Incisional hernia repair following pancreatic surgery-open vs laparoscopic approach

INTRODUCTION

For pancreatic procedures, transverse and midline or combined approaches are used. Having an increased morbidity after pancreatic surgery, these patients have an increased risk of developing an incisional hernia. In the following, we will analyze how the results of incisional hernia surgery after pancreatic surgery are presented in the Herniamed Registry.

METHODS

Hospitals and surgeons from Germany, Austria and Switzerland can voluntarily enter all routinely performed hernia operations prospectively into the Herniamed Registry. All patients sign a special informed consent declaration that they agree to the documentation of their treatment in the Herniamed Registry. Perioperative complications (intraoperative complications, postoperative complications, complication-related reoperations and general complications) are recorded up to 30 days after surgery. After 1, 5, and 10 years, patients and primary care physicians are contacted and asked about any pain at rest, pain on exertion, chronic pain requiring treatment or recurrence. This retrospective analysis of prospectively collected data compares the outcomes of minimally invasive vs open techniques in incisional hernia repair after pancreatic surgery.

RESULTS

Relative to the total number of all incisional hernia patients in the Herniamed Registry, the proportion after pancreatic surgery with 1-year follow-up was 0.64% (n = 461) patients. 95% of previous pancreatic surgeries were open. Minimally invasive incisional hernia repair was performed in 17.1% and open repair in 82.9% of cases. 23.2% of the defects were larger than 10 cm and 32.8% were located laterally or were a combination of lateral and medial defects. Among the few differences between the collectives, a significantly higher rate of defect closure (58.1% vs 25.3%; p < 0.001) and drainage (72.8% vs 13.9%; p < 0.001) was found in the open repairs, and larger meshes were seen in the minimally invasive procedures (340.6 cm2 vs 259.6 cm2; p < 0.001). No difference deemed a risk factor for chronic postoperative pain was seen in the rate of preoperative pain between the open and minimally invasive procedures (Appendix Table 4) No significant differences were found in either the perioperative complications or at 1-year follow-up.

CONCLUSIONS

Incisional hernias after complex pancreatic surgery can be repaired safely and with a low recurrence rate in both open and minimally invasive techniques.

Deep oncopanel sequencing reveals within block position-dependent quality degradation in FFPE processed samples

Background

Clinical laboratories routinely use formalin-fixed paraffin-embedded (FFPE) tissue or cell block cytology samples in oncology panel sequencing to identify mutations that can predict patient response to targeted therapy. To understand the technical error due to FFPE processing, a robustly characterized diploid cell line was used to create FFPE samples with four different pre-tissue processing formalin fixation times. A total of 96 FFPE sections were then distributed to different laboratories for targeted sequencing analysis by four oncopanels, and variants resulting from technical error were identified.

Results

Tissue sections that fail more frequently show low cellularity, lower than recommended library preparation DNA input, or target sequencing depth. Importantly, sections from block surfaces are more likely to show FFPE-specific errors, akin to “edge effects” seen in histology, while the inner samples display no quality degradation related to fixation time.

Conclusions

To assure reliable results, we recommend avoiding the block surface portion and restricting mutation detection to genomic regions of high confidence.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13059-022-02709-8.

Development and Validation of StrataNGS, a Multiplex PCR, Semiconductor Sequencing-Based Comprehensive Genomic Profiling Test

Despite widespread use in targeted tumor testing, multiplex PCR/semiconductor (Ion Torrent) sequencing-based assessment of all comprehensive genomic profiling (CGP) variant classes has been limited. Herein, we describe the development and validation of StrataNGS, a 429-gene, multiplex PCR/semiconductor sequencing-based CGP laboratory-developed test performed on co-isolated DNA and RNA from formalin-fixed, paraffin-embedded tumor specimens with ≥2 mm² tumor surface area. Validation was performed in accordance with MolDX CGP validation guidelines using 1986 clinical formalin-fixed, paraffin-embedded samples and an in-house developed optimized bioinformatics pipeline. Across CGP variant classes, accuracy ranged from 0.945 for tumor mutational burden (TMB) status to >0.999 for mutations and gene fusions, positive predictive value ranged from 0.915 for TMB status to 1.00 for gene fusions, and reproducibility ranged from 0.998 for copy number alterations to 1.00 for splice variants and insertions/deletions. StrataNGS TMB estimates were highly correlated to those from whole exome- or FoundationOne CDx-determined TMB (Pearson r = 0.998 and 0.960, respectively); TMB reproducibility was 0.996 (concordance correlation coefficient). Limit of detection for all variant classes was <20% tumor content. Together, we demonstrate that multiplex PCR/semiconductor sequencing-based tumor tissue CGP is feasible using optimized bioinformatic approaches described herein.

