Hybrid argon plasma coagulation-assisted endoscopic mucosal resection for large sessile colon polyps to reduce local recurrence: a prospective pilot study

Background Endoscopic mucosal resection (EMR) of large, sessile colon polyps often results in incomplete resection with subsequent recurrence. The aim of this prospective pilot study was to evaluate the efficacy and safety of a novel technique, hybrid argon plasma coagulation-assisted EMR (hAPC-EMR), to remove large, sessile polyps. Methods 40 eligible patients underwent hAPC-EMR for the removal of one or more nonpedunculated colon polyps ≥ 20 mm. Participants were contacted 30 days post-procedure to assess for adverse events and were recommended to return for a surveillance colonoscopy at 6 months to assess for local recurrence. Results At the time writing, 32 patients with 35 polyps (median size 27 mm; interquartile range 14.5 mm) resected by hAPC-EMR had undergone the 6-month follow-up colonoscopy. Recurrence rate was 0 % (95 % confidence interval [CI] 0–0) at follow-up. Post-polypectomy bleeding was experienced by three patients (7.5 %; 95 %CI 0.00–0.15), and no patients developed post-polypectomy syndrome. Conclusion These preliminary results showed 0 % local recurrence rate at 6 months and demonstrated the safety profile of hAPC-EMR. A large, randomized, controlled trial is required to confirm these results.

RADT-12. USE OF FDOPA PET FOR RADIATION THERAPY TARGETING IN GRADE 2 IDH MUTANT GLIOMA

BACKGROUND Low-grade, IDH mutant (IDHmt) gliomas typically do not enhance on MRI complicating radiotherapy (RT) target delineation. Amino acid PET using 3,4-dihydroxy-6-[18F]-fluoro-L-phenylalanine (FDOPA) has demonstrated avidity in IDHmt gliomas and may assist in RT planning for non-enhancing tumors. This study aims to compare conventional and FDOPA-defined target volumes in grade 2 IDHmt gliomas. METHODS In a prospective pilot study, patients underwent MRI and FDOPA PET using a 3T MRI/PET system followed by standard therapy. Gross tumor volumes (GTV) included the T2/FLAIR abnormality and surgical cavity; clinical target volumes (CTV) included a 1 cm expansion constrained anatomically. Metabolic target volumes (MTVs) were generated using the FDOPA SUV > 1.5-fold normal brain isocurve. Union of GTV and MTV generated a fusion GTV (fGTV); expanding fGTV by 1 cm yielded the fusion CTV (fCTV). Target volumes were compared volumetrically with overlap (Dice coefficient) and surface metrics (Hausdorff distance). Medians are reported with ranges. RESULTS Four patients with grade 2 IDHmt glioma (3 1p/19q codeleted oligodendrogliomas, 1 non-codeleted astrocytoma) received MRI/PET before treatment. All oligodendrogliomas exhibited FDOPA avidity; the astrocytoma showed no avidity. GTV and CTV measured 16.1 cc (4.9 - 82.2 cc) and 76.7 cc (29.5 - 256.1 cc), respectively. The MTV volume outside of GTV was 0.8 cc (0.2 – 6.1 cc), but was covered in each case by the CTV. Addition of FDOPA increased fGTV and fCTV volumes by 5.4% and 17.5%, respectively. Dice coefficient and Hausdorff distances for GTV vs fGTV were 0.96 (0.95 - 0.99) and 11.2 mm (10.0 – 11.9 mm), respectively, and for CTV vs fCTV were 0.87 (0.81 – 0.95) and 10.2 mm (10.0 - 11.0), respectively. CONCLUSIONS FDOPA PET identified tracer-avid regions outside of MRI-defined GTVs in a group of IDHmt gliomas. FDOPA PET provides useful metabolic information for RT planning and warrants further investigation.

Prospective pilot study protocol evaluating the safety and feasibility of robot-assisted nipple-sparing mastectomy (RNSM)

IntroductionNipple-sparing mastectomy (NSM) can be performed for the treatment of breast cancer and risk reduction, but total mammary glandular excision in NSM can be technically challenging. Minimally invasive robot-assisted NSM (RNSM) has the potential to improve the ergonomic challenges of open NSM. Recent studies in RNSM demonstrate the feasibility and safety of the procedure, but this technique is still novel in the USA.Methods and analysisThis is a single-arm prospective pilot study to determine the safety, efficacy and potential risks of RNSM. Up to 12 RNSM will be performed to assess the safety and feasibility of the procedure. Routine follow-up visits and study assessments will occur at 14 days, 30 days, 6 weeks, 6 months and 12 months. The primary outcome is to assess the feasibility of removing the breast gland en bloc using the RNSM technique. To assess safety, postoperative complication information will be collected. Secondary outcomes include defining benefits and challenges of RNSM for both surgeons and patients using surveys, as well as defining the breast and nipple-areolar complex sensation recovery following RNSM. Mainly, descriptive analysis will be used to report the findings.Ethics and disseminationThe RNSM protocol was reviewed and approved by the US Food and Drug Administration using the Investigational Device Exemption mechanism (reference number G200096). In addition, the protocol was registered with ClinicalTrials.gov (NCT04537312) and approved by The Ohio State University Institutional Review Board, reference number 2020C0094 (18 August 2020). The results of this study will be distributed through peer-reviewed journals and presented at surgical conferences.Trial registration numberNCT04537312.

The Role of Magnetic Resonance Imaging and the Expression of MMP-9 Protein in the Analysis of Carotid Atherosclerotic Plaques in Patients Undergoing Carotid Endarterectomy: A Prospective Pilot Study

Components of carotid atherosclerotic plaque can be analysed preoperatively by non-invasive advanced imaging modalities such as magnetic resonance imaging (MRI). The expression of matrix metalloproteinase-9 protein (MMP-9), which has a potential role in remodelling of atherosclerotic plaques, can be analysed immunohistochemically. The aim of the present prospective pilot study is to analyse histological characteristics and expression of MMP-9 in carotid plaques of patients undergoing carotid endarterectomy (CEA) and to investigate the correlation with preoperative clinical symptoms and MRI features. Preoperative clinical assessment, MRI imaging, postoperative histological and immunohistochemical analyses were performed. Fifteen patients with symptomatic (7/15; 47%) and asymptomatic carotid artery stenosis undergoing CEA were included. Among symptomatic patients, 5 (71%) had recent stroke and 2 (29%) had recent transient ischaemic attack with a median timing of 6 weeks (IQR:1, 18) before the surgery. Both groups did not significantly differ in respect to preoperative characteristics. Prevalence of unstable plaque was higher in symptomatic than asymptomatic patients, although it was not significant (63% vs. 37%, p=0.077). The expression of MMP-9 in CD68 cells within the plaque by semiquantitative analysis was found to be significantly higher in symptomatic as compared to asymptomatic patients (86% vs. 25% with the highest expression, p=0.014). The average microvascular density was found to be higher and lipid core area larger among both symptomatic patients and unstable carotid plaque specimens, although this did not reach statistical significance (p=0.064 and p=0.132, p=0.360 and p=0.569, respectively). Our results demonstrate that MRI is reliable in classifying carotid lesions and differentiating unstable from stable plaques. We have also shown that the expression of MMP-9 is significantly higher among symptomatic patients undergoing CEA. Trial Registration: This study has been registered at the ISRCTN registry (ID ISRCTN46536832), isrctn.org Identifier: https://www.isrctn.com/ISRCTN46536832 Keywords: atherosclerosis, carotid endarterectomy, unstable plaque, magnetic resonance imaging, matrix metalloproteinase.