Rectal Adenomas Research Articles

A Novel Case of Biallelic MLH3 Variants in a Patient With Rectal Cancer and Polyps.

An increasing number of autosomal recessive forms of adenomatous polyposis have been described, but some in very few cases. Here, we describe a rare case of biallelic germline pathogenic variants in the MLH3 gene, implicating it as a potential cause of early colorectal cancer. The patient, a 47-year-old woman, presented with rectal bleeding, leading to the discovery of a malignant rectal tumor and adenomas during colonoscopy. Histopathological examination confirmed adenocarcinoma without microsatellite instability, and genetic testing identified two likely pathogenic frameshift variants in MLH3 located in trans. These findings contribute to the expanding knowledge of MLH3-related polyposis and colorectal cancer and underscore the need for further research into the gene's broader implications, including its potential role in cancer and infertility pathways.

Early rectal neoplasm in dual-layer spectral detector computed tomography: dual-layer spectral computed tomography (CT) images improve tumor detection and staging.

Early rectal neoplasms can be treated endoscopically with good prognosis, yet usually present with unspecific or an absence of signs and symptoms and are detected largely by invasive endoscopy with less compliance to screening. The purpose of this cross-sectional study was to explore the diagnostic value of dual-layer spectral detector computed tomography (DSCT) imaging for early rectal neoplasm. Patients who underwent DSCT for evaluation of rectal lesion or routine examination between September 2022 to September 2023 at West China Hospital were prospectively included and identified as group A (control, n=76), group B (rectal advanced adenomas and ≤T1 rectal cancer, n=59), and group C (≥T2 staging rectal cancer, n=74). Lesion visualization was graded to assess image quality. Spectral quantitative measurement, such as Hounsfield unit (HU)40 keV, HU70 keV, iodine concentration (IC), effective atomic number (Zeff), and the slope of spectral curve (λ), was analyzed and compared. Receiver operating characteristic (ROC) curves were generated to evaluate the diagnostic efficacy of spectral parameters. A comparison of ROC curves was applied to test the significance of differences between the area under the curves (AUCs). Compared to poly-energetic images (PEIs), the multiple parameters from DSCT were of greater capability to recognize rectal lesions. There were significant differences in HU40 keV (208.01±43.60 vs. 255.53±45.16), HU70 keV (87.06±18.55 vs. 100.78±18.26), IC [1.91 (1.71, 2.28) vs. 2.58±0.49], Zeff [8.33 (8.25, 8.50) vs. 8.61±0.20], and λ [3.80 (3.41, 4.52) vs. 5.16±1.00] between the early neoplastic lesions in rectum and the advanced rectal cancer (P<0.001). Significant correlations were found between the DSCT parameters and tumor staging (P<0.001). Furthermore, the AUCs of IC, Zeff, λ, and HUPEI were all above 0.90 for early rectal neoplasm detection, with additional capability of discriminating early rectal neoplasm from advanced rectal cancer. DSCT improved tumor conspicuity and the detection of the early rectal neoplastic lesion, suggesting that it is a promising screening tool in clinical practice.

Retrospective Analysis of Rectal Endoscopic Submucosal Dissection at Ordensklinikum Linz and Kepler Universitätsklinikum Linz.

Background and study aim: Endoscopic submucosal dissection is a minimally invasive endoscopic procedure for the removal of neoplastic benign and early malignant lesions in the gastrointestinal tract. In this study, we analyse the success and safety of rectal ESD at Linz hospitals, focusing on a specific endoscopist. Additionally, we examine whether there is a learning curve regarding success parameters. Methods: This retrospective study included all 102 patients who underwent endoscopic submucosal dissection of the rectum by a defined endoscopist at Ordensklinikum Hospital and Kepler University Hospital between December 2010 and May 2021. With the collected data, a descriptive statistic was carried out and regression analyses were performed. Results: The en bloc resection rate was 78.4% and the rate of lesions removed in healthy tissue was 55.6%. The average procedure time was 179 min and the complication rate was 7.8%. In total, 26.4% of cases showed carcinoma; in 25.9% of these cases, an oncologically curative resection was achieved with ESD. Follow-up data were available for 61.1% of cases, with recurrence being diagnosed in 3.6% of cases. A learning curve was observed regarding the rate of lesions removed in healthy tissue and the procedure time, but not regarding the en bloc resection rate. Conclusions: Endoscopic submucosal dissection is a safe method for the removal of large rectal adenomas and early carcinomas. The en bloc resection rate of the analysed procedures is within the range of comparable European studies. The rate of lesions removed in healthy tissue is below the R0 resection rate of the comparative literature; however, a learning curve could be observed in this parameter.

