Prevalence of colorectal polyps in Filipinos

From May 1988 to May 1990, a prospective autopsy study was performed in patients who died at the Philippine General Hospital in Manila, Philippines. Patients younger than 10 years of age, patients with a history of large bowel resection, and patients whose deaths were related to trauma were excluded. There were 416 patients; 246 were males, and 170 were females. The mean age was 47 years (range, 11–95 years). Six of the 416 patients (1.4 percent) were found to have polyps. One patient had an inflammatory polyp, one was diagnosed with familial adenomatous polyposis, and one had an associated cecal carcinoma. Five sporadic adenomatous polyps were found in the remaining three patients (prevalence rate, 0.7 percent). All of the adenomatous polyps were located distal to the hepatic flexure and exhibited only mild atypia. The mean size was 6.4 mm (range, 2–20 mm). The incidence of colorectal adenomas in Filipinos is low compared with that in age-adjusted Western populations. This finding coincides with a low incidence of colorectal carcinoma. The documentation of a low risk for adenomatous polyps and colorectal cancer indicates that it would be difficult for massive screening programs to demonstrate a significant positive impact on the early detection of colorectal neoplasias in the Filipino general population.Supported in part by an educational grant from IVONYX.     

Carcinoid tumors of Meckel's diverticula

Two cases of carcinoid tumors in Meckel's diverticula are reported. Additionally, data of 104 published cases of carcinoids in this rare location are analyzed. The average age of the patients is 56.6 years and corresponds to the age of patients with ileal carcinoids. Carcinoids in Meckel's diverticula also resemble ileal carcinoids in their biological behavior more than they do appendiceal carcinoids. Tumors larger than 5 mm have a marked risk to metastasize. By the time symptoms are present, 77 percent of these tumors have already metastasized. Men are affected by this tumor 2.5 times more often than women. Carcinoids in Meckel's diverticula metastasize twice as often in female as in male patients. More than 70 percent of carcinoids in Meckel's diverticula are found at the tips of the diverticula. An aggressive surgical management of tumors larger than 5 mm is recommended.     

Immunohistochemical analysis of statin in colorectal adenocarcinoma,polyps, and normal mucosa

PURPOSE: The search for an understanding of the kinetics of the malignant cell is an ongoing focus of research. The aim of the present study was to determine whether there were any differences in the expression of statin, a nonproliferation-specific nuclear protein, among different colorectal tissues and whether there is any relationship between statin presence and neoplastic aggressivity. METHODS: The study population consisted of specimens from 19 patients who underwent resection for carcinoma, one for villous adenoma, and seven for colonoscopic polypectomies. Tissue samples were taken from the center of the specimen and from mucosa 10 cm from the lesion. RESULTS: Statin immunoreactivity was evaluated by counting stained nuclei in ten randomly chosen fields, and percent of positive cells was calculated. Average percentage of statin-positive cells was 34.33±6.81 in the normal crypt, 44.42±7.28 for polyps, and 7.74±5.67 for carcinomas (significantly lower than normal mucosa and polyps;P <0.001). CONCLUSION: Statin expression is dramatically diminished in invasive carcinoma tissue, but it did not help determine aggressivity with respect to Dukes stage.Supported by an operating grant (RO1 AGO7444) from the National Institute on Aging of the National Institutes of Health (to E.W.) and grants from the Foundation of the Sir Mortimer B. Davis-Jewish General Hospital (to P.H.G.) and the American Physician Fellowship (to S.K.).Poster presentation at the meeting of The American Society of Colon and Rectal Surgeons, Montreal, Quebec, Canada, May 7 to 12, 1995.     

Survival of colorectal carcinoma in the elderly

PURPOSE: Colorectal carcinoma in elderly patients has become a more common problem in the last decade. There are some physicians who tend to offer a less definitive treatment for these patients because of their chronologic age. The purpose of this study was to evaluate the long-term survival of elderly patients (>70) who underwent surgery for colorectal carcinoma in comparison with a younger group of patients with the same disease. METHODS: Long-term survival of patients with colorectal carcinoma who underwent surgery was prospectively evaluated. Long-term survival was compared between an elderly group of patients (age, >70) and a younger group of patients. RESULTS: There was no significant difference in the five-year survival between the two age groups. Patients' survival was influenced by stage of the disease and type of operation (emergency vs. elective). CONCLUSIONS: Treatment decisions in elderly patients with colorectal carcinoma should not be influenced by the chronologic age of the patient.     

