Management of the malignant colorectal polyp: ACPGBI position statement

Use of artificial intelligence to measure colorectal polyp size without a reference object

Background and study aims

Polyp size is crucial for determining colonoscopy surveillance intervals. We present an artificial intelligence (AI) model for colorectal polyp size measurement without a reference object.

Methods

The regression model for polyp size estimation was developed using outputs from two SegFormer models, segmentation and depth estimation. Initially built on colonoscopic images of polyp phantoms, the model underwent transfer learning with 1,304 real-world images. Testing was conducted on 178 images from 52 polyps, independent of the training set, using a snare as the ground truth for size comparison with the AI-based model. Polyps were classified into three size groups: ≤ 5 mm, 5-10 mm, and ≥ 10 mm. Error rates were calculated to evaluate discrepancies in actual size values between the AI model and the snare method. Precision indicated the positive predictive value per size group and recall and Bland-Altman were also conducted.

Results

The Bland-Altman analysis showed a mean bias of -0.03 mm between methods, with limits of agreement from -1.654 mm to 1.596 mm. AI model error rates for actual size discrepancies were 10.74%, 12.36%, and 9.89% for the ≤ 5 mm, 5-10 mm, and ≥ 10 mm groups, respectively, averaging 11.47%. Precision values were 0.870, 0.911, and 0.857, with overall recall of 0.846.

Conclusions

Our study shows that colorectal polyp size measurement by AI model is practical and clinically useful, exhibiting low error rates and high precision. AI shows promise as an accurate tool for measurement without the need for a reference object during screening colonoscopy.

Management of the Malignant Rectal Polyp-A Narrative Review

PURPOSE

The aim of this review is to provide a contemporary update on the current management approaches and options with specific considerations in malignant rectal polyps.

METHODS

A literature review was carried out in PubMed, Embase and Cochrane databases using the keywords "malignant" and "polyp*". Only publications in English language were included.

RESULTS

Histopathological features including margins, depth of invasion, tumour grade, LVI and tumour budding determines the risk of lymph node metastasis in malignant polyps. Rectal malignant polyps should be considered differently compared to their colonic counterpart. A low threshold should be considered for utilising transrectal excision to fully excise the polyp and to assess the margins. The rates of complete pathological response associated with total neoadjuvant therapy as well as the advent of "watch and wait" adds to the complexity of managing malignant rectal polyps.

CONCLUSIONS

The management of malignant colorectal polyps lies in risk-stratifying patients who will benefit from an oncological resection.

Significant variation in the assessment and management of screen-detected colorectal polyp cancers

PURPOSE

Endoscopic resection is appropriate for selected colorectal polyp cancers, but significant variation exists in treatment. This study aims to investigate variation in management of screen-detected polyp cancers (T1), factors predicting primary endoscopic polypectomy and threshold for subsequent surgical resection.

METHOD

Patients with polyp cancers (T1) diagnosed by the bowel cancer screening programme (BCSP) were investigated at two screening centres (5 individual sites and 4 MDTs, 2012-2022). Patient demographics, pathological characteristics, management and outcomes were recorded. Variation in management was compared between sites. Risk factors for primary endoscopic polypectomy and the need for subsequent surgical resection were analysed using multivariable binary logistic regression models.

RESULTS

Of 220 polyp cancers, 178 (81%) underwent primary endoscopic resection. Secondary surgical excision was required in 54 (30%). Study sites were not significantly different in their primary management for colonic or rectal polyps. Only the size of colonic polyps was associated with primary surgery rather than endoscopic polypectomy (OR 1.05 (95% CI 1.00-1.11); p = 0.038). There was a difference between study sites in the odds ratio for secondary surgery after primary polypectomy for colonic polyps (OR 3.97 (95% CI 1.20-16.0); p = 0.033) but not rectal. Other factors associated with the requirement for secondary surgery were as follows: sessile morphology for colonic polyps (OR 2.92 (95% CI 1.25-6.97); p = 0.013) and en-bloc resection for rectal polyps (OR 0.14 (0.02-0.85); p = 0.043).

CONCLUSION

There was significant variation in the assessment and treatment of colonic polyp cancers. Standardising pathology reporting and treatment algorithms may lead to better consistency of care and a reduction in secondary surgery.

Paris classification of colonic polyps using CT colonography: prospective cohort study of interobserver variation

BACKGROUND

The Paris classification categorises colorectal polyp morphology. Interobserver agreement for Paris classification has been assessed at optical colonoscopy (OC) but not CT colonography (CTC). We aimed to determine the following: (1) interobserver agreement for the Paris classification using CTC between radiologists; (2) if radiologist experience influenced classification, gross polyp morphology, or polyp size; and (3) the extent to which radiologist classifications agreed with (a) colonoscopy and (b) a combined reference standard.

METHODS

Following ethical approval for this non-randomised prospective cohort study, seven radiologists from three hospitals classified 52 colonic polyps using the Paris system. We calculated interobserver agreement using Fleiss kappa and mean pairwise agreement (MPA). Absolute agreement was calculated between radiologists; between CTC and OC; and between CTC and a combined reference standard using all available imaging, colonoscopic, and histopathological data.

RESULTS

Overall interobserver agreement between the seven readers was fair (Fleiss kappa 0.33; 95% CI 0.30-0.37; MPA 49.7%). Readers with < 1500 CTC experience had higher interobserver agreement (0.42 (95% CI 0.35-0.48) vs. 0.33 (95% CI 0.25-0.42)) and MPA (69.2% vs 50.6%) than readers with ≥ 1500 experience. There was substantial overall agreement for flat vs protuberant polyps (0.62 (95% CI 0.56-0.68)) with a MPA of 87.9%. Agreement between CTC and OC classifications was only 44%, and CTC agreement with the combined reference standard was 56%.

CONCLUSION

Radiologist agreement when using the Paris classification at CT colonography is low, and radiologist classification agrees poorly with colonoscopy. Using the full Paris classification in routine CTC reporting is of questionable value.

CLINICAL RELEVANCE STATEMENT

Interobserver agreement for radiologists using the Paris classification to categorise colorectal polyp morphology is only fair; routine use of the full Paris classification at CT colonography is questionable.

KEY POINTS

• Overall interobserver agreement for the Paris classification at CT colonography (CTC) was only fair, and lower than for colonoscopy. • Agreement was higher for radiologists with < 1500 CTC experience and for larger polyps. There was substantial agreement when classifying polyps as protuberant vs flat. • Agreement between CTC and colonoscopic polyp classification was low (44%).

How secure can we expect the surveillance policies to be after the implementation in T1 polyps with carcinoma?

Approximately 7% of the polyps resected endoscopically have an adenocarcinoma focus, with no previous endoscopic evidence of malignancy. This raises the question of whether endoscopic resection has been curative. Furthermore, there is no consensus on what the endoscopic and histological criteria for good prognosis are, the appropriate follow-up strategy and what are the long-term results. The aim of the retrospective study by Fábián et al was to evaluate the occurrence of local relapse or distant metastasis in those tumors that were resected endoscopically compared to those that underwent oncologic surgery. They concluded that, regardless of the treatment strategy chosen, there was a higher recurrence rate than described in the literature and that adherence to follow-up was poor. The management approach for an endoscopically benign polyp histologically confirmed as adenocarcinoma depends on the presence of any of the previously described poor prognostic histological factors. If none of these factors are present and the polyp has been completely resected en bloc (R0), active surveillance is considered appropriate as endoscopic resection is deemed curative. These results highlight, once again, the need for further multicentric clinical practice studies to obtain more evidence for the purpose of establishing appropriate treatment and follow-up strategies.

Endoscopic Assessment of Colorectal Polyps

Colorectal cancer is the third most common cancer among men and the second among women. In the United States alone, there are 150,000 cases diagnosed each year. Colonoscopy remains the best method for identifying, evaluating, and intervening on patients with precancerous lesions. Multiple guidelines and techniques are available to assist the endoscopist with accurate diagnosis of these lesions. These include the Paris, Narrow-Band Imaging (NBI) International Colorectal Endoscopic (NICE), Japan NBI Expert Team (JNET), Kudo, Hiroshima, and Shudo classifications which utilize techniques such as chromoendoscopy, narrow-band imaging, and endocytoscopy to evaluate pit pattern and surface morphology. Utilization of these tools can help the endoscopist predict the cytology of a colonic lesion and select the most appropriate method for resection while maximizing organ preservation.

Substratifying the risk of covert malignancy in significant rectal polyps: Outcomes from a specialist multidisciplinary team (MDT)

AIM

A treatment strategy for patients with a significant polyp or early colon cancer (SPECC) of the rectum presents a challenge due to the significant rate of covert malignancy and lack of standardized assessment. For this reason, NICE recommends multidisciplinary meetings to improve outcomes. The primary aim of the present study was to report the performance of our specialist early rectal cancer (SERC) multidisciplinary team (MDT) in correctly substratifying the risk of cancer and to discuss the limitations of staging investigations in those patients with "poor outcomes".

METHOD

This was a retrospective review of patients referred to our SERC MDT from 2014 to 2019. Lesions were assigned by the MDT to three pre-resection categories (low, intermediate, high) according to the risk of covert malignancy. Resection method and final histology were compared to the pre-resection categories.

