Interobserver variability in the pathological assessment of malignant colorectal polyps

Variation in the detection of lymphovascular invasion in T1 colorectal cancer and its impact on treatment: A nationwide Dutch study

BACKGROUND

Lymphovascular invasion (LVI) plays an important role in determining the risk of lymph node metastasis (LNM) in T1 colorectal cancer (CRC) patients and influencing treatment decisions and patient outcomes.

OBJECTIVE

This study evaluated how the detection of LVI varies between Dutch laboratories and investigated its impact on the treatment and oncological outcomes of T1 CRC patients.

METHODS

Pathology reports and clinical data of T1 CRC patients who underwent local resection between 2015 and 2019 were obtained from the Dutch nationwide pathology databank (Palga cohort, n = 5513). Data on the standard of LVI diagnosis (H&E/Immunohistochemistry) were not available. We categorized laboratories as low, average, or high detectors and evaluated the impact of LVI detection practice on the surgical resection rate and the proportion of LNM-negative (LNM-) surgeries. In the second part of the study, we used the Dutch T1 CRC Working Group cohort (n = 1268) to evaluate the impact of LVI detection practice on cancer recurrences during follow-up. Multivariable logistic regression analyses and Cox proportional hazard regression were used to study the association between LVI detection practice and the outcomes.

RESULTS

In the PALGA cohort, the proportion of surgical resections after local resection of a T1 CRC was significantly higher among patients diagnosed by laboratories with a high LVI detection rate (high vs. low: adjusted OR [aOR] 1.87; 95% confidence interval [CI] 1.52-2.31) as was the proportion of LNM-surgeries (aOR 1.73; 95% CI 1.39-2.15). In the second cohort, no significant difference was observed in cancer recurrences among patients diagnosed in laboratories with high detection rates compared with low detection rates (aHR 2.23; 95% CI 0.94-5.23).

CONCLUSION

These findings suggest that a high detection rate of LVI does not improve oncological outcomes and may expose more patients to unnecessary oncological surgery, emphasizing the need for standardization of LVI diagnosis.

LC-MS/MS analysis reveals plasma protein signatures associated with lymph node metastasis in colorectal cancer

Objectives

Colorectal cancer (CRC) is a major global health concern, ranking as the third most common cancer and the fourth leading cause of cancer-related deaths worldwide. Currently, the diagnostic accuracy of Lymph node metastasis (LNM) is currently unsatisfactory. Therefore, there is an urgent need to develop a reliable tool that can accurately predict lymph node metastasis (LNM) in patients diagnosed with CRC.

Methods

We conducted an extensive proteomics investigation aimed at examining lymph node metastasis (LNM) in individuals diagnosed with colorectal cancer (CRC). In the discovery stage, employing a mass spectrometry-based proteomic approach, we analyzed a cohort of 60 colorectal cancer patients (NM=30, LNM=30), identifying distinct molecular profiles that differentiate patients with and without lymph node metastasis (LNM). Subsequently, we validated the protein classifier associated with lymph node metastasis.

Results

We elucidated a combinatorial predictive protein biomarker that can distinguish patients with and without lymph node metastasis by LC-MS/MS. The classifier achieved an area under the curve (AUC) of 0.892 (95% CI, 0.842-0.941), while in the testing cohort, it attained an AUC of 0.929 (95% CI, 0.824-1.000). Furthermore, the four protein markers demonstrated an AUC of 0.84 (95% CI, 0.783-0.890) in the validation cohort. Additionally, we categorized patients into three types based on immunophenotyping. Type 1 primarily consisted of patients with negative lymph node metastasis (NM), characterized by immune cells such as NK cells, CD4 T effector memory cells, and memory B cells. Type 2 mainly included patients with positive lymph node metastasis (LNM), characterized by immune cells such as mesangial cells, epithelial cells, and mononuclear cells. In Type 1, a prominent upregulation observed in immune inflammation, as well as in glucose and lipid metabolism. In Type 2, significant upregulation was evident in pathways such as pyrimidine metabolism and cell cycle regulation. The findings of this study suggest that immune mechanisms may exert a pivotal role in the process of lymph node metastasis in CRC.

Conclusions

Here, we present plasma protein signatures associated with lymph node metastasis in colorectal cancer (CRC). However, further validation across multiple centers is necessary to generalize these findings.

Histopronostic factors in superficial colorectal adenocarcinomas treated by endoscopy: reproducibility and impact of immunohistochemistry and digital pathology

Endoscopic dissection is the first-choice treatment for superficial pT1 colorectal adenocarcinoma (sCRC). Complementary surgery decision is influenced by histopronostic factors. Prognostic significance and reproducibility of each factor are not well established. The role of immunohistochemistry (IHC) and digital pathology in this context is unknown. Our aims were (1) to evaluate each histopronostic factor reproducibility comparing HES and IHC ± digital pathology and (2) to evaluate how the different techniques would affect indications for additional surgery. We performed a single-centre retrospective study of 98 patients treated between 2010 and 2019 in Hospices Civils de Lyon, France. We analyzed physical or digital slides of HES and keratin/desmin immunostaining of 98 sCRC dissection specimens. Three pathologists evaluate the histopronostic factors including submucosal invasion depth (SMI) measured using different recommended methods. Assessment of SMI with Ueno or JSCCR methods showed good to excellent interobserver reproducibility (IOR) (ICCs of 0.858 to 0.925) using HES staining and IHC. Assessment of budding on HES sections was poorly reproducible compared to IHC which exhibit moderate IOR (κ = 0.714). IHC increased high-grade budding detection. For lymphovascular invasion and poor differentiation, the IOR was poor (κ = 0.141, 0.196 and 0.313 respectively). IHC gave a better reproducibility for further treatment indication according to JSCCR criteria (κ = 0.763) or forthcoming European guidelines (κ = 0.659). Digital pathology was equivalent to the microscope for all analyses. Histopronostic factor reproducibility in sCRC is moderate. Immunohistochemistry may facilitate the evaluation of certain criteria and improve the reproducibility of treatment decisions.

Use of artificial intelligence for the prediction of lymph node metastases in early-stage colorectal cancer: systematic review

BACKGROUND

Risk evaluation of lymph node metastasis for early-stage (T1 and T2) colorectal cancers is critical for determining therapeutic strategies. Traditional methods of lymph node metastasis prediction have limited accuracy. This systematic review aimed to review the potential of artificial intelligence in predicting lymph node metastasis in early-stage colorectal cancers.

METHODS

A comprehensive search was performed of papers that evaluated the potential of artificial intelligence in predicting lymph node metastasis in early-stage colorectal cancers. Studies were appraised using the Joanna Briggs Institute tools. The primary outcome was summarizing artificial intelligence models and their accuracy. Secondary outcomes included influential variables and strategies to address challenges.

