Forceps Biopsies Are Not Reliable in the Workup of Large Colorectal Lesions Referred for Endoscopic Resection: Should They Be Abandoned?

Diagnostic yield and repeat biopsies in rectal and nonrectal colorectal adenocarcinoma: Are we hedging on rectal biopsies?

Patients with rectal cancer undergo more repeat biopsies compared to those with nonrectal colon cancer prior to management. We investigated the factors driving the higher frequency of repeat biopsies in patients with rectal cancer. We compared clinicopathologic features of diagnostic and nondiagnostic (in regard to invasion) rectal (n = 64) and colonic (n = 57) biopsies from colorectal cancer patients and characterized corresponding resections. Despite similar diagnostic yield, repeat biopsy was more common in rectal carcinoma, especially in patients receiving neoadjuvant therapy (p < 0.05). The presence of desmoplasia (odds ratio 12.9, p < 0.05) was a strong predictor of making a diagnosis of invasion in both rectal and nonrectal colon cancer biopsies. Diagnostic biopsies had more desmoplasia, intramucosal carcinoma component and marked inflammation, and less low-grade dysplasia component (p < 0.05). Diagnostic yield of biopsy was higher for tumors with high-grade tumor budding, mucosal involvement by high-grade dysplasia/intramucosal carcinoma without low-grade dysplasia and diffuse surface desmoplasia irrespective of tumor location. Sample size, amount of benign tissue, appearance, and T stage did not affect diagnostic yield. Repeat biopsy of rectal cancer is primarily driven by management implications. Diagnostic yield in colorectal cancer biopsies is multifactorial and is not due to differing pathologists' diagnostic approach per tumor site. For rectal tumors, a multidisciplinary strategic approach is warranted to avoid repeat biopsy when unnecessary.

Discrepancy Between Forceps Biopsy and Resection in Colorectal Polyps: A 1686 Paired Screening-Therapeutic Colonoscopic Finding

Purpose

To identify pathology discrepancy between forceps biopsies and polypectomy specimens in colorectal polyps, as well as the reliability of biopsy-based treatment strategy.

Methods

All endoscopic polypectomy cases with forceps biopsies performed within 6 months were included in the study. The biopsies were compared with polypectomy specimens in terms of concordance of histological diagnosis. A logistic regression model was used to investigate the independent predictors of upgrade in histological diagnosis compared with concordance in histological diagnosis.

Results

A total of 1686 paired screening-therapeutic colonoscopies and 1739 paired biopsy-polypectomy specimens were enrolled in the study. The grade of dysplasia in 84.5% of biopsy specimens were concordant to polypectomy specimens, but this proportion decreased to 75.4% when the specimens were classified using tubular or villousness structure. 10.1% and 5.4% of biopsy specimens were upgraded and downgraded in assessing grade of dysplasia, respectively, while 14.3% and 10.3% of biopsy specimens were upgraded and downgraded in assessing tubular or villousness structure, respectively. In subgroup analysis stratified by size of polyps, 9.0% and 10.6% of biopsies obtained from polyps smaller than 10 mm were upgraded in assessing dysplasia and tubular or villousness structure, respectively. This proportion increased to 10.7% and 21.3%, respectively, in biopsies obtained from polyps larger than 10 mm. Larger size of polyps and pedunculated polyps were associated with a higher incidence of upgrade in histological diagnosis. Nearly 25% of biopsy specimens with high-grade dysplasia were identified as adenocarcinoma in polypectomy specimens.

Conclusion

The concordance between biopsy and polypectomy specimens is not adequate. The biopsy-based treatment strategy is not reliable and should not be considered as an indicator for further treatment, particularly in large or pedunculated polyps.

Quantitative parameters of magnetic resonance imaging cannot predict human epidermal growth factor receptor 2 (HER2) status in rectal cancer

PURPOSE

To retrospectively investigate whether magnetic resonance imaging (MRI) quantitative parameters can differentiate human epidermal growth factor receptor 2 (HER2) status in rectal cancer.

