Patient management after endoscopic removal of the cancerous colon adenoma

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.

Tumor Budding Detection by Immunohistochemical Staining is Not Superior to Hematoxylin and Eosin Staining for Predicting Lymph Node Metastasis in pT1 Colorectal Cancer

BACKGROUND

Tumor budding is recognized as an important risk factor for lymph node metastasis in pT1 colorectal cancer. Immunohistochemical staining for cytokeratin has the potential to improve the objective diagnosis of tumor budding over detection based on hematoxylin and eosin staining. However, it remains unclear whether tumor budding detected by immunohistochemical staining is a significant predictor of lymph node metastasis in pT1 colorectal cancer.

OBJECTIVE

The purpose of this study was to clarify the clinical significance of tumor budding detected by immunohistochemical staining in comparison with that detected by hematoxylin and eosin staining.

DESIGN

This was a retrospective study.

SETTINGS

The study was conducted at Niigata University Medical & Dental Hospital.

PATIENTS

We enrolled 265 patients with pT1 colorectal cancer who underwent surgery with lymph node dissection.

MAIN OUTCOME MEASURES

Tumor budding was evaluated by both hematoxylin and eosin and immunohistochemical staining with the use of CAM5.2 antibody. Receiver operating characteristic curve analyses were conducted to determine the optimal cutoff values for tumor budding detected by hematoxylin and eosin and CAM5.2 staining. Univariate and multivariate analyses were performed to identify the significant factors for predicting lymph node metastasis.

RESULTS

Receiver operating characteristic curve analyses revealed that the cutoff values for tumor budding detected by hematoxylin and eosin and CAM5.2 staining for predicting lymph node metastases were 5 and 8. On multivariate analysis, histopathological differentiation (OR, 6.21; 95% CI, 1.16-33.33; p = 0.03) and tumor budding detected by hematoxylin and eosin staining (OR, 4.91; 95% CI, 1.64-14.66; p = 0.004) were significant predictors for lymph node metastasis; however, tumor budding detected by CAM5.2 staining was not a significant predictor.

LIMITATIONS

This study was limited by potential selection bias because surgically resected specimens were collected instead of endoscopically resected specimens.

CONCLUSIONS

Tumor budding detected by CAM5.2 staining was not superior to hematoxylin and eosin staining for predicting lymph node metastasis in pT1 colorectal cancer.

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.

Rate of residual disease after complete endoscopic resection of malignant colonic polyp

BACKGROUND

Following polypectomy, colectomy is performed selectively to ensure complete clearance of neoplasia.

OBJECTIVE

This study aimed to determine the risk factors associated with residual disease at colectomy following malignant polypectomy.

DESIGN

This is a retrospective study.

SETTING

This investigation took place at a tertiary teaching cancer center.

PATIENTS

Consecutive patients undergoing polypectomy followed by colectomy from 1990 to 2007 were identified from a prospective database.

MAIN OUTCOME MEASURES

Factors associated with residual disease at colectomy were associated with clinicopathologic features.

RESULTS

Colectomy following polypectomy was performed in 143 patients: 127 with clear invasion of polyp submucosa (invasive disease), and 16 suspicious for submucosal invasion. Residual disease after colectomy was diagnosed in 27 (19%) of 143 patients. Disease was present in the colonic wall in 19 patients (13%): invasive in 16 (11%), and noninvasive in 3 (2.1%). Of the 16 patients with residual invasive disease at colectomy, 15 had clearly invasive disease at polypectomy and 1 was suspicious for invasive disease at polypectomy. Lymph node metastasis was noted in 10 (7.0%) patients. When analyzing patients with clearly invasive disease at polypectomy by margin status, residual invasive disease in the colon wall was noted in 8 of 50 (16%) with <1 mm (positive) polypectomy margin, 7 of 33 (21%) with indeterminate polypectomy margin, and 0 of 44 with ≥1 mm (negative) polypectomy margin (p = 0.009). Nodal metastasis was associated with the presence of lymphovascular invasion (p = 0.01).

LIMITATIONS

This study is limited by its retrospective nature and selection bias.

CONCLUSIONS

Following malignant polypectomy, colectomy should be considered in medically fit patients if the polypectomy margin is positive (≤1 mm) or unknown, or if lymphovascular invasion is present.

Management of malignant colonic polyps: a population-based analysis of colonoscopic polypectomy versus surgery

BACKGROUND

The management of colon polyps containing invasive carcinoma includes surgical resection or colonoscopic polypectomy. To date, there are very limited population-based data comparing outcomes with the 2 management approaches.

