Malignant colorectal polyps: venous invasion and successful treatment by endoscopic polypectomy

pT1 colorectal cancer: A treatment dilemma

The implementation of population screening programs for colorectal cancer (CRC) has led to a considerable increase in the prevalence pT1-CRC originating on polyps amenable by local treatments. However, a high proportion of patients are referred for unnecessary oncological surgeries without a clear benefit in terms of survival. Selecting the appropriate endoscopic resection technique in the moment of diagnosis becomes crucial to provide the best treatment alternative to each individual polyp and patient. For this, it is imperative to increase the optical diagnostic skill for differentiating pT1-CRCs and decide the appropriate initial therapy. En bloc resection is crucial to obtain an adequate histological specimen that might allow organ preserving therapeutic management. In this review, we address key challenges in T1 CRC management, explore the efficacy and safety of the available diagnostic and therapeutic approaches, and shed light on upcoming advances in the field.

Risk and Time Pattern of Recurrences After Local Endoscopic Resection of T1 Colorectal Cancer: A Meta-analysis

BACKGROUND & AIMS

Growing numbers of patients with T1 CRC are being treated with local endoscopic resection only and as a result, the need for optimization of surveillance strategies for these patients also increases. We aimed to estimate the cumulative incidence and time pattern of CRC recurrences for endoscopically treated patients with T1 CRC.

METHODS

Using a systematic literature search in PubMed, EMBASE, Web of Science and Cochrane Library (from inception till 15 May 2020), we identified and extracted data from studies describing the cumulative incidence of local or distant CRC recurrence for patients with T1 CRC treated with local endoscopic resection only. Pooled estimates were calculated using mixed-effect logistic regression models.

RESULTS

Seventy-one studies with 5167 unique, endoscopically treated patients with T1 CRC were included. The pooled cumulative incidence of any CRC recurrence was 3.3% (209 events; 95% CI, 2.6%-4.3%; I² = 54.9%), with local and distant recurrences being found at comparable rates (pooled incidences 1.9% and 1.6%, respectively). CRC-related mortality was observed in 42 out of 2519 patients (35 studies; pooled incidence 1.7%, 95% CI, 1.2%-2.2%; I² = 0%), and the CRC-related mortality rate among patients with recurrence was 40.8% (42/103 patients). The vast majority of recurrences (95.6%) occurred within 72 months of follow-up. Pooled incidences of any CRC recurrence were 7.0% for high-risk T1 CRCs (28 studies; 95% CI, 4.9%-9.9%; I² = 48.1%) and 0.7% (36 studies; 95% CI, 0.4%-1.2%; I² = 0%) for low-risk T1 CRCs.

CONCLUSIONS

Our meta-analysis provides quantitative outcome measures which are relevant to guidelines on surveillance after local endoscopic resection of T1 CRC.

Association of Poor Differentiation or Positive Vertical Margin with Residual Disease in Patients with Subsequent Colectomy after Complete Macroscopic Endoscopic Resection of Early Colorectal Cancer

In the presence of unfavorable pathologic results after endoscopic resection of colorectal cancer, colectomy is routinely performed. We determined the risk factors for residual diseases in patients with colectomy after complete macroscopic endoscopic resection of early colorectal cancer. We identified consecutive patients who underwent endoscopic resection of early colorectal cancer and subsequently underwent colectomy, from January 2011 to December 2014. Clinicopathologic risk factors related to the residual disease were analyzed. In total, 148 patients underwent endoscopic resection and subsequent colectomy. Residual disease on colectomy was noted in 16 (10.9%) patients. The rates of poorly differentiated/mucinous histology (p = 0.028) and of positive or unknown vertical resection margin (p = 0.047) were higher in patients with residual disease than in those without. In multivariate analysis, a poorly differentiated/mucinous histology and positive or unknown vertical resection margin were significantly associated with residual disease (odds ratio = 7.508 and 2.048, p = 0.015 and 0.049, resp.). After complete macroscopic endoscopic resection of early colorectal cancer, there is a greater need for additional colectomy in cases with a positive or unknown vertical resection margin or a poorly differentiated/mucinous histology, because of their higher risk of residual cancer and lymph node metastasis.

Management of Malignant Adenomas

Most polyps that originate in the colon and rectum are benign. A small subset of polyps will contain a malignancy. Although most malignant adenomas are managed with colonic resection a number can be approached with endoscopic, minimally invasive, and observational techniques. This article reviews the histologic characteristics and adverse risk factors that would portend a poor oncologic outcome and therefore suggest formal colonic resection. Modern endoscopic techniques such as endoscopic mucosal resection and endoscopic submucosal resection are discussed.

The Ueno method for substaging pT1 colorectal adenocarcinoma by depth and width measurement: an interobserver study

AIM

Early pT1 polyp colorectal cancers (CRCs) present challenges for accurate pathology substaging. Haggitt and Kikuchi stages depend on polyp morphology and are often difficult to apply due to suboptimal orientation or fragmentation, or absence of the muscularis propria in polypectomy or submucosal resection specimens. European guidelines for quality assurance suggest using Ueno's more objective approach, using depth and width measurements beyond muscularis mucosae. We have investigated interobserver variation using Ueno's approach.

METHOD

Ten consecutive pT1 polyp CRCs were identified and the slides assessed by six gastrointestinal pathologists for depth and width of invasion. A further 60 polyps were studied by a group of specialist and general pathologists. Agreement was assessed by analysis of variance. A polyp CRC is classified as high risk if it has a depth ≥ 2000 μm or a width ≥ 4000 μm and low risk with a depth < 2000 μm or a width < 4000 μm. Concordance for the dichotomized values was assessed using the kappa statistic.

