Stepwise Analysis of Resection Margin Impact on Survival and Distant Metastasis in Pancreatic Head Ductal Adenocarcinoma

The prognostic role of tumor cells in pancreatic ductal adenocarcinoma (PDAC) of the pancreatic head with direct microscopic infiltration (DMI) or in close proximity (≤1 mm) to the resection margin (RM) remains unclear. This single-center, retrospective study included specimens from 75 patients who underwent oncological resection of pancreatic head PDAC between February 2013 and July 2020. Two pathologists independently re-measured the distance between tumors and the multiple RMs. The impact of RM involvement for DMI, tumor cells within ≤1 mm, in general, and for individual RMs on overall survival (OS) and development of distant pulmonary (PM) and hepatic (HM) metastasis was analyzed. DMI of RMs was significantly associated with a shorter OS (median 5 vs 19 months, P = .02). The presence of tumor cells within ≤1 mm of RMs yielded a negative impact on OS with a trend toward significance (median 9 vs 21 months, P = .09). DMI and tumor cells within ≤1 mm of the pancreatic transection margin (PRM), individually, had a significant negative impact on OS (median 4 vs 19 months and 6 vs 19 months, P < .05), but not for any other individual RM. RM involvement of ≤1 mm of only the vascular circumferential resection margin (VCRM) resulted in a shorter time to HM development (P = 0.05). DMI of the posterior circumferential resection margin (PCRM) and VCRM, individually, showed shorter time to PM (P < .05). Potential clinical considerations include extended intraoperative evaluation of the PRM (1 mm) and intensified preoperative prediction of R1 resection as a basis for neoadjuvant therapy.

Mucosal microbiome of surgically treated terminal ileal Crohn's disease

Crohn's disease (CD) is associated with changes in the microbiome. The role of these changes and their precise association with disease course and activity remain ambiguous. In this prospective single-center study, the mucosal microbiome of surgical CD and non-CD patients was compared at the time of surgery. Microbial analyses were individually performed for ileal and colonic tissue samples obtained during surgery using 16S-rRNA-gene amplicon sequencing. Three groups out of the 46 included patients were formed: 1) a study group of CD of patients who received ileocecal resection due to CD involvement (CD study, n=10); 2) a control group of non-CD of patients who received intestinal resection due to indications other than CD (non-CD control, n=27); and 3) a second control group of CD who underwent resection of the intestine not affected by CD (CD non-affected control, n=9). Species richness and Shannon diversity were not different between all formed groups and regions analyzed (p>0.05). Several significant taxonomic differences were seen at the phylum-, order-, and genus-levels between the formed groups, such as a decrease of Firmicutes (phylum-level) and an increase of Bacteroides and Escherichia/Shigella/Pseudescherichia (genus-level) in CD study - colon vs. the non-CD control - colon (p ≤ 0.05). The CD non-affected control presented the largest amount of differentially abundant taxa in comparison to the other groups. These results underline that CD is accompanied by changes in affected and non-affected intestinal regions compared to non-CD controls. This study contributes the mucosal microbiome of a well-defined subset of surgical CD patients without confounding aspects of the fecal microbiome or regional microbial differences to the existing literature.

Diagnostic performance of Node Reporting and Data System (Node-RADS) for regional lymph node staging of gastric cancer by CT

OBJECTIVES

Diagnostic performance of imaging for regional lymph node assessment in gastric cancer is still limited, and there is a lack of consensus on radiological evaluation. At the same time, there is an increasing demand for structured reporting using Reporting and Data Systems (RADS) to standardize oncological imaging. We aimed at investigating the diagnostic performance of Node-RADS compared to the use of various individual criteria for assessing regional lymph nodes in gastric cancer using histopathology as reference.

METHODS

In this retrospective single-center study, consecutive 91 patients (median age, 66 years, range 33-91 years, 54 men) with CT scans and histologically proven gastric adenocarcinoma were assessed using Node-RADS assigning scores from 1 to 5 for the likelihood of regional lymph node metastases. Additionally, different Node-RADS criteria as well as subcategories of altered border contour (lobulated, spiculated, indistinct) were assessed individually. Sensitivity, specificity, and Youden's index were calculated for Node-RADS scores, and all criteria investigated. Interreader agreement was calculated using Cohen's kappa.

