Biopsies From Ascending and Descending Colon Are Sufficient for Diagnosis of Microscopic Colitis.

BACKGROUND & AIMS: Lymphocytic and collagenous colitis are types of microscopic colitis (MC) that commonly cause chronic watery diarrhea, but there are no macroscopic features of MC that can be detected during colonoscopy. Endoscopists therefore often collect multiple random colonic biopsies, potentially oversampling, increasing times of colonoscopy and slide review. We sought to identify sites from which biopsies could be taken and analyzed to identify patients with MC with a high level of sensitivity and determine the appropriate number of biopsies to take at these sites. METHODS: We performed a retrospective study using biopsies from 101 consecutive patients with MC (52 cases of collagenous colitis, 42 cases of lymphocytic colitis, 7 combined cases), without comorbidities, from 2017 through 2018. Slides were reviewed, and the proportion of biopsies that were diagnostic of MC were calculated at each biopsy site. RESULTS: The proportions of biopsy fragments from each site of the colon found to be positive for MC were as follows: cecum, 90.0%; ascending colon, 96.9%; hepatic flexure, 77.8%; transverse colon, 95.7%; splenic flexure, 75.0%; descending colon, 85.0%; sigmoid colon, 90.9%; and rectum, 82.2%. For biopsies labeled random, 95.7% were positive for MC. When findings from ascending and descending colon biopsies were combined, 100% of MC cases were detected. CONCLUSIONS: MC can be detected with certainty by analyzing biopsies from the ascending and descending colon. Fewer biopsies than were collected from our cases are sufficient for diagnosis. We propose a Western protocol (taking 2 biopsies from each of the ascending and descending colon) in evaluation of patients for MC.

Challenges with colorectal cancer staging: results of an international study.

Challenges exist with standardized colorectal cancer reporting despite adoption of the American Joint Committee on Cancer-Staging Manual 8th edition. We performed this study to gauge current practice patterns among a diverse group of surgical pathologists. A web-based questionnaire depicting problematic issues and images related to colorectal carcinoma staging was circulated among 118 surgical pathologists and their responses were correlated with their geographic location (North America vs. Europe vs. others), nature of practice (academic vs. community), the sign-out model (gastrointestinal subspecialty vs. general surgical pathology), and years of professional experience. We found that a substantial number of practicing pathologists ignore recommended-staging criteria in specific settings, particularly with respect to assessment of advanced T stage. Tumors that communicated with the serosa through inflammatory foci were staged as pT3 (49%) or pT4a (51%) by nearly equal numbers of pathologists regardless of level of experience, the sign-out model, or geographic location. Only 65% assigned T stage and margin status based on extent of viable tumor in the neoadjuvant setting. One-third of pathologists, particularly those in Europe (p = 0.015), classified acellular mucin deposits as N1 disease when detected in treatment-naive cases. Nearly 50% of pathologists classified isolated tumor cells (i.e., deposits <0.2 mm) in lymph nodes as metastatic disease (i.e., pN1, p = 0.02). Our results suggest that pathologists ignore recommendations that are based on insufficient data and apply individualized criteria when faced with situations that are not addressed in the American Joint Committee on Cancer Staging Manual 8th edition. These variations in practice limit the ability to compare outcome data across different institutions and draw attention to areas that require further study.

Evaluating the impact of lymph node resampling on colorectal cancer nodal stage.

AIMS: Nodal staging in colorectal cancer (CRC) informs prognosis and guides adjuvant treatment decisions. A standard minimum of 12 lymph nodes is widely used, with additional sampling being performed as required. However, there are few data on how lymph node resampling in this context has an impact on nodal stage. The aims of this study were to evaluate the effectiveness of resampling in detecting metastases and tumour deposits, and the impact on stage. METHODS AND RESULTS: A retrospective cohort analysis was performed on CRC resections that underwent resampling because of an initial yield of <12 lymph nodes, from 2008 to 2018. Data relating to patient demographics, specimen, malignancy and prosection were collected. Slides were reviewed to quantify nodal metastases and tumour deposits before and after resampling. Among ≥pN1 cases, logistic regression analysis was performed to evaluate factors that predicted the finding of additional metastases and tumour deposits. The cohort comprised 395 cases: resampling identified nodal metastases and/or tumour deposits in 30 (7.6%) cases; nodal upstaging occurred in 20 (5.1%) cases; and eight (2.0%) cases changed from pN0 to ≥pN1. No factors predicted resampling of positive lymph nodes or tumour deposits, and pN upstaging occurred across a variety of cases. A subgroup analysis was performed to assess the impact of resampling on high-risk features in stage II cases (n = 117). There were 33 (8.5%) patients who no longer had any high-risk features after resampling. CONCLUSIONS: Lymph node resampling has an impact on nodal staging and possible treatment decisions in a considerable proportion of patients, and is recommended in all cases with <12 lymph nodes.