RESULTS

The intraclass correlation coefficient (ICC) for depth was 0.83 and for width 0.56 in the 10-polyp group. The ICC for the 60-polyp CRCs was 0.67 for depth and 0.37 for width. In both groups, when polyp CRCs are divided into high- and low-risk categories based on depth, there was substantial and moderate agreement (κ = 0.80 and 0.47) but only fair agreement when based on width (κ = 0.34 and 0.35).

CONCLUSION

Ueno's method has the advantage of being independent of polyp morphology. Our study shows better concordance for depth measurement and reproducibility in nonfragmented specimens, with poorer agreement when based on width.

Bowel cancer screening-generated diagnostic conundrum of the century: pseudoinvasion in sigmoid colonic polyps

The introduction of bowel cancer screening, in the United Kingdom, United States of America, and many other Western countries, has provided considerable interest and no little diagnostic consternation for pathologists. In the United Kingdom, the universal introduction of bowel cancer screening, initially by fecal occult blood testing and more recently by the introduction of flexible sigmoidoscopy, has provided four main areas of pathological diagnostic difficulty. This is the biopsy diagnosis of adenocarcinoma, serrated pathology, the diagnosis and management of polyp cancer, and, finally, the phenomenon of pseudoinvasion/epithelial misplacement (PEM), particularly in sigmoid colonic adenomatous polyps. The diagnostic difficulties associated with the latter phenomenon have provided particular problems that have led to the institution of a UK national 'Expert Board', comprising three pathologists, who adjudicate on difficult cases. The pathological features favoring PEM are well recognized but there is no doubt that there can be profound mimicry of adenocarcinoma, and, as yet, no adjunctive diagnostic tools have been developed to allow the differentiation in difficult cases. Research in this area is proceeding and some methodologies do show promise in this difficult diagnostic area.

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.

Management of colorectal polyp cancers

INTRODUCTION

Management of malignant colorectal polyps is controversial. The options are resection or surveillance. Resection margin status is accepted as an independent predictor of adverse outcome. However, the rate of adverse outcome in polyps with a resection margin of <1mm has not been investigated.

METHODS

A retrospective search of the pathology database was undertaken. All polyp cancers were included. A single histopathologist reviewed all of the included polyp cancers. Polyps were divided into three groups: clear resection margin, involved resection margin and unknown resection margin. Polyps were also analysed for tumour grade, morphology, Haggitt/Kikuchi level and lymphovascular invasion. Adverse outcome was defined as residual tumour at the polypectomy site and/or lymph node metastases in the surgical group and local or distant recurrence in the surveillance group.

RESULTS

Sixty-five polyps (34 male patients, mean age: 73 years, range: 50–94 years) were included. Forty-six had clear polyp resection margins; none had any adverse outcomes. Sixteen patients had involved polyp resection margins and twelve of these underwent surgery: seven had residual tumour and two of these patients had lymph node metastases. Four underwent surveillance, of whom two developed local recurrence. Three patients had resection margins on which the histopathologist was unable to comment. All patients with a clear resection margin had no adverse outcome regardless of other predictive factors.

CONCLUSIONS

Polyp cancers with clear resection margins, even those with <1mm clearance, can be treated safely with surveillance in our experience. Polyp cancers with unknown or involved resection margins should be treated surgically.

Immunohistochemical alterations in invasive adenocarcinoma in endoscopically resected adenoma and factors associated with risk of residual or recurrent disease

AIM

We determined the pattern of immunohistochemical expression in invasive adenocarcinoma in endoscopically resected adenoma, its relationship with the risk of residual or recurrent disease and the related factors.

METHOD

We included individuals with malignant polyps resected endoscopically in the period 1999-2009. Clinical and endoscopic data were collected. All histological specimens were re-analysed. CD44, matrix metalloproteinase 9 (MMP-9), vascular endothelial growth factor-β (VEGF-β), β-catenin, laminin and cyclooxygenase 2 (COX-2) expression were determined by immunohistochemistry. A multivariate logistic regression was performed to determine variables independently associated with the risk of residual or recurrent disease.

RESULTS

One-hundred and fifty-one malignant polyps (114 pedunculated; mean size ± SD=22.61 ± 10.86 mm) were resected endoscopically. Resection was fragmented and incomplete in 26.5% and 8.6% of patients, respectively. Surgical resection was performed on 71 (47%) patients. After a median follow-up of 44 months, residual (n=12) or recurrent (n=6) disease was detected in 17 patients. Conventional histology showed that 32.1% met high-risk histological criteria. Immunohistochemical expression was positive for CD44, MMP-9, VEGF-β, β-catenin, laminin and COX-2 in 63.3%, 25.3%, 45%, 38.8%, 79% and 34.5% of specimens, respectively, with no differences between both groups. Variables associated with residual or recurrent disease in the univariate analysis were: nonpedunculated morphology (P=0.07); fragmented (P<0.001) or incomplete resection (P<0.001); margin infiltration (P=0.04); and histological high-risk lesion (P=0.003). Finally, incomplete resection (OR=12.16, 95% CI=3.15-46.98; P<0.001) and histological high risk (OR=4.73, 95% CI=1.33-16.74; P=0.002) were independently associated with the risk of residual or recurrent disease.

CONCLUSION

Immunohistochemistry could not predict residual or recurrent disease. Only incomplete excision and histological high risk did so. The factors independently associated were histological high-risk lesion and incomplete resection.

