Epidemiology, management, and prognosis of malignant large bowel polyps within a defined population

Completion total mesorectal excision following transanal endoscopic microsurgery does not compromise outcomes in patients with rectal cancer

BACKGROUND

Transanal endoscopic microsurgery (TEM) represents a choice of treatment in patients with neoplastic lesions in the rectum. When TEM fails, completion total mesorectal excision (cTME) is often required. However, a concern is whether cTME increases the rate of abdominoperineal resections (APR) and is associated with higher risk of incomplete mesorectal fascia (MRF) resection. The aim of this study was to compare outcomes of cTME with primary TME (pTME) in patients with rectal cancer.

METHODS

This was a nationwide study on all patients with cTME from the Danish Colorectal Cancer Group database between 2005 and 2015. Patients with cTME were compared to patients with pTME after propensity score matching (matching ratio 1:2). Matching variables were age, gender, tumor distance from anal verge, American Society of Anesthesiologists (ASA) score and American Joint Committee on Cancer (AJCC) stage.

RESULTS

A total of 60 patients with cTME were compared with 120 patients with pTME. Patients with cTME experienced more intraoperative complications as compared to pTME patients (18.3% vs. 6.7%, p = 0.021). However, there was no difference in the rate of perforations at or near the tumor/previous TEM site (6.7% vs. 2.5%, p = 0.224), conversion to open surgery (p = 0.733) or 30-day morbidity (p = 0.86). On multivariate analysis, cTME was not a risk factor for APR (OR 2.49; 95% CI 0.95-6.56; p = 0.064) or incomplete MRF (OR 1.32; 95% CI 0.48-3.63; p = 0.596). There was no difference in the rate of local recurrence between cTME and pTME (5.2% vs. 4.3%, p = 0.1), distant metastases (6.8% vs. 6.8%, p = 1), or survival (p = 0.081). The mean follow-up time was 6 years.

CONCLUSION

In our study, the largest so far on the subject, we find no difference in postoperative short- or long-term outcomes between cTME and pTME.

Long-term Outcomes of Primary Endoscopic Resection vs Surgery for T1 Colorectal Cancer: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

There is controversy over the best therapeutic approach for T1 colorectal cancer. We performed a systematic review and meta-analysis of long-term outcomes of endoscopic resection (ER) vs those of primary or additional surgery.

METHODS

We performed a systematic review of the PubMed, Embase, and Cochrane databases through October 2019 for studies that reported outcomes (overall survival, disease-specific survival, recurrence-free survival at 5 years, recurrence, and metastasis) of ER vs surgery in patients with colorectal neoplasms. Hazard ratios (HR) were calculated based on time to events.

RESULTS

In total, 17 published studies with 19,979 patients were included. The median follow-up time among the studies was 36 months. The meta-analysis found no significant differences between primary ER and primary surgery in overall survival (79.6% vs 82.1%, HR, 1.10; 95% CI, 0.84-1.45), recurrence-free survival (96.0% vs 96.7%, HR, 1.28; 95% CI, 0.87-1.88), or disease-specific survival (94.8% vs 96.5%; HR, 1.09; 95% CI, 0.67-1.78). Additional surgery and primary surgery did not produce significant differences in recurrence-free survival (HR, 1.27; 95% CI, 0.85-1.89). A significantly lower proportion of patients who underwent primary ER had procedure-related adverse events (2.3%) than patients who underwent primary surgery (10.9%) (P < .001). Lymphovascular invasion and rectal cancer, but not depth of submucosal invasion, were independently associated with recurrence for all T1 colorectal cancers.

CONCLUSIONS

In a systematic review and meta-analysis, we found that ER should be considered as the first-line treatment for endoscopically resectable T1 colorectal cancers. In cases of noncurative resection, additional surgery can have comparable outcomes to primary surgery.

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

OBJECTIVE

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

DESIGN

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

RESULTS

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

CONCLUSION

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

Malignant colorectal polyps: endoscopic polypectomy and watchful waiting is not inferior to subsequent bowel resection. A nationwide propensity score-based analysis

BACKGROUND AND AIMS

The optimal treatment of patients with malignant colorectal polyps is unsettled. The surgical dilemma following polypectomy is selecting between watchful waiting (WW) and subsequent bowel resection (SBR), but the long-term survival outcomes have not been established yet. This nationwide study compared survival of patients after WW or SBR.

METHODS

Danish nationwide study with 100% follow-up of all patients with malignant colorectal polyps (the Danish Colorectal Cancer Group database) in a 10-year period from 2001 to 2011. All patients' charts and histological reports were individually reviewed. Survival rates were calculated with Cox proportional hazard model after propensity score matching.