Pimping in Residency: The Emotional Roller-Coaster of a Pedagogical Method - A Qualitative Study Using Interviews and Rich Picture Drawings.

Phenomenon: Pimping has become a well-known and distinct form of questioning in medical education, and as a pedagogical method it has both proponents and detractors. Pimping occurs when a teacher (pimper) asks difficult questions of the learner (pimpee), usually in rapid succession. There is a paucity of literature formally studying this technique and its effects on teachers and learners. Our study examines the use of and attitudes toward pimping in a pathology residency program to better understand its perceived value and effectiveness. Approach: Using a qualitative approach, we conducted semistructured interviews with 8 pathology trainees and 9 pathologists. As part of the interview process, we asked participants to draw a rich picture of a pimping encounter. Consistent with this qualitative method, we analyzed data iteratively using constant comparison. Findings: Negative emotions including anxiety and self-doubt dominated among the learners during pimping encounters. For some, these resulted in motivation to study, and for others this was a futile, nonmotivating experience. Most trainees felt that they were being judged during pimping; however, they perceived that the intentions of pimping were not malicious and in their best interests. This was supported by pathologists, who stated that their motivation for pimping was to identify knowledge gaps, thus benefiting the trainee. Insights: Pimping created a dichotomy of emotions within the majority of learners in this study. Negative emotions occurred during pimping encounters; however, following the encounter, pimping was perceived in a more positive light. Recognizing when and how pimping can create negative emotions that may interfere with learning may enable educators to create more consistently meaningful interactions.

Grading of Total Mesorectal Excision Specimens: Assessment of Interrater Agreement.

BACKGROUND: Total mesorectal excision is the standard of care for patients with rectal cancer. Pathological evaluation of the quality of the total mesorectal excision specimen is an important prognostic factor that correlates with local recurrence, but is potentially subjective. OBJECTIVE: This study aimed to determine the degree of variation in grading, both between assessors and between fresh and formalin-fixed specimens. DESIGN: Raters included surgeons, pathologists, pathology residents, pathologists' assistants, and pathologists' assistant trainees. Specimens were assessed by up to 6 raters in the fresh state and by 2 raters postfixation. Four parameters were evaluated: mesorectal bulk, surface regularity, defects, and coning. Interrater agreement was measured using ordinal α-values. SETTING: The study was conducted at a single academic center. MAIN OUTCOME MEASURES: The primary outcome was agreement between individuals when grading total mesorectal excision specimens. RESULTS: A total of 37 total mesorectal excision specimens were assessed. Reliability between all raters for fresh specimens for mesorectal bulk, surface regularity, defects, coning, and overall grade were 0.85, 0.85, 0.92, 0.84, and 0.91. When compared with all raters, pathologists and residents had higher agreement and pathologists and surgeons had lower agreement. Ordinal α-values comparing pathologist and pathologist's assistant agreement for overall grade were similar pre- and postfixation (0.78 vs 0.80), but agreement for assessing defects decreased postfixation. Among pathologists' assistants, agreement was higher when grading specimens postfixation than when grading fresh specimens. LIMITATIONS: Assessment bias may have occurred because of the greater number of pathologists' assistants participating than the number of residents and pathologists. CONCLUSIONS: The results indicate good interrater agreement for the assessment of overall grade, with defects showing the best interrater agreement in fresh specimens. Although total mesorectal excision specimens may be consistently graded postfixation, the assessment of defects postfixation may be less reliable. This study highlights the need for additional knowledge-transfer activities to ensure consistency and accurate grading of total mesorectal excision specimens. See Video Abstract at http://links.lww.com/DCR/A497.

Development and validation of a histological index for UC.