Risk factors for lymph node metastasis in pT1 and pT2 rectal cancer: a single-institute experience in 943 patients and literature review

BACKGROUND

Local excision has become an alternative for radical resection in rectal cancer for selected patients. The purpose of this study was to assess the clinicopathologic factors determining lymph node metastasis (LNM) in patients with T1-2 rectal cancer.

METHODS

Between January 1995 and December 2009, a total of 943 patients with pT1 or pT2 rectal adenocarcinoma received radical resection at a single institution. Clinicopathologic factors were evaluated by univariate and multivariate analyses to identify risk factors for LNM.

RESULTS

A total of 943 patients (544 men and 399 women) treated for T1-2 rectal cancer were included in this study. LNM was found in 188 patients (19.9%). In multivariate analysis, lymphovascular invasion (LVI; P < 0.001, hazard ratio 11.472), poor differentiation (PD; P = 0.007, hazard ratio 3.218), and depth of invasion (presence of pT2; P = 0.032, hazard ratio 1.694) were significantly related to nodal involvement. The incidence for LNM lesions in the presence of LVI, PD, and pT2 was 68.8, 50.0, and 23.1%, respectively, while that for pT1 carcinomas with no LVI or PD was 7.5%.

CONCLUSIONS

LVI, PD, and pT2 are independent risk factors predicting LNM in pT1-2 rectal carcinoma.

Proposed objective criteria for "grade 3" in early invasive colorectal cancer

To establish objective criteria for "grade 3" (G3) in T1 (TNM staging) colorectal cancer (CRC), a total of 296 T1 CRC cases were reviewed. The incidence of nodal involvement differed most greatly between G3 and non-G3 (21/27 [27%] and 6/162 [3.7%], respectively; P < .0001), when G3 was applied to tumors containing either or both of the following: (1) 10 or more solid cancer nests in the microscopic field of a 4x objective lens and (2) a mucin-producing component fully occupied the microscopic field of a 40x objective lens. Regarding G3, vascular invasion, and tumor budding as indicating the risk of metastasis, nodal involvement rate was 21.0% in the tumors with 1 or more risk factors, whereas it was only 1.7% in the no-risk tumors (P < .0001). In patients treated with local excision only, nodal recurrence occurred in 3 (20%) of 15 risk-positive patients, whereas none of 42 patients without risk factors had nodal recurrence (P = .016). In cases of locally excised T1 CRC, G3 as determined by the proposed criteria, vascular invasion, and budding would comprise a useful combination of parameters for determining the indication for additional laparotomy.

The concurrence of histologically positive resection margins and sessile morphology is an important risk factor for lymph node metastasis after complete endoscopic removal of malignant colorectal polyps

INTRODUCTION

The optimal procedure to be followed after colonoscopic polypectomy of malignant colorectal polyps with nontumour-free resection margins at histology is a matter of controversy. While some authors recommend merely local or segmental follow-up resection, others favour an oncological resection.

PATIENTS AND METHODS

One hundred five patients, each with a single malignant polyp, were investigated. Patients with a macroscopically evident malignant polyp and those in whom the endoscopist reported incomplete polypectomy were excluded from the study.

RESULTS

Postpolypectomy morbidity was 4%, and postoperative was 14%. In only 39 cases were the resection margins adjudged to be tumour-free. Histology following subsequent surgery or the follow-up examinations revealed a local recurrence or residual carcinoma at the polypectomy site in only three (2.8%) cases and lymph node metastasis in eight (7.6%) cases. Five patients had remnant adenoma at the polypectomy site. Of the high-risk factors, histological incomplete removal (n = 66, p = 0.04, odds ratio (OR) 10.2) and lymph vessel infiltration (n = 7, p = 0.02, OR 9.2) revealed a significant correlation with lymph node metastasis, but not with remnant tumour. In the case of sessile polyp, the assessment of histological incomplete removal was highly significantly correlated with lymph node metastasis (n = 55, p = 0.007, OR 18.1).

CONCLUSIONS

Polypectomy artefacts appear to be responsible for the discrepancy between histology and the tumour remnants actually present. On the other hand, histologically incompletely removed sessile malignant polyps represent an appreciably higher risk for lymph node metastasis. Such cases should, therefore, be submitted to further oncological resection.

Lymphovascular invasion in colorectal cancer: an interobserver variability study

BACKGROUND

Lymphovascular invasion (LVI) in colorectal cancer (CRC) is considered a strong stage-independent prognostic factor and influences decisions regarding adjuvant chemotherapy in patients with stage II tumors. However, the degree of interobserver agreement among pathologists for LVI in CRC is largely unknown. This study was undertaken to examine such interobserver variability, and we hypothesized that the use of immunohistochemical markers for vascular and lymphatic channels could improve interobserver agreement.

DESIGN

Fifty cases of American Joint Committee on Cancer stage II moderately differentiated CRC from 1990 to 2005 from the pathology archives were selected; mucinous, medullary, and other recognized special subtypes were excluded. Fifty hematoxylin and eosin (H&E) slides (1 from each case) were circulated to 6 gastrointestinal pathologists, who independently assessed small and large vessel invasion. No diagnostic guidelines were given to the participating pathologists; each was instructed to apply the criteria for LVI that he or she used in daily practice. Immunohistochemistry (IHC) for D2-40 and CD31 was performed on corresponding paraffin blocks. The IHC slides were randomized, recirculated, and rescored for LVI. Results were analyzed by kappa (kappa) statistics, which correct for agreement by chance, and for percentage agreement.

