The colorectal malignant polyp: scoping a dilemma

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.

A Novel Model Predicts Postoperative Pathology of Colorectal High-Grade Intraepithelial Neoplasia

BACKGROUND

To analyze the consistency of endoscopic biopsy of colorectal high-grade intraepithelial neoplasia (HGIN) and pathological diagnosis and to explore the value of preoperative examination in differentiating HGIN from invasive carcinoma.

METHODS

Clinicopathological data of 79 patients with colorectal HGIN undergoing preoperative endoscopic biopsy from January 2012 to December 2017 were retrospectively analyzed.

RESULTS

Pathologically, 57 cases (72.8%) were diagnosed as invasive carcinoma and 22 (27.8%) as HGIN. Tumor size ≥3 cm, ulcer on the surface of the lesion, HGIN without adenoma, platelet to lymphocyte ratio, neutrophil to lymphocyte ratio, lymph node enlargement, and spiculation of the peri-intestinal fat on computed tomography were associated with postoperative invasive carcinoma. Multivariate analysis showed that a longest diameter ≥3 cm, preoperative diagnosis of HGIN without adenoma, and spiculation of the peri-intestinal fat were independent factors for a postoperative diagnosis of invasive carcinoma. Depending on the weight of these three independent factors in binary logistic regression analysis, a comprehensive scoring model was established. When the score was ≥1.5, the sensitivity and specificity for the diagnosis of invasive carcinoma were 86.0% and 81.8%, respectively. Utilizing the prediction index, the area under the receiver operating characteristic curve was 0.869.

CONCLUSIONS

A diagnosis of colorectal HGIN by colonoscopy is poorly consistent with the postoperative pathological diagnosis. The scoring model established in this study for identifying colorectal infiltrating carcinoma is simple and feasible. When the comprehensive score is ≥ 1.5, an aggressive approach of surgical treatment is recommended.

Outcomes following polypectomy for malignant colorectal polyps are similar to those following surgery in the general population

OBJECTIVE

Population-based studies on colorectal malignant polyps (MPs) are scarce. The aim of this study was to describe time trends in the incidence of colorectal MPs before and after the introduction of a colorectal mass-screening programmein 2003 and to assess outcomes (survival and recurrence) after endoscopic or surgical resection in patients with MPs.

DESIGN

We included 411 patients with MPs diagnosed between 1982 and 2011 in a well-defined population. Age-standardised incidence rates were calculated. Univariate and multivariate 5-year recurrence and net survival analyses were performed according to gross morphology.

RESULTS

Age-standardised incidence of MPs in patients aged 50-74 years doubled from 5.4 in 1982-2002 to 10.9 per 100 000 in 2003-2011. Pedunculated MPs were more frequently resected endoscopically (38.2%) than were sessile MPs (19.1%; p<0.001). For patients with pedunculated MPs and a pathological margin ≥1 mm, the 5 -year cumulative recurrence rate did not differ significantly between surgical and endoscopic resection (8.2% and 2.4%, respectively). For patients with sessile MPs, it was 3.0% after first-line or second-line surgical resection, 8.6% after endoscopic resection and 17.9% after transanal resection (p=0.016). The recurrence rate decreased dramatically for patients with sessile MPs from 11.3% (1982-2002) to 1.2% (2003-2009) (p=0.010) and remained stable for pedunculated MPs at 4.6% and 6.7%, respectively. Five-year net survival was 81.0% when pathological margins were <1 mm and 95.6% when ≥1 mm (p=0.024).

CONCLUSION

Outcomes following polypectomy in patients with a pathological margin ≥1 mm are similar to those following surgery in the general population. Endoscopic resection needs to be completed by surgery if pathological margins are less than 1 mm.

Transanal endoscopic surgery is effective and safe after endoscopic polypectomy of potentially malignant rectal polyps with questionable margins

AIM

To determine the percentage of residual lesion observed in the pathology study of transanal endoscopic surgery (TEM) specimens after endoscopic polypectomy of malignant rectal polyps with questionable margins, and the need for further surgery. Secondary aims: to determine the morbidity and mortality associated with this procedure and to identify the percentage of recurrence after excision by TEM.

METHODS

Observational study with prospective data collection of all patients undergoing TEM after endoscopic polypectomy for malignant rectal polyps or non-invasive high-grade neoplasia, from January 2004 to December 2016. An en bloc full-thickness wall excision of the scar was performed. Variables recorded: histology of TEM specimen, 30-day morbidity and mortality according to the Clavien-Dindo classification, need for salvage surgery and recurrence.