RESULTS

A total of 692 patients were included (WW, 424 (61.3%), SBR, 268 (38.7%)) with a mean follow-up of 7.5 years (3-188 months). Following propensity score matching, there was no significant difference in overall or disease-free survival (p = 0.344 and p = 0.184) or rate of local recurrence (WW, 7.2%, SBR, 2%, p = 0.052) or distant metastases (WW, 3.3%, SBR, 4.6%, p = 0.77). In the SBR group, there was no residual tumor or lymph node metastases in the resected specimen in 82.5% of the patients.

CONCLUSION

Subsequent bowel resection may not be superior to endoscopic polypectomy and watchful waiting with regard to overall and disease-free survival in patients with malignant colorectal polyps.

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.

Laparoscopic colectomy using cancer principles is appropriate for colonoscopically unresectable adenomas of the colon

PURPOSE

This study was undertaken to determine the risks of cancer in unresectable polyps and to compare the short-term outcome of laparoscopic colectomy with that of open colectomy for benign polyps.

METHODS

A retrospective review of all patients (n = 165) undergoing colectomy for an adenoma unresectable at colonoscopy was performed on patients collected in a prospective database. One hundred four patients underwent laparoscopic colectomy and 61 underwent open colectomy between 1991 and 2003. Follow-up was 7 to 155 (median, 90) months.

RESULTS

In the laparoscopic group, 85% of the patients underwent a right colectomy and 15% underwent a left colectomy or a sigmoidectomy. Conversion to open colectomy occurred in 4.8% of the cases. Complications occurred in 14% of the patients, including 1 death. The median length of stay was 4 days. At final pathology, cancer was diagnosed in 15 patients: stage I in 8 patients, stage II in 5, and stage III in 2. In the open colectomy group, 69% of the patients underwent right colectomy. The complication rate reached 23% (P = .13), including death in 2 patients. The median length of stay was 6 days (P < .01). Cancer was diagnosed in 6 patients: stage I in 5 patients, and stage II in 1. Proximal (10 cm) and distal (13 cm) margins, lymph nodes harvest (9), incidence of cancer (13%), and high-grade dysplasia (22%) were similar between groups. There were no local recurrences, trocar site implants, or deaths due to cancer.

CONCLUSION

Laparoscopic colectomy for polyps unresectable at colonoscopy is safe. Oncologic resection of the colon should be performed for all colonoscopically unresectable polyps due to the risk of cancer.

Value-of-information analysis to guide future research in the management of the colorectal malignant polyp

PURPOSE

The efficacy of surgery in the postendoscopic management of low-risk malignant polyps is unclear. Although interobserver variability in the histological diagnosis was shown, its importance is unknown. The purpose of this study was to guide future research on the optimal strategy for low-risk polyps with the use of value-of-information analysis.

METHODS

A decision-analysis model was constructed comparing the strategies of referring or not referring (waiting) to surgery patients with low-risk polyps. Probabilistic sensitivity analysis was performed to explore the effect of uncertainty about the input parameters. Value-of-information analysis was used to estimate the expected benefit of future research that would eliminate the decision uncertainty.

RESULTS

The number of postendoscopic surgeries to prevent 1 cancer-related death was 208. The incremental cost-effectiveness ratio of surgery vs waiting strategy was $215,291/life-year gained, surgery being a suboptimal choice in the reference case analysis. Probabilistic sensitivity analysis demonstrated that surgery was the optimal choice in 61% of the simulated scenarios. Most of the decision uncertainty was related with the combination of histological inaccuracy, prevalence of residual disease, and surgical mortality. The expected societal monetary benefit of further research from the perspective of the United States was estimated to be $1 billion.

CONCLUSIONS

The small benefit and the relatively high costs associated with surgery argue against surgical referral for low-risk malignant polyps; however, when a suboptimal histopathological accuracy was simulated, surgery appeared to be the most cost-effective option, prompting the need for further research.

The lymphatic infiltration identified by D2-40 monoclonal antibody predicts lymph node metastasis in submucosal invasive colorectal cancer

BACKGROUND AND STUDY AIMS

Lymphatic infiltration has been recognized as a significant risk factor for lymph node metastasis of submucosal invasive colorectal cancer (SICC), but it is difficult to detect microscopically on hematoxylin and eosin (H&E)-stained slides. We therefore identified lymphatic infiltration of tumor cells with D2-40 monoclonal antibody, which reacts specifically against the endothelium of lymphatic vessels, to make an objective and precise diagnosis.

PATIENTS AND METHODS

The surgical specimens of 122 consecutive patients with nonpedunculated SICC were examined for lymphatic infiltration by immunohistochemical staining with D2-40 monoclonal antibody (LI-D) and for venous infiltration by Elastica van Gieson staining (VI-E).