RESULTS

The average kappa values were determined for the H&E slides (large and small vessel), CD31 (small vessel), and D2-40 (small vessel) (Fig. 1). Agreement was fair for H&E small vessel invasion [kappa=0.28; 95% confidence interval (CI): 0.22-0.34]. The least agreement was seen in interpretation of H&E large vessel invasion (kappa=0.18; 95%CI: 0.11-0.26). Agreement was not improved by use of immunohistochemical stains: CD31 (large vessel, kappa=0.42, 95%CI: 0.20-0.63, small vessel, kappa=0.26, 95%CI: 0.10-0.42) and D2-40 (kappa=0.32, 95%CI: 0.21-0.42).

CONCLUSIONS

Interobserver variability in diagnosis of LVI was substantial on H&E slides and did not improve upon use of IHC. Agreement in evaluation of large vessel invasion was only slightly higher than would be seen by chance alone. This study highlights the need for criteria in evaluation of LVI, as this assessment may impact patient prognosis and thus change the course of clinical treatment.

The malignant colon polyp: diagnosis and therapeutic recommendations

This article discusses the proper handling of the malignant colon polyp, that is, polypoid lesions that appear endoscopically to represent adenomas and histologically reveal an invasive carcinoma component, from the time of endoscopy to the pathologic diagnosis. Prognostically important pathologic features and a paradigm to guide treatment decisions are presented.

The colorectal malignant polyp: scoping a dilemma

Colorectal adenomas containing invasive carcinoma represent the majority of early colorectal cancers. The malignant polyp carries a significant risk of lympho-haematic metastasis and mortality due to the penetration of cancerous cells into the submucosal layer. The therapeutic dilemma is whether to perform endoscopic or surgical resection. A thorough assessment of the endoscopic, histological and clinical variables is needed to unravel the best treatment for each patient. In particular, a unique staging of such lesions, based on certain histopathological features, has been deeply implicated in the therapeutic choice. Aim of this article is to review the main endoscopic, histological and clinical features of the malignant polyp in order to propose a systematic management of this lesion.

Predictors of recurrence in patients with T2 and early T3, N0 adenocarcinoma of the rectum treated by surgery alone

PURPOSE

Treatment of rectal cancer with neoadjuvant radiotherapy has been shown to reduce local recurrence and improve overall survival. The role of chemoradiotherapy in patients with T2, N0 and early T3, N0 rectal cancer, treated by radical surgery with total mesorectal excision, remains controversial. The aim of this study was to identify predictors of recurrence in this group of patients to enhance treatment selection.

PATIENTS AND METHODS

One hundred patients with primary T2-3, N0 adenocarcinoma of the rectum, uniformly treated by surgery alone, were studied. The pathology slides available for 97 patients were rereviewed. Three patients with incomplete data sets were excluded. Clinical and survival data were obtained from a prospective computerized database and updated from hospital and office charts. The study end points were disease-free survival, disease-specific survival (DSS), time to pelvic recurrence (PR), and distant recurrence.

RESULTS

Complete follow-up was available for all study patients. Median follow-up was 79.5 months (range, 57.7 to 105.9 months). During this time period 30 patients (31.9%) died as a result of disease and 64 patients (68.1%) remained alive and disease free. Five-year DSS was 73%. The cumulative risk for PR was 8% at 5 years and 10% at 8 years. Lymphovascular invasion, preoperative serum carcinoembryonic antigen (CEA > 5 ng/mL) level, and age older than 70 years were all associated with adverse outcome. CONCLUSION Patients with T2-3, N0 rectal cancers and either lymphovascular invasion or elevated CEA levels have reduced survival and a higher incidence of PR, and should be considered for future randomized trials.

Transabdominal Transcolonic Polypectomy

Up until now, 2%-10% of colonic polyps larger than 2 cm have been considered colonoscopically unresectable. These were commonly treated by piecemeal resection and observation by colonoscopists and hemicolectomy by surgeons. Our minimally invasive "rural solution" in this situation is transcolonic resection through a mini-laparotomy. We present 7 patients with large colonic villous adenomas not amenable to colonoscopic resection. Laporoscopy determined the location of the muscle-splitting incision. The segment of bowel containing the polyp was exteriorized: antimesentric polyps were excised together with the corresponding colonic wall; polyps in mesenteric location were removed transmurally through an anterior colotomy. There was no surgical morbidity. Five of the 7 patients were discharged within 24 hours. Preoperative tattooing of the lesions and laparoscopic mobilization of the involved segment--when necessary--proved to be useful adjuncts. This seems to be an attractive option that may be superior to formal colectomy or repeated endoscopic piecemeal excision of large polyps. It provides colonoscopists with the option of avoiding having to resect very difficult polyps while not subjecting their patients to unnecessarily morbid operations.

Histologic risk factors and clinical outcome in colorectal malignant polyp: a pooled-data analysis

PURPOSE

The malignant polyp carries a significant risk of lymphohematic metastasis and mortality. Clinical usefulness of histologic risk factors is still controversial. The study was designed to compute the association between the main histologic risk factors and the occurrence of unfavorable outcomes in patients with malignant polyps.

METHODS

A MEDLINE search regarding malignant polyps was performed. Three histologic risk factors (positive resection margin, poor differentiation of carcinoma, vascular invasion) and five (residual disease, recurrent disease, lymph node metastasis, hematogenous metastasis, mortality) unfavorable clinical outcomes were evaluated. Further analysis was performed by subgrouping polyps in high-risk and low-risk groups.