RESULTS

Among all criteria, best performance was found for Node-RADS scores ≥ 3 and ≥ 4 with a sensitivity/specificity/Youden's index of 56.8%/90.7%/0.48 and 48.6%/98.1%/0.47, respectively, both with substantial interreader agreement (κ = 0.73 and 0.67, p < 0.01). Among individual criteria, the best performance was found for short-axis diameter of 10 mm with sensitivity/specificity/Youden's index of 56.8%/87.0%/0.44 (κ = 0.65, p < 0.01).

CONCLUSION

This study shows that structured reporting of combined size and configuration criteria of regional lymph nodes in gastric cancer slightly improves overall diagnostic performance compared to individual criteria including short-axis diameter alone. The results show an increase in specificity and unchanged sensitivity.

CLINICAL RELEVANCE STATEMENT

The results of this study suggest that Node-RADS may be a suitable tool for structured reporting of regional lymph nodes in gastric cancer.

KEY POINTS

• Assessment of lymph nodes in gastric cancer is still limited, and there is a lack of consensus on radiological evaluation. • Node-RADS in gastric cancer improves overall diagnostic performance compared to individual criteria including short-axis diameter. • Node-RADS may be a suitable tool for structured reporting of regional lymph nodes in gastric cancer.

Feasibility of in vivo magnetic resonance elastography of mesenteric adipose tissue in Crohn's disease

Background

Although there is growing evidence that functional involvement and structural changes of mesenteric adipose tissue (MAT) influence the course of Crohn's disease (CD), its viscoelastic properties remain elusive. Therefore, we aimed to investigate the viscoelastic properties of MAT in CD using magnetic resonance elastography (MRE), providing reference values for CD diagnosis.

Methods

In this prospective proof-of-concept study, 31 subjects (CD: n=11; healthy controls: n=20) were consecutively enrolled in a specialized care center for inflammatory bowel diseases (tertiary/quaternary care). Inclusion criteria for the CD patients were a clinically and endoscopically established diagnosis of CD based on the clinical record, absence of other concurrent bowel diseases, scheduled surgery for the following day, and age of at least 18 years. Diagnoses were confirmed by histological analysis of the resected bowel the day after MRE. Subjects were investigated using MRE at 1.5-T with frequencies of 40-70 Hz. To retrieve shear wave speed (SWS), volumes of interest (VOIs) in MAT were drawn adjacent to CD lesions (MATCD) and on the opposite side without adjacent bowel lesions in patients (MATCD_Opp) and controls (MATCTRL). The presented study is not registered in the clinical trial platform.

Results

A statistically significant decrease in mean SWS of 7% was found for MATCD_Opp vs. MATCTRL (0.76±0.05 vs. 0.82±0.04 m/s, P=0.012), whereas there was a nonsignificant trend with an 8% increase for MATCD vs. MATCD_Opp (0.82±0.07 vs. 0.76±0.05 m/s, P=0.098) and no difference for MATCD vs. MATCTRL. Preliminary area under the receiver operating characteristic curve (AUC) analysis showed diagnostic accuracy in detecting CD to be excellent for SWS of MATCD_Opp [AUC =0.82; 95% confidence interval (CI): 0.64-0.96] but poor for SWS of MATCD (AUC =0.52; 95% CI: 0.34-0.73).

Conclusions

This study demonstrates the feasibility of MRE of MAT and presents preliminary reference values for CD patients and healthy controls. Our results motivate further studies for the biophysical characterization of MAT in inflammatory bowel disease.

cCPE Fusion Proteins as Molecular Probes to Detect Claudins and Tight Junction Dysregulation in Gastrointestinal Cell Lines, Tissue Explants and Patient-Derived Organoids

Claudins regulate paracellular permeability, contribute to epithelial polarization and are dysregulated during inflammation and carcinogenesis. Variants of the claudin-binding domain of Clostridium perfringens enterotoxin (cCPE) are highly sensitive protein ligands for generic detection of a broad spectrum of claudins. Here, we investigated the preferential binding of YFP- or GST-cCPE fusion proteins to non-junctional claudin molecules. Plate reader assays, flow cytometry and microscopy were used to assess the binding of YFP- or GST-cCPE to non-junctional claudins in multiple in vitro and ex vivo models of human and rat gastrointestinal epithelia and to monitor formation of a tight junction barrier. Furthermore, YFP-cCPE was used to probe expression, polar localization and dysregulation of claudins in patient-derived organoids generated from gastric dysplasia and gastric cancer. Live-cell imaging and immunocytochemistry revealed cell polarity and presence of tight junctions in glandular organoids (originating from intestinal-type gastric cancer and gastric dysplasia) and, in contrast, a disrupted diffusion barrier for granular organoids (originating from discohesive tumor areas). In sum, we report the use of cCPE fusion proteins as molecular probes to specifically and efficiently detect claudin expression, localization and tight junction dysregulation in cell lines, tissue explants and patient-derived organoids of the gastrointestinal tract.