METHODS

Using the linked Surveillance Epidemiology and End Results-Medicare database, we identified 2077 patients aged ≥66 years with an initial diagnosis of stage T1N0M0 malignant polyp from 1992-2005. Patients were categorized as surgical or polypectomy depending on the most invasive treatment. To adjust for potential selection bias in treatment assignment, using multivariate analysis, patients were divided into quintiles of likelihood of polypectomy (propensity scores), and outcomes were compared in each quintile.

RESULTS

Surgical resection was performed in 1340 (64.5%) patients and polypectomy was performed in 737 (35.5%) patients. Predictors for undergoing polypectomy (P<.001) included older age, greater comorbidity, no history of polyps, diagnosis in 2002 or later, left colon site of cancer, well-differentiated tumors, and colonoscopy performed in an outpatient setting. Both 1-year and 5-year survival were higher in the surgical group (92% and 75%, respectively) than in the polypectomy group (88% and 62%, respectively). The unadjusted hazard ratio was 1.51 (95% confidence interval [CI], 1.31-1.74). After adjusting for propensity quintile, the hazard ratio was 1.15 (95% CI, 0.98-1.33). Within each propensity quintile, the risk of death was similar between the 2 groups (interaction test P = .96).

CONCLUSIONS

In this large, population-based sample, more than one-third of patients with malignant polyps were treated with colonoscopic polypectomy. Outcomes were similar to surgical patients with comparable clinical characteristics and could be offered to patients who meet appropriate clinical criteria.

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 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.

Pathology of early lower GI cancer

Early colorectal cancer can be treated with curative resection if the depth of invasion is limited to the submucosa (pathologic T category pT1 in the TNM classification). Macroscopically early colorectal cancer and its precursor lesions present as elevated polyps or non-polypoid flat lesions. Microscopically, precursor lesions are characterized by intraepithelial neoplasia and present as classic adenomas or serrated adenomas. Precursor lesions may already contain foci of early colorectal cancer. Early colorectal cancer can be treated by endoscopic resection. Careful handling of the specimen is required in order to optimally identify the factors that may predict an adverse outcome. Whenever a favourable tumour grade is found, without vascular invasion and tumour budding, there seems to be a low risk for adverse outcome and laparotomy may thus be avoided.

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.

Clinical significance of nuclear morphometry at the invasive front of T1 colorectal cancer and relation to expression of VEGF-A and VEGF-C

OBJECTIVES

To better understand the metastatic potential of T1 colorectal cancer, we investigated variations in nuclear morphometry and expression of angiogenic factors in cancer cells at the invasive front. Sixty-five patients who had undergone curative resection were entered.

METHODS

Nuclear shape factor, area, width, and proportion of cells with large nucleoli in all cells were determined in two high-power magnification areas at the invasive front of the tumor. We then performed the Ward method for cluster analysis. A dendrogram revealed that cases fell into two clusters: cluster A with high atypical nuclei and cluster B with low atypical nuclei. Expression of vascular endothelial growth factor-A (VEGF-A) and -C were evaluated immunohistochemically at the invasive front of the tumor.

RESULTS

Nuclear atypia, and VEGF-C expression were associated significantly with lymph node metastasis by univariate analysis. Nuclear atypia was independently and significantly associated with lymph node metastasis by multivariate analysis. Whereas VEGF-A expression was associated with nuclear atypia, VEGF-C expression was not showed. Nuclear atypia, strong VEGF-A or -C expressions were not associated with the depth of invasion.

CONCLUSION

Nuclear morphometry and expression of angiogenic factors at the invasive front are useful prognostic markers of lymph node metastasis, even cases with slight invasion.

Laser photoablation of colorectal adenomas: a 12-year experience

BACKGROUND

We analyze laser photoablation as an alternative treatment of large sessile polyps in inoperable patients.

METHODS

Ninety-four colorectal polyps (mean diameter 3.09 +/- 2.7 cm, range 1-15 cm) were treated using high-energy lasers (Nd:YAG and diode). Grade of dysplasia was low in 51, high in 35, with focally invasive cancer in eight.

RESULTS

After 405 laser sessions (4.3 per polyp) five procedure-related complications were observed: two strictures, two bleedings, and one perforation. The last needed a surgical resection; the others were successfully treated by endoscopic therapy. Fifty-seven polyps (61%) were completely eradicated and the growth was controlled in all but two (98%). No degeneration was found after 28-month follow-up of treated adenomas with low- or high-grade dysplasia. Outcome of treatment was dependent on the dimension and grade of the dysplasia (p < 0.05), but not on the polyps' position (rectum or colon). Relief of rectal bleeding was obtained in 90%, of mucus discharge in 77%, and of tenesmus in 100% of cases.