RESULTS

Of 3190 screened manuscripts, 11 were included, involving 8648 patients from 1996 to 2023. Due to diverse artificial intelligence models and varied metrics, no data synthesis was performed. Models included random forest algorithms, support vector machine, deep learning, artificial neural network, convolutional neural network and least absolute shrinkage and selection operator regression. Artificial intelligence models' area under the curve values ranged from 0.74 to 0.9993 (slide level) and 0.9476 to 0.9956 (single-node level), outperforming traditional clinical guidelines.

CONCLUSION

Artificial intelligence models show promise in predicting lymph node metastasis in early-stage colorectal cancers, potentially refining clinical decisions and improving outcomes.

PROSPERO REGISTRATION NUMBER

CRD42023409094.

The role of histology in the diagnosis of non-erosive reflux disease: A systematic review and meta-analysis

BACKGROUND AND PURPOSE

Non-erosive reflux disease (NERD) accounts for over half of all gastroesophageal reflux cases and is characterized by reflux symptoms with pathologic acid exposure on pH monitoring but no evidence of erosions on upper endoscopy. Ambulatory pH monitoring is limited by availability and patient tolerance. The utility of performing esophageal mucosal biopsies in diagnosing NERD is unclear. We conducted a systematic review and meta-analysis to determine the sensitivity of esophageal mucosal biopsies in diagnosing NERD.

METHODS

Data were obtained from Embase and Ovid MEDLINE from inception to April 2021. Studies were included if esophageal mucosal biopsies were taken and analyzed using conventional histopathologic analysis in symptomatic NERD patients. Relevant data was including histologic abnormalities and location of the biopsy. Sensitivity and specificity were calculated against healthy controls or those with functional heartburn.

RESULTS

The search yielded 2871 studies, of which 10 studies met our inclusion criteria and contained raw data. Histological abnormalities included histologic sum scores, papillary elongation, basal cell hyperplasia, and dilated intraepithelial spaces. When assessing for the presence of any abnormality, biopsies taken <3 cm from the lower esophageal sphincter (LES) had a pooled sensitivity of 0.71 (95% CI 0.64-0.77) and specificity of 0.64 (95% 0.54-0.73); however, analysis of individual histologic features such as the presence of eosinophils improved the sensitivity.

CONCLUSIONS

Although esophageal mucosal biopsies had poor sensitivity at diagnosing NERD, biopsies taken within 3 cm of the LES had higher sensitivity when pathologists reported upon eosinophils and dilated intraepithelial spaces.

Desmin immunostaining is effective for improving interobserver variability in the depth assessment of the submucosal invasion of colorectal cancers

Tumor depth evaluation is essential for pathological tumor staging because it affects clinical management as an independent risk factor for lymph node metastasis in colorectal cancers. However, poor interobserver variability of invasion depth has been reported. This study aimed to clarify the effectiveness of desmin immunostaining in the histological diagnosis of colorectal cancer. Overall, 63 sets of slides of colorectal cancer stained with hematoxylin and eosin (H&E) and desmin were prepared and independently reviewed by four examiners. After reviewing the desmin-stained slides, the interobserver variability of H&E slides alone was significantly improved for all examiners. For the assessment of Tis vs. T1, the sensitivity and accuracy were significantly improved for all examiners by combining H&E and desmin immunostaining. For the diagnosis of T1b vs. Tis or T1a, specificity and accuracy were significantly improved by adding desmin immunostaining. Ancillary desmin staining to assess submucosal invasion in colorectal cancers significantly improved interobserver agreement, led to efficient screening of T1 cancers, and reduced excessive T1b diagnoses. The combination of desmin immunostaining and H&E staining is highly recommended for diagnosing invasive colorectal cancer.

A novel cost function for nuclei segmentation and classification in imbalanced histopathology data-sets

Cancer is a major global health problem, causing millions of deaths yearly. Histopathological analysis plays a crucial role in detecting and diagnosing various types of cancer, enabling an accurate diagnosis to inform targeted treatment planning, allowing for better cancer staging, and ultimately improving prognosis. We aim to detect cancer earlier, which can ultimately help reduce mortality rates and enhance patients' quality of life. However, detecting and classifying rare cells is a key challenge for pathologists and researchers. Many histopathological data-sets contain imbalanced data, with only a few instances of rare cells whose unique morphological structures can impede early diagnosis efforts. Our model, SPNet, a spatially aware convolutional neural network, addresses this problem by employing a spatial data balancing technique, enhancing the classification of rare nuclei by 21.8 %. Since nuclei often cluster and exhibit patterns of the same class, SPNet's novel cost function targets spatial regions, resulting in a 1.9 % increase in the F1 classification of rare class types within the CoNSeP dataset. When integrated with a ResNet50-SE encoder, SPNet increases the mean F1 score for classifying all nuclei in the CoNSeP dataset by 4.3 %, compared to the benchmark set by the state-of-the-art HoVer-Net model. The potential integration of SPNet into existing medical devices could allow us to streamline diagnostic processes and minimise false negatives.

Clinical consequences of diagnostic variability in the histopathological evaluation of early rectal cancer

INTRODUCTION

In early rectal cancer, organ sparing treatment strategies such as local excision have gained popularity. The necessity of radical surgery is based on the histopathological evaluation of the local excision specimen. This study aimed to describe diagnostic variability between pathologists, and its impact on treatment allocation in patients with locally excised early rectal cancer.

MATERIALS AND METHODS

Patients with locally excised pT1-2 rectal cancer were included in this prospective cohort study. Both quantitative measures and histopathological risk factors (i.e. poor differentiation, deep submucosal invasion, and lymphatic- or venous invasion) were evaluated. Interobserver variability was reported by both percentages and Fleiss' Kappa- (ĸ) or intra-class correlation coefficients.

RESULTS

A total of 126 patients were included. Ninety-four percent of the original histopathological reports contained all required parameters. In 73 of the 126 (57.9%) patients, at least one discordant parameter was observed, which regarded histopathological risk factors for lymph node metastases in 36 patients (28.6%). Interobserver agreement among different variables varied between 74% and 95% or ĸ 0.530-0.962. The assessment of lymphovascular invasion showed discordances in 26% (ĸ = 0.530, 95% CI 0.375-0.684) of the cases. In fourteen (11%) patients, discordances led to a change in treatment strategy.

CONCLUSION

This study demonstrated that there is substantial interobserver variability between pathologists, especially in the assessment of lymphovascular invasion. Pathologists play a key role in treatment allocation after local excision of early rectal cancer, therefore interobserver variability needs to be reduced to decrease the number of patients that are over- or undertreated.