MATERIALS AND METHODS

This study included 89 patients with surgically confirmed rectal cancer who underwent preoperative MRI from June 2014 to May 2019. Patients were divided into three groups: HER2 negative (HER2-Neg); HER2-low expression (HER2-L); and HER2 positive (HER2-Pos). Quantitative perfusion parameters derived from dynamic contrast-enhanced MRI (DCE-MRI) Tofts model (pharmacokinetic blood dual compartment model) were listed as follows: volume transfer constant (K^trans), rate constant (K_ep), and extracellular volume ratio (V_e). The mean, minimum, and maximum apparent diffusion coefficient (ADC) values at standard (800 s/mm²) b-values were obtained with diffusion-weighted imaging (DWI). Clinicopathologic characteristics and quantitative parameters were compared by Fisher's exact test and one-way analysis of variance (ANOVA), respectively.

RESULTS

The 89 patients included 52 (58.4%) with HER2-Neg, 31 (34.8%) with HER2-L, and 6 (6.8%) with HER2-Pos states. Fisher's exact test showed that clinicopathologic characteristics among the three groups were not significantly different (p = 0.281 to 1.000). Likewise, there were no associations between HER2 status and any quantitative parameters, including K^trans (p = 0.296), K_ep (p = 0.290), V_e (p = 0.184), ADC_mean (p = 0.181), ADC_min (p = 0.143), or ADC_max (p = 0.058).

CONCLUSION

Quantitative perfusion parameters (K^trans, K_ep, V_e) and ADC values were not able to discriminate HER2 status in patients with rectal cancer or evaluate treatment response in real time.

Systematic Review on Optical Diagnosis of Early Gastrointestinal Neoplasia

BACKGROUND

Meticulous endoscopic characterization of gastrointestinal neoplasias (GN) is crucial to the clinical outcome. Hereby the indication and type of resection (endoscopically, en-bloc or piece-meal, or surgical resection) are determined. By means of established image-enhanced (IEE) and magnification endoscopy (ME) GN can be characterized in terms of malignancy and invasion depth. In this context, the statistical evidence and accuracy of these diagnostic procedures should be elucidated. Here, we present a systematic review of the literature.

RESULTS

21 Studies could be found which met the inclusion criteria. In clinical prospective trials and meta-analyses, the diagnostic accuracy of >90% for characterization of malignant neoplasms could be documented, if ME with IEE was used in squamous cell esophageal cancer, stomach, or colonic GN.

CONCLUSIONS

Currently, by means of optical diagnosis, today's gastrointestinal endoscopy is capable of determining the histological subtype, exact lateral spread, and depth of invasion of a lesion. The prerequisites for this are an exact knowledge of the anatomical structures, the endoscopic classifications based on them, and a systematic learning process, which can be supported by training courses. More prospective clinical studies are required, especially in the field of Barrett's esophagus and duodenal neoplasia.

The Application of Core Needle Biopsy Through the Trocar Hole in the Surgical Operation of Endoscopically Unresectable Giant Colon Polyps: A Systematic Review Study

INTRODUCTION

The study aimed to investigate the application of core needle biopsy through the trocar hole during surgery on endoscopically unresectable giant colon polyps.

METHODS

The clinical data of 51 patients with endoscopically unresectable giant colon polyps from May 2016 to May 2020 were retrospectively analyzed. The primary observational outcomes were two comparative analyses of pathologic results, using the kappa index: comparison of the pathologic results from the preoperative colonoscopy and the postoperative pathologic results and comparison of the intraoperative pathologic results from core needle biopsy of the intestinal wall and the postoperative pathologic results. The secondary observational outcomes were duration of needle biopsy, operation duration, volume of intraoperative hemorrhage, rate of postoperative wound infection, rate of abdominal cavity infection, length of stay, and number and positivity of lymph node dissections after laparoscopic radical resection of colon cancer.

RESULTS

Poor consistency was found between the preoperative (colonoscopy) and postoperative pathologic results, with kappa = 0.222 (i.e., kappa < 0.4), P < 0.05. However, good consistency was found between the intraoperative (core needle biopsy) and postoperative pathologic results, with kappa = 0.923 (i.e., kappa ≥ 0.75), P < 0.05. The postoperative pathologic results were as follows: 7 cases of adenomatous polyps of the colon, 12 cases of low-grade intraepithelial neoplasia, 12 cases of high-grade intraepithelial neoplasia, and 25 cases of invasive colon cancer. There was no incision infection, no abdominal cavity infection or formation of an abdominal abscess, no anastomotic leakage, and no death for any of the 51 patients. Postoperative complications occurred in two cases (3.92%).