RESULTS

Fifty out of 690 patients undergoing TEM during the study period (36 adenocarcinomas, five non-invasive high-grade neoplasias and 9 neuroendocrine tumors) were included. Post-surgery histology showed residual lesion in 21 (42%) patients: 7 neuroendocrine tumors, 10 adenomas and 4 adenocarcinomas (two pT1, one pT2 and one pT3). The pT2 and pT3 patients (4%) underwent salvage surgery. No recurrence was observed, and mean follow-up was 29.1Â ± 21.6 months. The 30-day morbidity rate was 14%, but 4/7 with Clavien-Dindo grade I.

CONCLUSIONS

After endoscopic polypectomy of malignant rectal polyps with questionable margins, the presence of residual lesion in the pathology study of transanal resection specimens is high. TEM with full-thickness resection of these lesions is an appropriate treatment, allowing disease control and achieving minimal morbidity.

Optical diagnosis of malignant colorectal polyps: is it feasible?

BACKGROUND AND STUDY AIMS

As colorectal cancer screening programs are being implemented worldwide, an increasing number of early (T1) cancers are being diagnosed. These cancers should be recognized during colonoscopy because they require a specific therapeutic approach. Several studies have shown that Asian experts can reliably recognize T1 cancers during colonoscopy. In daily practice, however, accurate endoscopic diagnosis of T1 cancers still seems challenging. We evaluated the performance of optical diagnosis of T1 cancers by European colonoscopy experts, general gastroenterologists and gastrointestinal fellows.

PATIENTS AND METHODS

We collected endoscopic images of 43 colonic lesions: 19 T1 cancers (excluding intramucosal carcinoma) and 24 benign polyps ranging from 7 mm to 30 mm in size. Seven colonoscopy experts, 7 general gastroenterologists, and 14 gastrointestinal fellows assessed these images. We calculated sensitivity, specificity, negative predictive value (NPV) and positive predictive value (PPV) and their 95 % confidence intervals for optical diagnosis of T1 cancers.

RESULTS

Overall sensitivity for correct diagnosis of T1 cancers was 60 % (95 % CI;45 - 72). Sensitivity was highest for experts (67 %: 95 %CI; 48 - 81), when compared to general gastroenterologists (53 %: 95 %CI; 37 - 69) and gastrointestinal fellows (59 %: 95 %CI;45 - 72). The overall NPV was 75 % (95 %CI;60 - 86); NPV was lowest for general gastroenterologists 72 % (95 %CI;57 - 83) vs 78 % (95 %CI;63 - 89) for experts and 75 % (95 %CI;60 - 85) for gastrointestinal fellows.

CONCLUSIONS

In this image-based study, both sensitivity for the optical diagnosis of a T1 cancer and NPV for excluding a T1 cancer were insufficient. Experts performed best with a sensitivity of 67 % and a NPV of 78 %, while the performance of fellows in the last year of training was comparable to that of experts. Our study indicates that training for endoscopic diagnosis for T1 cancers is urgently needed to ensure optimal clinical practice for treatment of these lesions.

Malignant recurrence and distal metastasis after complete local resection of colorectal "high-grade intraepithelial neoplasia": incidence and risk factors

BACKGROUND

Colorectal high-grade intraepithelial neoplasia is defined as a high-grade neoplastic lesion with no invasion of submucosa. Because pathological evaluation has inevitable sampling errors, invasive cancer may be underdiagnosed as high-grade intraepithelial neoplasia by regarding submucosa invasion as an indispensable criterion for malignancy. This study was to evaluate the reliability of colorectal "high-grade intraepithelial neoplasia" diagnosis and identify predictive factors of underdiagnosis.

METHODS

Colorectal high-grade intraepithelial neoplasia patients treated with complete local excision were followed up. Clinicopathologic features were compared between cases with malignant recurrence or distal metastasis and those without.

RESULTS

Of 491 lesions reviewed, 13 (2.6 %) developed local malignant recurrence or distal metastasis, which were statistically significantly associated with rectal location (p = 0.047), sessile growth (p = 0.002), large diameter (p = 0.005), villous adenoma (p = 0.00), transanal local resection (p = 0.001), and piecemeal specimens (p = 0.009). Of the 13 cases, 11 were located in the rectum, including 10 in the low position (<=6 cm from the anal verge, mean 3.6 cm). Deeper pathological examination was performed on the paraffin-embedded tissue blocks of the 13 primary tumors and revealed no evidence of submucosa invasion.

