded. The incidence of vascular complications was not statistically significant in either group (P = 0.99). Tourniquet during cementation only group exhibited decreased postoperative pain on days 1, 2, and 3 (P < 0.01). But postoperative knee active range of motion was the same between the two groups with no significant postoperative complications. Tourniquet use only during cementation could result in faster recovery and less pain during the early rehabilitation period with no influence over the incidence of serious vascular events. AIIMS/IEC/2018/475. This study was approved by the Research Ethics Committee at All India Institute of Medical Sciences, Jodhpur and was carried out at AIIMS (Jodhpur), India.

Results in the surgical treatment of aneurysmal bone cysts – A retrospective data analysis

BackgroundAneurysmal bone cysts (ABC) are benign tumors mostly occurring in children and young adults. Different open and minimal invasive surgical approaches have been proposed for the treatment of ABCs and yet no consensus is defined to date. The aim of this study was to retrospectively review data of a large single center series of ABCs with patients treated by open curettage with or without filling of the cavity or en-bloc resection.Questions/purposes We asked: (1) What was the local recurrence rate of ABC after surgical treatment at our institution? (2) What were positive or negative predictors for local recurrence? (3) Was there a benefit from adjuvant burring, phenolization or filling, respectively? (4) Where there changes in recurrence free survival in different time periods of primary surgery? MethodsBy retrospective data analysis of the Vienna Bone and Soft Tissue Tumor Registry, 123 patients surgically treated for primary aneurysmal bone cysts were identified. After exclusion of 33 patients (27%) due to a postoperative follow up below one year, 90 patients who were treated for primary ABCs between 1986 and 2009 were evaluated. These included 50 males and 40 females with a mean age of 16 years (SD 10 years; range: 2 to 51 years). The mean follow-up was 99 months. (SD 72 months, range: 13 to 329 months) ResultsCurettage was performed in 84 patients, while 45 patients received adjuvant phenolization. Local recurrence occurred in 28 patients after a mean time of 16 months, with a corresponding local recurrence free survival (RFS) of 83% after one year, 77% after 2 years and 66% after 5 years. ABCs located in hands and feet (p=0.044) showed a superior RFS, while younger patients (p=0.001) displayed an inferior RFS. Regarding adjuvant surgical techniques, mechanical cavity burring (p=0.004) and filling with autologous cancellous bone graft (p=0.024) showed protective effects on RFS. Patients treated between 1986 and 1999 (n=47) had a higher RFS than patients treated between 2000 and 2009 (n=43, p=0.011), as surgeons and surgical indications changed over time. ConclusionAlthough curettage, burring, phenolization and reconstruction with bone grafts came with a relatively high risk of local recurrence, open surgery is still justified in aggressively growing ABCs of critical localizations. Level of evidenceIV; therapeutic study.

MA06.02 Impact of Heart and Lung Radiation Dose and Lymphopenia on Non-Small Cell Lung Cancer Outcomes