CONCLUSIONS

Laser photoablation of colonic adenomas can be considered a valid procedure not only to relieve symptoms, but also to control the risk of degeneration in patients unfit for surgery or when surgical treatment is considered excessively invalidating.

Endorectal ultrasound in the management of patients with malignant rectal polyps

PURPOSE

This study was designed to determine the efficacy of endorectal ultrasound in the management of patients with malignant rectal polyps removed by snare excision during colonoscopy.

METHODS

A retrospective review of the medical records and endorectal ultrasound images of 63 patients with endoscopically removed rectal polyps containing invasive adenocarcinoma subsequently staged by endorectal ultrasound. Patients underwent surgery or were followed at a single institution. The polyp characteristics and ultrasound images were compared with the presence of residual tumor in the surgical specimen in patients who underwent further surgery or with recurrence in patients who did not.

RESULTS

The morphology of the polyps was described in 31 patients (49 percent); they were sessile in 26 (41 percent) and pedunculated in 6 (9 percent). The margins were positive in 22 patients (35 percent), negative in 19 (30 percent), and not specified in 22 (35 percent). Most tumors were well or moderately differentiated; only 3 (5 percent) were poorly differentiated. Thirty-three patients underwent further surgery (3 low anterior resection, and 30 transanal excision); 30 had no further surgery. The accuracy of endorectal ultrasound in assessing the presence of residual cancer in the rectal wall in patients who had surgery was 54 percent, with a 39 percent positive predictive value and 65 percent negative predictive value. Endorectal ultrasound accurately identified metastatic lymph nodes in two of three patients who had radical surgery. Endorectal ultrasound was more useful than polyp morphologic or histologic criteria to determine the presence of residual cancer in the rectal wall.

CONCLUSIONS

Endorectal ultrasound does not definitely exclude the possibility of residual tumor in the rectal wall or mesenteric nodes of patients who had a malignant polyp snared endoscopically. Consequently, decisions regarding the definitive management of these patients cannot be based exclusively on the endorectal ultrasound images of the polypectomy site.

Interobserver variability in the pathological assessment of malignant colorectal polyps

Background

Treatment of patients with malignant large bowel polyps is highly dependent on pathological evaluation. The aim of this study was to evaluate interobserver variability in the pathological assessment of endoscopically removed polyps.

Methods

The records of 88 patients with colorectal cancer who underwent endoscopic removal of malignant polyps were reviewed. Study investigators reviewed the initial pathology report; three experienced gastrointestinal pathologists reviewed all slides in a blinded fashion. Interobserver variability of pathological assessment of malignant polyps was analysed by κ statistics.

Results

Seventy-six (86 per cent) of the 88 patients had malignant polyps and 12 (14 per cent) had carcinoma in situ. Agreement between experienced pathologists was substantial with regard to T stage (κ = 0·725), resection margin status (κ = 0·668) and Haggitt's classification (κ = 0·682), but comparison of initial and experienced pathologists' assessment demonstrated only moderate agreement in these areas (κ = 0·516, κ = 0·555 and κ = 0·578 respectively). Agreement between even experienced pathologists was poor with respect to histological grade of differentiated adenocarcinomas (κ = 0·163) and angiolymphatic vessel invasion (κ = − 0·017).

Conclusion

Pathological assessment of malignant polyps varies between observers. Specialist pathologists appear to have a higher degree of consensus among themselves than with generalist pathologists with respect to T stage. The high interobserver variability with regard to histological grade of differentiated tumours is clinically irrelevant. However, variability in the assessment of angiolymphatic vessel invasion limits the value of this measurement for clinical decision making.

Risk factors for an adverse outcome in early invasive colorectal carcinoma

BACKGROUND & AIMS

Various histologic findings exist for managing patients with malignant polyps. Our goal was to determine the criteria for a conservative approach to patients with locally excised early invasive carcinoma.

METHODS

In 292 early invasive tumors (local resection followed by laparotomy [80 tumors, group A], local resection only [41 tumors, group B], and primarily laparotomy [171 tumors, group C], potential parameters for nodal involvement were analyzed. The status of the endoscopic resection margin also was examined for the risk for intramural residual tumor.

