LekCheck: A Prospective Study to Identify Perioperative Modifiable Risk Factors for Anastomotic Leakage in Colorectal Surgery

OBJECTIVE

To assess potentially modifiable perioperative risk factors for anastomotic leakage in adult patients undergoing colorectal surgery.

SUMMARY BACKGROUND DATA

Colorectal anastomotic leakage (CAL) is the single most important denominator of postoperative outcome after colorectal surgery. To lower the risk of CAL, the current research focused on the association of potentially modifiable risk factors, both surgical and anesthesiological.

METHODS

A consecutive series of adult patients undergoing colorectal surgery with primary anastomosis was enrolled from January 2016 to December 2018. Fourteen hospitals in Europe and Australia prospectively collected perioperative data by carrying out the LekCheck, a short checklist carried out in the operating theater as a time-out procedure just prior to the creation of the anastomosis to check perioperative values on 1) general condition 2) local perfusion and oxygenation, 3) contamination, and 4) surgery related factors. Univariate and multivariate logistic regression analysis were performed to identify perioperative potentially modifiable risk factors for CAL.

RESULTS

There were 1562 patients included in this study. CAL was reported in 132 (8.5%) patients. Low preoperative hemoglobin (OR 5.40, P < 0.001), contamination of the operative field (OR 2.98, P < 0.001), hyperglycemia (OR 2.80, P = 0.003), duration of surgery of more than 3 hours (OR 1.86, P = 0.010), administration of vasopressors (OR 1.80, P = 0.010), inadequate timing of preoperative antibiotic prophylaxis (OR 1.62, P = 0.047), and application of epidural analgesia (OR, 1.81, P = 0. 014) were all associated with CAL.

CONCLUSIONS

This study identified 7 perioperative potentially modifiable risk factors for CAL. The results enable the development of a multimodal and multidisciplinary strategy to create an optimal perioperative condition to finally lower CAL rates.

Locoregional recurrences after transanal total mesorectal excision of rectal cancer during implementation

Background

Transanal total mesorectal excision (TaTME) has been proposed as an approach in patients with mid and low rectal cancer. The TaTME procedure has been introduced in the Netherlands in a structured training pathway, including proctoring. This study evaluated the local recurrence rate during the implementation phase of TaTME.

Methods

Oncological outcomes of the first ten TaTME procedures in each of 12 participating centres were collected as part of an external audit of procedure implementation. Data collected from a cohort of patients treated over a prolonged period in four centres were also collected to analyse learning curve effects. The primary outcome was the presence of locoregional recurrence.

Results

The implementation cohort of 120 patients had a median follow up of 21·9 months. Short‐term outcomes included a positive circumferential resection margin rate of 5·0 per cent and anastomotic leakage rate of 17 per cent. The overall local recurrence rate in the implementation cohort was 10·0 per cent (12 of 120), with a mean(s.d.) interval to recurrence of 15·2(7·0) months. Multifocal local recurrence was present in eight of 12 patients. In the prolonged cohort (266 patients), the overall recurrence rate was 5·6 per cent (4·0 per cent after excluding the first 10 procedures at each centre).

Conclusion

TaTME was associated with a multifocal local recurrence rate that may be related to suboptimal execution rather than the technique itself. Prolonged proctoring, optimization of the technique to avoid spillage, and quality control is recommended.

Use of an antibody-drug conjugate targeting tissue factor to induce complete tumor regression in xenograft models with heterogeneous target expression

3066

Background: Tissue factor (TF) is the main initiator of coagulation, that starts when circulating factor VII(a) (FVII(a)) binds membrane bound TF. In addition, the TF:FVIIa complex can initiate a pro-angiogenic signaling pathway by activation of PAR-2. TF is aberrantly expressed in many solid tumors, and expression has been associated with poor prognosis. TF-011-vcMMAE, an antibody-drug conjugate (ADC) under development for the treatment of solid tumors, is composed of a human TF specific antibody (TF-011), a proteaseEcleavable valine-citrulline (vc) linker and the microtubule disrupting agent monomethyl auristatin E (MMAE). Methods: TF-011 and TF-011-vcMMAE were functionally characterized using in vitro assays. In vivo anti-tumor activity of TF-011-vcMMAE was assessed in human biopsy derived xenograft models, which genetically and histologically resemble human tumors. TF expression in xenografts was assessed using immunohistochemistry. Results: TF-011 inhibited TF:FVIIa induced intracellular signaling and efficiently killed tumor cells by antibody dependent cell-mediated cytoxicity in vitro, but showed only minor inhibition of TF procoagulant activity. TF-011 was rapidly internalized and targeted to the lysosomes, a prerequisite for intracellular MMAE release and subsequent tumor cell killing by the ADC. Indeed, TF-011-vcMMAE efficiently and specifically killed TF-positive tumors in vitro and in vivo. Importantly, TF-011-vcMMAE showed excellent anti-tumor activity in human biopsyEderived xenograft models derived from bladder, lung, pancreas, prostate, ovarian and cervical cancer (n=7). TF expression in these models was heterogeneous, ranging from 25-100% of tumor cells. Complete tumor regression was observed in all models, including cervical and ovarian cancer xenografts that showed only 25-50% TF positive tumor cells. Conclusions: TF-011-vcMMAE is a promising new ADC with potent anti-tumor activity in xenograft models that represent the heterogeneity of human tumors, including heterogeneous TF expression. The functional characteristics of TF-011-vcMMAE allow efficient tumor targeting, with minimal impact on coagulation.