OBJECTIVE: Although the Geboes score (GS) and modified Riley score (MRS) are commonly used to evaluate histological disease activity in UC, their operating properties are unknown. Accordingly, we developed an alternative instrument. DESIGN: Four pathologists scored 48 UC colon biopsies using the GS, MRS and a visual analogue scale global rating. Intra-rater and inter-rater reliability for each index and individual index items were measured using intraclass correlation coefficients (ICCs). Items with high reliability were used to develop the Robarts histopathology index (RHI). The responsiveness/validity of the RHI and multiple histological, endoscopic and clinical outcome measures were evaluated by analyses of change scores, standardised effect size (SES) and Guyatt's responsiveness statistic (GRS) using data from a clinical trial of an effective therapy. RESULTS: Inter-rater ICCs (95% CIs) for the total GS and MRS scores were 0.79 (0.63 to 0.87) and 0.80 (0.69 to 0.87). The correlation estimates between change scores in RHI and change score in GS and MRS were 0.75 (0.67 to 0.82) and 0.84 (0.79 to 0.88), respectively. The SES and GRS estimates for GS, MRS and RHI were: 1.87 (1.54 to 2.20) and 1.23 (0.97 to 1.50), 1.29 (1.02 to 1.56) and 0.88 (0.65 to 1.12), and 1.05 (0.79 to 1.30) and 0.88 (0.64 to 1.12), respectively. CONCLUSIONS: The RHI is a new histopathological index with favourable operating properties.

Reproducibility of histological assessments of disease activity in UC.

OBJECTIVE: Histopathology is potentially an important outcome measure in UC. Multiple histological disease activity (HA) indices, including the Geboes score (GS) and modified Riley score (MRS), have been developed; however, the operating properties of these instruments are not clearly defined. We assessed the reproducibility of existing measures of HA. DESIGN: Five experienced pathologists with GI pathology fellowship training and expertise in IBD evaluated, on three separate occasions at least two weeks apart, 49 UC colon biopsies and scored the GS, MRS and a global rating of histological severity using a 100 mm visual analogue scale (VAS). The reproducibility of each grading system and for individual instrument items was quantified by estimates of intraclass correlation coefficients (ICCs) based on two-way random effects models. Uncertainty of estimates was quantified by 95% two-sided CIs obtained using the non-parametric cluster bootstrap method. Biopsies responsible for the greatest disagreement based on the ICC estimates were identified. A consensus process was used to determine the most common sources of measurement disagreement. Recommendations for minimising disagreement were subsequently generated. RESULTS: Intrarater ICCs (95% CIs) for the total GS, MRS and VAS scores were 0.82 (0.73 to 0.88), 0.71 (0.63 to 0.80) and 0.79 (0.72 to 0.85), respectively. Corresponding inter-rater ICCs were substantially lower: 0.56 (0.39 to 0.67), 0.48 (0.35 to 0.66) and 0.61 (0.47 to 0.72). Correlation between the GS and VAS was 0.62 and between the MRS and VAS was 0.61. CONCLUSIONS: Although 'substantial' to 'almost perfect' ICCs for intrarater agreement were found in the assessment of HA in UC, ICCs for inter-rater agreement were considerably lower. According to the consensus process results, standardisation of item definitions and modification of the existing indices is required to create an optimal UC histological instrument.

Venous invasion in oesophageal adenocarcinoma: enhanced detection using elastic stain and association with adverse histological features and clinical outcomes.

AIMS: In oesophageal adenocarcinoma, detection rates of venous invasion using haematoxylin and eosin (H&E) and elastic stains have not been compared. The aims of this study were to investigate whether or not elastic stains facilitate the detection of venous invasion, and to determine the prognostic significance of venous invasion following review with elastic stains. METHODS AND RESULTS: One hundred and three resection specimens containing oesophageal adenocarcinoma, all reported originally as negative for venous invasion, were examined for the presence of venous invasion using H&E and subsequently Movat pentachrome stains. Venous invasion was detected in eight cases with H&E and an additional 66 cases using Movat pentachrome; overall, 72% of cases contained venous invasion. Venous invasion was associated with advanced stage, tumour size, lymphatic and perineural invasion and subsequent distant metastases. Venous invasion, stage, size, grade, lymphatic invasion and perineural invasion were prognostically significant on univariate analysis. Only tumour stage was independently prognostic. Two of eight patients with venous invasion but no other indication for adjuvant treatment died of recurrent disease. CONCLUSIONS: Elastic stains improve detection of venous invasion significantly in oesophageal adenocarcinoma. Venous invasion is associated with multiple adverse clinicopathological features. Its identification may facilitate the stratification of patients at risk for visceral metastases and disease-related death.

Severe Ulcerative Colitis Complicated by Malakoplakia Resulting in Proctocolectomy.

We report a 45-year-old man with medically refractory ulcerative colitis with superimposed colonic malakoplakia, presumed related to chronic use of azathioprine and biologics. This is the first reported case of malakoplakia in a patient requiring high doses of combination therapy. Treatment of malakoplakia is not standardized, but can involve systemic antibiotics, or surgical resection, which in this case resulted in proctocolectomy.