Perioperative cell-free mutant KRAS dynamics in patients with pancreatic cancer

This prospective observational biomarker trial evaluated the diagnostic and prognostic value of circulating KRAS mutations (cmKRAS) and their perioperative dynamics in patients with resectable pancreatic ductal adenocarcinoma (PDAC). Plasma cmKRAS samples (G12D, G12V, G12R, and G12C) were analysed by droplet digital PCR in 51 patients with resectable PDAC, 20 with advanced PDAC, and 34 with non-malignant pancreatic pathology. Preoperative detection of cmKRAS alone did not correlate with poorer overall and disease-free survival in this patient cohort. However, a perioperative change in cmKRAS, particularly accurate when an intraoperative sample was included, was identified as a new and useful marker for prediction of prolonged survival.

Promising biomarker

Real-World Performance of a Comprehensive Genomic Profiling Test Optimized for Small Tumor Samples

PURPOSE

Tissue-based comprehensive genomic profiling (CGP) is increasingly used for treatment selection in patients with advanced cancer; however, tissue availability may limit widespread implementation. Here, we established real-world CGP tissue availability and assessed CGP performance on consecutively received samples.

MATERIALS AND METHODS

We conducted a post hoc, nonprespecified analysis of 32,048 consecutive tumor tissue samples received for StrataNGS, a multiplex polymerase chain reaction (PCR)-based comprehensive genomic profiling (PCR-CGP) test, as part of an ongoing observational trial (NCT03061305). Sample characteristics and PCR-CGP performance were assessed across all tested samples, including exception samples not meeting minimum input quality control (QC) requirements (< 20% tumor content [TC], < 2 mm2 tumor surface area [TSA], DNA or RNA yield < 1 ng/µL, or specimen age > 5 years). Tests reporting ≥ 1 prioritized alteration or meeting TC and sequencing QC were considered successful. For prostate carcinoma and lung adenocarcinoma, tests reporting ≥ 1 actionable or informative alteration or meeting TC and sequencing QC were considered actionable.

RESULTS

Among 31,165 (97.2%) samples where PCR-CGP was attempted, 10.7% had < 20% TC and 59.2% were small (< 25 mm2 tumor surface area). Of 31,101 samples evaluable for input requirements, 8,089 (26.0%) were exceptions not meeting requirements. However, 94.2% of the 31,101 tested samples were successfully reported, including 80.5% of exception samples. Positive predictive value of PCR-CGP for ERBB2 amplification in exceptions and/or sequencing QC-failure breast cancer samples was 96.7%. Importantly, 84.0% of tested prostate carcinomas and 87.9% of lung adenocarcinomas yielded results informing treatment selection.

CONCLUSION

Most real-world tissue samples from patients with advanced cancer desiring CGP are limited, requiring optimized CGP approaches to produce meaningful results. An optimized PCR-CGP test, coupled with an inclusive exception testing policy, delivered reportable results for > 94% of samples, potentially expanding the proportion of CGP-testable patients and impact of biomarker-guided therapies.

Cross-oncopanel study reveals high sensitivity and accuracy with overall analytical performance depending on genomic regions

BACKGROUND

Targeted sequencing using oncopanels requires comprehensive assessments of accuracy and detection sensitivity to ensure analytical validity. By employing reference materials characterized by the U.S. Food and Drug Administration-led SEquence Quality Control project phase2 (SEQC2) effort, we perform a cross-platform multi-lab evaluation of eight Pan-Cancer panels to assess best practices for oncopanel sequencing.

RESULTS

All panels demonstrate high sensitivity across targeted high-confidence coding regions and variant types for the variants previously verified to have variant allele frequency (VAF) in the 5-20% range. Sensitivity is reduced by utilizing VAF thresholds due to inherent variability in VAF measurements. Enforcing a VAF threshold for reporting has a positive impact on reducing false positive calls. Importantly, the false positive rate is found to be significantly higher outside the high-confidence coding regions, resulting in lower reproducibility. Thus, region restriction and VAF thresholds lead to low relative technical variability in estimating promising biomarkers and tumor mutational burden.