Case Report of Multiple Rectosigmoid Adenomatous Polyps and Its Management i.e. Transanal Endoscopic Microsurgery

Adenomatous polyps in the colorectal region are prevalent. On account of its rarity and effective excision using Transanal Endoscopic Microsurgery (TEM) with assistance from a Covidien Small Incision Laparoscopic System (SILS) Port, we present this case of an adenomatous polyp wherein the patient complaints of per rectal bleed. Most frequently asymptomatic, adenomatous polyps are the most prevalent. In the present case, five to six polyps were found in the rectosigmoid area during colonoscopy. Rectal bleeding, stomach pain, and changes in bowel function that have a high malignant potential are the most typical symptoms associated with polyps. Large rectal adenomas should only be treated with TEM at this time, and traditional Trans Endoscopic (EMR/ESD) should be stopped. Despite the availability of newer procedures like endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD), TEM is still the method of choice. TEM is not recorded in our country up till now. This is the first time it is performed in our country. Keywords: Adenomatous Polyp; Transanal Endoscopic Microsurgery; Small Incision Laparoscopic System; Endoscopic Mucosal Resection; Endoscopic Submucosal Dissection

Diagnostic advantages of transrectal ultrasound with gastrointestinal agent instillation for rectal adenoma and early-stage rectal cancer: comparison of conventional transrectal ultrasound techniques.

Despite being a major focus of medical research for decades, rectal cancer remains a major threat to human health. This study aimed to compare and analyze the diagnostic value of transrectal ultrasonography (TRUS) for rectal adenoma and early-stage rectal cancer before and after gastrointestinal agent instillation. In this prospective study, patients diagnosed with rectal adenomas and early-stage rectal cancer by ultrasound were randomly selected for inclusion. All patients underwent ultrasound examination at the Outpatient Department of the First Affiliated Hospital of China Medical University and underwent surgical treatment at the First Affiliated Hospital of China Medical University. Patients with a lesion located 13 cm or more from the edge of the anus, or history of surgery, and a history of radiation and chemotherapy were excluded. A gastrointestinal agent was directly instilled into the rectal cavity during conventional TRUS to compare and analyze the display of rectal lesions before and after such instillation and to evaluate the infiltration depth of rectal lesions. These findings were compared to the pathological findings to determine the diagnostic efficacy. Both the conventional TRUS and TRUS with gastrointestinal agent instillation were able to show the rectal wall structure and rectal lesions; the detection rate of rectal lesions of the former was 75.0%, and that of the latter was 97.1% (P<0.001). Of the 27 rectal adenomas, conventional TRUS detected 10, and TRUS with gastrointestinal agent instillation detected 25 lesions. The accuracy [90.54%; 95% confidence interval (CI): 81.48-96.11%; P=1.05E-08], specificity (87.88%; 95% CI: 71.80-96.60%; P=1.09E-05), and sensitivity (92.68%; 95% CI: 80.08-98.47%; P=1.05E-08) of TRUS in diagnosing early-stage rectal cancer were consistent with the pathological findings (P<0.001). The accuracy (95.95%, 95% CI: 88.61-99.16%; P=3.82E-11), specificity (93.94%, 95% CI: 79.77-99.26%; P=1.31E-07), and sensitivity (97.56%, 95% CI: 87.15-99.94%; P=3.82E-11) of TRUS after gastrointestinal agent infusion in diagnosing early-stage rectal cancer were consistent with the pathological findings (P<0.001). The specificity (87.88%; 95% CI: 71.80-96.60%; P=1.09E-05) of TRUS in diagnosing rectal adenomas was consistent with the pathological finding (P<0.001), but the accuracy (65%; 95% CI: 51.60-76.87%; P=0.25) and sensitivity (37.04%, 95% CI: 19.40-57.63%; P=0.25) were not (P>0.05). Meanwhile, the accuracy (93.33%; 95% CI: 83.80-98.15%; P=5.65E-06), specificity (93.94; 95% CI: 79.77-99.26%; P=1.31E-07), and sensitivity (92.59%; 95% CI: 75.71-99.09%; P=5.65E-06) of TRUS after gastrointestinal agent infusion in diagnosing rectal adenomas were consistent with the pathological findings (P<0.001). TRUS with gastrointestinal agent instillation had significantly improved accuracy in diagnosing early-stage rectal cancer and detecting intrarectal adenomatoid lesions.