RESULTS

Unfavorable tumor grade, definite vascular invasion, and tumor budding were the combination of qualitative factors that most effectively discriminated the risk for nodal involvement in patients in groups A-C. The nodal involvement rate was 0.7%, 20.7%, and 36.4% in the no-risk, single-risk, and multiple-risks group, respectively. Thirty-two and 9 patients from group B were assigned to the no-risk and one-risk group, respectively; extramural recurrence occurred in 2 patients with risk factors. Considering quantitative risk parameters for submucosal invasion (i.e., width > or =4000 microm or depth > or =2000 microm), nodal involvement (including micrometastases) was not observed in the redefined no-risk group that accounted for about 25% of the patients from groups A and C. An insufficiency of endoscopic resection could be evaluated most precisely based on the coagulation-involving tumor, rather than the 1-mm rule for the resection margin.

CONCLUSIONS

Provided that the criterion of sufficient excision is satisfied, the absence of an unfavorable tumor grade, vascular invasion, tumor budding, and extensive submucosal invasion would be the strict criteria for a wait-and-see policy.

Predictive factors for lymph node metastasis in T1 stage colorectal carcinomas

PURPOSE

Selective endoscopic resection may cure early colorectal cancer (T1), but the management is controversial. There is concern about the small risk of lymph node metastasis, which will not be treated by endoscopic resection alone. The authors sought predictive markers of lymph node metastasis to assist patient management.

METHODS

The authors retrospectively analyzed consecutive cases of T1 stage colorectal cancer resected using endoscopic resection or bowel surgery over the period 1979 to 2000. The risk of lymph node metastasis was analyzed using logistic regression model for the markers selected by univariate analysis: the type of initial treatment, depth of submucosal invasion, lymphatic channel invasion, differentiation of histology, and invasive front histology.

RESULTS

Two hundred seventy-eight patients were available for study. Twenty-one had lymph node metastasis. Depth of submucosal invasion (> or = 2,000 microm) and lymphatic channel invasion significantly predicted risk of lymph node metastasis in multivariate analysis. When these two factors were adopted for the prediction of lymph node metastasis, sensitivity, specificity, positive predictive value, and negative predictive value were 100, 55.6, 15.6, and 100 percent, respectively.

CONCLUSIONS

Depth of submucosal invasion and lymphatic channel invasion were accurate predictive factors for lymph node metastasis. These two factors could be used in selecting appropriate cases for surgery after endoscopic resection.

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)

Preoperative evaluation of colorectal neoplasms by colonoscopic miniprobe ultrasonography

OBJECTIVE

To investigate the value of colonoscopic miniprobe ultrasonography for preoperative staging of colorectal neoplasms.

SUMMARY BACKGROUND DATA

Endoscopic ultrasonography is the most accurate technique for staging colorectal cancer. However, limitations of this technique include the inability to examine stenotic tumors and the difficulty of reaching tumors proximal to the rectum.

METHODS

Miniprobe ultrasonography (12.5 MHz) was performed in 63 patients with tumors of the colon or rectum. The results of imaging were compared with endoscopic assessment of the lesions and histopathologic findings of the resected specimens.

RESULTS

Miniprobe ultrasonography allowed high-resolution imaging of colorectal tumors during routine colonoscopy. The infiltration depth was correctly classified in 22 adenoma, 3 T1, 10 T2, and 22 T3 or T4 tumors. The accuracy for tumors of the rectum and colon was 86% and 92%, respectively (overall accuracy 90%). The small diameter of the probe allowed examination of 21 stenotic tumors with an accuracy of 86%. Miniprobe ultrasonography revealed carcinoma in 5 of 30 broad-based polyps, although adenomas were diagnosed by endoscopy. Correct assessment of lymph node involvement was obtained in 47 of 55 patients. Based on the findings of miniprobe ultrasonography, management was modified in 7 of the 63 patients.

CONCLUSIONS

These preliminary results show that miniprobe ultrasonography improves preoperative staging of stenotic rectal cancer and colonic tumors. This technique can be easily performed during routine colonoscopy and may have considerable impact on surgical therapy.

American Joint Committee on Cancer Prognostic Factors Consensus Conference: Colorectal Working Group

BACKGROUND

The American Joint Committee on Cancer (AJCC), which regularly reviews TNM staging systems, established a working party to develop recommendations for colorectal carcinoma.

METHODS

A multidisciplinary consensus conference using published literature developed an arbitrary classification system of prognostic marker value (Category I, IIA, IIB, III, and IV), which forms the framework for this report.