CONCLUSION

The diagnosis of colorectal high-grade intraepithelial neoplasia based on local resection is relatively reliable. However, regarding invasion of submucosa as an indispensable criterion for malignancy may contribute to the choice of overly conservative treatment, especially in the situation that the radical resection requires removing the anus.

Clinical outcome of low- and high-risk malignant colorectal polyps: results of a population-based study and meta-analysis of the available literature

Some histological features of malignant polyps have been used to classify patients into low- and high-risk groups. This study proposed to evaluate the impact of this classification on the clinical outcome of patients with malignant polyps. Through the Colorectal Cancer Registry, 105 patients with endoscopically removed malignant polyps were selected. The presence of one of the following histological features defined malignant polyps as high-risk: infiltrated resection-margin, poorly differentiated carcinoma, lymphatic/vascular invasion and tumour budding and depth of submucosal invasion. Available literature was reviewed by applying a similar classification. Most of the malignant polyps were pedunculated and were localized in the left colon. Fifty-five malignant polyps were classified as low-risk lesions and 50 as high-risk. None of the patients at low-risk died of colorectal cancer. Of the patients at high-risk, three died of cancer; all three cases showed lymphatic/vascular invasion. Review of the literature reveals that an unfavourable clinical outcome is significantly more prevalent in the high-risk compared with the low-risk group (p > 0.005). Moreover, all histological risk factors show a specific predictive value of clinical adverse outcome. Our study and the pooled data analysis confirmed the usefulness of the subdivision into low- and high-risk malignant polyps for management of patients with endoscopically removed colorectal carcinoma.

Incidence trend of malignant polyps through the data of a specialized colorectal cancer registry: clinical features and effect of screening

OBJECTIVES

The purposes of the study are to describe the incidence trend of malignant polyp of large bowel over a 25-year period in the District of Modena and to assess the effect of an organized colorectal cancer screening program.

MATERIAL AND METHODS

Through the data of a specialized colorectal cancer Registry, we evaluate the clinical and pathological features of the polyps. Trend analysis was assessed with the Joinpoint Regression Program.

RESULTS

A total of 172 patients with malignant polyps were diagnosed throughout the study (3.5% of 4.835 registered patients); their overall frequency during the registration period increased from zero cases in the initial years (1984-85) to 57 cases in the past 3 years (2006-2008). Crude incidence rate passed from 0.37 in 1986-89 to 10.2 in 2006. Joinpoint trend analysis of crude rates showed a significant increase of incidence during the study period, with percent of annual variation ranging between 38.6% (95% CI 12.5-70.7) and 7.3% (95% CI 2.6-12.1). During the screening period (2005-2008, the past 4 years of registration) there was a significant increase of sessile polyps (p < 0.001), while other clinical and morphological features, including the number of low- and high-risk malignant polyps, remained unchanged. The surgery (after polypectomy) tended to raise both in low- and high-risk subgroups.

CONCLUSION

The incidence of malignant polyps increased significantly from the initial to the most recent periods of colorectal cancer registration. Screening was associated with changes in gross morphology of polyps and with an increased use of the surgery after endoscopic polypectomy.

Malignant colorectal polyps

Nowadays, the number of cases in which malignant colorectal polyps are removed is increasing due to colorectal cancer screening programmes. Cancerous polyps are classified into non-invasive high grade neoplasia (NHGN), when the cancer has not reached the muscularis mucosa, and malignant polyps, classed as T1, when they have invaded the submucosa. NHGN is considered cured with polypectomy, while the prognosis for malignant polyps depends on various morphological and histological factors. The prognostic factors include, sessile or pedunculated morphology of the polyp, whether partial or en bloc resection is carried out, the degree of differentiation of the carcinoma, vascular or lymphatic involvement, and whether the polypectomy resection margin is tumor free. A malignant polyp at T1 is considered cured with polypectomy if it is a pedunculated polyp (Ip of the Paris classification), it has been completely resected, it is not poorly differentiated, the resection edge is not affected by the tumor and there is no vascular or lymphatic involvement. The sessile malignant polyp (Is of the Paris classification) at T1 is considered not cured with polypectomy. Only in some cases (e.g. older people with high surgical risk) local excision (polypectomy or endoscopic submucosal dissection or conventional endoscopic mucosal resection) is considered the definitive treatment.