The Outcome of Local Excision of Rectal Adenomas with High-Grade Dysplasia by Transanal Endoscopic Microsurgery: A Single-Center Experience.

Background: Local excision by transanal endoscopic microsurgery (TEM) is considered an acceptable treatment for rectal adenomas with high-grade dysplasia (HGD). This study aims to assess the likelihood of harboring an invasive carcinoma in preoperatively diagnosed HGD polyps and evaluate the risk factors for tumor recurrence in patients with final HGD pathology. Methods: Data from patients who underwent TEM procedures for adenomatous lesions with HGD from 2005 to 2018 at the Rabin Medical Center, Hasharon Hospital, were analyzed. Collected data included patient demographics, preoperative workup, tumor characteristics and postoperative results. Follow-up data including recurrence assessment and further treatments were reviewed. The analysis included two subsets: preoperative pathology of HGD (sub-group 1) and postoperative final pathology of HGD (sub-group 2) patients. Results: Forty-five patients were included in the study. Thirty-six patients had a preoperative diagnosis of HGD, with thirteen (36%) showing postoperative invasive carcinoma. Thirty-two patients had a final pathology of HGD, and three (9.4%) experienced tumor recurrence. Large tumor size (>5 cm) was significantly associated with recurrence (p = 0.03). Conclusions: HGD rectal polyps are associated with a significant risk of invasive cancer. Tumor size was a significant factor in predicting tumor recurrence in patients with postoperative HGD pathology. The TEM procedure is an effective first-line treatment for such lesions.

High-grade dysplasia in giant tubular adenoma

Rectal adenomas with a high risk of cancer frequently occur in anal bleeding and mucus discharge. The risk of malignancy is greater than 50% in polyps larger than 2 cm and includes areas of dysplasia, and the likelihood of dysplasia is correlated with the excess of the villous component ratio, the proximity of the polyp to the anal region, and the increase in size. Large, lumen-encircling polyps are difficult to treat with endoscopic or transanal intervention and necessitate surgical intervention. In this article, we present a female patient who had rectal mucus discharge and had a lower anterior resection and coloanal anastomosis after developing a tubular adenoma with high-grade dysplasia and no villous component.

Recurrence after transanal endoscopic microsurgery for benign and malignant rectal tumours: experience of a single New Zealand centre.

Transanal endoscopic microsurgery (TEM) is an established technique for the resection of rectal adenomas and selected malignant tumours. It avoids the morbidity of radical resection for tumours not amenable to endoscopic resection. An important marker of quality is the local recurrence rate. The primary objective was to determine local recurrence rates for benign and malignant rectal tumours. We identified index TEM excisions of rectal adenomas and adenocarcinomas in patients age 18 and over at Dunedin Hospital, New Zealand, between 2000 and 2020, from a prospective database. Surveillance data were collected via chart review. The primary outcome was recurrence rate for adenomas and adenocarcinomas. Secondary outcomes included time to recurrence, association of recurrence with recognized risk factors, and adverse event rates. We identified 100 patients for analysis. Of 75 benign cases, 11 (14.7%) developed local recurrence, with 63.6% identified within 1 year. Of the 25 malignant cases (19 T1, 5 T2, 1 T3), 9 (36%) developed recurrence, with 77.8% identified within 2 years. Adverse events occurred in 26% of patients, with no reoperations or deaths. Our adenoma recurrence rate was at the higher end of the reported range of 2.4-16%. Minor complications were common, but not major morbidity. The propensity for rectal tumours to recur commonly and early reinforces the importance of regular standardized endoscopic surveillance.