RESULTS

The working party concluded that several T categories should be subdivided: pTis into intraepithelial carcinoma (pTie) and intramucosal carcinoma (pTim); pT1 into pT1a and pT1b corresponding to the absence or presence of blood or lymphatic vessel invasion, respectively; and pT4 into pT4a and pT4b according to the absence or presence of tumor involving the surface of the specimen, respectively. The working party also recommended that TNM groups be stratified based on the presence or absence of elevated serum levels of carcinoembryonic antigen (CEA) (>/= 5 ng/mL) on preoperative clinical examination. In addition, the working party also concluded that carcinoma of the appendix should be excluded from the colorectal carcinoma staging system because of fundamental differences in natural history.

CONCLUSIONS

The TNM categories and stage groupings for colorectal carcinoma published in the current AJCC manual have clinical and academic value. However, a few categories require subdivision to provide increasing discrimination for individual patients. The serum marker CEA should be added to the staging system, whereas multiple other factors should be recorded as part of good clinical practice. Although many molecular and oncogenic markers show promise to supplement or modify the current staging systems eventually, to the authors' knowledge none have yet been evaluated sufficiently to recommend their inclusion in the TNM system.

Indications for performing transanal endoscopic microsurgery (TEM) in rectal cancer patients

OBJECTIVE

The aim of this study was to clarify the application of a local excision using TEM for rectal cancer.

PATIENTS AND METHODS

Fifteen patients were preoperatively diagnosed to have cancer invasion in the submucosa (T1) and thus were treated by TEM, while 13 others were preoperatively diagnosed to have cancer invasion reaching the muscularis propria (T2) and thus were treated by a radical operation. Surgical specimens from all 28 patients were pathologically examined and compared with the preoperative evaluation.

RESULTS

The mean operating time for TEM was 53 min. The accuracy of the preoperative evaluation for the depth of cancer invasion was 68% (19/28). In the 15 patients with preoperative evaluation of T1 cancer, two pathologically showed cancer invasion into muscularis propria. In the 13 patients with a preoperative evaluation of T2 cancer, three pathologically showed cancer invasion within the submucosa.

CONCLUSION

Since some patients with a preoperative evaluation of T2 rectal cancer showed the possibility of a complete cure with a local excision, preoperative T2 stage rectal cancer is considered to be a good candidate for a local excision using TEM.

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.

Malignant Colorectal Polyps

When a patient undergoes colonoscopic resection of a colorectal polyp found to contain invasive cancer, I carefully analyze a number of pathologic and clinical features of the case to formulate an effective management plan. I usually consider colonoscopic treatment alone to be definitive therapy when the malignant polyp has favorable prognostic features. I find that the risk of residual colonic cancer or lymph node metastases usually is less than the risk of further cancer surgery when the polyp is considered to be completely resected by the endoscopist; and on pathologic examination, the resection margins are negative; and no evidence of vascular invasion, lymphatic invasion, or high-grade cancer exists. When unfavorable criteria are found and the patient is a good risk for surgery, I find that surgical resection of the involved colonic segment and draining lymphatic system usually is indicated. When formulating a management plan, I individualize treatment according to the location of the malignant polyp, risk of surgery, and wishes of an informed patient. I urge patients to adopt a healthy diet and lifestyle to reduce the risk of colorectal neoplasia. I cannot make specific recommendations for preventive dietary supplements such as vitamins, minerals, or drugs such as aspirin because efficacy and risk-benefit chemopreventive trials are ongoing.

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.

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.

Correlation between macroscopic morphologic features and malignant potential of colorectal sessile adenomas

PURPOSE AND METHODS

To clarify malignant potential of colorectal sessile adenomas, we investigated 46 colorectal sessile adenomas surgically resected from 44 patients. Lesions were divided into three types according to their macroscopic morphologic features: nodular-type (19 adenomas), villous-type (7), and creeping-type (20). Clinicopathologic features were investigated and compared among these three types.

RESULTS

Frequency of focal carcinoma in the nodular-type, villous-type, and creeping-type adenoma was 37, 29, and 55 percent, respectively. Frequency of submucosal invasion in these three types were 11, 14, and 20 percent, respectively. Irrespective of the type, large lesions (> 3 cm) tended to have a higher frequency of submucosal invasion than did smaller ones (60 vs. 20 percent; P = 0.063). Large creeping-type adenomas (> 3 cm) had a definitely higher frequency of submucosal invasion than smaller ones (36 vs. 0 percent; P < 0.05). Lymphatic or vascular invasion of carcinoma was present only in the lesion with submucosal invasion: 5 percent in the nodular-type; 14 percent in the villous-type; 20 percent in the creeping-type. Lymph node metastasis was present only in the creeping-type lesion.