Polyamines,diamine oxidase,and ornithine decarboxylase activity in colorectal cancer and in normal surrounding mucosa

We investigated the polyamine levels [putrescine (Put), spermidine (Spd), and spermine (Spm)] and their metabolism by simultaneously considering the ornithine decarboxylase (ODC) and diamine oxidase (DAO) activities in human colorectal cancer and in normal surrounding tissue. Single and total polyamine levels were significantly higher in the neoplastic tissue than in the surrounding mucosa from the same patients. Furthermore, the ODC activity was significantly higher and the DAO activity significantly lower in the neoplastic tissue than in the surrounding mucosa. Polyamine levels and enzymatic activities did not correlate with the clinical and histologic characteristics of patients. In normal tissue samples, no correlation was found between single and total polyamine levels and enzymatic activities (both DAO and ODC). On the contrary, in colorectal neoplastic samples, significant and positive correlations were found between the levels of total polyamines, Spd, and Spm and the ODC activity. In the same specimens, DAO activity was related to Spd levels and the Spd/Spm ratio, but, in those cases, the correlation was negative. Thus, our findings suggest that, during the neoplastic growth of the colorectal mucosa, the balance between polyamine degradation and biosynthesis is disengaged from the control exerted by the two enzymes.     

Colon carcinoid tumors

PURPOSE: The aim of our investigation was to evaluate the clinical presentation of patients with carcinoid tumors of the colon and to estimate the survival and potential prognostic factors of this tumor type. METHODS: A population-based study was performed using data from the Alberta Cancer Registry between 1964 and 1988 (inclusive). The clinical records and the pathologic material of eligible patients were reviewed. Survival was estimated both as crude survival and with the Kaplan-Meier method. RESULTS: During the 25-year study period (1964–1988), 36 true carcinoid tumors of the colon were diagnosed in Alberta. Carcinoids of the ileocecal region and of the rectum were excluded from the study. The average age at time of diagnosis was 68.4 years; there were 20 males and 16 females. Symptoms (abdominal pain, diarrhea, weakness, anorexia) occurred late in the course of the disease: 64 percent of the lesions were in Dukes D stage and 22 percent were Dukes C at diagnosis. Only one patient presented with a malignant carcinoid syndrome. Lesions occurred most frequently in the cecum (39 percent), followed by transverse and sigmoid colon. Most of the patients were managed surgically. The perioperative mortality rate was with 22 percent, which is quite high. The average size of the lesions was 5.8 (range, 2–10) cm, and most tumors (31/36) had invaded the pericolic fat. The most common immunohistochemical pattern was argentaffin/argyrophil negative and neuron-specific enolase positive. Two-year and five-year actuarial (Kaplan-Meier) survival was 34 percent and 26 percent, respectively. Survival for carcinoids of the colon was significantly lower compared with carcinoids of the rectum or appendix, and with colon adenocarcinomas. Size of the tumor and tumor invasion into the muscularis propria—the two major histopathologic prognostic factors for carcinoids of the gastrointestinal tract—were not found to influence survival significantly. Rather, tumor stage, histologic pattern, tumor differentiation, nuclear grade, and mitotic rate were found to significantly influence the survival rate. CONCLUSION: Carcinoid tumors of the colon are extremely rare tumors, diagnosed late in the course of the disease, and they carry a bad prognosis. Prognostic factors are tumor stage, histologic pattern, differentiation, nuclear grade, and mitotic rate of the tumor.Presented in part at the meetings of the International Society of University Colon and Rectal Surgeons, Crete, Greece, October 25 to 29, 1992, and the Royal College of Physicians and Surgeons, Quebec, Quebec, Canada, September 19 to 23, 1991.     

Flow cytometric examination of p53 protein in primary tumors and metastases to the liver and lymph nodes of colorectal cancer