Rectal Polyp Prolapse: A Case Report

Colorectal adenomas are polyps that develop from the mucosa and exhibit neoplastic characteristics. Adenomas’ increasing dysplasia and malignant potential are connected to their size, villous content, and patient’s age. An anorectal emergency is definitely a possibility when there are large villous polyps in the rectum. They could be involved in rectal bleeding, blockage, prolapse, or imprisonment. We describe a 53-year-old female who was treated successfully for giant tubulovillous rectal adenoma that was prolapsed through anal opening. The patient’s clinical symptoms and signs were mistaken for prolapsed hemorrhoids.

Endoscopic Submucosal Dissection of a Giant Rectal Adenoma Manifesting as McKittrick-Wheelock Syndrome.

McKittrick-Wheelock syndrome (MKWS) is an uncommon clinical manifestation of large, villous, epithelial lesions of the distal colon and rectum. Excessive secretion of electrolyte-rich mucus from these lesions leads to secretory diarrhea, electrolyte disorders and acute renal failure. Several cases of MKWS have been reported since its initial description in 1954. The definitive treatment for the great majority of MKWS cases has consisted of surgical resection of the affected part of the colorectum, usually in the form of a low anterior resection or an abdominoperineal resection with the formation of an ostomy. Recent developments in endoscopic resection techniques now offer new, minimally invasive treatment alternatives for MKWS patients. We present the first reported case in the Western world of MKWS caused by a rectal adenoma with a size of 19 × 10 cm, treated through endoscopic submucosal dissection. Through the lessons learned by this case, as well as by a thorough review of the literature, we discuss this uncommon syndrome, focusing on treatment alternatives.

McKittrick Wheelock Syndrome Secondary to Adenocarcinoma of the Rectum. Case Report and Diagnostic Considerations

Abstract Introduction McKittrick-Wheelock syndrome is a rare entity characterized by chronic diarrhea, acute kidney injury, and hydroelectrolytic imbalance associated with a large rectal tumor, frequently a villous adenoma. Case report A 69-year-old male with chronic diarrhea with mucus. He underwent a colonoscopy with biopsies, reporting adenocarcinoma of the rectum in situ, and underwent a robot assisted intersphincteric resection with colo-anal anastomosis and a protecitive ileostomy. Discussion Described in 1954, this syndrome is manifested by electrolyte imbalance and acute renal injury secondary to diarrhea associated with a rectal villous adenoma, often with long lasting symptoms. The most frequent symptom being watery diarrhea with mucus. The definitive treatment consists of surgical resection. Conclusion Although this is a rare pathology, it should be considered as a differential diagnosis in cases of chronic diarrhea associated with water and electrolyte disorders.

Gastrointestinal: Unusual pathology of an anorectal lesion mimicking a benign laterally spreading tumor.