Deep learning system for true- and pseudo-invasion in colorectal polyps.

Over 15 million colonoscopies were performed yearly in North America, during which biopsies were taken for pathological examination to identify abnormalities. Distinguishing between true- and pseudo-invasion in colon polyps is critical in treatment planning. Surgical resection of the colon is often the treatment option for true invasion, whereas observation is recommended for pseudo-invasion. The task of identifying true- vs pseudo-invasion, however, could be highly challenging. There is no specialized software tool for this task, and no well-annotated dataset is available. In our work, we obtained (only) 150 whole-slide images (WSIs) from the London Health Science Centre. We built three deep neural networks representing different magnifications in WSIs, mimicking the workflow of pathologists. We also built an online tool for pathologists to annotate WSIs to train our deep neural networks. Results showed that our novel system classifies tissue types with 95.3% accuracy and differentiates true- and pseudo-invasions with 83.9% accuracy. The system's efficiency is comparable to an expert pathologist. Our system can also be easily adjusted to serve as a confirmatory or screening tool. Our system (available at http://ai4path.ca ) will lead to better, faster patient care and reduced healthcare costs.

Staying Online in Uncertain Times: A Nationwide Canadian Survey of Pathology Resident Uses of and Adaptations to Online Learning During COVID-19.

CONTEXT.­: Because of restrictions as a result of the COVID-19 pandemic, medical educators rapidly transitioned to an online curriculum for pathology resident education. The benefits and challenges of the shift to online learning, as well as strategies to maximize learning, are yet to be fully elucidated. OBJECTIVE.­: To assess learner perception and satisfaction with the move to online learning. Understanding the benefits of online learning will allow future curricular changes to most effectively incorporate online learning. Understanding the common challenges will allow our current learning strategies to rapidly adapt and ideally mitigate these challenges as online learning is incorporated into medical education. DESIGN.­: This was a survey-based study distributed by email to pathology residents nationwide in Canada in anatomic pathology, general pathology, neuropathology, and hematopathology. Thirty residents participated, from anatomic pathology (n = 23; 76%), from general pathology (n = 5; 16%), and 1 participant each from hematopathology and neuropathology. RESULTS.­: All participants indicated that their program had transitioned to online learning at least in part. The majority of participants (n = 16; 53%) did not feel their pathology education was negatively affected by the transition to online learning; however, a significant minority (n = 6; 20%) felt their education had been negatively affected. Convenience and less intimidation were rated as benefits of online learning. Negative effects included technical issues and decreased engagement; we identified a number of strategies used by programs and pathology residents to mitigate these negative effects. CONCLUSIONS.­: Our survey points to a need to use adaptations and best-practice recommendations to maximize the benefits of online learning moving forward.

Impact of COVID-19-related health care disruptions on pathologic cancer staging during the first pandemic year: a retrospective cohort study from March 2018 to March 2021.

BACKGROUND: The COVID-19 pandemic has created major disruptions in cancer care, with reductions in diagnostic tests and treatments. We evaluated the impact of these health care-related changes on cancer staging by comparing cancers staged before and during the pandemic. METHODS: We performed a retrospective cohort study at London Health Sciences Centre and St. Joseph's Health Care London, London, Ontario, Canada. We evaluated all pathologically staged breast, colorectal, prostate, endometrial and lung cancers (the 5 most common cancers by site, excluding nonmelanoma skin cancer) over a 3-year period (Mar. 15, 2018-Mar. 14, 2021). The pre-COVID-19 group included procedures performed between Mar. 15, 2018, and Mar. 14, 2020, and the COVID-19 group included procedures performed between Mar. 15, 2020, and Mar. 14, 2021. The primary outcome was cancer stage group, based on the pathologic tumour, lymph node, metastasis system. We performed univariate analyses to compare demographic characteristics, pathologic features and cancer stage between the 2 groups. We performed multivariable ordinal regression analyses using the proportional odds model to evaluate the association between stage and timing of staging (before v. during the pandemic). RESULTS: There were 4055 cases across the 5 cancer sites. The average number of breast cancer staging procedures per 30 days increased during the pandemic compared to the yearly average in the pre-COVID-19 period (41.3 v. 39.6), whereas decreases were observed for endometrial cancer (15.9 v. 16.4), colorectal cancer (21.8 v. 24.3), prostate cancer (13.6 v. 18.5) and lung cancer (11.5 v. 15.9). For all cancer sites, there were no statistically significant differences in demographic characteristics, pathologic features or cancer stage between the 2 groups (p > 0.05). In multivariable regression analysis, for all cancer sites, cases staged during the pandemic were not associated with higher stage (breast: odds ratio [OR] 1.071, 95% confidence interval [CI] 0.826-1.388; colorectal: OR 1.201, 95% CI 0.869-1.661; endometrium: OR 0.792, 95% CI 0.495-1.252; prostate: OR 1.171, 95% CI 0.765-1.794; and lung: OR 0.826, 95% CI 0.535-1.262). INTERPRETATION: Cancer cases staged during the first year of the COVID-19 pandemic were not associated with higher stage; this likely reflects the prioritization of cancer procedures during times of reduced capacity. The impact of the pandemic period on staging procedures varied between cancer sites, which may reflect differences in clinical presentation, detection and treatment.