RESULTS

Lymph node metastasis was found in 20 patients. Multivariate analysis showed that LI-D (p = 0.0415) and VI-E (p = 0.0119) were significant risk factors for lymph node metastasis. Regardless of the presence of risk factors including at least either lymphatic infiltration or venous infiltration, no lymph node metastasis-positive patients were found (0%) among the 25 patients whose colorectal cancer had a submucosal invasive depth of less than 1,500 microm. No lymph node metastasis was found in any of the patients with a depth of submucosal invasion of less than 3,000 microm, who had no risk factors, including LI-D or VI-E.

CONCLUSIONS

Correct evaluation of lymphatic infiltration by immunohistochemical staining with D2-40 monoclonal antibody may play a crucial role in determining whether there are indications for additional treatment in the management of endoscopically resected SICC.

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.

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.

Predictive histopathologic factors for lymph node metastasis in patients with nonpedunculated submucosal invasive colorectal carcinoma

PURPOSE

Risk factors for lymph node metastasis in patients with nonpedunculated submucosal invasive colorectal carcinoma remain to be characterized. This study examines the relationship between lymph node metastasis and clinicopathologic factors in nonpedunculated submucosal invasive colorectal carcinoma.

METHODS

The study cohort comprised 155 patients who had undergone surgical treatment for nonpedunculated submucosal invasive colorectal carcinoma. The clinicopathologic factors investigated included gender, age, tumor location, macroscopic type, tumor size, histologic type and grade, intramucosal growth pattern, lymphatic invasion, venous invasion, degree of focal dedifferentiation at the submucosal invasive front, status of the remaining muscularis mucosa, and the depth and width of submucosal invasion.

RESULTS

Lymph node metastases were found in 19 patients (12.3 percent). Univariate analysis showed that lymphatic invasion, focal dedifferentiation at the submucosal invasive front, status of the remaining muscularis mucosa, and depth of submucosal invasion all had a significant influence on lymph node metastasis. Multivariate analysis showed lymphatic invasion (P = 0.014) and high-grade focal dedifferentiation at the submucosal invasive front (P = 0.049) to be independent factors predicting lymph node metastasis. No lymph node metastasis was found in tumors with a depth of submucosal invasion of <1.3 mm.

CONCLUSIONS

Lymphatic invasion and high-grade focal dedifferentiation at the submucosal invasive front are important predictors of lymph node metastasis in patients with nonpedunculated submucosal invasive colorectal carcinoma. Depth of submucosal invasion can be used as an identifying marker for patients who do not require subsequent surgery after endoscopic resection.

Clinical significance of small colorectal polyps

PURPOSE

Since the concept of "advanced" or "dangerous" adenomas was introduced in 1992, less concern has been directed to diminutive colorectal adenomas. They apparently confer no increased risk of metachronous colorectal cancer and some investigators have suggested that they need neither follow-up nor treatment. This study is intended to discover how often small colorectal adenomas have unfavorable histologic features.

METHODS

Since 1995 the details of all colorectal polyps have been entered into a database, along with data concerning patients, symptoms, treatment, and outcome. Using this database all adenomas were categorized into three groups: Group I, <6 mm diameter, Group II, 6 to 10 mm diameter, and Group III, >10 mm diameter. "High risk" adenomas were defined as those containing >25 percent villous architecture, those with severe dysplasia, and those over 10 mm in size. Thus all Group III adenomas are high-risk by definition. The effects of family history, patient age, and polyp location on the proportions of Group I and Group II adenomas that were histologically high risk were examined.

RESULTS

There were 5,722 polyps of which 4,381 (76.6 percent) were Group I, 666 (11.6 percent) were Group II, and 675 (11.8 percent) were Group III. These included 24 invasive cancers (2 in Group I, 1 in Group II, and 21 in Group III. Of the Group I adenomas, 91/2,064 (4.4 percent) were high risk compared to 65/417 (15.6 percent) in Group II. Of the 564 Group III adenomas, 326 (57.8 percent) had unfavorable histology. There was no effect of age, family history, or site of the polyp on the proportion of polyps that were high risk.

CONCLUSIONS

Four percent of adenomas less than 6 mm diameter and 16 percent of those between 6 and 10 mm have unfavorable histology. Small adenomas can still be clinically significant and should not be ignored. Since the concept of "advanced" or "dangerous" adenomas was introduced in 1992, less concern has been directed to diminutive colorectal adenomas. They apparently confer no increased risk of metachronous colorectal cancer and some investigators have suggested that they need neither follow-up nor treatment. This study is intended to discover how often small colorectal adenomas have unfavorable histologic features.

Trends in CT colonography

CT colonography (virtual colonoscopy) is a safe, noninvasive method of examining the large bowel. Since its first description in 1994, the technique has undergone rapid development, stimulating considerable interest in its potential as both a diagnostic and screening tool. Diagnostic performance statistics have been encouraging, with predictive values rivaling those of barium enema and approaching those of endoscopic colonoscopy. Improvements are underway in methods of bowel preparation, scanning procedure, and image display. Increasing experience with the technique is reflected in better understanding and characterization of both two-dimensional and three-dimensional findings, resulting in improved study performance and interpretation. This review attempts to chart the development of CT colonography, with an emphasis on published results and current research interests. We propose potential directions for future study and means toward effective implementation of CT colonography in clinical practice.