A 70-year-old woman was referred to our institution for the diagnosis and treatment of an anorectal lesion detected on colonoscopy performed at a previous hospital for hematochezia. Colonoscopy revealed a 32-mm flat elevated lesion in the lower rectum with an anal component extending to the dentate line (Fig. 1a). Chromoendoscopy with indigo carmine spraying demonstrated a papillary surface (Fig. 1b). Magnifying endoscopy with narrowband imaging (NBI) displayed an irregular vessel resembling the intrapapillary capillary loop (IPCL) of the Japan Esophageal Society Classification Type B1 (Fig. 1c). Magnifying endoscopy with 0.05% crystal violet staining revealed the absence of discernible glandular ducts, hindering the evaluation of the pit pattern (Fig. 1d). The endoscopic appearance resembled a large adenoma or condyloma acuminatum; however, the absence of a pit pattern indicated that the lesion was covered with squamous epithelium and not columnar. Moreover, the irregular vessel pattern suggested a neoplastic lesion. Based on these observations, the lesion was diagnosed as a neoplasm originating from the squamous epithelium of the anal canal. Thus, we performed endoscopic submucosal dissection for complete elimination. Histological examination revealed a papillary growing squamous cell carcinoma (SCC) exhibiting low-grade and high-grade atypia and abundant dilated vessels (Fig. 2a). The tumor extended from the anal transitional zone (ATZ) to the rectum and entrapped the rectal crypts (Fig. 2b). Some tumor cells had a clear cytoplasm, indicative of koilocytosis (Fig. 2c), and positive p16 immunohistochemical staining suggested human papillomavirus (HPV) infection (Fig. 2d). The final diagnosis was HPV-associated SCC in situ originating from the ATZ with rectal extension. Anal canal cancer (ACC) is a rare disease that accounts for only 0.3% of all malignancies and is strongly associated with high-risk HPV (HPV-16 and HPV-18). This case was unusual because of the extensive infiltration of the columnar epithelium. Therefore, it might be misidentified as a rectal adenoma. Early ACC shows irregular vessel patterns reminiscent of esophageal SCC on magnified endoscopic NBI, which has been reported to be useful in diagnosing ACC. However, laterally spreading tumor (LST) can exhibit similar irregular capillary vessels. The difference in endoscopic appearance between ACC and LST can be explained by their different epithelial anatomies. ACC develops in the squamous cell epithelium and has no orifice or crypt. In contrast, LST originates from the columnar epithelium and has crypt openings. Condyloma acuminatum has a similar endoscopic appearance but with milder vascular dilatation and caliber changes. In conclusion, HPV-associated anal canal cancer can be suspected in papillary tumors with an irregular esophageal SCC-like vascular pattern and absence of glandular structures. Piecemeal endoscopic mucosal resection can be selected for large adenomas; conversely, en bloc resection is the preferred method for ACC to mitigate the risk of recurrence. To ensure the implementation of appropriate treatment, more attention should be paid to lesions extending along the anal canal to the rectum.

A137 TRANSANAL ENDOSCOPIC COOPERATIVE SURGERY (TECS): COMBINED APPROACH FOR A LARGE POST-TRANSANAL RESECTION RECURRENCE. A CASE REPORT

Abstract Background Advancements in endoscopy and minimally invasive surgery have led to the development of organ-preserving resection techniques to manage rectal lesions. According to JGES, ESGE, and AGA, endoscopic mucosal dissection (ESD) is typically recommended for Kudo V/JNET 2b pit pattern, LST-NG/Paris Is/IIc/IIa+Is morphology, presence of submucosal fibrosis, and local residual/recurrent adenomas. ESD is not without its limitations including depth of resection, technical difficulty and time. In some instances, a transanal minimally invasive surgery (TAMIS) approach can overcome some of these limitations while also avoiding the morbidity of proctectomy. The ESD-TAMIS approach has been described by two groups in the USA and Germany demonstrating initial safety and feasibility for management of distal rectal adenomas. Purpose We present the first Canadian case to demonstrate the use of a combined ESD-TAMIS for the management of a large post-TAMIS recurrent rectal adenoma, involving the dentate line, not amenable to endoscopic resection or TAMIS alone. Method N/A Result(s) A healthy 78-yr-old woman was referred for consideration of ESD of a large recurrent low rectal adenomatous lesion which had undergone multiple prior endoscopic mucosal and TAMIS resections. Pathology from prior excisions never showed high grade dysplasia (HGD) or intramucosal cancer. The lesion was 4-5cm long and occupied 90% of the circumference of the lumen including the dentate line. It had Paris IIa+Is+IIb components with submucosal fibrosis. The pit pattern was JNET 2a/2b (Fig 1). Given the size and dramatic submucosal scarring, ESD was deemed extremely challenging, time consuming and would likely involve a full thickness resection. Similarly, given that the lesion involved the dentate line and the borders were difficult to delineate, a TAMIS would not be feasible. In collaboration with our surgical colleagues, we proceeded with the ESD-TAMIS. The borders of the lesion were first demarcated and marked endoscopically. Using standard ESD technique, a mucosal incision was performed on the anal side of the lesion, followed by submucosal dissection until sufficient space was created for the TAMIS platform. Then, using TAMIS technique, a full thickness resection was performed. The lesion was successfully removed en-bloc and pinned for pathology. The large size of the defect and proximity to the dentate line prevented surgical closure. Post-op course was complicated by fever successfully managed with antibiotics. Overall, the procedure was well tolerated. The final pathology revealed a tubulovillous adenoma with HGD and extensive submucosal fibrosis. Image Conclusion(s) A transanal endoscopic cooperative surgery combining ESD and TAMIS was safe and effective, combining the advantages of each procedural technique, in providing curative en-bloc resection of a recurrent large near-circumferential low rectal tubulovillous adenoma with HGD involving the dentate line. Here, we present the first reported Canadian case using this novel technique. Please acknowledge all funding agencies by checking the applicable boxes below None Disclosure of Interest None Declared