Current problems and perspectives of pathological risk factors for lymph node metastasis in T1 colorectal cancer: Systematic review

With the prevalence of endoscopic submucosal dissection and endoscopic full thickness resection, which enable complete resection of T1 colorectal cancer with a negative margin, the treatment strategy following endoscopic resection has become more important. The necessity of secondary surgical resection is determined on the basis of the risk of lymph node metastasis according to the histopathological findings of resected specimens because ~10% of T1 colorectal cancer cases have lymph node metastasis. The current Japanese treatment guidelines state four risk factors for lymph node metastasis: lymphovascular invasion, histological differentiation, depth of submucosal invasion, and tumor budding. These guidelines have succeeded in stratifying the low-risk group for lymph node metastasis, in which endoscopic resection alone is acceptable for cure. On the other hand, there are some problems: there is variation in diagnosis methods and low interobserver agreement for each pathological factor and 90% of surgical resections are unnecessary, with lymph node metastasis negativity. To ensure patients with T1 colorectal cancer receive more appropriate treatment, these problems should be addressed. In this systematic review, we gave some suggestions to these practical issues of four pathological factors as predictors.

Prediction of lymph node metastasis in early colorectal cancer based on histologic images by artificial intelligence

Risk evaluation of lymph node metastasis (LNM) for endoscopically resected submucosal invasive (T1) colorectal cancers (CRC) is critical for determining therapeutic strategies, but interobserver variability for histologic evaluation remains a major problem. To address this issue, we developed a machine-learning model for predicting LNM of T1 CRC without histologic assessment. A total of 783 consecutive T1 CRC cases were randomly split into 548 training and 235 validation cases. First, we trained convolutional neural networks (CNN) to extract cancer tile images from whole-slide images, then re-labeled these cancer tiles with LNM status for re-training. Statistical parameters of the tile images based on the probability of primary endpoints were assembled to predict LNM in cases with a random forest algorithm, and defined its predictive value as random forest score. We evaluated the performance of case-based prediction models for both training and validation datasets with area under the receiver operating characteristic curves (AUC). The accuracy for classifying cancer tiles was 0.980. Among cancer tiles, the accuracy for classifying tiles that were LNM-positive or LNM-negative was 0.740. The AUCs of the prediction models in the training and validation sets were 0.971 and 0.760, respectively. CNN judged the LNM probability by considering histologic tumor grade.

Diagnostic variability in the histopathological assessment of advanced colorectal adenomas and early colorectal cancer in a screening population

Aim

The aim of this study was to evaluate interobserver variability between individual pathologists and a panel of pathologists in the histopathological assessment of advanced colorectal neoplasms in the Dutch bowel cancer screening population.

Methods and results

Histological slides of adenomas with high‐grade dysplasia and early colorectal carcinomas (CRC) from 20 different laboratories were reviewed by the pathology panel of the Dutch bowel screening programme. Interobserver variability was reported by descriptive statistics. In addition, potential clinical consequences of discrepancies were evaluated. A total of 104 cases of adenomas with high‐grade dysplasia and 83 early CRCs were reviewed. Discrepancies were observed in 41 of 104 (39.4%) adenoma cases, which potentially had clinical consequences in 16 (15.4%) cases. For CRC, discrepancies were shown in 44 of 83 cases (53.0%) and would have potentially led to alternative treatment strategies in 25 (30.1%) cases. Most frequently, discrepancies were observed in the assessment of lymphovascular invasion (23 of 73 cases, 31.5%).

Conclusion

This study showed that considerable interobserver variability is present in the histopathological assessment of advanced colorectal neoplasia, which may impact upon treatment choices. Additional stains and education, as well as intercollegial consultation, might decrease this variability.

Deep Learning identifies inflamed fat as a risk factor for lymph node metastasis in early colorectal cancer

The spread of early-stage (T1 and T2) adenocarcinomas to loco-regional lymph nodes is a key event in disease progression of colorectal cancer (CRC). The cellular mechanisms behind this event are not completely understood and existing predictive biomarkers are imperfect. Here, we used an end-to-end Deep Learning algorithm to identify risk factors for lymph node metastasis (LNM) status in digitized histopathology slides of the primary CRC and its surrounding tissue. In two large population-based cohorts, we show that this system can predict the presence of more than one LNM in pT2 CRC patients with an area under the receiver operating curve (AUROC) of 0.733 (0.67-0.758) and patients with any LNM with an AUROC of 0.711 (0.597-0.797). Similarly, in pT1 CRC patients, the presence of more than one LNM or any LNM was predictable with an AUROC of 0.733 (0.644-0.778) and 0.567 (0.542-0.597), respectively. Based on these findings, we used the Deep Learning system to guide human pathology experts towards highly predictive regions for LNM in the whole slide images. This hybrid human observer and Deep Learning approach identified inflamed adipose tissue as the highest predictive feature for LNM presence. Our study is a first proof of concept that artificial intelligence (AI) systems may be able to discover potentially new biological mechanisms in cancer progression. Our Deep Learning algorithm is publicly available and can be used for biomarker discovery in any disease setting. This article is protected by copyright. All rights reserved.

Improving Generalization of Deep Learning Models for Diagnostic Pathology by Increasing Variability in Training Data: Experiments on Osteosarcoma Subtypes

BACKGROUND

Artificial intelligence has an emerging progress in diagnostic pathology. A large number of studies of applying deep learning models to histopathological images have been published in recent years. While many studies claim high accuracies, they may fall into the pitfalls of overfitting and lack of generalization due to the high variability of the histopathological images.

AIMS AND OBJECTS

Use the model training of osteosarcoma as an example to illustrate the pitfalls of overfitting and how the addition of model input variability can help improve model performance.

MATERIALS AND METHODS

We use the publicly available osteosarcoma dataset to retrain a previously published classification model for osteosarcoma. We partition the same set of images into the training and testing datasets differently than the original study: the test dataset consists of images from one patient while the training dataset consists images of all other patients. We also show the influence of training data variability on model performance by collecting a minimal dataset of 10 osteosarcoma subtypes as well as benign tissues and benign bone tumors of differentiation.

RESULTS

The performance of the re-trained model on the test set using the new partition schema declines dramatically, indicating a lack of model generalization and overfitting. We show the additions of more and moresubtypes into the training data step by step under the same model schema yield a series of coherent models with increasing performances.

CONCLUSIONS

In conclusion, we bring forward data preprocessing and collection tactics for histopathological images of high variability to avoid the pitfalls of overfitting and build deep learning models of higher generalization abilities.

