Left-Sided Colectomy: One of the Important Risk Factors of Metachronous Colorectal Adenoma After Colectomy for Colon Cancer

Establishment and validation of a clinical prediction model for colorectal adenoma risk factors

Colorectal adenomas are benign tumors of the colorectal mucosal epithelium that have malignant potential and are regarded as precancerous lesions of colorectal cancer, for which the specific risk factors are unclear. The present study aimed to identify independent risk factors for colorectal adenoma to develop a prediction model and test its predictive value. A retrospective analysis was performed using data from patients who underwent electronic colonoscopy at the Department of Proctology (Affiliated Hospital of Shandong University of Traditional Chinese Medicine; Jinan, China) from January 2013 to December 2023 and had polyps removed during colonoscopy. Patients with colorectal adenoma were included in the case group, whilst those with no visible abnormalities on endoscopy or with non-adenomatous polyps were included as a control group. The patients were randomly divided into a training and validation group in a 7:3 ratio. Variables were screened using single-component analysis and the filtered variables were employed in multivariate logistic regression to create a clinical prediction model. Finally, the model was internally and externally validated. A total of 730 patients were included in the present study, with 286 assigned to the case group and 444 to the control group. After the initial screening of 39 variables, 12 continued to the next round, resulting in four potential predictors including age, daily number of bowel movements, thrombin time and the number of polyps. A prediction model was created based on these variables. Regarding internal validation, the C-index was 0.7054 [95% confidence interval (CI), 0.6596-0.7512] and the prediction probability in the calibration curve was close to the diagonal line of the calibration graph, indicating that the prediction probability of the model was reasonable. Regarding external validation, the C-index in the validation cohort was 0.6306 (95% CI, 0.5560-0.7053) and the calibration curve also demonstrated good identification capabilities. The Hosmer-Lemeshow test revealed that the model had a reasonable calibration degree, with χ2=9.7893, degree of freedom=8 and P=0.28. The receiver operating characteristic curve and decision curve analysis for the training and validation cohorts demonstrated good efficacy and an ideal application value. In conclusion, the model constructed in the present study demonstrated moderate predictive accuracy for colorectal adenoma risk, laying the groundwork for early detection of colorectal adenoma and secondary prevention of colorectal cancer.

IMMUNOREACT 9 metachronous rectal cancers have high HLA-ABC expression on healthy epithelium but a lower infiltration of CD3+ T cells than primary lesions

Lynch syndrome is rarely associated with rectal cancer (RC) and thus, metachronous RC has been scarcely investigated. This study aimed to analyze the mucosal immune microenvironment in sporadic and metachronous RC. We analyzed the mucosal immune microenvironment in the 25 metachronous RCs present in the IMMUNOREACT 1 and 2 multicentre observational studies (624 patients). A panel of immune markers was retrospectively investigated at immunohistochemistry: CD3, CD4, CD8, CD8b, Tbet, FoxP3, PD-L1, MSH6, and PMS2 and CD80. Single-cell suspensions were subjected to flow-cytometry to determine the proportion of epithelial cells (pan-cytokeratin) acting as antigen-presenting cells (expressing CD80, CD86, HLA-ABC) and the proportion of activated CD8 + T cells (CD8 + positive for CD28, CD38), inhibitory T cells (CD3 + CTLA-4+) of activated CD4 + T helper cells (CD4 + CD25+) and activated T regulatory cells (CD4 + CD25 + FoxP3+). No mismatch repair gene deficiencies were observed in the patients. The previous history of colorectal adenoma was significantly more frequent in metachronous RC. In healthy epithelial cells, HLA-ABC expression was significantly higher in patients with metachronous RC. In therapy-naïve metachronous RC patients, a significantly lower level of circulating lymphocytes and CD3 + T-cell infiltration in the healthy mucosa surrounding the RC was observed compared to patients with non-metachronous cancer. Our study supports the hypothesis that metachronous RC can occur in a cancerization field in patients with weak systemic and local immune systems. The peculiar site of RC makes the mismatch-repair genes deficiency in metachronous cancer onset less relevant.