Parks retractor.

The use of a surgical speculum (latin for mirror, from specere: to watch) or retractor has been described since ancient times. An anal speculum (catopter) for haemorrhoids, abscesses, and fistulas was mentioned in Hippocrates’ dissertations from around 400 BC1. Many years followed without further advances in transanal surgery owing to pain, limited anaesthesia, morbidity, and even death2. Perhaps the most famous fistulotomy in history (1685) necessitated the development of new instruments, when King Louis XIV had an anal fistula treated by the ‘barber surgeon’ Charles-Francois Felix. He spent months developing new instruments and refining his technique by undertaking ‘surgical training’ on guinea pigs and less well-to-do patients. Among these instruments was a three-bladed self-retaining anal retractor (Fig. 1a), a predecessor of the retractor described in this article. The evolving interest in, and optimization of, transanal excisions of anal and rectal tumours at the beginning of the 20th century demanded improved access to, and visualization of, the rectum. In Benign Tumours of the Rectum3, Alan Guyatt Parks (1920–1988) described and illustrated the use of a two-bladed self-retaining speculum for excision of rectal adenomas. A three-bladed version (Parks retractor) (Fig. 1b) was described in a later article in 19734. It formed the basis of two principles essential for peranal excision: that the anal canal could be opened to achieve exposure with the retractor, and that submucosal injection facilitated dissection. As Parks stated, the key to optimal surgery is ‘good exposure, good exposure, good exposure’5. Parks had many other innovations and contributions from the aetiology and classification of anal fistula to pelvic floor physiology, haemorrhoid surgery, and ileal reservoir with ileoanal anastomosis6.

TRANSANAL ENDOSCOPIC MICROSURGERY FOR T2 RECTAL CANCER HAS HIGHER PERIOPERATIVE MORBIDITY

Background: Transanal-endoscopic-microsurgery (TEM) is a valid technique for rectal adenomas and selected early rectal cancer. The minimally invasiveness nature of the procedure decrease the perioperative and long term complications, and avoids the need for temporary or permanent stoma. One limitation of this technique lays in its disability to provide histopathologic lymph-node status. Currently, TEM is a valid and preferable option for T1sm1, well-differentiated rectal tumors. We aimed to assess wheatear higher T stage results in higher short- and long-term morbidity.

Rectal Cancer following Local Excision of Rectal Adenomas with Low-Grade Dysplasia-A Multicenter Study.

Purpose: Rectal polyps with low-grade dysplasia (LGD) can be removed by local excision surgery (LE). It is unclear whether these lesions pose a higher risk for recurrence and cancer development and might warrant an early repeat rectal endoscopy. This study aims to assess the rectal cancer rate following local excision of LGD rectal lesions. Methods: A retrospective multicenter study including all patients that underwent LE for rectal polyps over a period of 11 years was conducted. Demographic, clinical, and surgical data of patients with LGD werecollected and analyzed. Results: Out of 274 patients that underwent LE of rectal lesions, 81 (30%) had a pathology of LGD. The mean patient age was 65 ± 11 years, and 52 (64%) were male. The mean distance from the anal verge was 7.2 ± 4.3 cm, and the average lesion was 3.2 ± 1.8 cm. Full thickness resection was achieved in 68 patients (84%), and four (5%) had involved margins for LGD. Nine patients (11%) had local recurrence and developed rectal cancer in an average time interval of 19.3 ± 14.5 months, with seven of them (78%) diagnosed less than two years after the initial LE. Seven of the nine patients were treated with another local excision, whilst one had a low anterior resection, and one was treated with radiation. The mean follow-up time was 25.3 ± 22.4 months. Conclusions: Locally resected rectal polyps with LGD may carry a significant risk of recurring and developing cancer within two years. This data suggests patients should have a closer surveillance protocol in place.