Impact of Subspecialty Sign-Out on Interobserver Variability and Accuracy in Gastrointestinal Pathology

Subspecialty sign-out is increasingly common in academic medical centers as well as some community practices. Reducing interobserver variability in anatomic pathology is desirable so that clinicians can select the appropriate therapy. Many departments that elect subspecialty sign-out do so with the assumption that it will improve diagnostic accuracy and interobserver variability-but does it? The literature is mixed.

Artificial Intelligence-based Detection of FGFR3 Mutational Status Directly from Routine Histology in Bladder Cancer: A Possible Preselection for Molecular Testing?

BACKGROUND

Fibroblast growth factor receptor (FGFR) inhibitor treatment has become the first clinically approved targeted therapy in bladder cancer. However, it requires previous molecular testing of each patient, which is costly and not ubiquitously available.

OBJECTIVE

To determine whether an artificial intelligence system is able to predict mutations of the FGFR3 gene directly from routine histology slides of bladder cancer.

DESIGN, SETTING, AND PARTICIPANTS

We trained a deep learning network to detect FGFR3 mutations on digitized slides of muscle-invasive bladder cancers stained with hematoxylin and eosin from the Cancer Genome Atlas (TCGA) cohort (n = 327) and validated the algorithm on the "Aachen" cohort (n = 182; n = 121 pT2-4, n = 34 stroma-invasive pT1, and n = 27 noninvasive pTa tumors).

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary endpoint was the area under the receiver operating curve (AUROC) for mutation detection. Performance of the deep learning system was compared with visual scoring by an uropathologist.

RESULTS AND LIMITATIONS

In the TCGA cohort, FGFR3 mutations were detected with an AUROC of 0.701 (p < 0.0001). In the Aachen cohort, FGFR3 mutants were found with an AUROC of 0.725 (p < 0.0001). When trained on TCGA, the network generalized to the Aachen cohort, and detected FGFR3 mutants with an AUROC of 0.625 (p = 0.0112). A subgroup analysis and histological evaluation found highest accuracy in papillary growth, luminal gene expression subtypes, females, and American Joint Committee on Cancer (AJCC) stage II tumors. In a head-to-head comparison, the deep learning system outperformed the uropathologist in detecting FGFR3 mutants.

CONCLUSIONS

Our computer-based artificial intelligence system was able to detect genetic alterations of the FGFR3 gene of bladder cancer patients directly from histological slides. In the future, this system could be used to preselect patients for further molecular testing. However, analyses of larger, multicenter, muscle-invasive bladder cancer cohorts are now needed in order to validate and extend our findings.

PATIENT SUMMARY

In this report, a computer-based artificial intelligence (AI) system was applied to histological slides to predict genetic alterations of the FGFR3 gene in bladder cancer. We found that the AI system was able to find the alteration with high accuracy. In the future, this system could be used to preselect patients for further molecular testing.

Evaluation of KRAS, NRAS and BRAF mutational status and microsatellite instability in early colorectal carcinomas invading the submucosa (pT1): towards an in-house molecular prognostication for pathologists?

AIM

We aimed to study the prognostic value of KRAS, NRAS, BRAF mutations and microsatellite stable (MSS)/instable (MSI) in the field of colorectal cancer invading the submucosa (ie, pT1 colorectal cancer (CRC)).

METHODS

We led a case-control study in tumour samples from 60 patients with pT1 CRC with (20 cases) and without (40 cases) metastatic evolution (5 years of follow-up) which were analysed for KRAS, NRAS, BRAF mutations (Idylla testing and next generation sequencing, NGS) and MSS/MSI status (Idylla testing and expression of mismatch repair (MMR) proteins using immunohistochemistry).

RESULTS

KRAS mutations were encountered in 11/20 (55%) cases and 21/40 (52.5%) controls (OR=1.11 (0.38 to 3.25), p=0.8548), NRAS mutations in 1/20 (5%) cases and 3/40 (7.5%) controls (OR=3.08 (0.62 to 15.39), p=0.1698) and BRAF mutations in 3/20 (15%) cases and 6/40 (15%) controls (OR=1.00 (0.22 to 4.5), p=1.00). A MSI status was diagnosed in 3/20 (15%) cases and 5/40 (12.5%) controls (OR=1.2353 (0.26 to 5.79), p=0.7885). Beyond the absence of significant association between the metastatic evolution and any of the studied molecular parameters, we observed a very good agreement between methods analysing KRAS, NRAS and BRAF mutations (Kappa value of 0.849 (0.748 to 0.95) between Idylla and NGS) and MSS/MSI (Idylla)-proficient MMR/deficient MMR (immunohistochemistry) status (Kappa value of 1.00).

CONCLUSION

Although being feasible using the fully automated Idylla method as well as NGS, the molecular testing of KRAS, NRAS, BRAF and MSS/MSI status does not seem useful for prognostic purpose in the field of pT1 CRC.

Malignant Colorectal Polyp Pathology: Are We Getting Sufficient Information to Make Decisions?