Detection of colonic polyps according to insertion/withdrawal phases of colonoscopy

BACKGROUND AND AIMS

Issues on colonoscopy quality are crucial to reduce the advanced neoplasia miss rate of colonoscopy. Recently, a >6-min withdrawal time has been recommended. However, the relative prevalence of polyp detected during insertion and withdrawal phases of colonoscopy is unknown. Therefore, we designed this prospective, endoscopic study.

MATERIALS AND METHODS

Three hundred and sixty-eight patients with 396 adenomas were selected from a consecutive colonoscopic series of 1,205 cases. Detection rates of adenomas, advanced adenomas, and cancer according to withdrawal and insertion phases of colonoscopy, also subgrouping polyps for size and location, were compared.

RESULTS

Thirty-two (74%) advanced adenomas and 21 (95%) cancers were detected during the insertion, being only 11 (26%) and one (5%) identified during withdrawal, respectively. This was mainly due to a higher detection of >10 mm polyps during insertion than during withdrawal (75% versus 25%).

CONCLUSIONS

Most advanced neoplasia are detected during the insertion. Although withdrawal time has been shown to be important, the scope insertion phase related to polyp detection should be specifically addressed.

Clinical management of small (6- to 9-mm) polyps detected at screening CT colonography: a cost-effectiveness analysis. AJR Am J Roentgenol. 2008;191:1509-1516. [PMID: 18941093 DOI: 10.2214/ajr.08.1010]

OBJECTIVE

The primary aim of this model analysis was to compare the clinical and economic impacts of immediate polypectomy versus 3-year CT colonography (CTC) surveillance for small (6- to 9-mm) polyps detected at CTC screening.

MATERIALS AND METHODS

A decision analysis model was constructed incorporating the expected advanced neoplasia prevalence, frequency of measurable growth, colorectal cancer (CRC) prevalence and risk, CTC performance, and costs related to CRC screening and treatment. CRC risk was assumed to be independent of advanced adenoma size, which intentionally overestimates the risk related to small polyps. Clinical effectiveness and costs for 3-year CTC surveillance versus immediate colonoscopic polypectomy were compared for a concentrated cohort of patients with 6- to 9-mm polyps. For the CTC surveillance strategy, only cases with measurable growth (> or = 1 mm) at follow-up CTC were referred for polypectomy.

RESULTS

Without any intervention, the estimated 5-year CRC death rate from 6- to 9-mm polyps in this concentrated cohort was 0.08%, which is a sevenfold decrease over the 0.56% CRC risk for the general unselected screening population. The death rate was further reduced to 0.03% with the CTC surveillance strategy and to 0.02% with immediate colonoscopy referral. However, for each additional cancer-related death prevented with immediate polypectomy versus CTC follow-up, 9,977 colonoscopy referrals would be needed, resulting in 10 additional perforations and an incremental cost-effectiveness ratio of $372,853.

CONCLUSION

For patients with small (6- to 9-mm) polyps detected at CTC screening, the exclusion of large polyps (> or = 10 mm) already confers a very low risk of CRC. The high costs, additional complications, and relatively low incremental yield associated with immediate polypectomy of 6- to 9-mm polyps support the practice of 3-year CTC surveillance, which allows for selective noninvasive identification of small polyps at risk.

Endoscopic mucosal resection of colonic lesions: current applications and future prospects

The introduction of submucosal fluid injection has remarkably extended the range of endoscopically resectable polyps. The limiting factor for endoscopic resection is not polyp size, but polyp depth. Endoscopic ultrasound is a useful adjunctive diagnostic tool to assess the depth of invasion. The success of are section ultimately depends on pathologic confirmation of a benign nature of this lesion or of a cancer limited to the mucosa. Selected well-differentiated cancers without lymphovascular invasion of the superficial submucosa can be successfully resected endoscopically.

Risk factors for high-grade dysplasia or carcinoma in colorectal adenoma cases treated with endoscopic polypectomy

OBJECTIVE

Our aim is to establish the risk factors for carrying high-grade dysplasia or carcinoma by analyzing endoscopically treated adenoma cases.

METHODS

Patients who underwent endoscopic polypectomy at our hospitals between January 2003 and August 2004 were analyzed.