The absolute number of small and diminutive adenomas with high-grade dysplasia is substantially higher compared with large adenomas: a retrospective pooled study

Introduction

The risk that a large polyp (≥10 mm) evolves into high-grade dysplasia (HGD) is relatively high compared with that of a small/diminutive polyp (<10 mm). Recently, the detection of small and diminutive polyps has been substantially improved with the advancement of endoscopy. However, further research is needed on the role of the incidence of HGD caused by the co-occurrence of small and diminutive polyps in the progression of HGD. In this study, we aim to investigate whether and how the small and diminutive polyps correlate with the incidence of HGD in the population.

Methods

The pooled data were deeply analyzed from four published randomized controlled trials (RCTs) regarding colon polyp detection. All polyps detected were examined and confirmed by pathologists. The primary outcome was the composition ratio of the HGD polyps in each polyp size category.

Results

Among a total of 3,179 patients with 2,730 polyps identified, there were 83 HGD polyps confirmed, and 68 patients had at least one polyp with HGD. The risk of development of HGD was lower for a single small and diminutive polyp than for one large polyp (2.18% vs. 22.22%, P < 0.0001). On the contrary, the composition ratio for HGD from small and diminutive polyps was significantly higher than that from the large ones (68.67% vs. 31.33%, P < 0.0001). The combined number of HGD presented a trend negatively correlated to size.

Conclusions

Our data demonstrated that the absolute number of HGD significantly derives more from small and diminutive polyps than from the large ones, and the collective number of small and diminutive polyps per patient is indicative of his/her HGD exposure. These findings positively provide novel perspectives on the management of polyps and may further optimize the prevention of colorectal cancer.

Systematic Review Registration

http://www.chictr.org.cn, identifier ChiCTR1900025235, ChiCTR1800017675, ChiCTR1800018058, and ChiCTR1900023086.

Detection methods of synchronous colorectal lesions in proximal colon for patients with obstructive colorectal cancer: a literature review

INTRODUCTION

Colorectal cancer holds a high morbidity and mortality rate. As a common method for colorectal cancer detection, colonoscopy has difficulty in passing through the malignant stenosis in patients with obstructive colorectal cancer, which results in incomplete detection and missed diagnosis. The missed synchronous lesions increase the risk of metachronous cancer. Therefore, detecting proximal synchronous lesions in patients with obstructive colorectal cancer should be appreciated before operation.

AREA COVERED

This review evaluates related literature, aiming at providing clinicians with more ideas and attention for detecting proximal synchronous lesions in patients with obstructive colorectal cancer.

EXPERT OPINION

In patients with obstructive colorectal cancer, missed diagnosis of lesions proximal to the obstruction may lead to metachronous colorectal cancer. Except for preoperative colonoscopy which is difficult to pass through malignant stenosis, other methods that can evaluate proximal colon segment are critical. This article introduced several preoperative, intraoperative and postoperative measures for synchronous lesions detection. The choice of methods should base on patients' conditions, aiming at a high diagnostic yield and low risk. Early detection and resection of synchronous lesions in the proximal section of malignant obstruction are expected to minimize the risk of metachronous colorectal cancer and even effect follow-up treatment strategy, which deserves the attention of clinicians.

Design and verification of individualized follow-up strategy of colonoscopy for postoperative patients with colorectal cancer

BACKGROUND

Current guidelines do not establish an individual scheme for surveillance colonoscopy in postoperative colorectal cancer (CRC) patients.

AIMS

The purpose of the study was to screen possible risk factors for the development of metachronous adenoma in postoperative CRC patients and to develop a risk prediction model and verify it.