The College of American Pathologists has published guidelines for malignant colorectal polyp pathology reports that list histopathological features that are "core elements" and "optional." Lack of element reporting may result in inaccurate tumor risk stratification.This study aimed to perform a population-based assessment of pathology reporting for T1 colorectal cancers and determine the completeness of reporting for core and optional histopathological elements.This is a retrospective cohort study.This study reviews the pathology reports of endoscopically resected malignant colorectal polyps in Alberta, Canada between 2014 and 2016.Individuals aged 18 years or older with T1 colorectal polyps were selected.Histopathological elements were dichotomized into core and optional. Malignant polyps were classified as high risk or low risk for lymph node metastases and local intraluminal recurrence. Addendum reports were compared with first reports.After applying exclusion criteria, 431 polyps were analyzed. The mean age of patients was 65.5 years; 59.4% were male. Histological grade, deep margin, and lymphovascular invasion were reported in 82.4%, 86.8% and 75.6%; all 3 were reported in only 66.4%. Tumor budding (not in the 2016 guidelines) was reported in 14.4%. One hundred ninety polyps (44.1%) were high risk. Thirty-seven polyps (8.3%) had an addendum report. Following the addendum, 1 polyp was downgraded to low risk, and 9 polyps were upgraded to high risk.The main limitation of the study is its retrospective nature. The decision making surrounding treatment for T1 cancers is complex, and factors other than histopathological tumor features may have been part of treatment decisions.There is a high rate of incomplete reporting of core and optional elements for malignant colorectal polyp pathology reports in Alberta. Several variables used by colorectal surgeons for decision making, such as tumor budding and depth of submucosal invasion, are not considered core elements and are infrequently reported. A pathology review by a second pathologist often results in a change in risk stratification. See Video Abstract at http://links.lww.com/DCR/B98. PATOLOGÍA DEL PÓLIPO COLORRECTAL MALIGNO: ¿ESTAMOS OBTENIENDO INFORMACIÓN SUFICIENTE PARA TOMAR DECISIONES?: El Colegio de Patólogos Americanos publico pautas para informes de patología de pólipos colorrectales malignos que enumeran características histopatológicas como "elementos centrales" y "opcionales". La falta de información elemental puede resultar en una estratificación de riesgo tumoral imprecisa.Valoración basada en una población de los informes de patología para los cánceres colorrectales T1 y determinar la precisión de los informes en cuanto los elementos histopatológicos centrales y opcionales.Estudio de cohorte retrospectivo.Este estudio revisa los informes de patología de pólipos colorrectales malignos resecados endoscópicamente en Alberta, Canadá, entre 2014 y 2016.personas mayores de 18 años con pólipos colorrectales T1.Los elementos histopatológicos se dicotomizaron entre elementales y opcionales. Pólipos malignos se clasificaron como de alto riesgo o bajo riesgo de metástasis en los ganglios linfáticos y recurrencia intraluminal local. Los informes enmendados se compararon con los informes originales.Después de aplicar los criterios de exclusión, se analizaron 431 pólipos. La edad media fue 65.5 años, con 59.4% masculinos. El grado histológico, el margen profundo y la invasión linfovascular se informaron confirmaron en 82.4%, 86.8% y 75.6% respectivamente; las tres características se demostraron en solo 66.4%. Un patrón tumoral en ciernes se reporto en 14.4-una característica que no se usaba en las guías de 2016. Ciento noventa pólipos (44.1%) eran de alto riesgo. Treinta y siete pólipos (8.3%) requirieron de un informe enmendado. Aplicación de los nuevos criterios resulto en que 1 pólipo se redujo a bajo riesgo y 9 pólipos se actualizaron como a alto riesgo.La principal limitación del estudio es el diseño retrospectivo. La toma de decisiones en torno al tratamiento de los cánceres T1 es compleja y otros factores además de las características histopatológicas del tumor pueden haber sido parte de las decisiones terapéuticas.Hay una alta tasa de informes incompletos de elementos centrales y opcionales para informes de patología de pólipos colorrectales malignos en Alberta. Algunas variables utilizadas por los cirujanos colorrectales para la toma de decisiones, como el patrón tumoral en ciernes y la profundidad de la invasión submucosa, no se consideran elementos centrales y se informan con poca frecuencia. Una revisión de patología realizada por un segundo patólogo a menudo resulta en un cambio en la estratificación del riesgo. Consulte Video Resumen en http://links.lww.com/DCR/B98. (Traducción-Dr. Adrian E. Ortega).

Role of Endoscopic Resection Versus Surgical Resection in Management of Malignant Colon Polyps: a National Cancer Database Analysis

BACKGROUND

Endoscopic resection (polypectomy) or surgery, are the main approaches in management of malignant colon polyps. There are very few large population-based studies comparing outcomes between the two.

METHODS

Using the National Cancer Database, we identified patients ≥ 18 years with the first diagnosis of T1N0M0 malignant polyp from 2004 to 2015. Patients with a positive resection margin were excluded. Outcomes were compared between those who had surgery versus those who had polypectomy. Overall survival was compared using Kaplan-Meier curves. Multivariate Cox proportional hazards analysis was performed to generate hazard ratios, adjusted for patient, demographic, and tumor factors.

RESULTS

A total of 31,062 patients met the inclusion criteria, out of which 2593 (8.3%) underwent polypectomy alone and 28,469 (91.7%) had surgery. Overall survival was significantly better in the surgical group compared with the polypectomy group. One-year and 5-year survival for surgery were 95.8% and 86.1% respectively compared with 94.2% and 80.6% for polypectomy (p < .0001). Hazard ratio for surgery after adjusting for various clinical-, demographic-, and tumor-level factors was 0.53 (p < .0001).

CONCLUSION

Our study is the largest population-based analysis of patients with T1N0M0 malignant colon polyps. Overall survival was higher in patients who underwent surgery compared with polypectomy. This remained consistent even after adjusting for multiple patient and tumor factors between the two groups.

Recurrence and cancer-specific mortality after endoscopic resection of low- and high-risk pT1 colorectal cancers: a meta-analysis

BACKGROUND AND AIMS

Clinical management after complete endoscopic resection of pT1 colorectal cancers (CRCs) is still under debate. Follow-up data are heterogeneous and poorly reported, resulting in variable clinical management. Our aim was to meta-analyze recurrence and cancer-specific mortality (CSM) occurring after endoscopic resection of low- and high-risk pT1 CRCs undergoing conservative (nonsurgical) management.

METHODS

Literature was systematically searched until February 2019 for studies describing patients with pT1 CRCs, histologically classifiable as low or high risk, endoscopically resected without complementary surgery and with ≥12 months of follow-up. Pooled cumulative incidence (and incidence rate when specific follow-up intervals were available) of recurrence and CSM were calculated separately for low- and high-risk pT1 CRCs. Quality, publication bias, and heterogeneity were explored.

RESULTS

Pooled cumulative incidences of recurrence and CSM among high-risk lesions (5 studies, 571 patients) were, respectively, 9.5% (95% confidence interval [CI], 6.7%-13.3%; I² = 38.4%) and 3.8% (95% CI, 2.4%-5.8%; I² = 0%), whereas among low-risk lesions (7 studies, 650 patients) they were, respectively, 1.2% (95% CI, .6%-2.5%; I² = 0%) and .6% (95% CI, .2%-1.7%; I² = 0%). Pooled incidence rates of recurrence and CSM among high-risk lesions (3 cohorts, 237 patients) were, respectively, 11 (95% CI, 2-20; I² = 43.3%) and 4 (95% CI, 1-7; I² = 0%) per 1000 patient-years, whereas among low-risk lesions (3 cohorts, 229 patients) they were 3 (95% CI, 0-6; I² = 0%) and 2 (95% CI, 0-4; I² = 0%) per 1000 patient-years, respectively. No publication bias or significant heterogeneity was found.

CONCLUSIONS

Pooled estimates of adverse events after endoscopic resection of pT1 CRCs suggest a conservative approach for low-risk lesions. In high-risk lesions, increased surgical risk might justify a conservative management, whereas fitness for surgery makes surgical completion appropriate.

Evaluation of an early-stage innovation for full-thickness excision of benign colonic polyps using the IDEAL framework

AIMS

Colectomy is the current approach for patients with endoscopically unresectable benign polyps but risks considerable morbidity. Full-thickness laparoendoscopic excision (FLEX) is a novel procedure, specifically developed to treat endoscopically unresectable benign colonic polyps, which could reduce the treatment burden of the current approach and improve outcomes. However, traditional evaluations of surgical innovations lack methodological rigour. This study reports the development and feasibility of the FLEX procedure in selected patients.

