Clinicopathologic and genetic characteristics of interval colorectal carcinomas favor origin from missed or incompletely excised precursors

Clinicopathological and molecular differences between stage IV screen-detected and interval colorectal cancers in the Flemish screening program

Introduction

Interval cancer (IC) is an important quality indicator in colorectal cancer (CRC) screening. Previously, we found that fecal immunochemical test (FIT) ICs are more common in women, older age, right-sided tumors, and advanced stage. Here, we extended our existing stage IV patient cohort with clinicopathological and molecular characteristics, to identify factors associated with FIT-IC.

Methods

Logistic regression models were fit to identify variables associated with the odds of having a stage IV FIT-IC. Multivariate models were corrected for gender, age, and location.

Results

A total of 292 screen-detected (SD) CRCs and 215 FIT-IC CRCs were included. FIT-IC CRC had 5 fold higher odds to be a neuroendocrine (NET) tumor and 2.5 fold higher odds to have lymphovascular invasion. Interestingly, some variables lost significance upon accounting for location. Thus, tumor location is a critical covariate that should always be included when evaluating factors related to FIT-IC.

Conclusions

We identified NETs and lymphovascular invasion as factors associated with increased odds of having a stage IV FIT-IC. Moreover, we highlight the importance of tumor location as a covariate in evaluating FIT-IC related factors. More research across all stages is needed to clarify how these insights might help to optimize the Flemish CRC screening program.

Multifunctional two-component in-situ hydrogel for esophageal submucosal dissection for mucosa uplift, postoperative wound closure and rapid healing

Endoscopic submucosal dissection (ESD) for gastrointestinal tumors and premalignant lesions needs submucosal fluid cushion (SFC) for mucosal uplift before dissection, and wound care including wound closure and rapid healing postoperatively. Current SFC materials as well as materials and/or methods for post-ESD wound care have single treatment effect and hold corresponding drawbacks, such as easy dispersion, short duration, weak hemostasis and insufficient repair function. Thus, designing materials that can serve as both SFC materials and wound care is highly desired, and remains a challenge. Herein, we report a two-component in-situ hydrogel prepared from maleimide-based oxidized sodium alginate and sulfhydryl carboxymethyl-chitosan, which gelated mainly based on "click" chemistry and Schiff base reaction. The hydrogels showed short gelation time, outstanding tissue adhesion, favorable hemostatic properties, and good biocompatibility. A rat subcutaneous ultrasound model confirmed the ability of suitable mucosal uplift height and durable maintenance time of AM solution. The in vivo/in vitro rabbit liver hemorrhage model demonstrated the effects of hydrogel in rapid hemostasis and prevention of delayed bleeding. The canine esophageal ESD model corroborated that the in-situ hydrogel provided good mucosal uplift and wound closure effects, and significantly accelerated wound healing with accelerating re-epithelization and ECM remodeling post-ESD. The two-component in-situ hydrogels exhibited great potential in gastrointestinal tract ESD.

Comparison of adenoma detection rate and proximal serrated polyp detection rate and their effect on post-colonoscopy colorectal cancer mortality in screening patients

BACKGROUND

Patients with serrated polyps are at increased risk for post-colonoscopy colorectal cancer (PCCRC); however, evidence for a dedicated serrated polyp detection rate is lacking. The aim of this study was to investigate the association of the proximal serrated polyp detection rate (PSDR) and adenoma detection rate (ADR) with PCCRC death.

METHODS

This was a retrospective analysis within the Austrian quality assurance program for screening colonoscopy. Spearman's rank coefficient was calculated for the assessment of association between ADR and PSDR. Whether ADR or PSDR were associated with colorectal cancer mortality was assessed by Cox proportional hazards model.

RESULTS

229 /729 screening colonoscopies performed by 308 endoscopists were analyzed. The ADR (hazard ratio [HR] per 1 percentage point increase 0.98, 95 %CI 0.96-0.99) as well as the PSDR (HR per 1 percentage point increase 0.97, 95 %CI 0.94-0.99) were significantly associated with PCCRC death. The correlation coefficient of the ADR and PSDR calculated at every colonoscopy was 0.70 (95 %CI 0.70-0.71), and the corresponding PSDR value for an ADR performance standard of 25 % was 11.1 %. At the end of the study period, 86 endoscopists (27.9 %) reached an ADR of > 25 % and a PSDR of > 11.1 %.