RESULTS

Thirty-one studies enrolling 1,900 patients with malignant polyp were selected. Positivity of resection margin was significantly predictive of the presence of residual disease (odds ratio, 22; P < 0.0001), poorly differentiated carcinoma was associated with an increased mortality (odds ratio, 9.2; P < 0.05), and vascular invasion with a higher lymph node metastasis risk (odds ratio, 7; P < 0.05). Patients with high-risk polyps showed a significantly worse outcome than those with low-risk, especially for mortality (odds ratio, 11; P < 0.05). Surgical-related death was as low as 0.8 percent.

CONCLUSIONS

All three histologic risk factors are significantly associated with the clinical outcome. Classification in low-risk and high-risk patients may be regarded as a meaningful staging procedure.

Curative resection of T1 colorectal carcinoma: risk of lymph node metastasis and long-term prognosis

PURPOSE

The features of T1 colorectal adenocarcinoma and the risk determination of lymph node metastasis were reviewed. Prognostic factors were assessed to verify whether the risk of lymph node metastasis would influence the long-term prognosis.

METHODS

Patients undergoing curative resection of T1 colorectal adenocarcinoma at the Taipei Veterans General Hospital from December 1969 to August 2002 were retrospectively studied. Patients with synchronous colorectal cancer, distant metastasis, familiar adenomatous polyposis, or inflammatory bowel disease were excluded. The associations between lymph node metastasis and clinicopathologic variables were evaluated univariately using chi-squared test, Fisher's exact test, or Student's t -test, and multivariately using logistic regression. Univariate analysis by the log-rank test and multivariate analysis by Cox regression hazards model determined the factors influencing the overall survival.

RESULTS

A total of 159 patients were included. Sixteen patients (10.1 percent) had lymph node metastasis. The risk of lymph node metastasis included histologic grade (P = 0.005), lymphatic vessel invasion (P = 0.023), inflammation around cancer (P = 0.049), and budding at the invasive front of tumor (P = 0.022). Age (P = 0.001) and number of total sampling lymph nodes (P < 0.0001) were found to be the factors influencing the overall survival.

CONCLUSIONS

Variables that predict lymph node metastasis in surgically resected T1 colorectal carcinoma may not impact the long-term prognosis.

Colon cancer

Colon cancer is one of the leading tumours in the world and is considered among the big killers, together with lung, prostate and breast cancer. In the recent years very important advances occurred in the field of treatment of this frequent disease: adjuvant chemotherapy was demonstrated to be effective, chiefly in stage III patients, and surgery was optimized in order to achieve the best results with a low morbidity. Several new target-oriented drugs are under evaluation and some of them (cetuximab and bevacizumab) have already exhibited a good activity/efficacy, mainly in combination with chemotherapy. The development of updated recommendations for the best management of these patients is crucial in order to obtain the best results, not only in clinical research but also in everyday practice. This report summarizes the most important achievements in this field and provides the readers useful suggestions for their professional practice.

Immunohistochemical evaluation of tissue-specific proteolytic enzymes in adenomas containing foci of early carcinoma: correlations with cathepsin D expression and other malignant features

BACKGROUND

Cathepsin D (CD) is an aspartyl lysosomal protease, and the prognostic value of CD expression has been studied in a variety of tumors, however, its role in early adenocarcinomas remains unclear.

AIM OF THE STUDY

We evaluated the expression of CD in a series of colorectal adenomas with severe dysplasia containing foci of early carcinoma and compared the results to several histopathological and immunohistochemical features.

METHODS

Adenomas were obtained by endoscopic polypectomy from 33 patients. Twenty-four of the 33 adenomas contained well-differentiated adenocarcinomas and nine adenomas contained moderately differentiated adenocarcinomas.

RESULTS

Positive CD expressions were observed in 25% of well-differentiated adenocarcinomas and in 66.7% of moderately differentiated adenocarcinomas (p < 0.05). Of the 12 adenocarcinomas with positive CD expression, four had positive CD expression in their adenomas (p < 0.01), 6 showed positive Ki-67 expression in their adenomas (NS), and 10 had positive p53 expression in their adenomas (p < 0.05). No significant association was seen between the level of CD expression and adenoma size.

CONCLUSIONS

The expression of CD in adenocarcinoma correlated significantly with differentiation, and with the levels of CD and p53 expression in the adenomas of the polyp.

Transanal endoscopic microsurgery: a viable operative alternative in selected patients with rectal lesions

BACKGROUND

Local excision of rectal lesions is being increasingly undertaken, especially in those unfit for major surgery. The traditional transanal approach is often cumbersome and limited to low and mid rectal lesions. Transanal endoscopic microsurgery (TEMS) is being used to excise both benign and malignant rectal lesions, including those in the upper rectum.

METHODS

Prospective analysis of all patients undergoing a TEMS excision between January 1997 and December 2000 in a specialized colorectal unit.

RESULTS

Forty patients underwent a TEMS resection, with a mean age of 72 years (SD, 10 years). The mean distance of the lesions from the anal verge was 9.8 cm (SD, 3.1 cm). In 24 patients, the lesion was located >or=10 cm from the anal verge, making them unsuitable for traditional transanal resection. The mean operative time was 91 minutes (SD, 34 minutes), and the mean postoperative stay was 3 days (SD, 1.5 days). No mortality was associated with the procedure, and there was minimal morbidity in 15%. There has been no recurrence in the 18 patients who had a malignant lesion excised.