Lymphocytopenia may adversely affect survival. This effect has been hypothesised to be linked to heart and lung radiation and associated circulating immune cell dose. In this large single centre study of non-small-cell lung cancer (NSCLC) patients treated with radical chemo-radiotherapy (CRT), we assess the impact of lymphocytopenia in relation to heart and lung dose on survival and tumour control. We retrospectively analysed all NSCLC patients treated with CRT from January 2018 to December 2020. Patient, tumour and treatment characteristics, mean heart dose (MHD), mean lung dose (MLD) and relapse patterns were collected. Minimum lymphocyte count identified during and within 6 months of radiotherapy was classified ‘lymphocyte nadir’ and graded using CTCAEv5. EDIC, an estimate of effective radiation dose to circulating immune cells, was calculated based on Jin et al’s model. EDIC = (0.12xMLD) + (0.08xMHD) + (0.45+0.35x0.85x(n/45)ˆ0.5)) x (ITD/62x10ˆ3) integral body dose (ITD), fractions (n) Progression free survival (PFS) and overall survival (OS) were calculated from start of treatment and associations between variables assessed using Cox regression models. 150 of 164 patients treated with CRT had lymphocyte data. All patients received radical doses of radiotherapy with intensity-modulated radiation therapy and platinum doublet chemotherapy. 25 had adjuvant Durvalumab. Patients with ≥grade 2 lymphocytopenia at nadir (≥G2LN) had significantly worse PFS (HR=1.53, p<0.05) and OS (HR 1.69, p<0.05) than <grade 2 lymphocytopenia at nadir (<G2LN). Median OS was 26.5 and 35.1 months respectively. Patient and treatment characteristics are summarised in table 1. There was no significant difference in OS between sequential and concurrent CRT. Mean MHD and MLD were higher in patients with ≥G2LN compared to <G2LN (10.7Gy vs 7.8Gy and 13.4Gy vs 11Gy respectively) though not significantly. Larger planning target volume (PTV) was significantly associated with worse OS (HR=1.002, p<0.001) and correlated with lymphocyte nadir (Pearson r=-0.40, p<0.001). 111 patients had EDIC measures. EDIC negatively correlated with lymphocyte nadir (Pearson r=-0.237, p=0.017). Median EDIC was 2.38. EDIC ≥2.38 was associated with worse OS compared to <2.38 (19.5 vs 36.9 months respectively) (HR=1.75, p=0.067). Larger PTVs result in higher MHD, MLD and effective radiation dose to circulating immune cells, resulting in lower lymphocyte nadir which is associated with poorer outcomes. Lymphocyte nadir appears to be a surrogate for survival; we recommend closer surveillance of patients with ≥G2LN, reducing MHD and MLD to as low as possible and considering pneumocystis-jiroveci-pneumonia (PJP) prophylaxis. The additional impact of adjuvant immunotherapy would be interesting to assess.

S1385 Impact of Race and Ethnicity on Risks of Cardia and Non-Cardia Gastric Adenocarcinomas in the U.S., 2000-2019: A Large Single-Center Retrospective Cohort Study

S1385 Impact of Race and Ethnicity on Risks of Cardia and Non-Cardia Gastric Adenocarcinomas in the U.S., 2000-2019: A Large Single-Center Retrospective Cohort Study

Continued Discontinuation of TKI Treatment in Medullary Thyroid Carcinoma - Lessons From Individual Cases With Long-Term Follow-Up.

BackgroundThe tyrosine kinase inhibitors (TKI) vandetanib and cabozantinib are approved as targeted therapies in advanced medullary thyroid carcinoma (MTC) with symptoms or high tumour burden. Only recently, toxicity in long-time TKI usage was analysed. However, little is known about the impact of TKI discontinuation on MTC disease course after longer-term therapy. Here, we report our experience in a series of 7 MTC patients with vandetanib treatment of up to 87 months followed by discontinuation for concerns of toxicity or due to side-effects. The discontinuation of TKI therapy is a relevant clinical scenario. To our knowledge we present the largest single center series on an important aspect of TKI management.MethodsRetrospective analysis of MTC patients with continued discontinuation of vandetanib treatment in a tertiary referral endocrine tumour centre. Analysis included a review of patients’ records for TKI indication, and treatment response as well indications for continued TKI discontinuation and follow-up by clinical assessment, calcitonin and CEA doubling times as well as imaging (ultrasound, CT).ResultsSeven MTC patients [6 sporadic MTC, 1 Multiple Endocrine Neplasie Type 2a (MEN2a)] with previous vandetanib treatment (median: 41 months; range 7-87 months) and continued TKI discontinuation were identified out of 161 analysed MTC files. TKI treatment was initiated due to high tumour burden and symptoms or RECIST (Response Evaluation Criteria In Solid Tumors) progression in all patients. Two patients (29%) remained stable after discontinuation of vandetanib until now (follow-up of 47 and 61 months). Both patients had been on TKI therapy for 73 and 58 months. Five patients (71%) developed progressive disease after TKI discontinuation. In 2 patients, vandetanib was restarted after 45 and 52 months resulting again in disease control. One patient was enrolled in a new RET kinase inhibitor trial after 45 months of vandetanib discontinuation. Two patients declined restart of treatment due to mental health issues leading to discontinuation of vandetanib in the first place (after 7 and 38 months of treatment) and both patients died of rapidly progressive disease. At time points of tumour progression, calcitonin-doubling time (CDT) was < 2 years in all patients.ConclusionThis case series suggests that discontinuation of long-term vandetanib treatment with documented stable disease does not automatically result in rapid disease progression but may be followed by prolonged “TKI free” stable disease in individual patients. Analysis of calcitonin and CDT during discontinuation is indicated as it will unmask tumour progression earlier than imaging. Restart with the same TKI is possible in case of progression.