Impact of COVID-19 pandemic on neuropathology service: Experience at one Canadian center.

The COVID-19 pandemic has had a significant impact on medical services. Many countries postponed nonemergent procedures to preserve hospital resources for the unprecedented situation. Surgical backlogs caused by the COVID-19 pandemic have been evaluated by different groups. However, the impact of this pandemic on pathology and specifically neuropathology (NP) services has received limited attention. In this study, we reviewed all NP reports of the London Health Sciences Centre from January 2018 (2 years before the pandemic declaration) until the end of the year 2021. Demographic information and pathology details were collected. For tumors, site, histopathology types, and WHO grading were analyzed. In nontumoral specimens, pathological diagnoses were compared in pre- and postpandemic time. The total number of NP samples reached its lowest in April 2020, corresponding to the first Ontario provincial lockdown, and fluctuated throughout the studied period. Among the different types of NP surgical specimens, muscle and epilepsy-related specimens showed a more significant reduction, compared to neoplastic specimens. In 2020, the proportion of tumor specimens from patients older than 40 years of age increased. Similarly, the proportion of high-grade glioma and brain metastasis diagnoses also increased. Lastly, we observed a marked increase in biopsies for temporal arteritis and other inflammatory lesions.

Severity of coeliac disease and clinical management study when using a non-metabolised medication: a phase I pharmacokinetic study.

OBJECTIVE: The non-metabolised antihistamine fexofenadine has oral absorption resulting from transporter activity. Uptake by enterocyte organic anion transporting polypeptides and efflux by an ATP-binding cassette transporter (P-glycoprotein) are primary determinants. Coeliac disease-mediated lesions to the small intestinal mucosa may alter oral absorption of the drug probe, fexofenadine. DESIGN: A phase I, open-label, single-dose, pharmacokinetic study SETTING: London, Ontario, Canada PARTICIPANTS: Patients with coeliac disease (n=41) with positive serology and healthy individuals (n=48). MAIN OUTCOME MEASURES: Patients with coeliac disease-duodenal histology and oral fexofenadine pharmacokinetics within a 3-week period. Healthy individuals-oral fexofenadine pharmacokinetics with water and grapefruit juice. RESULTS: Patients with coeliac disease were stratified by disease severity: Group A (n=15, normal), B+C (n=14, intraepithelial lymphocytosis with/without mild villous blunting) and D (n=12, moderate to severe villous blunting). Patients with coeliac disease in groups A, B+C and D and healthy individuals receiving water had similar fexofenadine AUC0-8 (2038±304, 2259±367, 2128±410, 1954±138 ng.h/mL; p>0.05; mean±SEM) and Cmax (440±73, 513±96, 523±104, 453±32 ng/mL; p>0.05), respectively. These four groups all had higher fexofenadine AUC0-8 (1063±59; p<0.01) and Cmax (253±18; p<0.05) compared with those for healthy individuals receiving grapefruit juice. Coeliac groups had a positive linear trend between disease severity and fexofenadine Tmax (2.0±0.3, 2.7±0.4, 3.1±0.5 hours; p<0.05). CONCLUSIONS: Coeliac disease severity based on duodenal histopathology did not affect oral fexofenadine bioavailability. Increased Tmax suggested absorption distal to the duodenum (jejunum + ileum), where histology seems more normal which may be the key determinant. Patients with coeliac disease may not require consideration for alternative clinical drug management for a number of non-metabolised and transport-mediated medications.

Outcomes of a 5-year follow-up of patients with sessile serrated adenomas.