CONCLUSIONS

The TEMS operating system provides the surgeon with a suitable alternative for the resection of benign and malignant rectal neoplasms in selected patients. It has the advantage of providing visual clarity of the operative field, allowing more precise dissection and a minimally invasive approach to mid and upper rectal lesions. There has been no mortality and minimal morbidity. We advocate its inclusion as part of a colorectal surgeon's operative armamentarium for these selected cases.

The indication of local excision for T2 rectal carcinomas

BACKGROUND

Several researchers reported that local excision with or without postoperative chemo-radiation therapy is an alternative approach for sphincter preservation in patients with locally invasive rectal carcinoma. However, indications and long-term results have not yet been determined.

METHODS

Seventy-two patients with T2 colorectal carcinomas underwent bowel resection with regional lymph node dissection. The associations between lymph node metastasis (LNM) and clinicopathologic factors were examined with special reference to the presence or absence of moderate to severe degree of focal dedifferentiation or mucinous component at the invasive margin (unfavorable histology).

RESULTS

Multivariate logistic regression analysis revealed that both sex and unfavorable histology were significantly associated with LNM (P = 0.0102, 0.0226, respectively). However, the associations between LNM and lymphatic invasion or tumor location were not statistically significant (P = 0.0947, 0.1738).

CONCLUSIONS

When locally resected T2 rectal carcinoma specimens have unfavorable histology at the invasive margin, additional bowel resection with lymph node dissection should be recommended.

Prognostic factors in colorectal cancer. College of American Pathologists Consensus Statement 1999

BACKGROUND

Under the auspices of the College of American Pathologists, the current state of knowledge regarding pathologic prognostic factors (factors linked to outcome) and predictive factors (factors predicting response to therapy) in colorectal carcinoma was evaluated. A multidisciplinary group of clinical (including the disciplines of medical oncology, surgical oncology, and radiation oncology), pathologic, and statistical experts in colorectal cancer reviewed all relevant medical literature and stratified the reported prognostic factors into categories that reflected the strength of the published evidence demonstrating their prognostic value. Accordingly, the following categories of prognostic factors were defined. Category I includes factors definitively proven to be of prognostic import based on evidence from multiple statistically robust published trials and generally used in patient management. Category IIA includes factors extensively studied biologically and/or clinically and repeatedly shown to have prognostic value for outcome and/or predictive value for therapy that is of sufficient import to be included in the pathology report but that remains to be validated in statistically robust studies. Category IIB includes factors shown to be promising in multiple studies but lacking sufficient data for inclusion in category I or IIA. Category III includes factors not yet sufficiently studied to determine their prognostic value. Category IV includes factors well studied and shown to have no prognostic significance.

MATERIALS AND METHODS

The medical literature was critically reviewed, and the analysis revealed specific points of variability in approach that prevented direct comparisons among published studies and compromised the quality of the collective data. Categories of variability recognized included the following: (1) methods of analysis, (2) interpretation of findings, (3) reporting of data, and (4) statistical evaluation. Additional points of variability within these categories were defined from the collective experience of the group. Reasons for the assignment of an individual prognostic factor to category I, II, III, or IV (categories defined by the level of scientific validation) were outlined with reference to the specific types of variability associated with the supportive data. For each factor and category of variability related to that factor, detailed recommendations for improvement were made. The recommendations were based on the following aims: (1) to increase the uniformity and completeness of pathologic evaluation of tumor specimens, (2) to enhance the quality of the data needed for definitive evaluation of the prognostic value of individual prognostic factors, and (3) ultimately, to improve patient care.

RESULTS AND CONCLUSIONS

Factors that were determined to merit inclusion in category I were as follows: the local extent of tumor assessed pathologically (the pT category of the TNM staging system of the American Joint Committee on Cancer and the Union Internationale Contre le Cancer [AJCC/UICC]); regional lymph node metastasis (the pN category of the TNM staging system); blood or lymphatic vessel invasion; residual tumor following surgery with curative intent (the R classification of the AJCC/UICC staging system), especially as it relates to positive surgical margins; and preoperative elevation of carcinoembryonic antigen elevation (a factor established by laboratory medicine methods rather than anatomic pathology). Factors in category IIA included the following: tumor grade, radial margin status (for resection specimens with nonperitonealized surfaces), and residual tumor in the resection specimen following neoadjuvant therapy (the ypTNM category of the TNM staging system of the AJCC/UICC). (ABSTRACT TRUNCATED)

Accuracy of pathologic interpretation of colorectal polyps by general pathologists in community practice

BACKGROUND

The histologic features of colorectal polyps often guide colonoscopic surveillance and the need for surgical intervention. Our objective was to evaluate the pathologic interpretation of colorectal polyps by general pathologists in community practice.

METHODS

Twenty histologic slides of colorectal polyps were reviewed by 20 randomly selected general pathologists in community practice. There were 5 malignant polyps, 9 adenomas, and 6 miscellaneous polyps.

RESULTS

Cancer was correctly identified in 91% of readings and adenoma in 94%. The grade of differentiation of cancer was provided in 55% of readings, and comment regarding whether the resection margin was free of cancer was made by 50% of pathologists. Tubular adenoma was called tubulovillous or villous in 35% of readings, but tubulovillous or villous adenoma was seldom (2%) called tubular. High-grade dysplasia was correctly identified in 47% of 60 readings, was called invasive cancer in 22%, and was missed in 31%. Among miscellaneous polyps, hyperplastic polyp was correctly recognized in 75% of cases, and inflammatory polyp and juvenile polyp each were recognized by 16 of 20 pathologists (80%). Peutz-Jeghers hamartoma was identified by 4 of 20 pathologists (20%), and the polypoid phase of solitary rectal ulcer syndrome was recognized by 2 pathologists (10%).