N ε -(Carboxymethyl)lysine Depositions in Intramyocardial Blood Vessels in Human and Rat Acute Myocardial Infarction

Objective— Advanced glycation end products (AGEs), such as N ε -(carboxymethyl)lysine (CML), are implicated in vascular disease. We previously reported increased CML accumulation in small intramyocardial blood vessels in diabetes patients. Diabetes patients have an increased risk for acute myocardial infarction (AMI). Here, we examined a putative relationship between CML and AMI.

Methods and Results— Heart tissue was stained for CML, myeloperoxidase, and E-selectin in AMI patients (n=26), myocarditis patients (n=17), and control patients (n=15). In AMI patients, CML depositions were 3-fold increased compared with controls in the small intramyocardial blood vessels and predominantly colocalized with activated endothelium (E-selectin–positive) both in infarction and noninfarction areas. A trend of increased CML positivity of the intima of epicardial coronary arteries did not reach significance in AMI patients. In the rat heart AMI model, CML depositions were undetectable after 24 hours of reperfusion, but became clearly visible after 5 days of reperfusion. In line with an inflammatory contribution, human myocarditis was also accompanied by accumulation of CML on the endothelium of intramyocardial blood vessels.

Conclusions— CML, present predominantly on activated endothelium in small intramyocardial blood vessels in patients with AMI, might reflect an increased risk for AMI rather than being a result of AMI.

RT-PCR and immunohistochemical evaluation of sentinel lymph nodes after in vivo mapping with Patent Blue V in colon cancer patients

OBJECTIVE

Lymph node status is the most important predictive factor in the treatment of colorectal cancer. As sentinel lymph node (SLN) biopsy might upstage stage II colon cancer, it could have therapeutic consequences in the future. We investigated the feasibility of in vivo SLN detection with Patent Blue V dye and evaluated nodal microstaging and ultrastaging using cytokeratin immunohistochemistry and reverse transcriptase-polymerase chain reaction (RT-PCR).

MATERIAL AND METHODS

In 30 consecutive patients operated on for colon cancer, subserosal injection with Patent Blue dye was used for SLN detection in four different hospitals under the supervision of one regional coordinator. In searching for occult micrometastases, each SLN was examined at three levels. In tumor-negative SLNs at routine hematoxylin-eosin (H&E) examination (pN0) we performed CK8/CK18 immunohistochemistry (IHC) and RT-PCR for carcinoembryonic antigen (CEA).

RESULTS

The procedure was successful in 29 out of 30 patients (97%). The SLN was negative in 18 patients detected by H&E and IHC. In 16 patients the non-SLN was also negative, leading to a negative predictive value of 89% and an accuracy of 93%. Upstaging occurred in 10 patients (33%) - 7 by IHC and 3 by RT-PCR. Aberrant lymphatic drainage was seen in 3 patients (10%).

CONCLUSIONS

The SLN concept in colon carcinoma using Patent Blue V is feasible and accurate. It leads to upstaging of nodal status in 33% of patients when IHC and PCR techniques are combined. Therefore, the clinical value of SLN should be the subject of further studies.

Impact of antibody Fc carbohydrate fucosylation on antibody-dependent cellular cytotoxicity by HuMax-EGFr —A fully human epidermal growth factor receptor antibody