CONCLUSION

This comprehensive study provides actionable guidelines for oncopanel sequencing and clear evidence that supports a simplified approach to assess the analytical performance of oncopanels. It will facilitate the rapid implementation, validation, and quality control of oncopanels in clinical use.

Management and outcomes of intraductal papillary mucinous neoplasms

Background

This study evaluated the outcome and survival of patients with radiologically suspected intraductal papillary mucinous neoplasms (IPMNs).

Methods

IPMN management was reviewed according to Fukuoka risk factors and IPMN localization, differentiating main‐duct (MD), mixed‐type (MT) and branch‐duct (BD) IPMNs. Perioperative results were compared with those of patients undergoing resection of pancreatic ductal adenocarcinoma (PDAC) over the same interval (2010–2014). Overall (OS) and disease‐specific (DSS) survival rates were calculated and subgroups compared.

Results

Of 142 patients with IPMNs, 26 had MD‐IPMN, eight had MT‐IPMN and 108 had BD‐IPMN. Some 74 per cent of patients with MD‐ and MT‐IPMN were managed by primary resection, whereas this was used in only 27·8 per cent of those with BD‐IPMN. The risk of secondary resection and malignant transformation for BD‐IPMNs smaller than 20 mm was 8 and 2 per cent respectively during follow‐up. Pancreatic head resection of IPMNs was associated with an increased risk of postoperative pancreatic fistula grade B/C compared with resection of PDAC (12 of 33 (36 per cent) versus 41 of 221 (18·6 per cent) respectively; P = 0·010), and greater morbidity and mortality (Clavien–Dindo grade III: 15 of 33 (45 per cent) versus 56 of 221 (25·3 per cent) respectively; grade IV: 1 (3 per cent) versus 7 (3·2 per cent); grade V: 2 (6 per cent) versus 2 (0·9 per cent); P = 0·008). Five‐year OS and DSS rates in patients with MD‐IPMN were worse than those for MT‐ and BD‐IPMN (OS: 44, 86 and 97·4 per cent respectively, P < 0·001; DSS: 60, 100 and 98·6 per cent; P < 0·001). Patients with invasive IPMN had worse OS and DSS rates than those with non‐invasive dysplasia (OS: IPMN‐carcinoma (10 patients) 33 per cent, high‐grade dysplasia 100 per cent, intermediate‐grade dysplasia 63 per cent, low grade‐dysplasia 100 per cent, P < 0·001; DSS: IPMN‐carcinoma 43 per cent, all grades of dysplasia 100 per cent, P < 0·001). Patients with high‐risk stigmata had poorer survival than those without risk factors (OS: high‐risk stigmata (35 patients) 55 per cent, worrisome features (31) 95 per cent, no risk factors (76) 100 per cent, P < 0·001; DSS: 71, 100 and 100 per cent respectively, P < 0·001).

Conclusion

The risk of malignant transformation was very low for BD‐IPMNs, but the development of high‐risk stigmata was associated with disease‐specific mortality. Patients with IPMN had greater morbidity after resection than those having resection of PDAC.

Prospective evaluation of impact of using the Bethesda System for Reporting Thyroid Cytopathology: an institutional experience

INTRODUCTION

The Bethesda System for Reporting Thyroid Cytology (BSRTC) refines the definition of and provides specific diagnostic criteria for fine-needle aspiration (FNA) assessment of thyroid lesions. This study was conducted to prospectively evaluate the diagnostic and clinical impact of using BSRTC for management of thyroid lesions and to compare diagnostic performance of post-BSRTC period with that of pre-BSRTC period.

MATERIALS AND METHODS

The study included FNA specimens obtained in our institution 2.5 years prior to and 2.5 years after implementing BSRTC. Nondiagnostic rate, distribution of the diagnostic categories, rate of surgical follow-up, cytohistologic concordant rate, and risk of malignancy were calculated and compared between pre- and post-BSRTC periods.