CONCLUSION

Areas of strength with regard to interpretation of colon polyps by general pathologists in community practice included identification of cancer, adenoma, and certain non-neoplastic polyps (e.g., inflammatory and juvenile polyps). Areas of weakness included lack of comment on cancer differentiation and proximity to the resection line, erroneous identification of high-grade dysplasia, and identification of rare lesions. The results of this study suggest areas on which to focus continuing education and continuous quality improvement efforts with regard to polyp interpretation.

CD44 expression in benign and malignant colorectal polyps

PURPOSE

This retrospective study was undertaken to evaluate immunohistochemically the expression of CD44 standard protein and CD44v5 and CD44v6 isoforms in colorectal adenomas and early invasive cancers developing within adenomas as possible markers characterizing colorectal polyps with a more aggressive biologic potential.

METHODS

Archival tissues of 81 consecutive locally resected colorectal polyps, comprising 57 colorectal adenomas and 24 carcinomas-in-adenomas, were stained immunohistochemically with the use of commercially available mouse monoclonal antibodies: SFF-2 for CD44 standard protein, VFF-8 for CD44v5, and VFF-7 for CD44v6.

RESULTS

Sixty-three percent of the colorectal polyps were positive for CD44 standard protein, 59 percent were positive for CD44v5, and 27 percent were positive for CD44v6. Ninety-three percent of the low-grade adenomas were CD44 standard protein-positive, in contrast to 50 percent of the high-grade adenomas and only 42 percent of the carcinomas-in-adenomas (Kendall's Tau = -0.42; P < 0.0001). CD44v6 expression was more frequently found in early invasive cancers (54 percent) than in high-grade adenomas (25 percent) and low-grade adenomas (7 percent). This difference also was statistically significant (Kendall's Tau-b = 0.39; P = 0.00003). Surprisingly, a downregulation of CD44 standard protein expression was observed in the adenoma tissue adjacent to carcinomas (62 percent) and areas with high-grade atypia (71 percent), compared with low-grade adenomas (93 percent; Kendall's Tau-b = -0.28; P = 0.004).

CONCLUSIONS

Our data suggest that CD44 standard protein and CD44 isoform v6 expression differs considerably in benign and malignant colorectal polyps. Clinical studies with larger patient groups could clarify the prognostic potential of CD44 further.

Risk factor assessment of endoscopically removed malignant colorectal polyps

BACKGROUND

Malignant colorectal polyps are defined as endoscopically removed polyps with cancerous tissue which has invaded the submucosa. Various histological criteria exist for managing these patients.

AIMS

To determine the significance of histological findings of patients with malignant polyps.

METHODS

Five pathologists reviewed the specimens of 85 patients initially diagnosed with malignant polyps. High risk malignant polyps were defined as having one of the following: incomplete polypectomy, a margin not clearly cancer-free, lymphatic or venous invasion, or grade III carcinoma. Adverse outcome was defined as residual cancer in a resection specimen and local or metastatic recurrence in the follow up period (mean 67 months).

RESULTS

Malignant polyps were confirmed in 70 cases. In the 32 low risk malignant polyps, no adverse outcomes occurred; 16 (42%) of the 38 patients with high risk polyps had adverse outcomes (p<0.001). Independent adverse risk factors were incomplete polypectomy and a resected margin not clearly cancer-free; all other risk factors were only associated with adverse outcome when in combination.

CONCLUSION

As no patients with low risk malignant polyps had adverse outcomes, polypectomy alone seems sufficient for these cases. In the high risk group, surgery is recommended when either of the two independent risk factors, incomplete polypectomy or a resection margin not clearly cancer-free, is present or if there is a combination of other risk factors. As lymphatic or venous invasion or grade III cancer did not have an adverse outcome when the sole risk factor, operations in such cases should be individually assessed on the basis of surgical risk.

Significance of histologic criteria for the management of patients with malignant colorectal polyps and polypectomy

BACKGROUND

The management of invasive cancer in colorectal polyps (malignant polyps) is controversial, particularly with regard to the different sets of histologic criteria for deciding whether malignant colorectal polyps should be treated by polypectomy alone or be followed by surgical resection. We report on the outcome of patients in accordance with the histologic assessment of their malignant polyps.

METHODS

Malignant polyps were defined as having favourable histology (free margin, grade I or II, and no angiolymphatic invasion) or unfavorable histology (no free margin, grade III, or angiolymphatic invasion). Malignant polyps with favourable histology were treated by endoscopic polypectomy alone, whereas further therapy was recommended for malignant polyps with unfavourable histology. Residual cancer in a resection specimen and local or metastatic recurrence during the follow-up period (mean, 60 months; range, 12 - 120) were defined as adverse outcome.

RESULTS

Thirty-seven malignant polyps were detected in 35 (0.5%) of 6605 patients. Five of these 35 patients were treated by primary bowel resection and analysed separately. In the other 30 patients the following unfavourable histologic signs were detected in 20 (62.5%) of 32 malignant polyps; no free margin in 16, grade III in 1, and angiolymphatic invasion in 3 polyps. Twelve polyps with favourable histology had no adverse outcome; in contrast, 5 of 20 polyps with unfavourable histology had an average outcome (P < 0.05).