METHOD

A prospective development study using the Idea, Development, Evaluation, Assessment, Long-term study (IDEAL) framework was undertaken, by one surgeon, of the FLEX procedure in selected patients with endoscopically unresectable benign colonic polyps. Three-dimensional (3D)-CT colonography reconstructions were used preoperatively to rehearse patient-specific, critical manoeuvres. Targetted, full-thickness excision was performed: after marking the margin of the caecal polyp using circumferential endoscopic argon plasma coagulation, transmural endoscopic sutures were used to evert the bowel and resection was undertaken by laparoscopic linear stapling. Feasibility outcomes (establishing 'local success') included evidence of complete polyp resection without adverse events (especially safe closure of the excision site).

RESULTS

Ten patients [median (interquartile range) age: 74 (59-78) years] with polyp median diameters of 35 (30-41) mm, were referred for and consented to receive the FLEX procedure. During the same time frame, no patient underwent colectomy for benign polyps. One further patient received FLEX for local excision of a presumed malignant polyp because severe comorbidity prohibited standard procedures. The FLEX procedure was successfully performed locally, with complete resection of the polyp and safe closure of the excision site, in eight patients. Three noncompleted procedures were converted to laparoscopic segmental colectomy under the same anaesthetic because of endoscopic inaccessibility (two patients) and transcolonic suture failure (one patient).

CONCLUSIONS

The FLEX procedure is still under development. Early data demonstrate that it is safe for excision of selected benign polyps. Modifications to transcolonic suture delivery are now required and there is a need for wider adoption before more definitive evaluation can be performed.

Optimal Management of Malignant Polyps, From Endoscopic Assessment and Resection to Decisions About Surgery

Colorectal cancer is defined clinically as invasion of dysplastic cells into the submucosa. Lesions with submucosal invasion but without invasion into the muscularis propria are generally called malignant polyps. A stepwise approach produces optimal management of malignant polyps (including polypoid and flat/depressed lesions). The first step is to avoid endoscopic resection of non-pedunculated lesions with endoscopic features that predict deep submucosal invasion. Lesions without such features are candidates for endoscopic resection. The second step is to assess candidates for endoscopic resection for features that predict an increased risk of superficial submucosal invasion. Such lesions should be considered for en bloc endoscopic excision if feasible. The third step is giving patients with endoscopically resected malignant polyps good advice regarding whether to undergo adjuvant therapy, usually surgery. We review the endoscopic and histologic criteria that guide clinicians through these steps.

Diagnosis of T1 colorectal cancer in pedunculated polyps in daily clinical practice: a multicenter study

T1 colorectal cancer can be mimicked by pseudo-invasion in pedunculated polyps. British guidelines are currently one of the few which recommend diagnostic confirmation of T1 colorectal cancer by a second pathologist. The aim of this study was to provide insights into the accuracy of histological diagnosis of pedunculated T1 colorectal cancer in daily clinical practice. A sample of 128 cases diagnosed as pedunculated T1 colorectal cancer between 2000 and 2014 from 10 Dutch hospitals was selected for histological review. Firstly, two Dutch expert gastrointestinal pathologists reviewed all hematoxylin-eosin stained slides. In 20 cases the diagnosis T1 colorectal cancer was not confirmed (20/128; 16%). The discordant cases were subsequently discussed with a third Dutch gastrointestinal pathologist and a consensus diagnosis was agreed. The revised diagnoses were pseudo-invasion in 10 cases (10/128; 8%), high-grade dysplasia in 4 cases (4/128; 3%), and equivocal in 6 cases (6/128; 5%). To further validate the consensus diagnosis, the discordant cases were reviewed by an independent expert pathologist from the United Kingdom. A total of 39 cases were reviewed blindly including the 20 cases with a revised diagnosis and 19 control cases where the Dutch expert panel agreed with the original reporting pathologists diagnosis. In 19 of the 20 cases with a revised diagnosis the British pathologist agreed that T1 colorectal cancer could not be confirmed. Additionally, amongst the 19 control cases the British pathologist was unable to confirm T1 colorectal cancer in a further 4 cases and was equivocal in 3 cases. In conclusion, both generalist and expert pathologists experience diagnostic difficulty distinguishing pseudo-invasion and high-grade dysplasia from T1 colorectal cancer. In order to prevent overtreatment, review of the histology of pedunculated T1 colorectal cancers by a second pathologist should be considered with discussion of these cases at a multidisciplinary meeting.

Gland segmentation in colon histology images: The glas challenge contest

Colorectal adenocarcinoma originating in intestinal glandular structures is the most common form of colon cancer. In clinical practice, the morphology of intestinal glands, including architectural appearance and glandular formation, is used by pathologists to inform prognosis and plan the treatment of individual patients. However, achieving good inter-observer as well as intra-observer reproducibility of cancer grading is still a major challenge in modern pathology. An automated approach which quantifies the morphology of glands is a solution to the problem. This paper provides an overview to the Gland Segmentation in Colon Histology Images Challenge Contest (GlaS) held at MICCAI'2015. Details of the challenge, including organization, dataset and evaluation criteria, are presented, along with the method descriptions and evaluation results from the top performing methods.

Interobserver variability amongst gastrointestinal pathologists in assessing prognostic parameters of malignant colorectal polyps: a cause for concern

BACKGROUND

Malignant colorectal polyps (MCRP) have become a major challenge in the field of coloproctology from diagnosis to full treatment. One important facet of the challenge is the histopathological staging of the lesion and identifying various prognostic parameters. The primary aim of this study was to find the interobserver variation amongst 4 experienced gastrointestinal pathologists when assessing important parameters and staging systems (Haggitt, Kikuchi and Ueno) in MCRPs.

METHODS

Four experienced gastrointestinal pathologists independently assessed 56 cases of MCRP, and each pathologist completed a pro forma for each case. The results were collated and statistically analysed.

RESULTS

There was a significant variation in the assessments using the various published staging systems agreed upon on important prognostic parameters.

CONCLUSIONS

None of the staging systems used is suitable for all polyp types or has good reproducibility. There is an urgent need to make pathologists' assessment of MCRPs easier and more reproducible.

The Ueno method for substaging pT1 colorectal adenocarcinoma by depth and width measurement: an interobserver study

AIM

Early pT1 polyp colorectal cancers (CRCs) present challenges for accurate pathology substaging. Haggitt and Kikuchi stages depend on polyp morphology and are often difficult to apply due to suboptimal orientation or fragmentation, or absence of the muscularis propria in polypectomy or submucosal resection specimens. European guidelines for quality assurance suggest using Ueno's more objective approach, using depth and width measurements beyond muscularis mucosae. We have investigated interobserver variation using Ueno's approach.