Ex vivo magnetic resonance elastography of the small bowel in Crohn's disease

Background

Conventional magnetic resonance enterography is limited in differentiating active inflammation and fibrosis in lesions of Crohn's disease (CD), thus providing a restricted basis for therapeutic decision making. Magnetic resonance elastography (MRE) is an emerging imaging tool that differentiates soft tissues on the basis of their viscoelastic properties. The aim of this study was to demonstrate the feasibility of MRE in assessing the viscoelastic properties of small bowel samples and quantifying differences in viscoelastic properties between healthy ileum and ileum affected by CD.

Methods

Twelve patients (median age: 48 years) were prospectively enrolled in this study between September 2019 and January 2021. Patients of the study group (n=7) underwent surgery for terminal ileal CD, while patients of the control group (n=5) underwent segmental resection of healthy ileum. MRE of ileal tissue samples of surgical specimens from both groups was performed in a compact tabletop MRI scanner. Penetration rate (a in m/s) and shear wave speed (c in m/s) were determined as markers of viscosity and stiffness for vibration frequencies f of 1,000, 1,500, 2,000, 2,500, and 3,000 Hz. Additionally, damping ratio γ was deduced, and frequency-independent viscoelastic parameters were calculated using the viscoelastic spring-pot model.

Results

Penetration rate a was significantly lower in CD-affected ileum compared to healthy ileum for all vibration frequencies (P<0.05). Consistently, damping ratio γ was higher in CD-affected ileum, averaged over all frequencies (healthy: 0.58±0.12, CD: 1.04±0.55, P=0.03), as well as at 1,000 and 1,500 Hz individually (P<0.05). Spring-pot-derived viscosity parameter η was also significantly reduced in CD-affected tissue (2.62±1.37 versus 10.60±12.60 Pa·s, P=0.02). No significant difference was found for shear wave speed c between healthy and diseased tissue at any frequency (P>0.05).

Conclusions

MRE of surgical small bowel specimens is feasible, allowing determination of viscoelastic properties and reliable quantification of differences in viscoelastic properties between healthy and CD-affected ileum. Thus, the results presented here are an important prerequisite for future studies investigating comprehensive MRE mapping and exact histopathological correlation including characterization and quantification of inflammation and fibrosis in CD.

The Immune Checkpoint Landscape in Tumor Cells of Pancreatic Ductal Adenocarcinoma

Immune checkpoint therapy (ICT) has shown promising potential in the treatment of multiple solid tumors. However, the role of ICT in pancreatic ductal adenocarcinoma (PDAC) remains limited. Patterns of immune checkpoints (ICs) in PDAC represent the basis for establishing a potent ICT. The aim of this study is to create a profile of IC expression and its prognostic relevance in cancer cells of PDAC. Therefore, tumor cells from peripheral and central tissue microarray (TMA) spots from histologically confirmed PDAC of 68 patients after tumor resection were investigated in terms of expressions of TIM3, IDO, B7H4, LAG3, VISTA, and PD-L1 using immunohistochemistry. The presence of the respective ICs was compared to overall survival (OS). The presence of VISTA and PD-L1 significantly correlates with shorter OS (median OS: 22 months vs. 7 months and 22 months vs. 11 months, respectively, p < 0.05). For the presence of TIM3, IDO, B7H4, and LAG3, no difference in OS was observed (p > 0.05). The analysis of OS of combined subgroups for VISTA and PD-L1 (VISTA and PD-L1 neg., VISTA pos. and PD-L1 neg., VISTA neg. and PD-L1 pos., and VISTA and PD-L1 pos.) yielded overall statistical significance difference (p = 0.02). These results suggest that the presence of VISTA and PD-L1 is of prognostic relevance and potentially qualifies them as targets for ICT.

Prognostic value of primary tumor sidedness in patients with non-metastatic IBD related CRC - Is it the exception to the rule?