RESULTS

Of 350 SPECC lesions, 174 were assessed as low-risk, 108 intermediate-risk and 68 high-risk. The cancer incidence was 4.8%, 8.3% and 53%, respectively (15.5% overall). Eight lesions were categorized as low-risk but following piecemeal resection were found to be malignant. Five lesions, three of which were categorized as high-risk, were ultimately benign following conventional surgery. One pT1sm1 cancer, removed by anterior resection, may have been treated by local excision.

CONCLUSION

A total of 83% of malignant polyps were triaged to an en bloc resection technique and surgical resection avoided for nearly all benign lesions. However, 12 patients from this cohort were deemed to have a poor outcome because of miscategorization. Further comparative research is needed to establish the optimum strategy for rectal SPECC lesion assessment.

ORIGINALITY STATEMENT

There is currently no consensus for staging significant polyps of the rectum. This paper reports the effectiveness of a specialist early rectal cancer MDT to correctly risk-stratify significant rectal polyps. It underscores the importance of accurate categorization for treatment decision-making, while acknowledging the limitations of current staging modalities.

Evaluation and Management of Malignant Colorectal Polyps

The detection rate of dysplastic colorectal polyps has significantly increased with improved screening programs. Treatment of dysplastic polyps attempt to limit morbidity of a procedure while also considering the risk of occult lymph node metastasis. Therefore, a variety of methods have been developed to predict the rate of lymph node metastasis to help identify the optimal treatment of patients. These include both the endoscopic and pathologic assessment of the lesion. In order to reduce the morbidity of surgery for patients with low-risk lesions, multiple endoscopic therapies have been developed, including endoscopic mucosal resection, endoscopic submucosal dissection, endoscopic intermuscular dissection, and transanal endoscopic surgery.

Long-term outcomes after endoscopic removal of malignant colorectal polyps: Results from a 10-year cohort

BACKGROUND

Choosing an optimal post-polypectomy management strategy of malignant colorectal polyps is challenging, and evidence regarding a surveillance-only strategy is limited.

AIM

To evaluate long-term outcomes after endoscopic removal of malignant colorectal polyps.

METHODS

A single-center retrospective cohort study was conducted to evaluate outcomes after endoscopic removal of malignant colorectal polyps between 2010 and 2020. Residual disease rate and nodal metastases after secondary surgery and local and distant recurrence rate for those with at least 1 year of follow-up were investigated. Event rates for categorical variables and means for continuous variables with 95% confidence intervals were calculated, and Fisher's exact test and Mann-Whitney test were performed. Potential risk factors of adverse outcomes were determined with univariate and multivariate logistic regression models.

RESULTS

In total, 135 lesions (mean size: 22.1 mm; location: 42% rectal) from 129 patients (mean age: 67.7 years; 56% male) were enrolled. The proportion of pedunculated and non-pedunculated lesions was similar, with en bloc resection in 82% and 47% of lesions, respectively. Tumor differentiation, distance from resection margins, depth of submucosal invasion, lymphovascular invasion, and budding were reported at 89.6%, 45.2%, 58.5%, 31.9%, and 25.2%, respectively. Residual tumor was found in 10 patients, and nodal metastasis was found in 4 of 41 patients who underwent secondary surgical resection. Univariate analysis identified piecemeal resection as a risk factor for residual malignancy (odds ratio: 1.74; P = 0.042). At least 1 year of follow-up was available for 117 lesions from 111 patients (mean follow-up period: 5.59 years). Overall, 54%, 30%, 30%, 11%, and 16% of patients presented at the 1-year, 3-year, 5-year, 7-year, and 9-10-year surveillance examinations. Adverse outcomes occurred in 9.0% (local recurrence and dissemination in 4 patients and 9 patients, respectively), with no difference between patients undergoing secondary surgery and surveillance only.

CONCLUSION

Reporting of histological features and adherence to surveillance colonoscopy needs improvement. Long-term adverse outcome rates might be higher than previously reported, irrespective of whether secondary surgery was performed.

Estimation of risk posed by malignant polyps amongst colorectal surgeons in Australia and New Zealand

PURPOSE

The estimation of the risk posed by malignant polyps for residual or lymphatic disease plays a central role. This study investigated colorectal surgeons' assessment of these risks associated with malignant polyps.

METHODS

A cross-sectional questionnaire was electronically administered to colorectal surgeons in Australia and New Zealand in October 2022. The questionnaire contained 17 questions on demographics, when surgeons consider colorectal resection appropriate, and the risk assessment for 5 hypothetical malignant polyps.

RESULTS

The mean risk of residual or lymphatic disease that would prompt surgeons to recommend colonic resection was 5%. However, this increased to a mean risk of 10% if the malignant polyp was located in the rectum, and the only resection option was abdominoperineal resection with end-colostomy. There was high concordance between the estimated risk of residual or lymphatic disease by colorectal surgeons and the Association of Coloproctology of Great Britain and Ireland (ACPGBI) guidelines for the 5 hypothetical malignant polyps, with the ACPGBI estimated risk lying within the 95% confidence interval for 4 of the 5 malignant polyps. Nonetheless, 96.6% of surgeons felt that an online risk calculator would improve clinical practice.

CONCLUSION

Colorectal surgeons in Australia and New Zealand accurately estimated the risk posed by malignant polyps. An online risk calculator may assist in better conveying risk to patients.

Sporadic Polyps of the Colorectum

Colorectal polyps are common, and their diagnosis and classification represent a major component of gastrointestinal pathology practice. The majority of colorectal polyps represent precursors of either the chromosomal instability or serrated neoplasia pathways to colorectal carcinoma. Accurate reporting of these polyps has major implications for surveillance and thus for cancer prevention. In this review, we discuss the key histologic features of the major colorectal polyps with a particular emphasis on diagnostic pitfalls and areas of contention.

An Unusual and Protracted Course of a Haggitt 3 Malignant Polyp Recurrence

Timely detection of colorectal cancer recurrence is paramount, as treatment of early-stage recurrence greatly improves survival and outcomes. Current guidelines outline post-resection surveillance through endoscopy, CT imaging, and tumor markers for five years; however, there is minimal data to guide follow-up beyond this. We present the case of a 60-year-old female with locoregional recurrence 15 years after endoscopic mucosal resection of a low-grade Haggit level 3 sigmoid colon polyp. Unusually the recurrence was noted as an incidental finding following investigation of an elevated alpha-fetoprotein level post liver transplant, and a retrospective review of imaging revealed a calcified sigmoid mesentery mass. While surgical pathology revealed locoregional recurrence, there was no evidence of this on surveillance and preoperative colonoscopy. Through this case, we discuss the risk factors for late recurrence of colorectal cancer whilst exploring the literature and guidelines around this subset of patients. As new guidelines are developed, it may be important to consider late recurrence and individualize follow-up regimes based on risk factors.

Management after non-curative endoscopic resection of T1 rectal cancer

Since the introduction of population-based screening, increasing numbers of T1 rectal cancers are detected and removed by local endoscopic resection. Patients can be cured with endoscopic resection alone, but there is a possibility of residual tumor cells remaining after the initial resection. These can be located intraluminally at the resection site or extraluminally in the form of (lymph node) metastases. To decrease the risk of residual cells progressing towards more advanced disease, additional treatment is usually needed. However, with the currently available risk stratification models, it remains challenging to determine who should and should not be further treated after non-curative endoscopic resection. In this review, the different management strategies for patients with non-curatively treated T1 rectal cancers are discussed, along with the available evidence for each strategy and relevant considerations for clinical decision making. Furthermore, we provide practical guidance on the management and surveillance following non-curative endoscopic resection of T1 rectal cancer.

Management of malignant T1 colorectal cancer polyps: results from a 10-year prospective observational study

AIM

The recurrence risk associated with residual malignant cells (bowel wall/regional nodes) following T1 colorectal cancer (CRC) polypectomy must be weighed against operative morbidity. Our aim was to describe the management and outcomes of a large prospective cohort of T1 CRCs.

METHOD

All T1 CRCs diagnosed between March 2007 and March 2017 at the Glasgow Royal Infirmary were included. Patients were grouped by polypectomy, rectal local excision and formal resection status. χ2 testing, multivariate binary logistic and Cox regression were performed.

RESULTS

Of 236 patients, 90 (38.1%) underwent polypectomy only, six (2.6%) polypectomy and then rectal excision, 57 (24.2%) polypectomy and then resection, 14 (5.9%) rectal excision only and 69 (29.2%) primary resection. Polypectomy only correlated with male sex (P = 0.028), older age (P < 0.001), distal CRCs (P < 0.001) and pedunculated polyps (P < 0.001); primary resection with larger polyps (P < 0.001); polypectomy then resection with piecemeal excision (P = 0.002) and involved polypectomy margin (P < 0.001). Poor differentiation (OR 7.860, 95% CI 1.117-55.328; P = 0.038) independently predicted lymph node involvement. Submucosal venous invasion (hazard ratio [HR] 10.154, 95% CI 2.087-49.396; P = 0.004) and mucinous subtype (HR 7.779, 95% CI 1.566-38.625; P = 0.012) independently predicted recurrence. Submucosal venous invasion (HR 5.792, 95% CI 1.056-31.754; P = 0.043) predicted CRC-specific survival. Although 64.4% of polypectomy-only patients had margin involvement/other risk factors, none developed recurrence. Of 94 with polypectomy margin involvement, five (5.3%) had confirmed residual tumour. Overall, lymph node metastases (7.1%), recurrence (4.2%) and cancer-specific mortality (3.0%) were rare. Cancer-specific 5-year survival was high: polypectomy only (100%), polypectomy and then resection (98.2%), primary resection (100%).