METHODS

Consecutive postoperative patients with CRC were enrolled from April 2007 to December 2013 as the derivation group. Baseline data of patients and clinicopathological features of the tumor were collected, logistic regression analysis was performed, and clinical model was established and was verified internally. The model was externally validated in an independent cohort (validation group) from January 2014 to October 2017 in the same hospital.

RESULTS

A total of 734 patients were included, with average (64.6 ± 11.5) years old. The overall incidence of metachronous adenoma was 35.4%. There was no significant difference in the incidence of metachronous adenoma between the derivation group and validation group (P > 0.05). Age, diabetes mellitus, right colon cancer, moderately to poorly differentiated adenocarcinoma and synchronous adenoma were independent risk factors for metachronous adenoma. The C-index of the metachronous adenoma line chart model was 0.932, and the index decreased by 0.022 after internal verification. The C-index of external validation was 0.910. The Hosmer-Lemeshow test showed that the P value of metachronous adenoma risk prediction model was 0.247.

CONCLUSIONS

Individual surveillance strategies should be designed for postoperative patients with CRC. For high-risk patients, it is appropriate to undergo more than two colonoscopies in 36 months after operation.

Hazard function analysis for development of second primary colorectal cancer after surgery for primary colorectal cancer

BACKGROUND AND AIM

Although history of colorectal cancer (CRC) is a known risk factor for developing second CRC, the optimal surveillance protocol has not been established. Using hazard function analysis to evaluate changes in the hazard rate for the development of second primary CRCs or high-grade adenomas (HGAs), we aimed to clarify when and on whom to focus in order to effectively identify second primary colorectal neoplasms after initial surgery for CRC.

METHODS

We retrospectively enrolled 1823 consecutive patients with stage 0-III CRCs who underwent radical surgery between 2004 and 2015, and subsequent colonoscopic surveillance after surgery. The time-course changes in the risk rates for developing metachronous CRC and HGA after surgery were assessed.

RESULTS

A peak was observed at 1.22 years after surgery in the hazard function curve for secondary colorectal neoplasms, which decreased until 4 years, then plateaued. Older patients were at higher risk than younger patients, both showing a peak at 1 year. Another peak at 6 to 8 years was observed in younger patients. Male patients showed a higher risk than female patients, and patients with synchronous lesions showed a markedly higher hazard rate than those without, with two distinct peaks around 1 and 9 years after surgery.

CONCLUSIONS

Intensive colonoscopic surveillance is recommended after surgery for CRC during the first 2 to 3 years, and if the patient is under 60 years old and has concomitant CRC or HGA, surveillance is also recommended at 6 to 8 years after surgery.

Risk factors for metachronous adenoma in patients with stage I/II colorectal cancer after radical surgery

Background

It is important to implement a preventive strategy for early detection and endoscopic removal of metachronous adenoma in patients with colorectal cancer (CRC). Here, we retrospectively explored the associated factors of metachronous adenoma in these patients.

Methods

This study recruited 551 patients with stage I and II CRC who underwent radical surgery between January 1, 2012 and July 1, 2017 with postoperative colonoscopic surveillance. Data on clinicopathological characteristics and surveillance colonoscopies were obtained from medical records. Univariate analysis by Kaplan-Meier method and multivariate analysis by Cox proportional hazards model were used to identify the factors associated with metachronous adenoma.

Results

Metachronous adenoma was detected in 110 (20.0%) patients. In these patients, 94.5% (104/110) had metachronous adenoma within 3 years postoperatively. Age, synchronous adenoma, hypertension, tumor stage, and surgical resection were correlated with metachronous adenoma in patients with stage I-II CRC after radical resection (log rank test, P<0.05). Multivariate analyses showed that synchronous adenoma (HR =2.515, 95% CI: 1.691-3.742, P<0.01); stage II (HR =2.066, 95% CI: 1.329-3.210, P<0.01); and left-side colorectal resection (HR =2.207, 95% CI: 1.292-3.772, P<0.01) were independent risk factors.