2543

Background: HuMax-EGFr - a human IgG1 EGF-R antibody in phase II clinical trials - was demonstrated to block EGF binding, to interfere with cellular signaling and to efficiently recruit effector cells for ADCC. Triggering of ADCC requires antibody binding to cellular Fc receptors which can be modulated by antibody glycosylation. Here, we investigated whether the glycosylation profile of HuMax-EGFr altered effector functions, and compared the contribution of mononuclear (MNC) and polymorphonuclear (PMN) cells for ADCC in human blood. Methods: Varying concentrations of two HuMax-EGFr batches, differing in the level of fucosylation of the complex-type oligosaccharides present in the Fc fragment, were compared in their capacity to kill EGF-R expressing tumor cells. Antibody binding and inhibition of proliferation was analyzed by flow cytometry and measuring vital cell mass, respectively. ADCC by isolated PMN, MNC and human whole blood was analyzed by chromium release assays. Results: Both batches of HuMax-EGFr bound similarly to target cells, and inhibited their proliferation to a similar extent. Low-fucosylated HuMax-EGFr demonstrated higher affinity for recombinant FcγRIIIa than fully fucosylated antibody. As expected, low-fucosylated antibody was significantly better in mediating ADCC by MNC (EC50 obtained at 10-fold lower antibody concentrations, p<0.05). In contrast, PMN-mediated ADCC was unaffected by the antibody fucosylation level. Importantly, whole blood ADCC assays also revealed little differences between both batches. ADCC was significantly enhanced by blood from G-CSF-primed patients, but again both high- and low-fucosylated antibody performed similarly. Conclusions: Both HuMax-EGFr batches were equally potent in inhibiting cell proliferation, and were highly active in triggering ADCC by MNC and PMN. Differences in fucosylation of Fc carbohydrate affected MNC-mediated lysis, whereas PMN- and whole blood-mediated cell killing were only minimally affected. Thus, fucosylation of antibody Fc may only prove critical for therapeutic antibodies which predominantly recruit NK cells for ADCC, while it may be less relevant for PMN-recruiting antibodies.

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Hybrid zones between invasive Rorippa austriaca and native R. sylvestris (Brassicaceae) in Germany: ploidy levels and patterns of fitness in the field

Hybrid zones may serve as natural laboratories for evolutionary studies. One common viewpoint is that hybrids may always be less fit than their parents due to genetic discontinuities. An alternative idea is that genotype-environment interactions influence the outcome of natural hybridization. Our comparative study of two different natural hybrid zones between the invasive diploid Rorippa austriaca and the native polyploid R. sylvestris in Germany identified the ploidy level as a major determinant of hybrid fitness. Different ploidy levels and patterns of fitness were detected in different hybrid zones. In one hybrid zone (Mülheim, Ruhr valley) hybrids were pentaploid and showed a relatively high seed set, whereas in the second hybrid zone (Randersacker, Main valley) hybrids were triploid and displayed extremely low fitness values. Analyses of fitness values in different natural hybrid zones between the same two species may lead to very different conclusions about the evolutionary significance of natural hybridization.

Hybridization and Rorippa austriaca (Brassicaceae) invasion in Germany

Introgressive hybridization between the invasive Rorippa austriaca and the native R. sylvestris in Germany has been studied using chloroplast DNA (trnL intron) and amplified fragment length polymorphism. Three hybrid zones between the invasive and native species were located in the Ruhr Valley (Mülheim) and at the River Main near Würzburg (Randersacker, Winterhausen). In each hybrid zone hybridization was indicated by additivity of region-specific amplified fragment length polymorphism markers proving independent hybridization events. The hybrids were either morphologically intermediate (R. x armoracioides) or were close to R. sylvestris. The trnL intron of R. austriaca is characterized by a species-specific deletion. This diagnostic chloroplast marker of R. austriaca was detected in three individuals of R. sylvestris providing evidence for introgression of the invasive chloroplast into the native species. Bidirectional introgression of R. austriaca markers into R. sylvestris and of R. sylvestris markers into R. austriaca was detected in the amplified fragment length polymorphism analysis. Some of the invasive R. austriaca populations showed high within-population variation. A possible association among introgression, within-population variation and invasion success is discussed. The morphologically intermediate hybrid R. x armoracioides is currently spreading in northern Germany. It forms large populations without its parent species R. austriaca and R. sylvestris. It is concluded that hybridization between invasive R. austriaca and native R. sylvestris may lead to the evolution of a new invasive species R. x armoracioides.

Introgressive hybridization in Rorippa (Brassicaceae): gene flow and its consequences in natural and anthropogenic habitats

Introgressive hybridization between three Rorippa species (R. amphibia, R. palustris and R. sylvestris) in northern Germany has been studied using isozymes and noncoding chloroplast DNA (trnL/F spacer). Our results provide substantial evidence for different patterns of gene flow in natural and in anthropogenic environments. Hybridization and bi-directional introgression (chloroplast DNA and allozymes) between R. amphibia and R. sylvestris were detected at the river Elbe, which is one of the last rivers in Central Europe showing a natural dynamic of erosion and sedimentation. The natural dynamic of the Elbe leads to periodic habitat disturbance and the temporal breakdown of ecological isolation barriers between R. amphibia and R. sylvestris. However, the high dynamic does not provide the opportunity for persistence of the morphologically intermediate hybrid R. x anceps (R. amphibia x R. sylvestris). We did not find hybrid zones between R. amphibia and R. sylvestris in the more anthropogenic landscape of northwest Germany. However, contact zones between R. amphibia and R. palustris were detected in drainage ditches in northwest Germany. We found substantial evidence for unidirectional introgression of R. palustris markers (chloroplast DNA and allozymes) into R. amphibia in the man-made habitats. The R. amphibia introgressants in the drainage ditches often showed strongly serrate upper cauline leaves instead of the entire upper cauline leaves typical for R. amphibia. We argue that landscape melioration in northwest Germany, particularly the creation of drainage ditches, favoured both hybrid-zone formation and ecotypic differentiation within R. amphibia.