CONCLUSION

Surveillance may be safe for more T1 CRC polyp patients. Multidisciplinary team discussion and informed patient choice are critical.

Pathological features associated with metastasis in patients with early invasive (pT1) colorectal carcinoma in colorectal polyps

AIMS

Colorectal carcinoma (CRC) arising in a colorectal polyp with invasion limited to the submucosa is sufficiently treated by complete endoscopic resection alone in many cases. Histological features of the carcinoma including tumour size, vascular invasion and poor tumour differentiation or evidence of de-differentiation, such as tumour budding, are associated with a higher risk for metastasis such that oncological resection is recommended. However, most malignant polyps with these features do not have lymph node metastases at the time of resection, so there is a need for better refinement of the histological risk features.

METHODS AND RESULTS

A total of 437 consecutive colorectal polyps with submucosal invasive carcinoma from a single centre, 57 of which had metastatic disease, were supplemented by 30 cases with known metastatic disease from two additional centres. Clinical and histological features of the polyp cancers were reviewed looking for differences between the 87 cancers with metastatic disease and the remaining cases without metastasis. A subgroup of 204 polyps removed intact was also analysed to ensure maximum histological accuracy.

CONCLUSIONS

This study confirmed larger invasive tumour size, vascular invasion and poor tumour differentiation as adverse predictive features. Prominent peritumoral desmoplasia and high cytological grade were additional adverse features. A predictive logistic regression model comprised of (i) presence of any form of vascular invasion; (ii) presence of high tumour budding (BD3); (iii) width of invasive tumour component > 8 mm; (iv) depth of invasive tumour > 1.5 mm; and (v) the finding of prominent expansile desmoplasia located within and beyond the deep invasive edge of the carcinoma, showed excellent performance in predicting metastatic disease.

AI in colonoscopy - detection and characterisation of malignant polyps

The medical technological revolution has transformed the nature with which we deliver care. Adjuncts such as artificial intelligence and machine learning have underpinned this. The applications to the field of endoscopy are numerous. Malignant polyps represent a significant diagnostic dilemma as they lie in an area in which mischaracterisation may mean the difference between an endoscopic procedure and a formal bowel resection. This has implications for patients’ oncological outcomes, morbidity and mortality, especially if post-procedure histopathology upstages disease. We have made significant strides with the applications of artificial intelligence to colonoscopic detection. Deep learning algorithms are able to be created from video and image databases. These have been applied to traditional, human-derived, classification methods, such as Paris or Kudo, with up to 93% accuracy. Furthermore, multimodal characterisation systems have been developed, which also factor in patient demographics and colonic location to provide an estimation of invasion and endoscopic resectability with over 90% accuracy. Although the technology is still evolving, and the lack of high-quality randomised controlled trials limits clinical usability, there is an exciting horizon upon us for artificial intelligence-augmented endoscopy.

Recommendations for Optimal Endoscopic Localization of Colorectal Neoplasms: A Delphi Consensus of National Experts

BACKGROUND

Colonoscopy is the standard of care for diagnosis and evaluation of colorectal cancers before surgery. However, varied practices and heterogenous documentation affects communication between endoscopists and operating surgeons, hampering surgical planning.

OBJECTIVE

This study aimed to develop recommendations for the use of standardized localization and reporting practices for colorectal lesions identified during lower GI endoscopy.

DESIGN

A systematic review of existing endoscopy guidelines and thorough narrative review of the overall endoscopy literature were performed to identify existing practices recommended globally.

SETTING

An online Delphi process was used to establish consensus recommendations based on a literature review.

PATIENTS

Colorectal surgeons and gastroenterologists from across Canada who had previously demonstrated leadership in endoscopy, managed large endoscopy programs, produced high-impact publications in the field of endoscopy, or participated in the development of endoscopy guidelines were selected to participate.

PRIMARY OUTCOME MEASURES

The primary outcomes measured were colorectal lesion localization and documentation practice recommendations important to planning surgical or advanced endoscopic excisions.

RESULTS

A total of 129 of 197 statements achieved consensus after 3 rounds of voting by 23 experts from across Canada. There was more than 90% participation in each round. Recommendations varied according to lesion location in the cecum, colon, or rectum and whether the referral was planned for surgical or advanced endoscopic resection. Recommendations were provided for appropriate documentation, indications, location, and method of tattoo placement, in addition to photograph and real-time 3-dimensional scope configuration device use.

LIMITATIONS

Because of a paucity of evidence, recommendations are based primarily on expert opinion. There may be bias, as all representatives were based in Canada.

CONCLUSIONS

Best practices to optimize endoscopic lesion localization and communication are not addressed in previous guidelines. This consensus involving national experts in colorectal surgery and gastroenterology provides a framework for efficient and effective colorectal lesion localization. See Video Abstract at http://links.lww.com/DCR/C71 .

RECOMENDACIONES PARA LA LOCALIZACIN ENDOSCPICA PTIMA DE LAS NEOPLASIAS COLORRECTALES UN CONSENSO DELPHI DE EXPERTOS NACIONALES

ANTECEDENTES:La colonoscopia es el estándar de atención para el diagnóstico y la evaluación de los cánceres colorrectales antes de la cirugía. Sin embargo, las prácticas variadas y la documentación heterogénea afectan la comunicación entre los endoscopistas y los cirujanos operadores, lo que dificulta la planificación quirúrgica.OBJETIVO:Este estudio tuvo como objetivo desarrollar recomendaciones para el uso de prácticas estandarizadas de localización y notificación de lesiones colorrectales identificadas en la endoscopia gastrointestinal inferior.DISEÑO:Se realizó una revisión sistemática de las pautas de endoscopia existentes y una revisión narrativa exhaustiva de la literatura general sobre endoscopia para identificar las prácticas existentes recomendadas a nivel mundial. Se utilizó un proceso Delphi en línea para establecer recomendaciones de consenso basadas en la revisión de la literatura.PARTICIPANTES:Se seleccionaron para participar cirujanos colorrectales y gastroenterólogos de todo Canadá que previamente habían demostrado liderazgo en endoscopia, manejado grandes programas de endoscopia, producido publicaciones de alto impacto en el campo de la endoscopia o que habían participado en el desarrollo de pautas de endoscopia.RESULTADOS:Localización de lesiones colorrectales y recomendaciones prácticas de documentación importantes para planificar escisiones quirúrgicas o endoscópicas avanzadas.RESULTADOS:129 de 197 declaraciones lograron consenso después de tres rondas de votación de 23 expertos de todo Canadá. Hubo >90% de participación en cada ronda. Las recomendaciones variaron según la ubicación de la lesión en el ciego, colon o recto, y si se planificó la derivación para resección quirúrgica o endoscópica avanzada. Se proporcionaron recomendaciones para la documentación adecuada, las indicaciones, la ubicación y el método de colocación del tatuaje, además de la fotografía y el uso del dispositivo de configuración del alcance 3D en tiempo real.LIMITACIONES:Debido a la escasez de evidencia, las recomendaciones se basan principalmente en la opinión de expertos. Puede haber sesgo, ya que los representantes tenían su sede en Canadá.CONCLUSIONES:Las mejores prácticas para optimizar la localización y comunicación de lesiones endoscópicas no se abordan en las guías anteriores. Este consenso que involucra a expertos nacionales en cirugía colorrectal y gastroenterología proporciona un marco para la localización eficiente y efectiva de lesiones colorrectales. Consulte Video Resumen en http://links.lww.com/DCR/C71 . (Traducción-Dr. Mauricio Santamaria ).

Development and validation of an artificial intelligence-based system for predicting colorectal cancer invasion depth using multi-modal data

OBJECTIVES

Accurate endoscopic optical prediction of the depth of cancer invasion is critical for guiding an optimal treatment approach of large sessile colorectal polyps but was hindered by insufficient endoscopists expertise and inter-observer variability. We aimed to construct a clinically applicable artificial intelligence (AI) system for the identification of presence of cancer invasion in large sessile colorectal polyps.

METHODS

A deep learning-based colorectal cancer invasion calculation (CCIC) system was constructed. Multi-modal data including clinical information, white light (WL) and image-enhanced endoscopy (IEE) were included for training. The system was trained using 339 lesions and tested on 198 lesions across three hospitals. Man-machine contest, reader study and video validation were further conducted to evaluate the performance of CCIC.

RESULTS

The overall accuracy of CCIC system using image and video validation was 90.4% and 89.7%, respectively. In comparison with 14 endoscopists, the accuracy of CCIC was comparable with expert endoscopists but superior to all the participating senior and junior endoscopists in both image and video validation set. With CCIC augmentation, the average accuracy of junior endoscopists improved significantly from 75.4% to 85.3% (P = 0.002).

CONCLUSIONS

This deep learning-based CCIC system may play an important role in predicting the depth of cancer invasion in colorectal polyps, thus determining treatment strategies for these large sessile colorectal polyps.