METHOD

Ten consecutive pT1 polyp CRCs were identified and the slides assessed by six gastrointestinal pathologists for depth and width of invasion. A further 60 polyps were studied by a group of specialist and general pathologists. Agreement was assessed by analysis of variance. A polyp CRC is classified as high risk if it has a depth ≥ 2000 μm or a width ≥ 4000 μm and low risk with a depth < 2000 μm or a width < 4000 μm. Concordance for the dichotomized values was assessed using the kappa statistic.

RESULTS

The intraclass correlation coefficient (ICC) for depth was 0.83 and for width 0.56 in the 10-polyp group. The ICC for the 60-polyp CRCs was 0.67 for depth and 0.37 for width. In both groups, when polyp CRCs are divided into high- and low-risk categories based on depth, there was substantial and moderate agreement (κ = 0.80 and 0.47) but only fair agreement when based on width (κ = 0.34 and 0.35).

CONCLUSION

Ueno's method has the advantage of being independent of polyp morphology. Our study shows better concordance for depth measurement and reproducibility in nonfragmented specimens, with poorer agreement when based on width.

Clinical outcome of low- and high-risk malignant colorectal polyps: results of a population-based study and meta-analysis of the available literature

Some histological features of malignant polyps have been used to classify patients into low- and high-risk groups. This study proposed to evaluate the impact of this classification on the clinical outcome of patients with malignant polyps. Through the Colorectal Cancer Registry, 105 patients with endoscopically removed malignant polyps were selected. The presence of one of the following histological features defined malignant polyps as high-risk: infiltrated resection-margin, poorly differentiated carcinoma, lymphatic/vascular invasion and tumour budding and depth of submucosal invasion. Available literature was reviewed by applying a similar classification. Most of the malignant polyps were pedunculated and were localized in the left colon. Fifty-five malignant polyps were classified as low-risk lesions and 50 as high-risk. None of the patients at low-risk died of colorectal cancer. Of the patients at high-risk, three died of cancer; all three cases showed lymphatic/vascular invasion. Review of the literature reveals that an unfavourable clinical outcome is significantly more prevalent in the high-risk compared with the low-risk group (p > 0.005). Moreover, all histological risk factors show a specific predictive value of clinical adverse outcome. Our study and the pooled data analysis confirmed the usefulness of the subdivision into low- and high-risk malignant polyps for management of patients with endoscopically removed colorectal carcinoma.

Incidence trend of malignant polyps through the data of a specialized colorectal cancer registry: clinical features and effect of screening

OBJECTIVES

The purposes of the study are to describe the incidence trend of malignant polyp of large bowel over a 25-year period in the District of Modena and to assess the effect of an organized colorectal cancer screening program.

MATERIAL AND METHODS

Through the data of a specialized colorectal cancer Registry, we evaluate the clinical and pathological features of the polyps. Trend analysis was assessed with the Joinpoint Regression Program.

RESULTS

A total of 172 patients with malignant polyps were diagnosed throughout the study (3.5% of 4.835 registered patients); their overall frequency during the registration period increased from zero cases in the initial years (1984-85) to 57 cases in the past 3 years (2006-2008). Crude incidence rate passed from 0.37 in 1986-89 to 10.2 in 2006. Joinpoint trend analysis of crude rates showed a significant increase of incidence during the study period, with percent of annual variation ranging between 38.6% (95% CI 12.5-70.7) and 7.3% (95% CI 2.6-12.1). During the screening period (2005-2008, the past 4 years of registration) there was a significant increase of sessile polyps (p < 0.001), while other clinical and morphological features, including the number of low- and high-risk malignant polyps, remained unchanged. The surgery (after polypectomy) tended to raise both in low- and high-risk subgroups.

CONCLUSION

The incidence of malignant polyps increased significantly from the initial to the most recent periods of colorectal cancer registration. Screening was associated with changes in gross morphology of polyps and with an increased use of the surgery after endoscopic polypectomy.

Indirect Comparison of Two Quantitative Immunochemical Faecal Occult Blood Tests in a Population with Average Colorectal Cancer Risk

Magstream and OC Sensor quantitative immunochemical faecal occult blood tests (IFOBT) have shown better performances than guaiac (G) tests in colorectal cancer screening, however Magstream and OC Sensor have never been compared. We hypothesized that similar performances could be observed with Magstream and OC Sensors, provided a similar cut-off (expressed in concentration of haemoglobin in the stools) is used. We performed a literature-based indirect comparison between these tests, taking into account the cut-off, the number of samples, and the way they were combined (I2+: at least one positive sample of 2; I2++: both positive samples; I1: only one sample). Six studies conducted in general average-risk populations were included in this review. For each [test]*[cut-off], positivity rate (PR) decreased and predictive positive value (PPV) increased from I2+ to I1 and I2++. For similar PR, PPV with OC Sensor was greater than with Magstream. This could be due to factors other than the test, because PPVs associated with GFOBT in studies evaluating OC Sensor were greater than PPVs associated with GFOBT in the study evaluating Magstream. Direct comparison between Magstream and OC Sensor is needed to confirm the suspected superiority of OC Sensor.

Malignant colorectal polyps

Nowadays, the number of cases in which malignant colorectal polyps are removed is increasing due to colorectal cancer screening programmes. Cancerous polyps are classified into non-invasive high grade neoplasia (NHGN), when the cancer has not reached the muscularis mucosa, and malignant polyps, classed as T1, when they have invaded the submucosa. NHGN is considered cured with polypectomy, while the prognosis for malignant polyps depends on various morphological and histological factors. The prognostic factors include, sessile or pedunculated morphology of the polyp, whether partial or en bloc resection is carried out, the degree of differentiation of the carcinoma, vascular or lymphatic involvement, and whether the polypectomy resection margin is tumor free. A malignant polyp at T1 is considered cured with polypectomy if it is a pedunculated polyp (Ip of the Paris classification), it has been completely resected, it is not poorly differentiated, the resection edge is not affected by the tumor and there is no vascular or lymphatic involvement. The sessile malignant polyp (Is of the Paris classification) at T1 is considered not cured with polypectomy. Only in some cases (e.g. older people with high surgical risk) local excision (polypectomy or endoscopic submucosal dissection or conventional endoscopic mucosal resection) is considered the definitive treatment.