The Effect of Low Doses of Acetylsalicylic Acid on the Occurrence of Rectal Aberrant Crypt Foci.

Background and Objectives: Aberrant crypt foci (ACF) are one of the earliest putative preneoplastic and, in some cases, neoplastic lesions in human colons. Many studies have confirmed the reduction of ACFs and colorectal adenomas after treatment with acetylsalicylic acid (ASA) commonly referred to as ASA; however, the minimum effective dose of ASA and the duration of use has not been fully elucidated. The objective of our study was to assess the significance of low dose ASA (75-mg internally once daily) to study the chemopreventive effect of ASA in ACF and adenomas development in patients taking this drug for a minimum period of 10 years. Materials and&amp;nbsp;Methods: Colonoscopy, combined with rectal mucosa staining with 0.25% methylene blue, was performed on 131 patients. The number of rectal ACF in the colon was divided into three groups: ACF &lt; 5; ACF 5-10; and ACF &gt; 10. Patients were divided into two groups: the "With ASA" group (the study group subjects taking ASA 75-mg daily for 10 years); and "Without ASA" group (control group subjects not taking ASA chronically). The incidence of different types of rectal ACF and colorectal polyps in both groups of subjects was analysed and ascertained. Results: Normal ACF was found in 12.3% in the study group vs. 87.7% control group, hyperplastic 22.4% vs. 77.6%, dysplastic 25% vs. 75%, mixed 0% vs. 100%. Treatment with ASA affects the occurrence of colorectal adenomas. The amount of dysplastic ACFs was lower in the study group than in the control group. The increase in dysplastic ACFs decreases with age in both groups, with the increase greater in those not taking ASA. Conclusions: Patients who take persistent, chronic (&gt;10 years) low doses of ASA have a lower total number of all types of rectal ACFs and adenomas compared to the control group.

Relationship of diffusion kurtosis imaging parameters with the pathologic type and prognosis of rectal tumors

Objective: To explore the application value of diffusion kurtosis imaging (DKI) in the differential diagnosis of rectal tumors and evaluating the prognostic factors associated with rectal adenocarcinoma. Methods: A total of 105 patients with rectal tumors admitted in the First Affiliated Hospital of Zhengzhou University from December 2018 to August 2020 were retrospectively analyzed. All patients underwent high-resolution magnetic resonance DKI scanning. The mean diffusivity (MD), mean kurtosis (MK) and apparent diffusion coefficient (ADC) were measured and the relationship of these parameters with pathological types and prognostic factors of rectal tumor were analyzed. The diagnostic efficacy of MD, MK, and ADC for positive circumferential resection margin (CRM) and extramural venous invasion (EMVI) of rectal adenocarcinoma was evaluated by the receiver operating characteristic (ROC) curve. Results: MD and ADC were only related to pathological type. The MD and ADC were (2.091±0.390)×10(-3) and (1.478±0.265)×10(-3) mm(2)/s in mucinous adenocarcinoma, higher than (1.136±0.182)×10(-3) and (0.767±0.077)×10(-3) mm(2)/s in unspecified adenocarcinoma and (1.617±0.697)×10(-3) and (0.940±0.179)×10(-3) mm(2)/s in tubulo-villous adenoma. The MD and ADC in unspecified adenocarcinoma were lower than those in tubule-villous adenoma (P<0.05). Nevertheless, MK was associated with pathological type, N stage, CRM and EMVI. The MK was 0.566±0.110 in mucinous adenocarcinoma, lower than 0.982±0.135 in unspecified adenocarcinoma and 0.827±0.121 in tubulo-villous adenoma. The MK in unspecified adenocarcinoma was higher than that in intubulo-villous adenoma. The MK was 0.984±0.107 in pN1-2, higher than 0.881±0.146 in pN0. The MK was 0.990±0.142 in positive CRM, higher than 0.862±0.114 in negative CRM. The MK was 0.996±0.140 in positive EMVI, higher than 0.832±0.100 in negative EMVI (P<0.05). The ROC curves showed that the AUCs of MD, MK and ADC in diagnosing positive CRM were 0.459, 0.653 and 0.408, respectively; with MK=1.006 as the optimal diagnostic threshold, the diagnostic sensitivity and specificity were 51.9% and 81.0%, respectively. The AUCs of MD, MK and ADC values in diagnosing positive EMVI were 0.510, 0.662 and 0.388, respectively; with MK=1.010 as the optimal diagnostic threshold, the diagnostic sensitivity and specificity were 50.9% and 87.5%, respectively. Conclusions: DKI quantitative parameter is helpful for discriminating rectal tubulo-villous adenoma, unspecified adenocarcinoma, and mucinous adenocarcinoma, and is helpful for predicting the prognosis of patients with rectal adenocarcinoma. High MK is associated with positive CRM and EMVI.