BACKGROUND

Although primary tumor sidedness (PTS) has a known prognostic role in sporadic colorectal cancer (CRC), its role in Inflammatory Bowel Disease related CRC (IBD-CRC) is largely unknown. Thus, we aimed to evaluate the prognostic role of PTS in patients with IBD-CRC.

METHODS

All eligible patients with surgically treated, non-metastatic IBD-CRC were retrospectively identified from institutional databases at ten European and Asian academic centers. Long term endpoints included recurrence-free (RFS) and overall survival (OS). Multivariable Cox proportional hazard regression as well as propensity score analyses were performed to evaluate whether PTS was significantly associated with RFS and OS.

RESULTS

A total of 213 patients were included in the analysis, of which 32.4% had right-sided (RS) tumors and 67.6% had left-sided (LS) tumors. PTS was not associated with OS and RFS even on univariable analysis (5-year OS for RS vs LS tumors was 68.0% vs 77.3%, respectively, p = 0.31; 5-year RFS for RS vs LS tumors was 62.8% vs 65.4%, respectively, p = 0.51). Similarly, PTS was not associated with OS and RFS on propensity score matched analysis (5-year OS for RS vs LS tumors was 82.9% vs 91.3%, p = 0.79; 5-year RFS for RS vs LS tumors was 85.1% vs 81.5%, p = 0.69). These results were maintained when OS and RFS were calculated in patients with RS vs LS tumors after excluding patients with rectal tumors (5-year OS for RS vs LS tumors was 68.0% vs 77.2%, respectively, p = 0.38; 5-year RFS for RS vs LS tumors was 62.8% vs 59.2%, respectively, p = 0.98).

CONCLUSIONS

In contrast to sporadic CRC, PTS does not appear to have a prognostic role in IBD-CRC.

Diagnostic Accuracy of Magnetic Resonance Enterography for the Evaluation of Active and Fibrotic Inflammation in Crohn’s Disease

Background

Despite the success of standard magnetic resonance enterography (MRE) in detecting Crohn’s disease (CD), characterization of strictures and, thus, therapy guidance is still limited. The aim of the study was to determine diagnostic accuracy of MRE in detecting or ruling out active inflammation and identifying fibrotic lesions in patients with terminal ileal CD with histopathology as reference.

Methods

Sixty-seven consecutive patients (median age 32 years, range 19–79 years) with terminal ileal CD were retrospectively enrolled between January 2015 and October 2020. The median interval between MRE and surgery was 9 days (range 0–86 days). Sensitivity, specificity, positive and negative predictive value (PPV and NPV, respectively), and area under the curve (AUC) with 95% confidence intervals (CIs) were calculated for the MRE-based AIS (acute inflammation score) using the histopathology of surgical specimens as the reference standard.

Results

Sensitivity, specificity, PPV, and NPV for detecting or ruling out active inflammation were 100% (CI, 0.94–1.00; 0.44–1.00; 0.93–1.00; 0.31–1.00) using an AIS cut-off of >4.1. AUC was 1.00 (CI, 1.00–1.00; p < 0.01). In all patients with fibrotic changes only and no active inflammation, AIS was <4.1. Interobserver agreement was substantial (κ = 0.65, p < 0.01).

Conclusion

Our study has shown an excellent diagnostic performance of the MRE-based AIS for determining whether active inflammation is present or lesions are due to chronic changes in ileal CD using the histopathology of surgical specimens as reference. These findings indicate that the MRE-based AIS allows a better determination of the inflammatory stage of terminal ileal CD, which facilitates the decision to perform surgery.

Rethinking the TNM Classification Regarding Direct Lymph Node Invasion in Pancreatic Ductal Adenocarcinoma

Simple Summary

Due to the rising burden of pancreatic cancer and poor outcomes, a precise, post-operative cancer staging for further and individualized therapy is needed. In the latest cancer classification system, the lymph node invasion mechanism is not addressed. Due to different outcomes regarding the lymph node invasion, we suggest a rethinking of the current system.