CONCLUSIONS

The ADR as well as the PSDR were associated with PCCRC death. Striving for a high PSDR in addition to a high ADR might reduce the risk for PCCRC mortality in patients undergoing screening colonoscopy.

Clinically significant serrated polyp detection rates and risk for postcolonoscopy colorectal cancer: data from the New Hampshire Colonoscopy Registry

BACKGROUND AND AIMS

Higher adenoma detection rates reduce the risk of postcolonoscopy colorectal cancer (PCCRC). Clinically significant serrated polyps (CSSPs; defined as any sessile serrated polyp, traditional serrated adenoma, large [≥1 cm] or proximal hyperplastic polyp >5 mm) also lead to PCCRC, but there are no data on associated CSSP detection rates (CSSDRs). We used data from the New Hampshire Colonoscopy Registry (NHCR) to investigate the association between PCCRC risk and endoscopist CSSDR.

METHODS

We included NHCR patients with 1 or more follow-up events: either a colonoscopy or a colorectal cancer (CRC) diagnosis identified through linkage with the New Hampshire State Cancer Registry. We defined our outcome, PCCRC, in 3 time periods: CRC diagnosed 6 to 36 months, 6 to 60 months, or all examinations (6 months or longer) after an index examination. We excluded patients with CRC diagnosed at or within 6 months of the index examination, with incomplete examinations, or with inflammatory bowel disease. The exposure variable was endoscopist CSSDR at the index colonoscopy. Cox regression was used to model the hazard of PCCRC on CSSDR controlling for age, sex, index findings, year of examination, personal history of colorectal neoplasia, and having more than 1 surveillance examination.

RESULTS

One hundred twenty-eight patients with CRC diagnosed at least 6 months after their index examination were included. Our cohort included 142 endoscopists (92 gastroenterologists). We observed that the risk for PCCRC 6 months or longer after the index examination was significantly lower for examinations performed by endoscopists with CSSDRs of 3% to <9% (hazard ratio [HR], .57; 95% confidence interval [CI], .39-.83) or 9% or higher (HR, .39; 95% CI, .20-.78) relative to those with CSSDRs under 3%.

CONCLUSIONS

Our study is the first to demonstrate a lower PCCRC risk after examinations performed by endoscopists with higher CSSDRs. Both CSSDRs of 9% and 3% to <9% had statistically lower risk of PCCRC than CSSDRs of <3%. These data validate CSSDR as a clinically relevant quality measure for endoscopists.

Atypical Presentation of Interval Colorectal Cancer/Post-Colonoscopy Colorectal Cancer in a Nursing Home Patient

The Centers for Disease Control and Prevention estimates that there are around 1.7 million beds in certified nursing homes across the United States and approximately 1.3 million residents in long-term and end-of-life care. There could be several factors causing a delayed recovery in such patients, such as decreased ambulation, multiple comorbidities, and polypharmacy.

An 83-year-old Caucasian woman sustained a fall resulting in compression fractures of the thoracic and lumbar spine. She had multiple comorbidities, including anemia of chronic disease, malnutrition, and a significant weight loss of 30 lbs over the four months prior to hospitalization. She was on antihypertensives, antidepressants, vitamin D, and calcium supplementation. Her medical history was significant for constipation with the passage of stools once in three days. Her family history was significant for colorectal cancer (CRC) and her screening colonoscopy three years ago was normal. Physical examination revealed no abdominal tenderness or distention. Subsequently, she developed edema in the left lower extremity. She underwent a venous Doppler/ultrasound study, which showed an occlusive thrombus from the common femoral vein to the popliteal vein. She was started on anticoagulants and supportive therapy. Four months later, while at the nursing home, she developed bloating and flatulence, in addition to pre-existing constipation. Examination revealed a 6 x 7 cm mass in the right lower quadrant without peritoneal signs. Bowel sounds were significantly decreased. CT imaging showed a 6-cm diameter cecal mass. The tumor was a low-grade 4 x 9 cm T4N0M0 cecal cancer, and she underwent placement of a Greenfield filter and subsequent hemicolectomy. She had methicillin-resistant Staphylococcus aureus infection and right upper extremity deep vein thrombosis (DVT), urinary tract infection, Clostridium difficile colitis, and depression, all managed successfully and without sequelae in the post-operative period. Treatment on discharge comprised Coumadin maintenance for nine months with an international normalized ratio goal of 2-3, a back brace, antidepressants, and antihypertensive medications. She received follow-up care at home.