CONCLUSIONS

The large creeping-type adenomas (> 3 cm) have a definitely high frequency of submucosal invasive carcinoma. Endoscopic polypectomy or local resection may be adequate for most sessile adenomas. However, we recommend segmental resection of the colon with regional lymph node dissection for a creeping-type adenoma that is larger than 3 cm because of increased risk of submucosal carcinomatous invasion and lymph node involvement.

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.

Endoscopic treatment of submucosal invasive colorectal carcinoma with special reference to risk factors for lymph node metastasis

A clinicopathological analysis of the risk factors for lymph node metastasis was performed in 177 patients with submucosal invasive colorectal carcinoma (CRC). The submucosal deepest invasive portion was histologically subclassified as well (W), moderately (M), or poorly (Por) differentiated. M type was further subdivided into moderately-well (Mw) and moderately-poorly (Mp) differentiated. The pattern of tumor growth was classified as polypoid growth (PG) and non-polypoid growth (NPG). Lymph node metastasis was detected in 21 (12%) of the 177 patients. Macroscopically, type IIc and IIa + IIc lesions showed a significantly higher incidence of lymph node metastasis (44% and 30%) than type IIa and I (4% and 8%). Regarding the histologic subclassification, Por and Mp lesions showed a significantly higher incidence of lymph node metastasis (67% and 37%) than W and Mw lesions (4% and 14%). NPG tumors showed a significantly higher incidence of lymph node metastasis (29%) than PG tumors (7%). The depth of submucosal invasion and lymphatic invasion (ly) were also significantly correlated with the incidence of lymph node metastasis (submucosal scanty (sm-s) invasion 4%, massive invasion 20%; ly(+) 23%, ly(-) 5%). None of the lesions with both sm-s invasion and of W or Mw type showed lymph node metastasis. These results indicate that submucosal invasive CRC with both sm-s invasion and of W or Mw type, which shows no ly, is the appropriate indication for endoscopic curative treatment.

Clinicopathologic features of early rectal carcinoma and indications for endoscopic treatment

PURPOSE

This study was undertaken to clarify the indications for endoscopic treatment.

METHODS

Clinical and pathologic features of 191 lesions in 180 patients with early rectal carcinoma were examined, including 110 intramucosal carcinomas and 81 carcinomas with submucosal invasion (submucosal carcinomas). All lesions had been endoscopically or surgically resected at the National Cancer Center Hospital between 1976 and 1990.

RESULTS

Metastasis to regional lymph nodes (LN metastasis) was seen in 0 percent (0/39) of intramucosal carcinomas and 9.2 percent (6/65) of submucosal carcinomas in the surgically treated patients. The incidence of LN metastasis was higher for lesions larger than 10 mm in diameter, for those showing massive submucosal invasion, and for moderately differentiated adenocarcinomas. LN metastases were associated significantly with lymphatic invasion.

CONCLUSIONS

These results suggest that early rectal carcinomas should be resected surgically if they 1) show massive submucosal invasion, 2) are classified as moderately differentiated adenocarcinomas, and 3) are larger than 10 mm in diameter. In patients with both scanty submucosal invasion and features of well-differentiated adenocarcinoma or intramucosal carcinoma and if no other risk factors for LN metastasis are present, such as lymphatic invasion by the primary lesion, surveillance may suffice after endoscopic resection.

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.

Long-term results of curative resection of "minimally invasive" colorectal cancer

PURPOSE

The aim of this study was to determine the long-term outcome after curative resection of colorectal cancers that extend only into the submucosa ("minimally invasive") and to evaluate potential histologic predictors of lymph node metastases.

METHODS

Seventy-nine patients who underwent curative resection of minimally invasive colorectal cancer and were followed for at least five years were studied retrospectively.

RESULTS

The series was comprised of 53 men and 26 women, with a mean age of 61 years. The lesion was in the colon in 47 patients and the rectosigmoid or rectum in 32 patients. Open surgery followed attempted endoscopic tumor removal in 25 patients. Lymph node metastasis, found in 11/79 patients (13.9 percent), was associated with worse outcome: 36.4 percent of node(+) patients developed recurrence, vs. only 5.9 percent of node(-) patients (P < 0.005). The cumulative survival rate was also worse in node(+) vs. node(-) patients: 72.7 percent vs. 91.1 percent at five years (P < 0.05) and 45.5 percent vs. 65.3 percent at ten years (P < 0.05). Five histopathologic characteristics were identified as risk factors for lymph node metastasis: 1) small clusters of undifferentiated cancer cells ahead of the invasive front of the lesion ("tumor budding"); 2) a poorly demarcated invasive front; 3) moderately or poorly differentiated cancer cells in the invasive front; 4) extension of the tumor to the middle or deep submucosal layer; 5) cancer cells in lymphatics. Whereas patients with three or fewer risk factors had no nodal spread, the rate of lymph node involvement with four or more risk factors was 33.3 percent and 66.7 percent, respectively.