Endoscopic surveillance after surgery for colorectal cancer

Colorectal cancer (CRC) is one of the most common cancers worldwide and its global incidence is rapidly increasing among adults younger than 50 years, especially in the 20-39 age group. Once a curative resection is achieved, surveillance is mandatory. Colonoscopy has a pivotal role aimed at resecting premalignant neoplasms and detecting cancer at a curable stage. In the current review, an update on the role of surveillance colonoscopy after CRC is provided, considered the most recent international guidelines and evidence published on this issue. In particular, several questions have been answered, why, how and how often colonoscopy should be performed, whether intensive surveillance is more effective than standard surveillance, how endoscopically resected T1 cancer should be followed, the different management existing between colon and rectal cancer, and, finally, how to improve the endoscopic surveillance. In a period of resource constraints, appropriateness will be mandatory, thus understanding how to optimize the role of colonoscopy in the surveillance of patients with a history of CRC is of crucial importance. Improving the quality of colonoscopy and identifying risk factors for recurrent and new-onset CRC, will allow us to individualize the surveillance program while sparing health care cost.

Through the Looking Glass: Surveillance Following Colonoscopic Polypectomy of Malignant Polyps

Introduction Colonoscopic polypectomy is a well-established screening and surveillance modality for malignant colorectal polyps. Following the detection of a malignant polyp, patients are either put on endoscopic surveillance or planned for a surgical procedure. We studied the outcome of colonoscopic excision of malignant polyps and their recurrence rates. Methods We performed a retrospective analysis over a period of five years (2015-2019) of patients who underwent colonoscopy and resection of malignant polyps. Size of polyp, follow-up with tumour markers, CT scan, and biopsy were considered individually for pedunculate and sessile polyps. We analysed the percentage of patients who underwent surgical resection, the percentage of patients who were managed conservatively, and the percentage of recurrence post-excision of malignant polyps. Results A total of 44 patients were included in the study. Of the 44 malignant polyps, most were present in the sigmoid colon at 43% (n=19), with the rectum containing 41% (n=18). The ascending colon accounted for 4.5% (n=2), transverse colonic polyps were 7% (n=3), and the descending colon polyps were 4.5% (n=2). Pedunculated polyps made up 55% (n=24). These were Level 1-3 based on Haggits classification; 14 were Haggits Level 1, eight were Haggits Level 2, and two were Haggits Level 3. The rest were sessile polyps making up 45% (n=20). Based on the Kikuchi classification, these were predominantly SM1 (n=12) and SM2 (n=8). Out of 44 cases, 11% (n=5) underwent surgical resection on follow-up in the form of bowel resection. This included three right hemicolectomies, one sigmoid colectomy, and one low anterior resection. Seven per cent (n=3) underwent endoscopic resection as trans-anal endoscopic mucosal resection (TEMS) and 82% (n=36) of the remaining cases were managed with regular follow-up and surveillance. Conclusions Colonoscopic polypectomy offers excellent benefits in detecting colorectal cancer and treating pre-malignant polyps. Colonoscopic polypectomy provides excellent benefits in colorectal cancer (CRC) detection and treatment of malignant polyps. However, it remains to be seen if post-polypectomy surveillance for low-risk polyp cancers would require a change in surveillance.

Resection margin involvement after endoscopic excision of malignant colorectal polyps: definition of margin involvement and its impact upon tumour recurrence

AIMS

Malignant polyps are examined to assess histological features which predict residual tumour in the unresected bowel and guide surgical decision-making. One of the most important of these features is resection margin involvement, although the best definition of margin involvement is unknown. In this study we aimed to investigate three different definitions and determine their impact on clinical outcomes.

METHODS AND RESULTS

One hundred and sixty-five malignant polyps removed endoscopically were identified and histological features correlated with either residual tumour in subsequent surgical resections or tumour recurrence following a period of clinical follow-up. Involvement of the polyp margin by cancer was defined in three different ways and outcomes compared. Tumour recurrence was associated with tumour grade, mucinous histology and resection margin involvement. All three definitions of margin involvement separated polyps into clinically significant categories; however, a margin ≤ 1 mm identified 73% of polyps as 'high-risk' compared with 59.1% when involvement was defined as tumour within the zone of coagulation artefact at the polyp base or 50% when tumour was present at the margin. All three 'low-risk' groups had a locoregional recurrence rate < 6.5%.

CONCLUSIONS

Definitions of margin involvement for endoscopically removed malignant polyps in the colon and rectum vary between health-care systems, but a 1-mm clearance is widely used in Europe and North America. Our results suggest that a 1-mm margin is unnecessary and should be replaced by a definition based on tumour at the margin or within coagulation artefact at the polyp base.

Timing of surveillance colonoscopy following malignant colorectal polypectomy in Queensland

INTRODUCTION

The management of malignant polyps presents a treatment challenge between a colorectal resection and polypectomy alone. Patients managed with polypectomy alone typically undergo surveillance for recurrent or metastatic disease, however, optimal timing of surveillance methods remains unclear. Guidelines recommend for completely resected malignant polyps, that a surveillance colonoscopy be perform 12 months from diagnosis. This study sought to clarify how patients with a malignant polyp were being colonoscopically surveilled if they did not undergo colorectal resection.

METHODS

A retrospective, population-wide cohort analysis of all patients from 2011 to 2019 was performed using data from the Queensland Oncology Repository. Patient, procedural and pathological data were extracted for all patients diagnosed with a malignant polyp and timing of the first surveillance endoscopy was calculated. Statistical analysis comparing the timing of surveillance colonoscopy across multiple patients, procedural and histological characteristics were assessed.

RESULTS

A total of 1646 patients were identified with a malignant polyp, with 797 patients managed with polypectomy and surveillance alone. The median time to surveillance endoscopy was 182 days with the mean 220.01 days. This was substantially sooner than the recommended clinical guidelines of 365 days. There were no patient or procedural characteristics which predicted a difference in the timing of surveillance colonoscopy. No pathological factors appeared to change the timing for surveillance endoscopy (P > 0.05).

CONCLUSION

Overall, patients had surveillance endoscopy procedures substantially earlier than guideline recommendations. However, evidence underlying these guidelines and other surveillance methods for malignant polyps are not strong. Future technological developments, including improvements in imaging techniques, may provide additional options for surveillance of malignant polyps.

Missing parameters in malignant polyp histology reports: can appropriate decisions be made?

The treatment of colorectal malignant polyps is dependent upon quality reporting of the histopathological features known to predict the risk of residual disease or lymph node metastasis. The Royal College of Pathologists of Australasia (RCPA) has produced protocols covering mandatory and recommended pathological parameters to be included in the pathology reporting of malignant polyps. This paper aimed to assess the quality of the pathological reporting in a population-wide analysis from 2011-2019 in Queensland, Australia. A retrospective population-wide cohort study was performed using the Queensland Oncology Repository as a data source. The number of missing pathological parameters (assessed against the RCPA protocol standards and guidelines) for each patient was then summed. Demographic and other patient details were collated. The number of patients whose recommended treatment could theoretically be altered by the full reporting of missing parameters was calculated. A total of 1,646 histopathological reports of malignant polyps were reviewed. From this, 30.8% of all reports had a sufficient number of missing parameters that may have seen an alternate management strategy chosen. The most commonly under-reported parameter from the standards was either a Haggitt or Kikuchi level with 48.6% missing. Synoptic reporting significantly reduced the mean number of missing pathological parameters (p<0.001) There was a significant improvement in the number of missing pathological details over time (p<0.001). Accurate and complete pathology reports are essential to formulate appropriate surgical recommendations after the resection of malignant polyps. In this population-based study, pathology reports remain incomplete for the established parameters despite the introduction of an RCPA structured reporting protocol. Fortunately, the quality of pathological reporting has improved since the introduction of the first RCPA protocol covering reporting of malignant polyps.

Malignant Colorectal Polyps: Are Pathology Reports Sufficient for Decision Making?

AIM

This study aims to assess the completeness of pathology reports of T1 colorectal cancers from different healthcare centers and the change of treatment decision after reevaluation of the polyps.

MATERIALS AND METHODS

In this single-center retrospective cohort study, several pathology reports of endoscopically excised malignant colorectal polyps at diverse healthcare centers in Turkey were reassessed at a comprehensive cancer center in Istanbul. Reassessment was mainly focused on core elements such as the size of invasive carcinoma, histologic type and grade, tumor extension, surgical margin (deep and mucosal), and lymphovascular invasion.

RESULTS

Sixty-seven endoscopically resected malignant polyps were analyzed. The mean age of patients was 62.2 years and 38 (58%) patients were males. Tumor size, histologic type and grade, surgical margin (deep and mucosal), and lymphovascular invasion were reported in 11%, 100%, 31%, 9%, and 19%, respectively. All 5 prognostic factors were reported only in 1 (1.5%) pathology report. Because of the missing (incomplete) data, the pathologic examination of 59 (88%) patients was determined to be inadequate to make an accurate treatment decision.

CONCLUSION

Several variables are not considered and frequently missing for decision-making, suggesting the reassessment of the specimen by a second pathologist at a high-volume comprehensive cancer center.

In comparison with polypectomy, colorectal resection is associated with improved survival for patients diagnosed with malignant polyps

AIM

Patients diagnosed with a malignant polyp generally have favourable overall survival (OS) and cancer-specific survival (CSS). However, it is unclear how choice in management for malignant polyps may affect survival.