CONCLUSION

Biopsy through the trocar hole during laparoscopic surgery produced highly accurate pathologic results and was a fast, safe, and effective diagnostic method. Pathologic results from intraoperative biopsy could accurately determine the nature of colon polyps and provide a basis for choosing an appropriate surgical scheme.

Endoscopic management versus transanal surgery for early primary or early locally recurrent rectal neoplasms-a systematic review and meta-analysis

BACKGROUND

Both endoscopic techniques and transanal surgery are viable options that allow organ preservation for early rectal neoplasms. Whilst endoscopic approaches are less invasive and carry less morbidity, it is unclear whether they are as oncologically effective.

AIM

To compare endoscopic techniques with transanal surgery in the management of early rectal neoplasms.

METHODS

A systematic literature search was performed for randomised and observational studies comparing these techniques. The pre-specified main outcomes measured were en bloc and R0 resection rates and recurrence. Pair-wise meta-analysis was performed.

RESULTS

This review included 1044 patients. Transanal surgery had increased R0 resection rates (odds ratio (OR) 2.66; 95% CI 1.64; 4.31; p < 0.001) versus endoscopic management. The latter was associated with higher rates of incomplete resection (OR 2.25; 95% CI 1.14, 4.46; p = 0.02) and further intervention (OR 1.78; 95% CI 1.09, 2.88; p = 0.02). There was no difference in the rates of late recurrence (OR 1.01; 95% CI 0.53, 1.91; p = 0.99) or further major surgery (OR 0.87; 95% CI 0.39, 1.94; p = 0.73) between the groups. Endoscopic treatment was associated with a shorter operating time (weighted mean difference (WMD) - 12.08; 95% CI - 18.97, - 5.19; p < 0.001) and LOS (WMD - 1.94; 95% CI - 2.43, - 1.44; p < 0.001), as well as lower rates of urinary retention post-operatively (OR 0.12; 95% CI 0.02, 0.63; p = 0.01).

CONCLUSION

Endoscopic techniques should be favoured in the setting of benign early rectal neoplasms given their decreased morbidity and increased cost-effectiveness. However, where malignancy is suspected transanal surgery should be the preferred option given the superior R0 resection rate.

Characterizing MRI features of rectal cancers with different KRAS status

BACKGROUND

To investigate whether MRI findings, including texture analysis, can differentiate KRAS mutation status in rectal cancer.

METHODS

Totally, 158 patients with pathologically proved rectal cancers and preoperative pelvic MRI examinations were enrolled. Patients were stratified into two groups: KRAS wild-type group (KRAS^wt group) and KRAS mutation group (KRAS^mt group) according to genomic DNA extraction analysis. MRI findings of rectal cancers (including texture features) and relevant clinical characteristics were statistically evaluated to identify the differences between the two groups. The independent samples t test or Mann-Whitney U test were used for continuous variables. The differences of the remaining categorical polytomous variables were analyzed using the Chi-square test or Fisher exact test. A receiver operating characteristic (ROC) curve analysis was performed to evaluate the discriminatory power of MRI features. The area under the ROC curve (AUC) and the optimal cut-off values were calculated using histopathology diagnosis as a reference; meanwhile, sensitivity and specificity were determined.

RESULTS

Mean values of six texture parameters (Mean, Variance, Skewness, Entropy, gray-level nonuniformity, run-length nonuniformity) were significantly higher in KRAS^mt group compared to KRAS^wt group (p < 0.0001, respectively). The AUC values of texture features ranged from 0.703~0.813. In addition, higher T stage and lower ADC values were observed in the KRAS^mt group compared to KRAS^wt group (t = 7.086, p = 0.029; t = - 2.708, p = 0.008).

CONCLUSION

The MRI findings of rectal cancer, especially texture features, showed an encouraging value for identifying KRAS status.