RESULTS

A total of 889 patients (mean age: 63+/-11 years), and 1486 adenomas resected from these patients, were included in the analysis. Seventy-five adenomas (5%) from 72 patients (8%) were found to have high-grade dysplasia or carcinoma. Among patient factors, female sex [odds ratio (OR) 2.25, 95% confidence intervals (CI)=1.34-3.76], presence of multiple adenomas (OR=2.15, 95% CI=1.15-4.00), older age (OR=1.02, 95% CI=1.00-1.04), and rectal bleeding as the indication for colonoscopy (OR=2.57, 95% CI=1.34-4.92) were identified as the significant risk factors for carrying high-grade dysplasia or carcinoma using the multivariate analysis. In addition, a size of > or = 10 mm (OR=10.83, 95% CI=5.86-20.0), flat appearance (OR=3.91, 95% CI=2.20-6.95), and location on the left side of the colon (OR=1.80, 95% CI=1.03-3.13) were identified as tumor risk factors.

CONCLUSION

Distinct factors were proved to be associated with high-grade dysplasia or carcinoma. These results are useful to select lesions that require immediate treatment. Moreover, female sex as a risk factor raises an interesting problem regarding the progression from adenoma to carcinoma.

Q&A on diagnosis, screening and follow-up of colorectal neoplasia

The impressive and brisk evolution of medical science prevents many physicians from a thorough update on all the research fields. Colorectal cancer diagnosis, screening and follow-up is well known to require a multi-disciplinary approach, as it is faced by several specialties such as primary care physicians, gastroenterologists, non-gastroenterologist internists, radiologists and surgeons. To address this issue in a mutual perspective, we focused on the main points of the epidemiology, diagnosis, screening and follow-up of colorectal neoplasia by using a simple "Question & Answers" structure.

Poorly differentiated colorectal carcinoma with invasion restricted to lamina propria (intramucosal carcinoma): a follow-up study of 15 cases

Invasive colorectal carcinomas (CRCs) with invasion confined to the lamina propria (LP) [intramucosal carcinoma (IMC)] lack access to lymphatics and therefore have no potential for metastases and local intervention (usually polypectomy) should be adequate treatment. For this reason, they are classified as "Tis" in the TNM system. It is believed that carcinomas invading the submucosa with unfavorable histology (tumors at/near the margin, and/or vascular invasion, and/or poor differentiation) require additional intervention after polypectomy, whereas those with favorable histology can be safely treated endoscopically. However, there are few data on poorly differentiated (PD) carcinomas showing invasion confined to the LP. Polypectomy is theoretically curative but in practice this has not been well demonstrated. Thus, the clinicopathologic features of 15 cases of PD CRCs with invasion limited to the LP on initial biopsies were studied to determine the best course of management for this rare subset of carcinomas. A computer search and histologic review of cases seen at Johns Hopkins Hospital was performed. Fifteen cases of PD CRC with invasion limited to the LP were identified. The clinicopathologic features of these tumors were reviewed. All 15 cases showed PD IMC with single cells infiltrating only the LP. Patients were 38 to 79 years (median, 62) of age with a male predominance (M:F=4:1). Three cases had signet ring cell differentiation, 1 had focal small cell features, and another had focal squamous differentiation. Fourteen of the cases were associated with background adenomas or adenomalike lesions including: 7 involving tubulovillous or villous adenomas, 6 involving tubular adenomas, 1 involving dysplasia associated with chronic inflammatory bowel disease. Nine of the lesions had surrounding high-grade dysplasia. One case showed no background dysplasia or adenoma. One patient was lost to follow-up and the remaining 14 were followed for 1 to 96 months (mean, 21.3 mo; median, 13 mo). Seven patients had no residual disease on follow-up colonoscopy, and no resection was performed. The remaining 7 patients were treated with partial colectomy (6) or low anterior resection (1), and of these, 5 had no infiltrating carcinoma and negative lymph nodes. One patient had a separate large colorectal (T3) carcinoma with 8/10 positive regional lymph nodes; the IMC seen on biopsy was presumably a metastasis as it was unassociated with an in situ component. Finally, the resected rectum from which an IMC had been previously detected had no residual invasive carcinoma, but the anal skin was involved by Paget disease. Thus, of the 15 cases of PD CRCs limited to the LP, 1 was a metastasis from a separate CRC and another had associated Paget disease of the anal skin. As such, even in the setting of PD carcinomas, no metastatic disease was seen arising from any of the cases that were confirmed as early primary lesions. These preliminary findings suggest that patients with isolated intramucosal PD CRCs may be managed endoscopically.