METHODS

Data from the Queensland Oncology Repository was analysed to derive a population wide assessment of the impact of management strategy on OS and CSS for patients diagnosed with malignant polyps. Log-rank testing, Kaplan-Meier and Cox-regression models were performed. Patients were matched using propensity score and Mahalanobis distance matching.

RESULTS

A total of 1,646 patients were included with 240 deaths and 52 colorectal cancer related deaths until censor date. Following propensity score and Mahalanobis distance matching of patients undergoing polypectomy alone versus colorectal resection, there was no significant difference in the age groups (<60 years of age or ≥60 years of age), American Society of Anesthesiology score, comorbidity count or Association of ColoProctology of Great Britain and Ireland risk category. However, of note Log-rank testing demonstrated a significant difference in OS (p < 0.001) and CSS (p = 0.0061) between management strategies. Multivariable Cox-regression models in matched and un-matched patient cohorts demonstrated significantly lower hazards of death for OS with resection (p < 0.001). However, CSS was no longer significantly different between management groups in multivariable Cox-regression analysis (p = 0.073).

CONCLUSION

Patients who underwent colorectal resection had significantly improved OS and CSS compared with polypectomy alone. Improved OS was furthermore seen on multivariable analysis, and in matched cohorts. Future research should investigate why this unexpected finding may be the case and whether updates to guidelines should be considered.

Malignant polyps in the COVID-19 era: a population-based analysis

BACKGROUND

Malignant polyps represent the early development of colorectal adenocarcinoma. During 2020, there was widescale rationing of health-care resources in response to the COVID-19 pandemic. In particular there was deferral of some colonoscopy procedures required for timely malignant polyp detection. This study sought to assess how these deferrals affected the diagnosis of malignant polyps.

METHODS

A population wide analysis was performed of 2079 malignant polyps, diagnosed in Queensland, Australia from 2011 to 2020. A regression analysis, with 95% prediction intervals, was produced to determine whether there was a significant impact on the number of malignant polyps diagnosed in 2020 compared to previous years. Univariate statistical analysis of patient, procedural, and pathological variables was also performed.

RESULTS

In 2020 there were 211 malignant polyps diagnosed, which was significantly lower than was predicted by the univariate regression analysis (r²  = 0.85, 95% prediction interval: 255.07-323.91, P < 0.001). These malignant polyps were less likely to be diagnosed in a private setting (P < 0.001), and exhibited significantly less depth of submucosal invasion (P = 0.017). There was no significant difference in the management strategy (polypectomy, resection or trans-anal resection) between 2011 and 2019 and 2020.

CONCLUSION

Because of the significant decrease in the number of malignant polyps, and the natural history of the disease, it is expected that there will be an increase in more advanced colorectal adenocarcinomas presenting in 2021 and beyond. This has implications for healthcare resources, particularly in light of the ongoing strain on health departments as a result of the COVID-19 pandemic.

Long-term results of minimally invasive transanal surgery for rectal tumors in 249 consecutive patients

PURPOSE

To delineate the long-term results of minimally invasive transanal surgery (MITAS) for selected rectal tumors.

METHODS

We analyzed data, retrospectively, on consecutive patients who underwent MITAS between 1995 and 2015, to establish the feasibility, excision quality, and perioperative and oncological outcomes of this procedure.

RESULTS

MITAS was performed on 243 patients. The final histology included 142 cancers, 47 adenomas, and 52 neuroendocrine tumors (NET G1). A positive margin of 1.6% and 100% en bloc resection were achieved. The mean operative time was 27.4 min. Postoperative morbidity occurred in 7% of patients, with 0% mortality. The median follow-up was 100 months (up to ≥ 5 years or until death in 91.8% of patients). Recurrence developed in 2.9% of the patients. The 10-year overall survival rate was 100% for patients with NET G1 and 80.3% for those with cancer. The 5-year DFS was 100% for patients with Tis cancer, 90.6% for those with T1 cancer, and 87.5% for those with T2 or deeper cancers. MITAS for rectal tumors ≥ 3 cm resulted in perioperative and oncologic outcomes equivalent to those for tumors < 3 cm.

CONCLUSION

MITAS is feasible for the local excision (LE) of selected rectal tumors, including tumors ≥ 3 cm. It reduces operative time and secures excision quality and long-term oncological outcomes.

Management of high and low risk malignant polyps: a population-wide analysis

AIM

The management of malignant polyps is a treatment dilemma in selecting between polypectomy and colorectal resection. To assist clinicians, guidelines have been developed by the Association of Coloproctology of Great Britain and Ireland (ACPGBI) to provide treatment recommendations.

METHODS

This study compared management strategy based on the ACPGBI risk categorization for malignant polyps. Univariable and multivariable statistical analysis was undertaken to assess the factors predicting management strategy. A population-wide analysis was performed of 1646 malignant polyps and the factors that predicted their management strategy, from Queensland, Australia, from 2011 to 2019.

RESULTS

Overall, 31.55% of patients with very low or low risk disease proceeded to resection. Of those with high or very high risk disease, 36.69% did not proceed to resection. In very low and low risk polyps, age (P = 0.003) and polyp location (P < 0.001) were significantly different between the colorectal resection group and the polypectomy alone group. In those with very high or high risk polyps age (P < 0.001), type of facility (public or private) for the colonoscopy (P = 0.037), right colonic polyps compared to left colonic polyps (P = 0.015) and rectal polyps (P < 0.001) and mismatch repair mutations present (P = 0.027) were predictive of resection in high risk disease using a multivariable model.

CONCLUSION

Over 30% of patients with very low and low risk malignant polyps proceeded to resection, against the advice of guidelines. Furthermore, over 35% of patients with very high or high risk malignant polyps did not proceed to resection. Education strategies may improve management decision choices. Furthermore, improvements in data collation will improve the understanding of management choices in the future.

Long-term oncological outcomes of endoscopic full-thickness resection after previous incomplete resection of low-risk T1 CRC (LOCAL-study): study protocol of a national prospective cohort study

BACKGROUND

T1 colorectal cancer (CRC) without histological high-risk factors for lymph node metastasis (LNM) can potentially be cured by endoscopic resection, which is associated with significantly lower morbidity, mortality and costs compared to radical surgery. An important prerequisite for endoscopic resection as definite treatment is the histological confirmation of tumour-free resection margins. Incomplete resection with involved (R1) or indeterminate (Rx) margins is considered a strong risk factor for residual disease and local recurrence. Therefore, international guidelines recommend additional surgery in case of R1/Rx resection, even in absence of high-risk factors for LNM. Endoscopic full-thickness resection (eFTR) is a relatively new technique that allows transmural resection of colorectal lesions. Local scar excision after prior R1/Rx resection of low-risk T1 CRC could offer an attractive minimal invasive strategy to achieve confirmation about radicality of the previous resection or a second attempt for radical resection of residual luminal cancer. However, oncologic safety has not been established and long-term data are lacking. Besides, surveillance varies widely and requires standardization.

METHODS/DESIGN

In this nationwide, multicenter, prospective cohort study we aim to assess feasibility and oncological safety of completion eFTR following incomplete resection of low-risk T1 CRC. The primary endpoint is to assess the 2 and 5 year luminal local tumor recurrence rate. Secondary study endpoints are to assess feasibility, percentage of curative eFTR-resections, presence of scar tissue and/or complete scar excision at histopathology, safety of eFTR compared to surgery, 2 and 5 year nodal and/or distant tumor recurrence rate and 5-year disease-specific and overall-survival rate.

DISCUSSION

Since the implementation of CRC screening programs, the diagnostic rate of T1 CRC is steadily increasing. A significant proportion is not recognized as cancer before endoscopic resection and is therefore resected through conventional techniques primarily reserved for benign polyps. As such, precise histological assessment is often hampered due to cauterization and fragmentation and frequently leads to treatment dilemmas. This first prospective trial will potentially demonstrate the effectiveness and oncological safety of completion eFTR for patients who have undergone a previous incomplete T1 CRC resection. Hereby, substantial surgical overtreatment may be avoided, leading to treatment optimization and organ preservation. Trial registration Nederlands Trial Register, NL 7879, 16 July 2019 ( https://trialregister.nl/trial/7879 ).

Ex vivo explant model of adenoma and colorectal cancer to explore mechanisms of action and patient response to cancer prevention therapies

Colorectal cancer (CRC) is the second leading cause of cancer death in the UK. Novel therapeutic prevention strategies to inhibit the development and progression of CRC would be invaluable. Potential contenders include low toxicity agents such as dietary-derived agents or repurposed drugs. However, in vitro and in vivo models used in drug development often do not take into account the heterogeneity of tumours or the tumour microenvironment. This limits translation to a clinical setting. Our objectives were to develop an ex vivo method utilizing CRC and adenoma patient-derived explants (PDEs) which facilitates screening of drugs, assessment of toxicity, and efficacy. Our aims were to use a multiplexed immunofluorescence approach to demonstrate the viability of colorectal tissue PDEs, and the ability to assess immune cell composition and interactions. Using clinically achievable concentrations of curcumin, we show a correlation between curcumin-induced tumour and stromal apoptosis (P < .001) in adenomas and cancers; higher stromal content is associated with poorer outcomes. B cell (CD20+ve) and T cell (CD3+ve) density of immune cells within tumour regions in control samples correlated with curcumin-induced tumour apoptosis (P < .001 and P < .05, respectively), suggesting curcumin-induced apoptosis is potentially predicted by baseline measures of immune cells. A decrease in distance between T cells (CD3+ve) and cytokeratin+ve cells was observed, indicating movement of T cells (CD3+ve) towards the tumour margin (P < .001); this change is consistent with an immune environment associated with improved outcomes. Concurrently, an increase in distance between T cells (CD3+ve) and B cells (CD20+ve) was detected following curcumin treatment (P < .001), which may result in a less immunosuppressive tumour milieu. The colorectal tissue PDE model offers significant potential for simultaneously assessing multiple biomarkers in response to drug exposure allowing a greater understanding of mechanisms of action and efficacy in relevant target tissues, that maintain both their structural integrity and immune cell compartments.