Colon cancer screening update and management of the malignant polyp

Colorectal carcinoma is common, but screening for this cancer has found less acceptance with the public than screening for breast, prostate, and cervical cancer. Available methods include fecal occult blood tests (FOBTs), flexible sigmoidoscopy (FOS), double-contrast barium enema, colonoscopy, computed tomographic colography, and fecal DNA. Evaluation of these options demonstrates that colonoscopy at ages 55 and 65 offers the best combination of reduction in colorectal cancer at the lowest cost. However, when compliance with screening recommendations is very high, costs are high, and the proportion of cancers arising from adenomas is low, the combination of FOS and FOBT is most cost effective. Malignant polyps look friable and irregular and feel hard. Sessile malignant polyps need to be treated by formal resection. Patients with pedunculated polyps with favorable histology (clear margin, well or moderately differentiated, no lymphovascular invasion) can be observed, and those whose polyps show unfavorable histology should have the polyp-bearing segment of colon resected along with its draining lymph nodes.

Value-of-information analysis to guide future research in the management of the colorectal malignant polyp

PURPOSE

The efficacy of surgery in the postendoscopic management of low-risk malignant polyps is unclear. Although interobserver variability in the histological diagnosis was shown, its importance is unknown. The purpose of this study was to guide future research on the optimal strategy for low-risk polyps with the use of value-of-information analysis.

METHODS

A decision-analysis model was constructed comparing the strategies of referring or not referring (waiting) to surgery patients with low-risk polyps. Probabilistic sensitivity analysis was performed to explore the effect of uncertainty about the input parameters. Value-of-information analysis was used to estimate the expected benefit of future research that would eliminate the decision uncertainty.

RESULTS

The number of postendoscopic surgeries to prevent 1 cancer-related death was 208. The incremental cost-effectiveness ratio of surgery vs waiting strategy was $215,291/life-year gained, surgery being a suboptimal choice in the reference case analysis. Probabilistic sensitivity analysis demonstrated that surgery was the optimal choice in 61% of the simulated scenarios. Most of the decision uncertainty was related with the combination of histological inaccuracy, prevalence of residual disease, and surgical mortality. The expected societal monetary benefit of further research from the perspective of the United States was estimated to be $1 billion.

CONCLUSIONS

The small benefit and the relatively high costs associated with surgery argue against surgical referral for low-risk malignant polyps; however, when a suboptimal histopathological accuracy was simulated, surgery appeared to be the most cost-effective option, prompting the need for further research.

Diagnostic accuracy of community pathologists in the interpretation of colorectal polyps

BACKGROUND AND AIMS

Management of patients with endoscopically removed colorectal polyps is generally dependent on pathological evaluation. The aim of this study was to assess the accuracy and clinical impact of pathologic interpretation of colorectal polyps by community pathologists.

METHODS

Two expert gastrointestinal pathologists reviewed the slides of 300 colorectal polyps initially examined by 14 general pathologists. Polyps had been detected by a fecal occult blood test colorectal cancer screening program in Haut-Rhin, a French administrative district.

RESULTS

Villous histology was overread in 24.8% of cases and high-grade dysplasia in 22.0%. The diagnosis of serrated adenoma was confirmed in 15.7% of cases. The diagnosis of T1 carcinoma was overestimated in seven cases (17.9%) and missed in four. In the screening program, the proportion of correct diagnoses of community pathologists was estimated at 45.3% of polyps, of misclassification without clinical impact at 27.5%, and of misclassification with a theoretical impact on management at 27.2%, leading to over-surveillance in 20.3% of polyps and to unnecessary surgical resection in three individuals. Overall, 37.5% of the pathology reports of malignant polyps were complete, presenting all criteria necessary for therapeutic decision-making.

CONCLUSION

Community pathologists exhibited moderate accuracy for interpreting colorectal polyps, with an impact on patient management for around one out of five individuals. Our results confirm the intrinsic poor reliability of the pathologic interpretation of villous histology and high-grade dysplasia and suggest that these advanced pathologic features should be abandoned for clinical use. They illustrate the need for a clarification of the nomenclature of serrated polyps.

The colorectal malignant polyp: scoping a dilemma

Colorectal adenomas containing invasive carcinoma represent the majority of early colorectal cancers. The malignant polyp carries a significant risk of lympho-haematic metastasis and mortality due to the penetration of cancerous cells into the submucosal layer. The therapeutic dilemma is whether to perform endoscopic or surgical resection. A thorough assessment of the endoscopic, histological and clinical variables is needed to unravel the best treatment for each patient. In particular, a unique staging of such lesions, based on certain histopathological features, has been deeply implicated in the therapeutic choice. Aim of this article is to review the main endoscopic, histological and clinical features of the malignant polyp in order to propose a systematic management of this lesion.

A population-based study of colorectal cancer histology in the United States, 1998-2001

BACKGROUND

Histology is an important factor in the etiology, treatment, and prognosis of cancer. The purpose of this study was to descriptively characterize colorectal cancer (CRC) histology in the United States population.

METHODS

Data from cancer registries in the National Program of Cancer Registries (NPCR) or Surveillance, Epidemiology and End Results (SEER) program, representing 88% of the U.S. population, were used in the study. The analysis included 522,630 microscopically confirmed CRC cases diagnosed from 1998-2001.

RESULTS

About 96% of CRCs were adenocarcinomas, approximately 2% were other specified carcinomas (including carcinoid tumors), about 0.4% were epidermoid carcinomas, and about 0.08% were sarcomas. The proportion of epidermoid carcinomas, mucin-producing carcinomas, and carcinoid tumors was greater among females. Several histologic patterns with regard to race and ethnicity existed, including a higher percentage of carcinoid tumors among most non-white populations. With respect to age, higher percentages of sarcomas, mucin-producing adenocarcinomas, signet ring cell tumors, and carcinoid tumors were found in individuals under age 40. Overall, adenocarcinomas were more likely to be diagnosed at regional stages with moderate differentiation. Compared with other adenocarcinomas, signet ring cell tumors were more often poorly differentiated and were at distant stage at diagnosis. Carcinoid tumors and sarcomas were mainly poorly differentiated and were at localized stage at diagnosis. Small cell carcinomas were more likely undifferentiated and were at distant stage at diagnosis.

CONCLUSIONS

To date, this is the largest population-based study to analyze CRC histology in the United States. Distinct demographic and clinical patterns associated with different histologies may be helpful for future epidemiologic, laboratory, and clinical studies.

Staging and prognosis of colon cancer

Significant advances have been made in all aspects of care relating to colorectal cancer. Although surgery will likely remain the mainstay of definitive treatment for the majority of colorectal malignancies, a better understanding of tumor progression and biology will help guide the choice of surgical therapy to best achieve a curative resection. Additionally, advances in the use of neoadjuvant and adjuvant therapies should continue to increase disease-free and overall survival when combined with appropriate operative resection. Although TNM staging remains our strongest tool at this point for establishing prognosis and directing therapy, expansion of our knowledge of the molecular events underlying colorectal tumorigenesis undoubtedly will lead to the refinement of our current staging and prognostic systems.