RESULTS

In comparison to the pre-BSRTC period, the post-BSRTC period generated a lower nondiagnostic rate (19.9% versus 15.8%), a greater proportion of benign (65.3% versus 69.2%) and atypia of undetermined significance or follicular lesion of undetermined significance (4.4% versus 7.4%) in contrast with a decreased proportion of follicular neoplasm or suspicious for follicular neoplasm categories (5.6% versus 2.2%). Rate of surgical follow-up decreased for benign (13.8% versus 7.6%) and atypia of undetermined significance or follicular lesion of undetermined significance (61.5% versus 42.1%) categories, and overall surgical rate reduced (24.2% versus 18.1%). Implementation of BSRTC did not affect overall rate of cytohistologic concordance (78.4% versus 80.5%) or the overall rate of histologically proven malignancy (30.6 versus 36.9%), whereas the individual cytohistologic concordant rate and the malignant rate for each of the diagnostic categories did not differ between pre- and post-BSRTC.

CONCLUSIONS

The implementation of BSRTC resulted in a decreased overall surgical rate, particularly for benign and follicular lesion of undetermined significance categories, without affecting overall cytohistologic concordance and rate of malignancy.

SIVQ-aided laser capture microdissection: A tool for high-throughput expression profiling

Introduction:

Laser capture microdissection (LCM) facilitates procurement of defined cell populations for study in the context of histopathology. The morphologic assessment step in the LCM procedure is time consuming and tedious, thus restricting the utility of the technology for large applications.

Results:

Here, we describe the use of Spatially Invariant Vector Quantization (SIVQ) for histological analysis and LCM. Using SIVQ, we selected vectors as morphologic predicates that were representative of normal epithelial or cancer cells and then searched for phenotypically similar cells across entire tissue sections. The selected cells were subsequently auto-microdissected and the recovered RNA was analyzed by expression microarray. Gene expression profiles from SIVQ–LCM and standard LCM–derived samples demonstrated highly congruous signatures, confirming the equivalence of the differing microdissection methods.

Conclusion:

SIVQ–LCM improves the work-flow of microdissection in two significant ways. First, the process is transformative in that it shifts the pathologist's role from technical execution of the entire microdissection to a limited-contact supervisory role, enabling large-scale extraction of tissue by expediting subsequent semi-autonomous identification of target cell populations. Second, this work-flow model provides an opportunity to systematically identify highly constrained cell populations and morphologically consistent regions within tissue sections. Integrating SIVQ with LCM in a single environment provides advanced capabilities for efficient and high-throughput histological-based molecular studies.

Prediction of successful discectomy using MRI quantitation of dural sac and herniated disc dimensions

OBJECTIVE

To evaluate the ability of magnetic resonance imaging (MRI) quantitation of disc prolapse and dural sac to identify those who would benefit from discectomy.

METHODS

Thirty consecutive patients with disc herniation and leg pain who had MRI of lumbar spine and subsequently underwent discectomy were prospectively enrolled and compared with 30 controls. The anteroposterior (AP) diameter and the cross-sectional area of disc prolapse and of dural sac were measured. The ratios of AP diameters and cross-sectional areas were calculated. The measurements were correlated with the relief of symptoms based on a visual analogue scale assessment preoperatively and 1 week postoperatively.

RESULTS

All patients preoperatively had a pain score of seven or higher (mean +/- SD = 7.9 +/- 0.3) and postoperatively a score of < or = 2(mean +/- SD = 1.1 +/- 0.2). The AP diameter of disc prolapse and the ratio of AP diameters demonstrated the highest sensitivity and specificity: an AP diameter of 3.3 mm was 99% sensitive and specific and a ratio of the AP diameters of 0.37 was 100% sensitive and 99% specific.

CONCLUSION

Quantitative measurements of MRI can improve significantly the ability to identify the patients who would benefit from discectomy.

Wall shear stress in intracranial self-expanding stents studied using ultra-high-resolution 3D reconstructions

BACKGROUND AND PURPOSE

Imaging of intracranial stents is constrained by resolution limits of current clinical imaging techniques providing insufficient visualization of deployment details and impeding its use for computational hemodynamic (CHD) simulations. The purpose of our study was to evaluate whether ultra-high-resolution MicroCT scans can illuminate detailed aspects of realistic in vitro stent deployment and serve as a reliable basis for CHD simulations of blood flow through self-expanding intracranial stents.