Rationalising the use of specimen pots following colorectal polypectomy: a small step towards greener endoscopy

Aims

In this study, we aim to determine whether combining multiple small colorectal polyps within a single specimen pot can reduce carbon footprint, without an associated deleterious clinical impact.

Methods

This was a retrospective observational study of colorectal polyps resected during 2019, within the Imperial College Healthcare Trust. The numbers of pots for polypectomy specimens were calculated and corresponding histology results were extracted. We modelled the potential reduction in carbon footprint if all less than 10 mm polyps were sent together and the number of advanced lesions we would not be able to locate if we adopted this strategy. Carbon footprint was estimated based on previous study using a life-cycle assessment, at 0.28 kgCO2e per pot.

Results

A total of 11 781 lower gastrointestinal endoscopies were performed. There were 5125 polyps removed and 4192 pots used, equating to a carbon footprint of 1174 kgCO2e. There were 4563 (89%) polyps measuring 0-10 mm. 6 (0.1%) of these polyps were cancers, while 12 (0.2%) demonstrated high-grade dysplasia. If we combined all small polyps in a single pot, total pot usage could be reduced by one-third (n=2779).

Conclusion

A change in practice by placing small polyps collectively in one pot would have resulted in reduction in carbon footprint equivalent to 396 kgCO2e (emissions from 982 miles driven by an average passenger car). The reduction in carbon footprint from judicious use of specimen pots would be amplified with a change in practice on a national level.

A population-based study of the management of rectal malignant polyps and the use of trans-anal surgery

INTRODUCTION

Rectal malignant polyps can be managed by use of trans-anal resections (TAR). Traditional techniques of resection have been replaced by use of platforms such as trans-anal minimally invasive surgery (TAMIS) or trans-anal endoscopic microsurgery (TEM). This study reviewed the management of rectal malignant polyps, in particular focussing on when clinicians used TAR.

METHODS

A population wide cohort study of all malignant rectal polyps diagnosed in Queensland, Australia from 2011 to 2018 was undertaken. Patient and pathological factors were compared across the management strategies of polypectomy, TAR and rectal resection.

RESULTS

Overall 430 patients were diagnosed with a malignant rectal polyp during the study period, with 103 undergoing a TAR. There was increasing use of TAR across the study period as a management strategy (P < 0.001). Polypectomy alone was more likely to be the management strategy over TAR or rectal resection if there were clear margins (P < 0.001). The distance to the closest polypectomy margin was also significantly higher in the polypectomy group with mean clearance 2.09 mm in polypectomy group versus 0.86 mm in TAR group and 0.99 mm in resection group (P < 0.001). Rectal resection was more likely to be the management strategy over TAR if there was LVI (P < 0.001), depth of invasion was deeper (P < 0.001) and there was tumour budding (P = 0.001).

CONCLUSION

TAR is an effective management strategy for rectal polyps and is utilized particularly in rectal malignant polyps when there are close or involved margins. Future guideline development should consider incorporation of TAR given the advances in techniques afforded by TAMIS or TEM platforms.

[Treatment of the colorectal polyps]

Bevezetés és célkitűzés

A colorectális polypok komplex ellátása komoly kihívást jelent nemcsak az endoszkópos szakemberek, hanem a sebészek számára is.

Anyag és módszerek

A colorectális polypok sebészeti ellátását 2014-ig a hagyományos sebészi per anum polypectomiák vagy lokális excisók (LE) jelentették a szegedi Sebészeti Klinikán. Ezen hagyományos transanális műtéti technikák hátrányai mindenki számára jól ismertek: magas resectiós szél pozitivitás arány, alacsony „en bloc” resectiós arány, valamint a magasabban, 5 cm felett elhelyezkedő léziók eltávolításának nehézségei stb. Mindezek alapján felmerült az igény, hogy a transanális műtétek technikai fejlődésével lépést tartva, nemcsak új műtéti módszert (TAMIS, transanális minimálisan invazív sebészet) vezessünk be, hanem a már jól ismert, de még nem alkalmazott műtéti technikát, úgymint a TEM (transanális endoszkópos mikrosebészet) is alkalmazni kezdjük. Klinikánkon az új sebészi módszerek bevezetése mellett fontosnak tartottuk a sebészi gasztroenterológia, azon belül is a sebészi endoszkópia humán és tárgyi feltételeinek fejlesztését, valamint bővítését is.

Eredmények/következtetések

Az újabb műtéti technikák bevezetése mellett a Sebészeti Klinika Endoszkópos Laborjának fejlesztésével komoly lépéseket tettünk a colorectalis polypok komplex, multidiszciplináris ellátásának terén.

Management of Significant Polyp and Early Colorectal Cancer Is Optimized by Implementation of a Dedicated Multidisciplinary Team Meeting: Lessons Learned From the United Kingdom National Program

BACKGROUND

The concept of significant polyps and early colorectal cancer encompasses complex polyps not amenable to routine snare polypectomy or where malignancy cannot be excluded. The assessment and management of these lesions is contentious and increasingly important due to the significant risk of over- or undertreatment.

OBJECTIVE

Following the recommendations of the Significant Polyps and Early Colorectal Cancer National Program, we implemented a dedicated multidisciplinary team meeting and analyzed the influence on patient outcomes.

DESIGN

This was a retrospective study using a prospectively collected database of patients discussed at the dedicated multidisciplinary team meeting.

SETTINGS

This study was conducted in a single tertiary-care center.

PATIENTS

Consecutive patients with significant polyps and early colorectal cancer were identified either through the Bowel Cancer Screening Program or colonoscopy for symptomatic patients.

MAIN OUTCOME MEASURES

Proportions of patients who had organ preservation, and secondary treatment and recurrence rate served as outcome measures.

RESULTS

Overall, 135 patients discussed at the dedicated multidisciplinary team meeting were included, with a median age of 71 years. Median size of the lesions was 25 mm, and 39% were in the rectum. Patients were discussed either after the lesion was removed during the initial colonoscopy (n = 38), of whom 16 (42%) had unexpected cancer, or had no initial treatment with subsequent case review (n = 97). Of these 97 patients, 46 underwent endoscopic excision (26% cancer), 20 trans-anal excision (10% cancer), 23 primary surgical resection (35% cancer), and 8 had no treatment. In 104 (82%) patients, organ preservation was achieved. Secondary surgery was required in 7 of 104 (6.7%) patients after local excision due to radical treatment of high-risk T1 lesions, local recurrence, or patients' decisions. The cumulative hazard estimates for recurrence after a median follow-up of 18.5 months was less than 10% for both benign and malignant lesions.

LIMITATIONS

This study was limited by its relatively small sample size and single-center setting.

CONCLUSIONS

A dedicated multidisciplinary team meeting improved the management of significant polyps and early colorectal cancer, safely refining organ preservation for patients, with low recurrence rates. See Video Abstract at http://links.lww.com/DCR/B826.

MANEJO DE SPECC PLIPO COMPLEJO Y CNCER COLORRECTAL TEMPRANO ES OPTIMIZADO MEDIANTE LA IMPLEMENTACIN DE REUNIONES DE UN EQUIPO MULTIDISCIPLINARIO ESPECIALIZADOS LECCIONES APRENDIDAS DEL PROGRAMA NACIONAL DEL REINO UNIDO

ANTECEDENTES:El concepto de pólipos complejos y cáncer colorrectal temprano abarca engloba pólipos avanzados que no es posible la reseccion endoscopica rutinaria, o aquellos en los que no se puede excluir malignidad. La evaluación y el manejo de estas lesiones es controversial y cada vez más importante debido al riesgo significativo de ser tratadas o no.OBJETIVO:Siguiendo las recomendaciones del Programa Nacional de Pólipos Complejos y Cáncer Colorrectal Temprano, implementamos reuniónes del equipo multidisciplinario especializado y analizamos el impacto en los resultados de los pacientes.DISEÑO:Estudio retrospectivo sobre una base de datos recopilada prospectivamente de los pacientes discutidos en la reunión del equipo multidisciplinario especializado.AJUSTE:Este estudio se realizó en un centro de atención terciaria.PACIENTES:Pacientes consecutivos con pólipos complejos y cáncer colorrectal temprano identificado a través del Programa de detección de cáncer intestinal o colonoscopia para pacientes sintomáticos.PRINCIPALES MEDIDAS DE RESULTADO:Proporción de pacientes que tuvieron preservación de órganos, tratamiento secundario y tasa de recurrencia.RESULTADOS:En total, se incluyeron 135 pacientes discutidos en la reunión del equipo multidisciplinario especializado dedicada, con una media de edad de 71 años. El tamaño medio de las lesiones fue de 25 mm y el 39% estaban en el recto. Se discutio de los pacientes después de que se resecara la lesión durante la colonoscopia inicial [n = 38, de los cuales 16 (42%) tenían un cáncer imprevisto] o no recibieron tratamiento de inicio, con revisión posterior del caso (n = 97). De estos, 46/97 fueron sometidos a resección endoscópica (26% cáncer), 20/97 resección transanal (10% cáncer), 23/97 resección quirúrgica primaria (35% cáncer) y 8/97 no recibieron tratamiento. En 104 (82%) pacientes, se logró la preservación de órgano. Cirugía secundaria fue requeria en 7/104 (6,7%) pacientes después de la resección local debido a tratamiento radical de lesiones T1 de alto riesgo, recidiva local o decisión del paciente. Las estimaciones de riesgo acumulativo de recurrencia después de una media de seguimiento de 18,5 meses fue inferior al 10% tanto para las lesiones benignas como para las malignas.LIMITACIONES:Tamaño de muestra relativamente pequeño y entorno de un solo centro.CONCLUSIONES:La Reunion del equipo multidisciplinario especializado mejoró el manejo de los pólipos complejos y cáncer colorrectal temprano, refinando de manera segura la preservación de órganos para los pacientes, con bajas tasas de recurrencia. Consulte Video Resumen en http://links.lww.com/DCR/B826. (Traducción- Dr. Francisco M. Abarca-Rendon).