Maintaining a high degree of suspicion for new and persistent symptoms in the elderly is essential to identify the underlying cause. One of the leading causes of post-colonoscopy CRC is a missed lesion. Careful attention to all cases of anemia as well as DVT in the elderly is also imperative to diagnose such missed cases. Future research should focus on the methods of CRC diagnosis in elderly patients with comorbidities apart from using colonoscopy alone.

Molecular pathways in post-colonoscopy versus detected colorectal cancers: results from a nested case-control study

BACKGROUND

Post-colonoscopy colorectal cancers (PCCRCs) pose challenges in clinical practice. PCCRCs occur due to a combination of procedural and biological causes. In a nested case-control study, we compared clinical and molecular features of PCCRCs and detected CRCs (DCRCs).

METHODS

Whole-genome chromosomal copy number changes and mutation status of genes commonly affected in CRC were examined by low-coverage WGS and targeted sequencing, respectively. MSI and CIMP status was also determined.

RESULTS

In total, 122 PCCRCs and 98 DCRCs with high-quality DNA were examined. PCCRCs were more often located proximally (P < 0.001), non-polypoid appearing (P = 0.004), early stage (P = 0.009) and poorly differentiated (P = 0.006). PCCRCs showed significantly less 18q loss (FDR < 0.2), compared to DCRCs. No significant differences in mutations were observed. PCCRCs were more commonly CIMP high (P = 0.014) and MSI (P = 0.029). After correction for tumour location, only less 18q loss remained significant (P = 0.005).

CONCLUSION

Molecular features associated with the sessile serrated lesions (SSLs) and non-polypoid colorectal neoplasms (CRNs) are more commonly seen in PCCRCs than in DCRCs. These together with the clinical features observed support the hypothesis that SSLs and non-polypoid CRNs are contributors to the development of PCCRCs. The future focus should be directed at improving the detection and endoscopic removal of these non-polypoid CRN and SSLs.

CLINICAL TRIAL REGISTRATION

NTR3093 in the Dutch trial register ( www.trialregister.nl ).

The Frontiers of Serrated Polyps

The serrated pathway of carcinogenesis has been the subject of intense investigation over the past 2 decades, but many gaps in our understanding still need to be resolved. Serrated polyp precursors include hyperplastic polyps, sessile serrated polyps, and traditional serrated adenomas. These are considered discrete entities, but there is emerging molecular data to suggest that they may be more closely related to each other than currently believed. The recent US Multi-Society Task Force surveillance guidelines for patients with serrated polyps are admittedly based on low quality evidence. In this brief review, we discuss the limitations in endoscopic detection and pathologic interpretation of serrated polyps and the implications of these diagnostic difficulties on risk prediction and postpolypectomy surveillance recommendations.

Colorectal adenocarcinomas diagnosed following a negative faecal immunochemical test show high-risk pathological features in a colon screening programme

AIMS

The faecal immunochemical test (FIT) is used every 2 years to screen average-risk British Columbians aged 50-74 years, with follow-up colonoscopy for positive results. Non-screen-detected colorectal adenocarcinomas are defined as those detected within 25 months following a negative FIT. We aimed to more clearly characterise these malignancies.

METHODS AND RESULTS

A medical chart and focused pathology review of colorectal malignancies from 926 individuals who completed FIT in the British Columbia Colon Screening Program in 2014, and whose pathology reports were available for review, was conducted. This cohort was divided into two groups: individuals with colorectal adenocarcinomas diagnosed following a positive FIT (screen-detected) and individuals with colorectal adenocarcinoma diagnosed within 25 months of a negative FIT (FIT-interval cancers). Rates of clinically relevant pathological parameters, as outlined in the American Joint Committee on Cancer (AJCC), 8th edition, were compared between the screen-detected and FIT-interval cancer groups. A total of 876 screen-detected and 50 FIT-interval cancers were identified. FIT-interval cancers exhibited higher rates of high-grade differentiation (including poorly differentiated and undifferentiated cases; P < 0.01) and aggressive histotype (signet ring cell and mucinous carcinomas; P < 0.01) than did screen-detected cancers after Bonferroni correction. Colorectal adenocarcinoma diagnosed after a negative FIT may therefore be associated with worse prognostic determinants than screen-detected cancers.