OBJECTIVE: Sessile serrated adenomas (SSAs) are precursors to colorectal cancer (CRC). The purpose of this study is to determine the occurrence of new polyps and CRC in patients with an SSA over a 5-year follow-up interval. METHODS: This study is a retrospective chart review of patients with SSAs diagnosed at colonoscopy in 2005. Abstracted information included patient demographics, colonoscopy information, and polyp characteristics. RESULTS: During 2005, 34 SSAs and 5 mixed SSAs were identified in 33 patients. The mean patient age was 66 years and 58% were female. There was a family history of CRC in 45%, prior polyps in 33%, and previous CRC in 15%. The mean SSA size was 11 mm. SSAs were located proximal to the splenic flexure in 70%. Low-grade dysplasia was present in 3% of SSAs and 80% mixed SSAs. Synchronous adenomatous and hyperplastic polyps occurred respectively in 45% and 21%. High-grade dysplasia was present in 12% of the adenomas. Twenty-two patients underwent subsequent colonoscopies with 20 new SSAs and 1 mixed SSA identified. In SSAs low-grade dysplasia occurred in 10% and high-grade dysplasia in 5%. Low-grade dysplasia was present in the mixed SSA. Synchronous adenomatous and hyperplastic polyps occurred respectively in 45% and 37%. High-grade dysplasia was present in 10% of adenomas and CRC occurred in 1 (5%) patient. CONCLUSIONS: SSAs occurred more frequently in females and in the right colon. Dysplasia occurred in a small subset of SSAs. There was a high rate of prior and subsequent CRC in patients with SSAs.

Wait times for diagnostic colonoscopy among outpatients with colorectal cancer: a comparison with Canadian Association of Gastroenterology targets.

BACKGROUND: Timely access to colonoscopy is a nationally recognized issue in Canada, with previous studies documenting significant wait times for a variety of indications. However, specific wait times for colonoscopy among patients diagnosed with colorectal cancer remain unknown. METHODS: A review of all outpatient cases of colorectal cancer diagnosed at colonoscopy in London, Ontario, in 2010 was performed. Wait times from the date of referral to colonoscopy were reviewed and compared with maximal wait times established by the Canadian Association of Gastroenterology (CAG) stratified according to indication. Cancer stage at the time of diagnosis was compared with colonoscopy wait times. RESULTS: A total of 106 colorectal cancer patients meeting the inclusion and exclusion criteria were included in the study. Forty-six per cent of patients waited longer than CAG targets, with a mean (± SD) wait time of 79 ± 101 days. Higher cancer stage was associated with shorter wait time, likely as a result of triaging. CONCLUSION: Long wait times for diagnostic colonoscopy among patients with colorectal cancer remain an issue, with a significant proportion of cases not meeting maximal CAG wait time targets.

Routine Elastin Staining in Surgically Resected Colorectal Cancer: Impact on Venous Invasion Detection and its Association With Oncologic Outcomes.

Venous invasion (VI) is a powerful yet underreported prognostic factor in colorectal cancer (CRC). Its detection can be improved with an elastin stain. We evaluated the impact of routine elastin staining on VI detection in resected CRC and its relationship with oncologic outcomes. Pathology reports from the year before (n=145) and the year following (n=128) the implementation of routine elastin staining at our institution were reviewed for established prognostic factors, including VI. A second review, using elastin stains, documented the presence/absence, location, number, and size of VI foci. The relationship between VI and oncologic outcomes was evaluated for original and review assessments. VI detection rates increased from 21% to 45% following implementation of routine elastin staining (odds ratio [OR]=3.1; 95% confidence interval [CI]: 1.8-5.3; P<0.0001). The second review revealed a lower VI miss rate postimplementation than preimplementation (22% vs. 48%, respectively; P=0.007); this difference was even greater for extramural VI-positive cases (9% vs. 38%, respectively; P=0.0003). Missed VI cases postimplementation had fewer VI foci per missed case (P=0.02) and a trend towards less extramural VI than those missed preimplementation. VI assessed with an elastin stain was significantly associated with recurrence-free survival (P=0.003), and cancer-specific survival (P=0.01) in contrast to VI assessed on hematoxylin and eosin alone (P=0.053 and 0.1, respectively). The association between VI and hematogenous metastasis was far stronger for elastin-detected VI (OR=11.5; 95% CI: 3.4-37.1; P<0.0001) than for hematoxylin and eosin-detected VI (OR=3.7; 95% CI: 1.4-9.9; P=0.01). Routine elastin staining enhances VI detection and its ability to stratify risk in CRC and should be considered for evaluation of CRC resection specimens.