Impact of ≥ 0.1-mm free resection margins on local intramural residual cancer after local excision of T1 colorectal cancer

Background and study aims  A free resection margin (FRM) > 1 mm after local excision of a T1 colorectal cancer (CRC) is known to be associated with a low risk of local intramural residual cancer (LIRC). The risk is unclear, however, for FRMs between 0.1 to 1 mm. This study evaluated the risk of LIRC after local excision of T1 CRC with FRMs between 0.1 and 1 mm in the absence of lymphovascular invasion (LVI), poor differentiation and high-grade tumor budding (Bd2-3). Patients and methods  Data from all consecutive patients with local excision of T1 CRC between 2014 and 2017 were collected from 11 hospitals. Patients with a FRM ≥ 0.1 mm without LVI and poor differentiation were included. The main outcome was risk of LIRC (composite of residual cancer in the local excision scar in adjuvant resection specimens or local recurrence during follow-up). Tumor budding was also assessed for cases with a FRM between 0.1 and 1mm. Results  A total of 171 patients with a FRM between 0.1 and 1 mm and 351 patients with a FRM > 1 mm were included. LIRC occurred in five patients (2.9 %; 95 % confidence interval [CI] 1.0-6.7 %) and two patients (0.6 %; 95 % CI 0.1-2.1 %), respectively. Assessment of tumor budding showed Bd2-3 in 80 % of cases with LIRC and in 16 % of control cases. Accordingly, in patients with a FRM between 0.1 and 1 mm without Bd2-3, LIRC was detected in one patient (0.8%; 95 % CI 0.1-4.4 %). Conclusions  In this study, risks of LIRC were comparable for FRMs between 0.1 and 1 mm and > 1 mm in the absence of other histological risk factors.

Colorectal Cancer Diagnosis: The Obstacles We Face in Determining a Non-Invasive Test and Current Advances in Biomarker Detection

Simple Summary

Colorectal cancer (CRC) is one of the most common cancers in the western world. CRC originates from precursor adenomatous polyps, which may over time develop into cancer. Endoscopic evaluation remains the gold-standard investigation for the disease. In the absence of molecular tools for early detection, the removal of neoplastic adenomas via polypectomy remains an important measure to prevent dysplastic adenomas from evolving into invasive carcinoma. Colonoscopy is an intrusive procedure that provides an uncomfortable experience for patients. Kits for testing for the presence of blood hemoglobin in the stool are now widely used, and DNA methylation-based detection kits have been approved in the USA for testing the stool and plasma, but few other molecular biomarkers have found their way into medical practice. This review summarizes current trends in the detection and screening of CRC and provides a definitive review of emerging molecular biomarkers for CRC.

Abstract

Globally, colorectal cancer (CRC) is the third most common cancer, with 1.4 million new cases and over 700,000 deaths per annum. Despite being one of the most common cancers, few molecular approaches to detect CRC exist. Carcinoembryonic antigen (CEA) is a known serum biomarker that is used in CRC for monitoring disease recurrence or response to treatment. However, it can also be raised in multiple benign conditions, thus having no value in early detection or screening for CRC. Molecular biomarkers play an ever-increasing role in the diagnosis, prognosis, and outcome prediction of disease, however, only a limited number of biomarkers are available and none are suitable for early detection and screening of CRC. A PCR-based Epi proColon^® blood plasma test for the detection of methylated SEPT9 has been approved by the USFDA for CRC screening in the USA, alongside a stool test for methylated DNA from CRC cells. However, these are reserved for patients who decline traditional screening methods. There remains an urgent need for the development of non-invasive molecular biomarkers that are highly specific and sensitive to CRC and that can be used routinely for early detection and screening. A molecular approach to the discovery of CRC biomarkers focuses on the analysis of the transcriptome of cancer cells to identify differentially expressed genes and proteins. A systematic search of the literature yielded over 100 differentially expressed CRC molecular markers, of which the vast majority are overexpressed in CRC. In terms of function, they largely belong to biological pathways involved in cell division, regulation of gene expression, or cell proliferation, to name a few. This review evaluates the current methods used for CRC screening, current availability of biomarkers, and new advances within the field of biomarker detection for screening and early diagnosis of CRC.

Head to head: should we adopt the term "sessile serrated lesion"?

The precursor lesion for the ~30% of colon carcinomas developing along the serrated pathway was first described in detail in 1996, and was named sessile serrated adenoma in 2003. Although the entity itself was controversial initially, over time the concept of a serrated pathway initiated by this lesion has become well accepted in the medical community. The name sessile serrated adenoma, however, has been controversial since the beginning and continues to be controversial. Alternative names, including serrated polyp with abnormal proliferation, sessile serrated polyp and, most recently, sessile serrated lesion, have been proposed. Despite the fact that the term sessile serrated lesion was adopted by the World Health Organization in 2019, none of these terms has received universal acceptance. In this article, arguments for and against adopting the term sessile serrated lesion are discussed in detail.

Cancer in a polyp of the large intestine - an interdisciplinary decision problem

Large intestine polyps are commonly found during colonoscopies. Pedunculated colon polyps can be totally removed using an endoscopic invasive technique. A problem arises when the pendulated polyp contains cancerous infiltration. The aim of the article was a presentation of the clinical decision process concerned with the presence of cancer invasion tissue within colorectal polyps. Review of literature source and presentation of histological sample photography. A correct interpretation of the pathomorphological protocol is crucial for the therapeutic decision, which should be consistent with the actual recommendations of gastroenterological societies. Local treatment is considered as complete when the adenocarcinoma is well or moderately differentiated without any microinvasion of blood and lymphatic vessels and the resection margin is more than 1 mm from the cancer tissue infiltration. In the contemporary clinical practice patients with a colon polyp require rational clinical decisions, which are based on the actual recommendations.

Patient and pathological predictors of management strategy for malignant polyps following polypectomy: a systematic review and meta-analysis

PURPOSE

Malignant polyps present a treatment dilemma for clinicians and patients. This meta-analysis sought to identify the factors that predicted the management strategy for patients diagnosed with a malignant polyp.

METHODS

A literature search was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and the Cochrane Collaboration prognostic studies guidelines. Reports from 1985 onwards were included, data on patient and pathological factors were extracted and random effects meta-analysis models were used.

RESULTS

Fifteen studies were included. Seven studies evaluated lymphovascular invasion (LVI). The odds of surgery were significantly higher in malignant polyps with LVI (OR 2.20, 95% CI 1.36-3.55). Ten studies revealed the odds of surgery were significantly higher with positive polypectomy margins (OR 8.09, 95% CI 4.88-13.40). Tumour differentiation was compared in eight studies. There were significantly lower odds of surgery in malignant polyps with well/moderate differentiation compared with poor differentiation (OR 0.31, 95% CI 0.21-0.46). There were non-significant trends favouring surgical resection in younger patients, males and Haggitt 4/Kikuchi Sm3 lesions. There was considerable heterogeneity in the meta-analyses for the variables age, gender, polyp morphology and Haggitt/Kikuchi level (I² > 75%).

CONCLUSION

This meta-analysis has demonstrated that LVI, positive polypectomy resection margins, and poor tumour differentiation significantly predict malignant polypectomy patients who underwent subsequent surgery. Age and gender were important factors predicting management, but not consistently across studies, whilst polyp morphology and Haggitt/Kikuchi levels did not significantly predict the management strategy. Further research may assist in understanding the management preferences.