CONCLUSIONS

Metastasis is not infrequent in "minimally invasive" colorectal cancer. Appropriate bowel resection with lymph node dissection is indicated if such a lesion exhibits more than three histologic risk factors for metastasis.

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.

The care of patients with colorectal polyps that contain invasive adenocarcinoma. Endoscopic polypectomy or colectomy?

BACKGROUND

The appropriateness of resection in patients from whom polyps with invasive adenocarcinoma were excised has been questioned.

METHODS

To determine the results of this policy, the authors reviewed the outcome of 42 patients from whom 44 such polyps were removed. Each polyp was categorized for the level of invasion according to the classification of Haggitt.

RESULTS

Level 1 invasion was found in 27%; level 2, in 9%; level 3, in 11%; level 4, in 39%; and uncertain, in 14%. The histologic grade was well differentiated in 48% of patients and moderately differentiated in 52%. No polyps contained poorly differentiated adenocarcinoma; lymphatic and vascular invasion were not encountered. Excision was judged complete in 23 patients; 11 underwent resection, and in none was residual adenocarcinoma identified. In 14 patients, margins could not be evaluated; of 12 patients who underwent resection, residual adenocarcinoma was found in 1. Of the seven patients with positive margins who underwent resection, residual adenocarcinoma was found in only two. In the resected specimens in which residual carcinoma was encountered, all original lesions were designated level 4. None of the patients treated by polypectomy alone has experienced a recurrence at a mean follow-up time of 66 months (range, 12-152 months).

CONCLUSIONS

The authors conclude that only patients with level 4 invasion require resection.

The fate of patients following polypectomy alone for polyps containing invasive carcinoma

Eighty-two patients with colon and rectal polyps containing invasive adenocarcinoma treated by polypectomy alone were studied. Seven of 34 patients (21 percent) with sessile lesions had an adverse outcome, including five local recurrences and two distant metastases. They occurred from 4 to 68 months after the polypectomy. Forty-seven pedunculated polyps with invasion to the head (Level 1) or to the stalk (Level 3) and one polyp to the base of the stalk (Level 4) had no evidence of local recurrence or signs of metastasis. Twenty-eight percent of patients were found to have adenomatous polyps, and 4 percent had malignant polyps during the follow-up examinations (range, 3-119 months; mean, 53 months). The findings suggested that pedunculated polyps with invasion to the head (Level 1), neck (Level 2), or stalk (Level 3) can be safely treated with a complete polypectomy provided that the carcinoma is not undifferentiated. Sessile lesions as well as Level 4 pedunculated lesions should be treated aggressively. If resection is not performed, a long-term follow-up in these patients is essential.

The value of nuclear morphometry in the management of patients with colorectal polyps that contain invasive adenocarcinoma

Haggitt's classification is a useful guide in the management of patients with large bowel polyps which contain invasive adenocarcinoma in that patients with levels 1 to 3 require no operation. Nuclear morphometry has been shown to be a useful prognostic discriminant for patients with invasive carcinoma of the large bowel. The nuclear shape factor of 44 polyps with invasive carcinoma was studied to determine whether this parameter was of value to define those patients with Haggitt level 4 who should have a resection. The shape factor of 50 interphase nuclei was obtained through the use of image analysis by tracing the nuclear profiles as digitized on a video screen. The nuclear shape factor was defined as the degree of circularity of the nucleus, a perfect circle recorded as 1.0. Our previous experience showed a nuclear shape factor greater than 0.84 was associated with a poor outcome. The overall mean shape factor was 0.71 (0.59-0.85). There was a tendency for the patients with residual disease to have values in the upper range. Our findings suggest that nuclear morphometry fails to add any predictive information in this clinical situation.