CONCLUSIONS

Locally excised malignant polyps without unfavourable histologic signs may not need further surgical treatment; for all other malignant polyps an ensuing bowel resection is recommended.

Long-term survival after treatment of malignant colonic polyps

PURPOSE

This study was designed to evaluate the long-term outcome and survival of patients treated for malignant colonic polyps.

METHODS

A retrospective review of 15,975 cases of colonoscopies with 8,685 endoscopic polypectomies performed between 1972 and 1990 was undertaken. In 65 patients, the polypectomy specimens contained invasive carcinoma. Six patients were excluded (follow-up, <6 months). Polyp data, operative findings, and follow-up on the remaining 59 patients were recorded.

RESULTS

Malignant polyps were found in 35 males and 24 females who had an average age of 64 (range, 39-81) years. Follow-up ranged from 12 to 202 (mean, 90) months. Tumor differentiation was poor in one and well or moderately differentiated in 58 patients. Positive or indeterminate margins were found in 13 patients. Thirty-seven (63 percent) patients were managed with polypectomy and surveillance. Four of these (with rectal tumors) also had an additional local excision for questionable margins. One recurrence was noted in a patient who refused surgery, which was recommended because of indeterminate margins. Twenty-two patients (37 percent) underwent colectomy. Indications included Haggitt Level 3 or 4 invasion (19), inadequate margins (7), patient preference (1), and poor differentiation (1). Residual disease was found in colectomy specimens of three patients (14 percent). There were no cancer-related deaths in either treatment group. Life table analysis demonstrated a five-year survival of 82 percent for the colectomy group and 95 percent for the polypectomy group (P = 0.15).

CONCLUSION

Treatment of patients with malignant polyps must be individualized based on evolving criteria. Patients in whom polypectomy margins are inadequate should undergo colectomy. With appropriate selection criteria, patients selected for colectomy had a five-year survival rate similar to the rate of those treated by polypectomy alone.

Management and outcome of patients with invasive carcinoma arising in colorectal polyps

BACKGROUND & AIMS

Treatment for invasive adenocarcinoma in colorectal polyps (malignant polyps) is controversial. The aim of this study was to evaluate our institutional treatment strategy for malignant polyps.

METHODS

Malignant polyps were designated as having favorable histology (grade I or II carcinoma with at least a 2-mm free margin) or unfavorable histology (grade III invasive adenocarcinoma, invasive adenocarcinoma with an unassessable margin, or a margin of < 2 mm). Malignant polyps with favorable histology were considered treated adequately by endoscopic polypectomy, whereas further therapy was recommended for malignant polyps with unfavorable histology. Recurrence, residual adenocarcinoma in a follow-up resection specimen, or metastasis during follow-up were considered adverse outcomes.

RESULTS

Of the 47 patients identified, 17 (36%) had favorable histology. Sixteen patients (94%) were treated with polypectomy alone. None had an adverse outcome (median follow-up, 70 months). Thirty patients (64%) had unfavorable histology, and 21 patients (70%) underwent colectomy. Five patients underwent radiation therapy alone. Four patients underwent no additional therapy. Ten of 30 patients with unfavorable histology had adverse outcomes that differed significantly from the favorable histology group (P = 0.03).

CONCLUSIONS

Endoscopic polypectomy alone is adequate therapy for malignant polyps with favorable histology.

Endoscopically removed malignant colorectal polyps: clinicopathologic correlations

BACKGROUND/AIMS

Treatment options for patients with endoscopically removed malignant colorectal polyps are polypectomy alone vs. polypectomy followed by surgery. The aim of this study was to define histopathologic parameters that can be used for clinically relevant treatment decisions.

METHODS

Five pathologists evaluated 140 polyps for the presence or absence of unfavorable histology. Unfavorable histology was tumor at or near (< or = 1.0 mm) the margin and/or grade III and/or lymphatic and/or venous invasion. Adverse outcome was recurrent and/or local cancer and/or lymph node metastasis.

RESULTS

Adverse outcome was 19.7% (14 of 71), 8.6% (2 of 23), and 0% (0 of 46) when unfavorable histology was present, indefinite (lack of agreement), and absent, respectively (P < 0.0005, present vs. absent). Four patients with cancer > 1.0 mm from the margin had an adverse outcome (2 with lymphatic invasion and 2 indefinite for lymphatic invasion). Four patients with negative resections later developed distant metastases. Eight patients (6.3%) died of disease, and 2 of 69 without unfavorable histology (both indefinite for lymphatic invasion) had an adverse outcome. Interobserver strength of agreement was substantial to almost perfect for margin, grade, and venous invasion and fair to substantial for lymphatic invasion.

CONCLUSIONS

This system is usable clinically. Patients with unfavorable histology are probably best managed by resection postpolypectomy, whereas in the absence of unfavorable histology, they probably can be treated by polypectomy only.

Management of the malignant colorectal polyp: the importance of clinicopathological correlation

The results of management of colorectal adenomas removed endoscopically and found to contain invasive cancer seen in a single institution over a 10 year period are presented. Clinical data were obtained retrospectively from patient case notes and all specimens were reviewed by one pathologist. Fifty-four patients with malignant polyps were studied after exclusion of others with polypoid carcinomas, epithelial misplacement and cases managed by primary segmental resection. Of the various considered predictors of adverse outcome, only histologically incomplete excision proved significant. However, when excision was considered macroscopically complete there was no significant association between incomplete histological excision and adverse outcome. Consideration should be given to conservative management of such cases.