Overview of the Large Bowel Assessment using Magnetic Resonance Imaging: Different Techniques for Current and Emerging Clinical Applications

Radiological assessments of the small and large bowel are essential in daily clinical practice. Over X-ray plain films and ultrasound, cross-sectional techniques are considered the most comprehensive imaging modalities. "Cross-sectional techniques" refers to CT and MRI, as stated in the following sentence. In fact, computed tomography and magnetic resonance imaging take great advantage of the three-dimensional appraisal and the extensive evaluation of the abdominal cavity, allowing intestinal evaluation as well as detection of extra-intestinal findings. In this context, the chief advantage of computed tomography is the fast scan time, which is crucial for emergency cases. Nonetheless, it is undeniably impaired using ionizing radiation. As the awareness of radiation exposure is a topic of increasing importance, magnetic resonance imaging is not only becoming a mere alternative but also a primary imaging technique used in assessing intestinal diseases. Specifically, the evaluation of the large bowel through MRI can still be considered relatively uncharted territory. Although it has demonstrated superior accuracy in the assessment of some clinical entities from inflammatory bowel disease to rectal carcinoma, its role needs to be consolidated in many other conditions. Moreover, different technical methods can be applied for colonic evaluation depending on the specific disease and segment involved. This article aims to provide a thorough overview of the techniques that can be utilized in the evaluation of the large bowel and a discussion on the major findings in different colonic pathologies of primary interest.

Colorectal malignant polyps: a modern approach

Colorectal malignant polyps (MP) are polyps with invasive cancer into the submucosa harboring a variable risk of lymph node involvement, which can be estimated through evaluation of morphological, endoscopic, and histologic features. The recent advances in imaging endoscopic techniques have led to the possibility of performing an optical diagnosis of T1 colorectal cancer, allowing the selection of the best therapeutic modality to optimize outcomes for the patient. When MP are diagnosed after endoscopic removal, their management can be challenging. Differentiating low- and high-risk histologic features that influence the possibility of residual tumor, the risk of recurrence and the risk of lymph node metastasis, is crucial to further optimize treatment and surveillance plans. While the presence of high-risk features indicates a need for surgery in the majority of cases, location, comorbidities and the patient’s preference should be taken in account when making the final decision. This is a particularly important issue in the management of low rectal MP presenting with high-risk features, where chemoradiotherapy followed by a watch-and-wait strategy has demonstrated promising results. In this review we discuss the important prognostic features of MP and the most modern approaches regarding their management.

Decision making in the management of adults with malignant colorectal polyps: An exploration of the experiences of patients and clinicians

AIM

A diagnosis of colorectal polyp cancer presents a treatment dilemma. The decision between segmental resection versus endoscopic surveillance is difficult due to a lack of good quality clinical evidence for either option. The aim of this study was to understand the decision making experiences of both clinicians and patients when faced with such a diagnosis.

METHODS

Qualitative, semi-structured interviews were undertaken with 10 clinicians involved in the care of patients diagnosed with polyp cancer and five patients who had experience of a diagnosis of polyp cancer. All clinicians and patients were from four hospital trusts across the north of England. Interviews were audio-recorded, transcribed verbatim and analysed using the principles of interpretative phenomenological analysis.

RESULTS

Analysis of the interview transcripts evidenced that clinicians and patients were supportive of a shared approach to treatment decision making in the context of a diagnosis of colorectal polyp cancer. Uncertainty, influences and information were among the themes identified to be preventing this happening at present. This study identified themes which were common to both groups. These were complexity of the risk information, lack of patient information resources, and system factors and time.

CONCLUSION

This research study has evidenced several factors such as uncertainty, complexity of risk information and influences on decisions which are preventing patients being involved in treatment decisions following a diagnosis of colorectal polyp cancer. Recommendations for improvements in practice, including a framework to assist treatment decision making in the future, are highlighted.

Long-term outcomes of patients with poor prognostic factors following transanal endoscopic microsurgery for early rectal cancer

AIM

Management of early rectal cancer following transanal microscopic anal surgery poses a management dilemma when the histopathology reveals poor prognostic features, due to high risk of local recurrence. The aim of this study is to evaluate the oncological outcomes of such patients who undergo surgery with total mesorectal excision (TME), receive adjuvant chemo/radiotherapy (CRDT/RT) or receive close surveillance only (no further treatment).

METHODS

We identified patients with poor prognostic factors-pT2 adenocarcinoma, poor differentiation, deep submucosal invasion (Kikuchi SM3), lymphovascular invasion, tumour budding or R1 resection margin-between 1 September 2012 and 31 January 2020 and report their oncological outcomes.

RESULTS

Of the 53 patients, 18 had TME, 14 had CRDT and 14 had RT; seven patients did not have any further treatment. The median follow-up was 48 months, 12 developed recurrence and six died. Overall, 5-year survival (OS) was 88.9% and disease-free survival (DFS) was 79.2%. Compared to the surgical group, in which there were eight recurrences and two deaths, there were zero recurrences or deaths in the CRDT group, log-rank test P = 0.206 for OS and P = 0.005 for DFS. The 5-year survival rates in the RT and surveillance only groups were OS 78.6%, DFS 85.7% and OS 71.5%, DFS 71% respectively. TME assessment in the surgical group revealed Grade 3 quality in seven of the 16 available reports.

CONCLUSION

These findings support the strategy of adjuvant CRDT as first line treatment for patients undergoing transanal endoscopic microsurgery for early rectal cancer with poor prognostic factors on initial histological assessment.

Management of early rectal cancer; current surgical options and future direction

Rectal cancer is the second commonest cause of cancer death within the United Kingdom. Utilization of national screening programmes have resulted in a greater proportion of patients presenting with early-stage disease. The technique of transanal endoscopic microsurgery was first described in 1984 following which further options for local excision have emerged with transanal endoscopic operation and, more recently, transanal minimally invasive surgery. Owing to the risks of local recurrence, the current role of minimally invasive techniques for local excision in the management of rectal cancer is limited to the treatment of pre-invasive disease and low risk early-stage rectal cancer (T1N0M0 disease). The roles of chemotherapy and radiotherapy for the management of early rectal cancer are yet to be fully established. However, results of high-quality research such as the GRECCAR II, TESAR and STAR-TREC randomised control trials may highlight a wider role for local excision surgery in the future, when used in combination with oncological therapies. The aim of our review is to provide an overview in the current management of early rectal cancer, the surgical options available for local excision and the future multimodal direction of early rectal cancer treatment.

The impact of transanal local excision of early rectal cancer on completion rectal resection without neoadjuvant chemoradiotherapy: a systematic review

BACKGROUND

The impact of transanal local excision (TAE) of early rectal cancer (ERC) on subsequent completion rectal resection (CRR) for unfavorable histology or margin involvement is unclear. The aim of this study was to provide a comprehensive review of the literature on the impact of TAE on CRR in patients without neoadjuvant chemoradiotherapy (CRT).

METHODS

We performed a systematic review of the literature up to March 2020. Medline and Cochrane libraries were searched for studies reporting outcomes of CRR after TAE for ERC. We excluded patients who had neoadjuvant CRT and endoscopic local excision. Surgical, functional, pathological and oncological outcomes were assessed. The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines were followed.

RESULTS

Sixteen studies involving 353 patients were included. Pathology following TAE was as follows T0 = 2 (0.5%); T1 = 154 (44.7%); T2 = 142 (41.2%); T3 = 43 (12.5%); Tx = 3 (0.8%); T not reported = 9. Fifty-three percent were > T1. Abdominoperineal resection (APR) was performed in 80 (23.2%) patients. Postoperative major morbidity and mortality occurred in 22 (11.4%) and 3 (1.1%), patients, respectively. An incomplete mesorectal fascia resulting in defects of the mesorectum was reported in 30 (24.6%) cases. Thirteen (12%) patients developed recurrence: 8 (3.1%) local, 19 (7.3%) distant, 4 (1.5%) local and distant. The 5-year cancer-specific survival was 92%. Only 1 study assessed anal function reporting no continence disorders in 11 patients. In the meta-analysis, CRR after TAE showed an increased APR rate (OR 5.25; 95% CI 1.27-21.8; p 0.020) and incomplete mesorectum rate (OR 3.48; 95% CI 1.32-9.19; p 0.010) compared to primary total mesorectal excision (TME). Two case matched studies reported no difference in recurrence rate and disease free survival respectively.

CONCLUSIONS

The data are incomplete and of low quality. There was a tendency towards an increased risk of APR and poor specimen quality. It is necessary to improve the accuracy of preoperative staging of malignant rectal tumors in patients scheduled for TAE.

Accurate measurement of colorectal polyps using computer-aided analysis

INTRODUCTION

As we know, the majority of colorectal cancers are thought to evolve from colorectal adenomas. In this study, we explored the use of Computer-aided diagnosis (CAD) in the detection of colorectal polyps and the estimation of their sizes, which is important for the diagnosis and management of colorectal cancer.

MATERIALS AND METHODS

As the distance between colonoscopy and lesion increases, magnification tends to decrease. Therefore, the size of colorectal polyps can be calculated by taking into account the captured image and the shooting distance. In this study, the fitting curve of the magnification of electronic colonoscopy was obtained by simulating intestinal tract and polyps in vitro. Then, the distance was artificially controlled in the endoscopic operation, and the image was taken at a preset distance. The CAD system was then trained on the overall shape of colorectal polyps. Image segmentation was employed to accurately identify colorectal polyps. Finally, on the basis of the magnification factor, the real value of polyps was predicted from the shooting distance and the segmentation image size.

RESULTS

The CAD system can automatically calculate the range of colorectal polyps and calculate the true size of the colorectal polyps according to the magnification of the corresponding distance.

CONCLUSIONS

In this study, we developed a method of accurately estimating the size of colorectal polyps. This approach is compatible with many devices, which would expand its range of applications. This method has the potential for application in other areas of clinical diagnosis.