The risk of lymph node metastasis in colorectal polyps with invasive adenocarcinoma

One hundred fifty-one patients with colorectal polyps containing invasive adenocarcinoma treated by resection were studied to determine the incidence of lymph node metastasis and whether lymph node metastasis was related to the depth of invasion. Other variables evaluated included size and configuration of the polyp, grade of adenocarcinoma, presence or absence of lymphovascular invasion, and degree of differentiation. In patients with sessile polyps, the incidence of lymph node metastasis was 10 percent. Eighty percent of these lesions had lymphovascular invasion. For pedunculated polyps, the overall incidence of lymph node metastasis was 6 percent. However, there was no incidence of lymph node metastasis when the depth of invasion was limited to the head, neck, and stalk of the polyp (Levels 1, 2, and 3). Only when the depth of invasion reached to the base of the stalk (Level 4) was the risk of lymph node metastasis high (27 percent). The other risk factors were not associated with lymph node metastasis. We concluded that the most significant risk factor for lymph node metastasis in patients with invasive carcinoma in a polyp was invasion into the submucosa of the bowel wall (Level 4).

Treatment of carcinoma in adenomas

Invasive carcinomas in polyps removed during endoscopy are described. Most of them can be treated adequately by polypectomy alone, but some need additional surgical treatment. Incomplete excision, poorly-differentiated carcinoma, and lymphatic invasion are associated with increased risk of residual carcinoma and lymph node metastases, making colorectal resection more attractive; however, in elderly patients and poor-risk patients, the risks of surgery should be balanced against the possible advantage of curative surgery. Rectal polyps may be large but sphincter preservation can usually be achieved by different types of local excision. Recently described flat adenomas may contain carcinoma, but may also be treated by polypectomy using snare or hot biopsy.

When is polypectomy sufficient treatment for colorectal cancer in a polyp?

Eighty-seven patients with a carcinoma in a polyp were reviewed over a 12-year period. Ten histologic criteria were analyzed for an association with the presence of residual carcinoma. Four factors were identified as having prognostic value: size greater than 1.5 cm, sessility, cancer of at least 50% of the adenoma volume, and invasive carcinoma. Polypectomy alone is adequate treatment unless the carcinoma invades deeper to the muscularis mucosa and is associated with one or more of these characteristics.

Invasive colorectal adenomas: surgery versus colonoscopic polypectomy

Of 6,426 colonoscopies performed in 1978-1987, 66 invasive colorectal adenomatous polyps were removed in 58 examinations. The study group included 36 (62%) men and 22 (38%) women with an age range of 42-96 years. Forty-three patients had invasive pedunculated polyps and 15 had invasive sessile polyps. Following the colonoscopic polypectomy, secondary surgical resection was done in 19 patients with pedunculated polyps and in 13 patients with sessile polyps. The operative specimens showed that the colonoscopic polypectomy removed the entire cancerous focus in all patients with pedunculated polyps, including those with stalk invasion. In contrast, most cases with sessile polyps turned out on operation to be Dukes' B or C carcinoma. Follow-up (mean 4.4 years) was available for 53 (93%) patients: none of 24 unoperated patients with pedunculated polyps suffered from local recurrence. We conclude that colonoscopic polypectomy is sufficient for invasive pedunculated polyps, provided that histology shows that the resection margins are free of tumoral cells. Surgery is recommended for all invasive sessile polyps.

Management of patients with invasive carcinoma removed by colonoscopic polypectomy

The management of patients with invasive carcinoma removed by colonoscopic polypectomy remains controversial. In order to assess the criteria for subsequent surgery after polypectomy, the histologic findings and outcome of 25 patients with invasive carcinomas treated by polypectomy were analyzed. Subsequent surgery was indicated when removed invasive carcinoma showed at least one of the following findings: 1) carcinoma near the surgical margin, 2) vessel invasion, 3) massive invasion, and 4) poorly differentiated adenocarcinoma. The authors considered those findings to be a risk factor for local residual carcinoma or lymph-node metastases, or both. Of 25 patients, 18 showed risk factors, with 16 receiving surgery. Only one had residual carcinoma in the lymphatic vessel of the surgical specimen. The remaining 15 had no carcinoma in the surgical specimens, however, one died of recurrent disease 55 months later. Two patients with risk factors received no surgery for various reasons. Local recurrent carcinoma developed in one 39 months later and the other had no recurrent carcinoma at autopsy. Seven patients without risk factors were adequately treated by polypectomy without recurrent disease 34 to 96 months later (average, 69 months). Consequently, of 18 patients with risk factors, 3 showed either residual carcinoma in the surgical specimens or recurrent carcinoma was found later. None of 7 patients without risk factors developed recurrent disease. We recommend that patients with risk factors be followed by surgery; however, patients without risk factors can be adequately treated by polypectomy alone.