Conclusions

Synchronous adenoma, left-side colorectal resection, and stage II cancer are independent risk factors of metachronous adenoma in patients with previous stage I and II CRC. In patients with risk factors, an enhanced colonoscopic strategy might be needed for early detection and timely endoscopic removal of metachronous adenoma.

Risk factors of advanced metachronous neoplasms in surveillance after colon cancer resection

BACKGROUND/AIMS

Regular surveillance colonoscopy after colon cancer resection is recommended for detecting metachronous adenoma and cancer. However, risk factors for metachronous neoplasms have not been fully evaluated. We aimed to assess risk factors for advanced metachronous neoplasms during surveillance colonoscopy after colon cancer resection.

METHODS

Patients who underwent curative colectomy for nonmetastatic colon cancer between January 2002 and December 2012 were evaluated and followed up to December 2017.

RESULTS

A total of 293 patients were enrolled in this study. Among these, 179 (61.1%) were male, and the mean age was 63.2 ± 10.4 years. On perioperative clearing colonoscopy, synchronous high-risk adenomas (number ≥ 3, size ≥ 10 mm, high-grade dysplasia, villous histology, and serrated adenoma ≥ 10 mm) were detected in 95 patients (32.4%), and they were significantly associated with male sex, old age (≥ 65 years), current alcohol consumption, and current smoking (p < 0.05). During the follow-up period (mean 74.4 ± 36.4 months), advanced metachronous neoplasms were found in 45 patients (15.4%), including metachronous cancer in four (1.4%). In multivariate analysis, distal colon cancer (distal-to-splenic flexure; odds ratio [OR], 4.402; 95% confidence interval [CI], 1.658 to 11.689; p = 0.003), synchronous highrisk adenomas (OR, 3.225; 95% CI, 1.503 to 6.918; p = 0.003), and hypertension (OR, 2.270; 95% CI, 1.058 to 4.874; p = 0.035) were significant risk factors for advanced metachronous neoplasms.

CONCLUSION

During surveillance after curative colon cancer resection, patients with distal colon cancer, synchronous high-risk adenomas, and hypertension may need meticulous follow-up to improve overall outcomes.

The incidence and risk factors of sessile serrated adenomas in left side colon cancer patients after curative surgery

Sessile serrated adenomas (SSAs) are precursors of colorectal cancer (CRC). However, there are limited data on detection rates of this premalignant lesion during colonoscopy surveillance in patients with a history of left side colonic resection for cancer. We aimed to identify the incidence and risk factors of SSAs in post-left side colectomy patients.We retrospectively reviewed the medical records of patients who had undergone left side colectomy for colon and rectal cancer between September 2009 and September 2016 and had at least 1 follow-up colonoscopy. Patient baseline characteristics, SSA diagnoses and characteristics, and colonoscopy information were collected.In total, 539 patients were enrolled. At the first follow-up (mean duration 11.5 months), 98 SSAs were identified (22.2%). At the second follow-up (mean duration 25.8 months), 51 SSAs were identified in 212 patients (24.0%). Multivariate analysis showed that alcohol intake (hazard ratio [HR] 1.524; 95% confidence interval [CI] .963-2.411, P = .041), excellent bowel preparation (HR 2.081; 95% CI 1.214-3.567, P = .049), and use of a transparent cap (HR 1.702; 95% CI 1.060-2.735, P = .013) were associated with higher SSA incidence in the first surveillance colonoscopy, while body mass index (BMI) ≥ 25.0 (HR 1.602; 95% CI 1.060-2.836) was associated with a significantly increased risk of SSAs in the second surveillance.Considering the endoscopic appearance of SSAs, adequate bowel preparation and use of transparent caps during postoperative surveillance colonoscopy can increase the diagnosis rate. Modification of alcohol intake and BMI may reduce the incidence of SSAs in left side colon cancer patients.