MATERIALS AND METHODS

A Neuroform Treo (NF) stent and an Enterprise (ENT) stent were deployed in identical straight polytetrafluoroethylene tubes filled with contrast agent. MicroCT scans were obtained at a spatial resolution of 14 mum and used for ultra-high-resolution 3D reconstructions. CHD simulations were performed, with particular emphasis on local flow behavior near the wall and struts. Flow differences between the geometrically different stents were studied.

RESULTS

MicroCT data revealed strut prolapse near the markers for the closed-cell design (ENT) stent and at some of the unconnected vertices of the open-cell design (NF) stent, which also showed some misalignments. CHD simulations showed that reverse wall shear stress occurred near some of the strut vertices and markers for the NF but only near the markers for the ENT.

CONCLUSIONS

This work demonstrates the feasibility of ultra-high-resolution MicroCT imaging in elucidating important details of intracranial stent deployment as a basis for accurate CHD simulations and in enabling a structural and hemodynamic study of realistically deployed stents with different geometry and design.

Cytotoxic T cell immunity against telomerase reverse transcriptase in humans

Telomerase is a ribonucleoprotein enzyme which has been linked to malignant transformation in human cells. Telomerase activity is increased in the vast majority of human tumors, making its gene product the first molecule common to all human tumors. The generation of endogenously processed telomerase peptides bound to Class I MHC molecules could therefore target cytotoxic T lymphocytes (CTL) to tumors of different origins. This could advance vaccine therapy against cancer provided that precursor CTL recognizing telomerase peptides in normal adults and cancer patients can be expanded through immunization. We demonstrate here that the majority of normal individuals and patients with prostate cancer immunized in vitro against two HLA-A2.1 restricted peptides from telomerase reverse transcriptase (hTRT) develop hTRT-specific CTL. This suggests the existence of precursor CTL for hTRT in the repertoire of normal individuals and in cancer patients. Most importantly, the CTL of cancer patients specifically lysed a variety of HLA-A2(+) cancer cell lines, demonstrating immunological recognition of endogenously processed hTRT peptides. Moreover, in vivo immunization of HLA-A2.1 transgenic mice generated a specific CTL response against both hTRT peptides. Based on the induction of CTL responses in vitro and in vivo, and the susceptibility to lysis of tumor cells of various origins by hTRT CTL, we suggest that hTRT could serve as a universal cancer vaccine for humans.

Synthesis and structure-activity relationships of 3,7-dimethyl-1-propargylxanthine derivatives, A2A-selective adenosine receptor antagonists

A series of 8-substituted derivatives of 3,7-dimethyl-1-propargylxanthine (DMPX) was synthesized and investigated as A2A adenosine receptor antagonists. Different synthetic strategies for the preparation of DMPX derivatives and analogues were explored. A recently developed synthetic procedure starting from 3-propargyl-5,6-diaminouracil proved to be the method of choice for the preparation of this type of xanthine derivatives. The novel compounds were investigated in radioligand binding studies at the high-affinity adenosine receptor subtypes A1 and A2A and compared with standard A2A adenosine receptor antagonists. Structure-activity relationships were analyzed in detail. 8-Styryl-substituted DMPX derivatives were identified that exhibit high affinity and selectivity for A2A adenosine receptors, including 8-(m-chlorostyryl)-DMPX (CS-DMPX, Ki A2A = 13 nM, 100-fold selective), 8-(m-bromostyryl)-DMPX (BS-DMPX, Ki A2A = 8 nM, 146-fold selective), and 8-(3,4-dimethoxystyryl)-DMPX (Ki A2A = 15 nM, 167-fold selective). These and other novel compounds are superior to the standard A2A adenosine receptor antagonists KF17837 (4) and CSC (5) with respect to A2A affinity and/or selectivity.