Abstract

Mechanisms of lymph node invasion seem to play a prognostic role in pancreatic ductal adenocarcinoma (PDAC) after resection. However, the 8th edition of the TNM classification of the American Joint Committee on Cancer (AJCC) does not consider this. The aim of this study was to analyse the prognostic role of different mechanisms of lymph node invasion on PDAC. One hundred and twenty-two patients with resected PDAC were examined. We distinguished three groups: direct (per continuitatem, Nc) from the main tumour, metastasis (Nm) without any contact to the main tumour, and a mixed mechanism (Ncm). Afterwards, the prognostic power of the different groups was analysed concerning overall survival (OS). In total, 20 patients displayed direct lymph node invasion (Nc = 16.4%), 44 were classed as Nm (36.1%), and 21 were classed as Ncm (17.2%). The difference in OS was not statistically significant between N0 (no lymph node metastasis, n = 37) and Nc (p = 0.134), while Nm had worse OS than N0 (p < 0.001). Direct invasion alone had no statistically significant effect on OS (p = 0.885). Redefining the N0 stage by including Nc patients showed a more precise OS prediction among N stages (p = 0.001 vs. p = 0.002). Nc was more similar to N0 than to Nm; hence, we suggest a rethinking of TNM classification based on the mechanisms of lymph node metastases in PDAC. Overall, this novel classification is more precise.

Peptide Signatures for Prognostic Markers of Pancreatic Cancer by MALDI Mass Spectrometry Imaging

Despite the overall poor prognosis of pancreatic cancer there is heterogeneity in clinical courses of tumors not assessed by conventional risk stratification. This yields the need of additional markers for proper assessment of prognosis and multimodal clinical management. We provide a proof of concept study evaluating the feasibility of Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) to identify specific peptide signatures linked to prognostic parameters of pancreatic cancer. On 18 patients with exocrine pancreatic cancer after tumor resection, MALDI imaging analysis was performed additional to histopathological assessment. Principal component analysis (PCA) was used to explore discrimination of peptide signatures of prognostic histopathological features and receiver operator characteristic (ROC) to identify which specific m/z values are the most discriminative between the prognostic subgroups of patients. Out of 557 aligned m/z values discriminate peptide signatures for the prognostic histopathological features lymphatic vessel invasion (pL, 16 m/z values, eight proteins), nodal metastasis (pN, two m/z values, one protein) and angioinvasion (pV, 4 m/z values, two proteins) were identified. These results yield proof of concept that MALDI-MSI of pancreatic cancer tissue is feasible to identify peptide signatures of prognostic relevance and can augment risk assessment.

Feasibility of Intestinal MR Elastography in Inflammatory Bowel Disease

BACKGROUND

While MR enterography allows detection of inflammatory bowel disease (IBD), the findings continue to be of limited use in guiding treatment-medication vs. surgery.

PURPOSE

To test the feasibility of MR elastography of the gut in healthy volunteers and IBD patients.

STUDY TYPE

Prospective pilot.

POPULATION

Forty subjects (healthy volunteers: n = 20, 37 ± 14 years, 10 women; IBD patients: n = 20 (ulcerative colitis n = 9, Crohn's disease n = 11), 41 ± 15 years, 11 women).

FIELD STRENGTH/SEQUENCE

Multifrequency MR elastography using a single-shot spin-echo echo planar imaging sequence at 1.5 T with drive frequencies of 40, 50, 60, and 70 Hz.

ASSESSMENT

Maps of shear-wave speed (SWS, in m/s) and loss angle (φ, in rad), representing stiffness and solid-fluid behavior, respectively, were generated using tomoelastography data processing. Histopathological analysis of surgical specimens was used as reference standard in patients.

STATISTICAL TESTS

Unpaired t-test, one-way analysis of variance followed by Tukey post hoc analysis, Pearson's correlation coefficient and area under the receiver operating characteristic curve (AUC) with 95%-confidence interval (CI). Significance level of 5%.

RESULTS

MR elastography was feasible in all 40 subjects (100% technical success rate). SWS and φ were significantly increased in IBD by 21% and 20% (IBD: 1.45 ± 0.14 m/s and 0.78 ± 0.12 rad; healthy volunteers: 1.20 ± 0.14 m/s and 0.65 ± 0.06 rad), whereas no significant differences were found between ulcerative colitis and Crohn's disease (P = 0.74 and 0.90, respectively). In a preliminary assessment, a high diagnostic accuracy in detecting IBD was suggested by an AUC of 0.90 (CI: 0.81-0.96) for SWS and 0.84 (CI: 0.71-0.95) for φ.

DATA CONCLUSION

In this pilot study, our results demonstrated the feasibility of MR elastography of the gut and showed an excellent diagnostic performance in predicting IBD.