Role of Intravenous Immunoglobulin in Necrotizing Autoimmune Myopathy.

Immune-mediated necrotizing myopathy (IMNM) is a subtype of myositis that is associated with a refractory phenotype and poorer prognosis. The aim of the study was to provide single large center experience of outcomes of intravenous immunoglobulin (IVIg) for patients with IMNM using longitudinally collected data. This case series longitudinally evaluated 4 of the 6 myositis core set measures at baseline and at 3 and 6 months after IVIg on 20 adult IMNM patients from 2014 to 2019 at the University of Pittsburgh. We assessed patients for improvement in core set measures, prednisone dose, adverse effects, and by the "limited" ACR/EULAR 2016 myositis response criteria. The mean differences in CK and manual muscle testing (MMT-8) were compared using a paired t test. A clinically significant response was defined as a >10% absolute improvement in the MMT-8 and a >50% absolute reduction in serum CK at 6 months of IVIg. Intravenous immunoglobulin treatment was associated with marked improvement in IMNM patients, with 85% of patient meeting clinically significant response. The median (interquartile range) relative percent improvement in CK level was 96% (85%-98%) and in MMT was 29% (14%-36%) at 6 months.There was a significant reduction in the mean (SD) dose of prednisone at 6 months and had minimal adverse effects. In addition, with IVIg, most (13/14) patients had at least minimal improvement as per ACR/EULAR 2016 myositis response criteria. Based on objective, meaningful improvement in MMT-8 and CK as well as marked reduction in prednisone doses with acceptable tolerability, early implementation of IVIg should be considered in adult IMNM.

Well-differentiated gastroenteropancreatic G3 NET: findings from a large single centre cohort

Neuroendocrine neoplasms are known to have heterogeneous biological behavior. G3 neuroendocrine tumours (NET G3) are characterized by well-differentiated morphology and Ki67 > 20%. The prognosis of this disease is understood to be intermediate between NET G2 and neuroendocrine carcinoma (NEC). Clinical management of NET G3 is challenging due to limited data to inform treatment strategies. We describe clinical characteristics, treatment, and outcomes in a large single centre cohort of patients with gastroenteropancreatic NET G3. Data was reviewed from 26 cases managed at Queen Elizabeth Hospital, Birmingham, UK, from 2012 to 2019. Most commonly the site of the primary tumour was unknown and majority of cases with identifiable primaries originated in the GI tract. Majority of cases demonstrated somatostatin receptor avidity. Median Ki67 was 30%, and most cases had stage IV disease at diagnosis. Treatment options included surgery, somatostatin analogs (SSA), and chemotherapy with either platinum-based or temozolomide-based regimens. Estimated progression free survival was 4 months following initiation of SSA and 3 months following initiation of chemotherapy. Disease control was observed following treatment in 5/11 patients treated with chemotherapy. Estimated median survival was 19 months; estimated 1 year survival was 60% and estimated 2 year survival was 13%. NET G3 is a heterogeneous group of tumours and patients which commonly have advanced disease at presentation. Prognosis is typically poor, though select cases may respond to treatment with SSA and/or chemotherapy. Further study is needed to compare efficacy of different treatment strategies for this disease.

From Fork Decoupling to Star-Topology Decoupling

Fork decoupling is a recent approach to exploiting problem structure in state space search. The problem is assumed to take the form of a fork, where a single (large) center component provides preconditions for several (small) leaf components. The leaves are then conditionally independent in the sense that, given a fixed center path p, the compliant leaf moves - those leaf moves enabled by the preconditions supplied along p - can be scheduled independently for each leaf. Fork-decoupled state space search exploits this through conducting a regular search over center paths, augmented with maintenance of the compliant paths for each leaf individually. We herein show that the same ideas apply to much more general star-topology structures, where leaves may supply preconditions for the center, and actions may affect several leaves simultaneously as long as they also affect the center. Our empirical evaluation in planning, super-imposing star topologies by automatically grouping the state variables into suitable components, shows the merits of the approach.