Reinterpretation of endothelial cell gaps induced by vasoactive mediators in guinea-pig, mouse and rat: many are transcellular pores

1. In response to vascular permeabilizing agents, particulates circulating in the blood extravasate from venules through endothelial cell openings. These openings have been thought to be intercellular gaps though recently this view has been challenged. 2. To define the precise location of endothelial cell gaps, serial section electron microscopy and three-dimensional reconstructions were performed in skin and cremaster muscle of guinea-pigs, mice and rats injected locally with agents that enhance microvascular permeability: vascular permeability factor, histamine or serotonin. Ferritin and colloidal carbon were injected intravenously as soluble and particulate macromolecular tracers, respectively. 3. Both tracers extravasated from venules in response to all three permeability enhancing agents. The soluble plasma protein ferritin extravasated primarily by way of vesiculo-vacuolar organelles (VVOs), interconnected clusters of vesicles and vacuoles that traverse venular endothelium. In contrast, exogenous particulates (colloidal carbon) and endogenous particulates (erythrocytes, platelets) extravasated from plasma through transendothelial openings. 4. Serial electron microscopic sections and three-dimensional reconstructions demonstrated that eighty-nine of ninety-two openings were transendothelial pores, not intercellular gaps. Pore frequency increased 3- to 33-fold when carbon was used as tracer. 5. The results demonstrate that soluble and particulate tracers extravasate from venules by apparently different transcellular pathways in response to vasoactive mediators. However, some pores may derive from rearrangements of VVOs.

Vesiculo-vacuolar organelles and the regulation of venule permeability to macromolecules by vascular permeability factor, histamine, and serotonin

In contrast to normal microvessels, those that supply tumors are strikingly hyperpermeable to circulating macromolecules such as plasma proteins. This leakiness is largely attributable to a tumor-secreted cytokine, vascular permeability factor (VPF). Tracer studies have shown that macromolecules cross tumor vascular endothelium by way of a recently described cytoplasmic organelle, the vesiculo-vacuolar organelle or VVO (VVOs are grapelike clusters of interconnected, uncoated vesicles and vacuoles). However, equivalent VVOs are also present in the cytoplasm of normal venules that do not leak substantial amounts of plasma protein. To explain these findings, we hypothesized that VPF increased the permeability of tumor blood vessels by increasing VVO function and that the VVOs of normal venules were relatively impermeable in the absence of VPF stimulation. To test this hypothesis, VPF was injected intradermally in normal animals after intravenous injection of a soluble macromolecular tracer, ferritin, whose extravasation could be followed by electron microscopy. VPF caused normal venules to leak ferritin, and, as predicted by our hypothesis, ferritin extravasated by way of VVOs, just as in hyperpermeable tumor microvessels. Ultrathin (14-nm) serial electron microscopic sections and computer-aided three-dimensional reconstructions better defined VVO structure. VVOs occupied 16-18% of endothelial cytoplasm in normal venules. Individual VVOs were clusters of numerous (median, 124) interconnected vesicles and vacuoles that formed complex pathways across venular endothelium with multiple openings to both luminal and abluminal surfaces. Like VPF, histamine and serotonin also stimulated ferritin extravasation across venules by way of VVOs. Together, these data establish VVOs as the major pathway by which soluble plasma proteins exit venules in response to several mediators that increase venular hyperpermeability. These same mediators also increased the extravasation of colloidal carbon, but this large particulate nonphysiological tracer exited venules primarily through endothelial gaps.

Healing segmental femoral defects in sheep using recombinant human bone morphogenetic protein

A middiaphyseal, 2.5-cm osteoperiosteal segmental defect stabilized by plate fixation was created in the right femur of 17 sheep. Four treatment groups were included: Group I, no implant; Group II, inactive bone matrix; Group III, recombinant human bone morphogenetic protein (rhBMP-2) mixed with inactive bone matrix; and Group IV, autogeneic bone graft. Three animals had early failure of fixation, and the remaining 14 were evaluated at three months after implantation. Radiographs showed bony union of all defects treated with rhBMP-2 (six) and a lack of bony union in the negative-control groups treated with no implant (three) and inactive bone matrix without BMP (three). Both defects treated with autograft healed. New bone formation in the defect sites treated with rhBMP-2 first appeared one month after implantation and had a mean bending strength (expressed as a percentage of the contralateral femur) of 91% +/- 59% (mean +/- standard deviation) for defects treated with BMP-2, 77% +/- 34% for autograft, 9% +/- 8% for no implant, and 11% +/- 7% for inactive matrix without BMP. Three sheep treated with rhBMP-2 had their fixation plates removed at four months and were followed for one year. Their bone defect sites remained solidly healed one year after the initial operation.