Analysis of the therapeutic effect of transanal endoscopic microsurgery on large rectal adenoma.

Rectal adenoma, a pre-cancerous lesion, is one of the indications for transanal endoscopic microsurgery (TEM). TEM has its unique advantages in the treatment of rectal adenomas. However, there are few reports on the therapeutic effects of large rectal adenoma (LRA). The objective of this study was to investigate the value of TEM in the treatment of LRA. We collected data from patients who underwent surgery at our center from 2007 to 2017. The postoperative pathology of all patients was rectal adenoma and the diameter of the adenoma was 3 cm or greater. Moreover, all patients underwent TEM. We followed up to observe the incidence of no wound healing, rectal stenosis and recurrence rate of rectal adenoma. The risk factors of adenoma recurrence and wound healing were analysed using single- and multiple-factor analysis. The clinicopathological data of 85 patients with LRA were collected through a pre-set table. During the follow-up period, eight patients were lost to follow-up, and three (3.90%) patients developed rectal stenosis. After 2 years of post-operative follow-up, 20 (25.97%) patients had recurrence and 57 (74.03%) patients had no recurrence. Multivariate analysis showed that positive margin was an independent risk factor for recurrence of adenoma. TEM is feasible in the treatment of large rectal tumours in Centers of Expertise with the technique.

Endorectal Ultrasound Shear-Wave Elastography of Complex Rectal Adenoma and Early Rectal Cancer.

Purpose: To investigate the diagnostic performance of endorectal ultrasound (ERUS), shear-wave elastography (SWE), and magnetic resonance imaging (MRI) in patients with a complex rectal adenoma or an early rectal cancer, i.e., T1 or T2 adenocarcinoma in a clinical setting, and to evaluate the association between SWE and stromal fraction (SF) and apparent diffusion coefficient (ADC) and SF. Method: This prospective study included patients undergoing ERUS and SWE for a rectal tumor subsequently confirmed by histopathology to be an adenoma or a T1 or T2 adenocarcinoma. The accuracy of the imaging methods was assessed by comparing the T category as determined by ERUS and MRI with histopathology, which served as the gold standard. SF was assessed on surgical specimens. Results: A total of 86 patients were included. Of these, 62 patients had adenomas and 24 patients had carcinomas, of which 11 were T1 tumors and 13 were T2 tumors. ERUS and MRI yielded sensitivity, specificity, and accuracy of 0.79 and 0.73, 0.95 and 0.90, and 0.86 and 0.78, respectively, for discrimination between benign and malignant lesions. The area under the receiver operating characteristics curve for SWE was 0.88, and with a cut-off value of 40 kPa the sensitivity, specificity, and accuracy were 0.79, 0.89, and 0.86, respectively. There was a positive correlation between SF and SWE with a p-value of <0.001 and a negative correlation between SF and ADC with a p-value of 0.011. Conclusion: Both ERUS and MRI classified T categories with a high accuracy; however, ERUS classified more adenomas correctly than MRI. In this small population, SWE could differentiate an adenoma from early carcinoma. SF was correlated with both SWE and ADC, as increasing SF tended to yield higher SWE and lower ADC values.