Electrocautery snare resection stimulates cellular proliferation of residual colorectal tumor: an increasing gene expression related to tumor growth

PURPOSE

Recently, endoscopic mucosal resection has been performed commonly for colorectal tumors. However, incomplete endoscopic mucosal resection produces a residual tumor that grows rapidly. The aim of this study was to clarify the characteristics of the residual tumor using the nude mouse model.

METHODS

Human colon cancer cells (colo201 or colo320DM) were implanted subcutaneous into nude mice. We then removed more than one-half of the tumor with an electrocautery snare or a surgical knife, and compared the tumor growth rate with that of control tumors. Before and after resection, we examined the Ki-67 labeling index of the tumors with an immunohistochemical assay and mRNA expression for epidermal growth factor receptor, vascular endothelial growth factor, and transforming growth factor alpha.

RESULTS

Residual tumors showed a higher growth rate in tumor volume than control tumors using both methods (electrocautery snare and surgical knife). Colo201 groups showed a higher total volume change per day than colo320DM groups after resection. Furthermore, these tumors also showed a higher Ki-7 labeling index, and a stronger epidermal growth factor receptor and transforming growth factor alpha mRNA expression than primary and control tumors in the colo201 implanted groups. There was no significant difference in vascular endothelial growth factor mRNA expression between groups implanted with colo201 or colo320DM.

CONCLUSION

Our results suggest that residual tumors caused by incomplete endoscopic mucosal resection may have a higher growth potential than the tumors before resection.

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.

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.

Transanal endoscopic microsurgery in large, sessile adenomas of the rectum. A 10-year experience

The clinical and long-term results of 286 cases encountered from 1983 to 1993 in our Department of Surgery regarding the local excision of large, sessile rectal adenomas (> 2 cm2) by the endoscopic surgical method and the influence of this selected series of adenomas on age, sex, size, grade of dysplasia, and architecture are subjects of this study. Histologically proven rectal carcinomas as well as non-neoplastic polyps were excluded from this trial. Early postoperative complications amounted to 3.4%. The 1-year and 5-year recurrence rates +/- SE of adenomas were 1.2 +/- 0.7% and 7.0 +/- 1.9%, respectively. Remarkably, there was no significant relationship between the histological type of the adenoma and the grade of dysplasia nor between the size and grade of dysplasia. However, there was a significant relationship between the size and histological type of the adenoma (P < 0.01). With the endoscopic minimal-invasive system, we are able to achieve a superior rate of recurrence compared to any other local treatment as well as a more favorable operative result compared to extensive surgical procedures.

Colorectal adenomas and diet: a case-control study of subjects participating in the Nottingham faecal occult blood screening programme

Diets high in animal fat and protein and low in fibre and calcium are thought to be factors in the etiology of colorectal cancer. Intakes of these nutrients were determined in three groups participating in a randomised trial of faecal occult blood (FOB) screening. A diet history was obtained by interview from 147 patients with colorectal adenomas, 153 age and sex matched FOB-negative controls (a) and 176 FOB-positive controls without colorectal neoplasia (b). Unconditional logistic regression was used to estimate relative risks (RR) and 95% confidence limits (increases) adjusted for age, sex and social class. After adjustment for total energy intake, no associations were found with total, saturated or mono-unsaturated fat, or calcium intake. For total fibre intake there were non-linear relationships with both control groups with the crude RR for highest quintiles of total fibre intake compared to the lowest being 0.6, although this pattern was no longer apparent after adjustment for energy intake with group (a). In comparison with group (b) cereal fibre intake showed a more consistent inverse relationship with adenoma prevalence with the RR for ascending quintiles of intake being 1.0, 0.7 (0.3-1.6), 0.5 (0.3-1.1), 0.7 (0.4-1.4) and 0.3 (0.1-0.6) (trend chi 2 = 8.80, p = 0.003). In comparison with group (a), the adjusted RR for the highest quintile of cereal fibre intake compared with the lowest was 0.6, but no clear trend was apparent. There was an unexpected positive relationship between adenomas and polyunsaturated fat intake with the RR for having an adenoma being 1.0, 2.8 (1.3-6.1), 1.6 (0.7-3.4), 3.5 (1.6-7.5) and 2.3 (1.1-5.0) for ascending quintiles of polyunsaturated fat intakes (trend chi 2 = 4.8, P = 0.03) in comparison with group (a) only. Our data, while providing no support for the role of dietary animal fat or protein, do support the protective role of dietary cereal fibre in the etiology of colorectal adenomas.