EVIDENCE LEVEL

1 TECHNICAL EFFICACY: Stage 1.

Accuracy of various criteria for lymph node staging in ductal adenocarcinoma of the pancreatic head by computed tomography and magnetic resonance imaging

BACKGROUND

Lymph node staging of ductal adenocarcinoma of the pancreatic head (PDAC) by cross-sectional imaging is limited. The aim of this study was to determine the diagnostic accuracy of expanded criteria in nodal staging in PDAC patients.

METHODS

Sixty-six patients with histologically confirmed PDAC that underwent primary surgery were included in this retrospective IRB-approved study. Cross-sectional imaging studies (CT and/or MRI) were evaluated by a radiologist blinded to histopathology. Number and size of lymph nodes were measured (short-axis diameter) and characterized in terms of expanded morphological criteria of border contour (spiculated, lobulated, and indistinct) and texture (homogeneous or inhomogeneous). Sensitivities and specificities were calculated with histopathology as a reference standard.

RESULTS

Forty-eight of 66 patients (80%) had histologically confirmed lymph node metastases (pN+). Sensitivity, specificity, and Youden's Index for the criterion "size" were 44.2%, 82.4%, and 0.27; for "inhomogeneous signal intensity" 25.6%, 94.1%, and 0.20; and for "border contour" 62.7%, 52.9%, and 0.16, respectively. There was a significant association between the number of visible lymph nodes on preoperative CT and lymph node involvement (pN+, p = 0.031).

CONCLUSION

Lymph node staging in PDAC is mainly limited due to low sensitivity for detection of metastatic disease. Using expanded morphological criteria instead of size did not improve regional nodal staging due to sensitivity remaining low. Combining specific criteria yields improved sensitivity with specificity and PPV remaining high.

Novel methods for in vitro modeling of pancreatic cancer reveal important aspects for successful primary cell culture

Background

Pancreatic cancer remains a fatal disease. Experimental systems are needed for personalized treatment strategies, drug testing and to further understand tumor biology. Cell cultures can serve as an excellent preclinical platform, but their generation remains challenging.

Methods

Tumor cells from surgically removed pancreatic ductal adenocarcinoma (PDAC) specimens were cultured under novel protocols. Cellular growth and composition were analyzed and culture conditions were continuously optimized. Characterization of cell cultures and primary tumors was performed via hematoxylin and eosin (HE) and immunofluorescence (IF) staining.

Results

Protocols for two- and three-dimensional PDAC primary cell cultures could successfully be established. Primary cell culture depended on dissociation techniques, growth factor supplementation and extracellular matrix components containing Matrigel being crucial for the transformation to three-dimensional PDAC organoids. The generated cultures showed to be highly resemblant to established PDAC primary cell cultures. HE and IF staining for cell culture and corresponding primary tumor characterization could successfully be performed.

Conclusions

The work presented herein shows novel and effective methods to successfully establish primary PDAC cell cultures in a distinct time frame. Factors contributing to cell growth and differentiation could be identified with important implications for further primary cell culture protocols. The established protocols might serve as novel tools in personalized tumor therapy.

Accuracy of Various Lymph Node Staging Criteria in Rectal Cancer with Magnetic Resonance Imaging

INTRODUCTION

The accuracy of pretherapeutic staging of lymph nodes (LN) in rectal cancer by MR imaging (MRI) is still limited. The aim of the study was to determine the sensitivity and specificity of different morphological criteria in nodal staging.

MATERIAL AND METHODS

LN were analyzed by MRI in 60 patients with rectal cancer and primary surgery. Signs of LN metastasis (cN+) were spiculated/indistinct border contour, inhomogeneous signal intensity, or LN size. The accuracy of these signs for clinical LN staging was analyzed with conclusive postoperative histological lymph node examination.

RESULTS

68.3% of patients with nodal metastasis (pN+) were correctly identified by size with a cutoff value of 7.2 mm. This, however, was not inferior to the 76.7% identified using the inhomogeneous morphological signal intensity and spiculated/indistinct border contour criteria (p = 0.096). 3.3 versus 5% were overstaged, and 28.3 versus 18.3% understaged by these criteria. Sensitivities/specificities for (a) size, (b) spiculated/indistinct border contour, and (c) inhomogeneous signal intensity and spiculated/indistinct border contour were (a) 32%/94%, (b) 56%/86%, and (c) 56%/91%, respectively.

CONCLUSIONS

The accuracy of LN staging in rectal cancer was not improved by morphological criteria. These limitations suggest being reticent when recommending neoadjuvant chemoradiation merely based on preoperative positive LN staging.