CONCLUSION

FIT-interval cancers are associated with high-risk pathological features; the possibility that more aggressive, fast-growing lesions which arise in the interval after truly negative FITs cannot be ruled out. Further study of a larger cohort of FIT-interval cancers controlling for interaction among the different pathologic parameters will be undertaken.

Endoscopically Injectable Shear-Thinning Hydrogels Facilitating Polyp Removal

Submucosal elevation, the process of instilling material in the submucosal space for separation of the surface mucosa and deeper muscularis layer, is a significant aspect of the endoscopic mucosal resection of large lesions performed to facilitate lesion removal and maximize safety. Submucosal injection, when applied, has historically been performed with normal saline, though this is limited by its rapid dissipation; solutions ideally need to be easily injectable, biocompatible, and provide a long-lasting submucosal cushion with a desirable height. Here, reported is a new set of materials, endoscopically injectable shear-thinning hydrogels, meeting these requirements because of their biocompatible components and ability to form a solid hydrogel upon injection. These findings are supported by evaluation in a large animal model and ultimately demonstrate the potential of these shear-thinning hydrogels to serve as efficient submucosal injection fluids for cushion development. Given these unique characteristics, their broad application in mucosal resection techniques is anticipated.

An update on the morphology and molecular pathology of serrated colorectal polyps and associated carcinomas

Our understanding of serrated colorectal polyps has increased dramatically over the past two decades and has led to a modern classification scheme for these lesions. Sessile serrated polyps with dysplasia represent the most clinically significant serrated polyp; however, the morphologic heterogeneity of dysplasia in sessile serrated polyps has only recently been recognized and correlated with MLH1 immunohistochemistry. Detailed morphologic analysis of traditional serrated adenomas has led to the recognition of flat and early forms of this polyp. Robust data on the risk of metachronous lesions in patients with serrated polyps are also beginning to emerge. This review will summarize our current understanding of serrated polyps and associated carcinomas with a focus on diagnostic criteria, morphologic heterogeneity, molecular findings, and natural history. Controversial issues in the diagnosis and classification of these polyps are also discussed.

Post-colonoscopy colorectal cancers identified by probabilistic and deterministic linkage: results in an Australian prospective cohort

OBJECTIVE

Post-colonoscopy colorectal cancers (PCCRCs) are recognised as a critical quality indicator. Benchmarking of PCCRC rate has been hampered by the strong influence of different definitions and methodologies. We adopted a rigorous methodology with high-detail individual data to determine PCCRC rates in a prospective cohort representing a single jurisdiction.

SETTING

We performed a cohort study of individuals who underwent colonoscopy between 2001 and 2008 at a single centre serving Australian Capital Territory (ACT) and enclaving New South Wales (NSW) region. These individuals were linked to subsequent colorectal cancer (CRC) diagnosis, within 5 years of a negative colonoscopy, through regional cancer registries and hospital records using probabilistic and deterministic record linkage. All cases were verified by pathology review. Predictors of PCCRCs were extracted.

PARTICIPANTS

7818 individuals had a colonoscopy in the cohort. Linkage to cancer registries detected 384 and 98 CRCs for notification dates of 2001-2013 (ACT) and 2001-2010 (NSW). A further 55 CRCs were identified from a search of electronic medical records using International Classification of Diseases-10 diagnosis codes. After verification and exclusions, 385/537 CRCs (58% male) were included.

PRIMARY OUTCOME MEASURE

PCCRC rates.

RESULTS

There were 15 PCCRCs in our cohort. The PCCRC incidence rate was 0.384/1000 person-years and the 5-year PCCRC risk was estimated as 0.192% (95% CI 0.095 to 0.289). The index colonoscopy prior to PCCRC was more likely to show diverticulosis (p=0.017 for association, OR 3.56, p=0.014) and have poor bowel preparation (p=0.017 for association, OR 4.19, p=0.009).

CONCLUSION

In this population-based cohort study, the PCCRC incidence rate was 0.384/1000 person-years and the 5-year PCCRC risk was 0.192%. These data show the 'real world' accuracy of colonoscopy for CRC exclusion.