New comprehensive denaturing-gradient-gel- electrophoresis assay for KRAS mutation detection applied to paraffin-embedded tumours

A comprehensive mutation detection assay is presented for the entire coding region and all splice site junctions of the KRAS oncogene. The assay is based on denaturing gradient gel electrophoresis and applicable to archival paraffin-embedded tumour material. All KRAS amplicons are analysed within two lanes of a DGGE gel under a single set of experimental conditions. Six known codon 12 mutations in genomic DNA from different paraffin-embedded tumours could readily be detected. When testing 35 paraffin-embedded Dukes' C colorectal carcinomas for unknown mutations, 12 tumours were found with mutations in codons 12 or 13. None of the tumours appeared to have a codon 61 mutation. In nine tumours, however, 11 additional sequence variations were found outside the hot-spot codons. None of these occurred in germline DNA from 57 individuals. Of these variations, three are considered as significant mutations, as they result in a non-conservative substitution of amino acid residues essential for the functioning of the KRAS protein. Thus, in total, 15 of the 35 Dukes' C tumours (43%) had a KRAS mutation of functional significance. Moreover, a novel exon 4B polymorphism was found to occur in 10 of the 35 tumours. The results of this study suggest that in restricting analysis of KRAS to hot-spot mutation sites only, significant information may be missed.

In vivo effects of Hb solutions on blood viscosity and rheologic behavior of RBCs: comparison with clinically used volume expanders

BACKGROUND

Hb-based oxygen carriers (HbOCs) have vasoactive effects that are still poorly understood. Factors known to have vasoactive effects, such as plasma, whole-blood viscosity, and the rheologic behavior of RBCs, are modulated by HbOCs in vitro, but few in vivo studies have been performed.

STUDY DESIGN AND METHODS

Rabbits were phlebotomized (30%) and resuscitated with unmodified stroma-free Hb (SFHb), dextran-tetracarboxylate-Hb (Dex-BTC-Hb), O-raffinose-polymerized Hb (OrpHb), HSA, or hydroxyethyl starch 200 (HES). Plasma viscosity was assessed with a capillary viscometer and whole-blood viscosity with a rotational viscosimeter. RBC aggregation kinetics were determined by analysis of back-scattered light in a rotating device.

RESULTS

As compared to that in the control RBC suspension, resuscitation with SFHb, OrpHb, or HSA decreased plasma and whole-blood viscosity as well as RBC aggregation; resuscitation with Dex-BTC-Hb increased whole-blood viscosity at low shear rates as well as RBC aggregation, whereas that with HES decreased whole-blood viscosity but increased RBC aggregation.

CONCLUSION

HbOCs have different rheologic effects in vitro and in vivo. There are marked differences among the Hb solutions in their in vivo effects on viscosity and RBC rheologic behavior (especially at low shear rates encountered in the venous circulation and the microcirculation), which may be related to the chemical modifications applied to hemoprotein. These results could contribute to an understanding of the vasoactive effects of HbOCs.

Comprehensive TP53-denaturing gradient gel electrophoresis mutation detection assay also applicable to archival paraffin-embedded tissue

A comprehensive mutation detection assay is described for the entire coding region and all splice site junctions of TP53. The assay is based on denaturing gradient gel electrophoresis, which follows either multiplex polymerase chain reaction (PCR) applied to DNA extracted from fresh or frozen tissue samples or nested PCR applied to DNA extracted from paraffin-embedded tissue samples. In both instances, the analysis can be performed under a single set of conditions. When testing the assay on DNA from cultured lung cancer cell lines and from paraffin-embedded Dukes C colorectal carcinomas, significant TP53 mutations were observed at high frequencies in 15 of 16 lung cancer cell lines (94%) and in 21 of 30 paraffin-embedded tissue samples of Dukes C colorectal carcinomas (70%). A substantial proportion of these significant mutations occurred outside the evolutionary conserved region of TP53 in 4 of 16 lung cancer cell lines (25%) and in 11 of 30 paraffin-embedded colorectal carcinomas (37%). This underscores the importance of a comprehensive TP53 mutation analysis in those instances that TP53 mutation is taken into account for diagnostic and prognostic purposes.