PURPOSE AND METHODS: To confirm prognostic significance of overexpression of p53 in cases of colorectal cancer, expression of p53 protein was examined by flow cytometry in 113 cases of colorectal cancer and its metastasis to the liver and lymph nodes. RESULTS: Overexpression of p53 was found in 44 (39 percent) of the 113 primary tumors. There were no significant correlations among the level of p53 protein in the primary tumor, clinicopathologic features, and prognosis of colorectal cancer. Overexpression of p53 protein was detected in 72 percent (18/25) of liver metastases and in 40 percent (10/25) of lymph node métastases. Frequency of samples that were positive for p53 was significantly higher for liver metastases than for primary tumors and lymph node metastases (P<0.01). By comparing overexpression of p53 in primary tumors with that in corresponding secondary tumors, a decrease of more than 5 percent in the fluorescence index, compared with primary tumor, was not found in liver metastasis but was found in 20 percent of lymph node metastases. Incidence of cases with lower level expression of p53, compared with primary tumor, was significantly higher in lymph node metastases (32 percent) than in liver metastases (8 percent;P<0.05). CONCLUSIONS: From these results, it seems possible that overexpression of p53 may not be a good prognostic indicator of colorectal cancer and may be influenced by environments of the tumor.Presented at the meeting of the Japanese Gastroenterological Surgery, Fukui City, Japan, July 20 and 21, 1995.     

Observer variability in the assessment of type and dysplasia of colorectal adenomas,analyzed using kappa statistics

PURPOSE: The aim of this study was to establish the intraobserver and interobserver variability in the assessment of histologic type (tubular, villous, and tubulovillous) and grade of cytologic dysplasia (mild, moderate, and severe) in colorectal adenomas. METHODS: One hundred eighty-seven slides of adenomas were assessed twice by three experienced pathologists, with an interval of two months. Results were analyzed using kappa statistics. RESULTS: For agreement between first and second assessment (both type and grade of dysplasia), kappa values for the three specialists were 0.5345, 0.9022, and 0.4100, respectively. Agreement was better for type than for dysplasia. The strength of agreement was moderate for Observers A and C and almost perfect for Observer B. Agreement between all three observers was seen in 35.2 percent for both type and dysplasia in 61 percent for type and in 47.8 percent for dysplasia. The kappa values for Observer A vs. B and Observer C vs. B were 0.3480 and 0.3770, respectively (both type and dysplasia). Values for type were better than for dysplasia, but agreement was only fair to moderate. CONCLUSION: The interobserver agreement was moderate to almost perfect, but the intraobserver agreement was only fair to moderate. A simpler classification system or a centralization of assessments would probably increase kappa values.Supported by grants from the Danish Cancer Society, Danish Medical Research Council (Grant 12-6355), Thomas Bartholin's Fund, Gundelach Meller's Fund, and Emmy Lange, born Kramp's Fund.     

Heredity and colorectal cancer

The frequency of colorectal neoplasia was assessed through colonoscopy in 114 patients with a family history of colorectal cancer. In over 90 percent of patients, a first-degree relative was affected. Twenty-one percent of patients who were studied endoscopically were positive for neoplastic disease, including two invasive cancers. Twenty-eight percent of patients had adenomas beyond the splenic flexure. Multiple primary relatives further increased risk with 36 percent positive for neoplasia. Neoplasia was common in young patients, with 25 percent under the age of 40 years positive for adenomas. These findings are identical to recent pedigree studies and further support a genetic basis for common colorectal cancers. First-degree relatives of patients with colorectal cancer should be considered at high-risk for colorectal neoplasia. Screening and surveillance with colonoscopy is recommended.     

Tumor angiogenesis in primary and metastatic colorectal cancers

PURPOSE: Angiogenesis is needed to sustain growth of both primary and metastatic lesions; however, comparisons in microvessel density between a primary tumor and its metastases have not been widely performed. We studied microvessel density in primary colorectal cancers and their liver metastases. METHODS: Sections from 32 primary lesions and 53 hepatic metastases were immunostained with a monoclonal antibody for von Willebrand's factor, an endothelial cell marker. Blood vessels were quantified under X 100 magnification using both conventional light microscopy and computer-assisted image analysis. Primary and metastatic angiogenesis scores (AS),i.e.,vessel counts, were analyzed with respect to tumor size, hepatic multicentricity, synchronicity, resectability, and patient survival. Using computer-assisted calculations, the same analyses were performed using blood vessel to tumor surface area ratios, vessel wall thickness, and intensity of immunostaining. RESULTS: Angiogenesis scores were significantly lower in metastatic lesions compared with their primary tumors (P< 0.0001). Primary AS did not correlate with metastatic tumor size, resectability, multicentricity, or patient survival. Metastatic AS strongly predicted patient survival (P <0.0009) but with a negative coefficient,i.e.,higher scores were associated with improved survival. Metastatic AS were higher in resectable than in nonresectable metastases and in solitary than in multiple metastases; however, these trends were not statistically significant. Metachronous liver lesions had significantly higher angiogenesis scores than synchronous metastases (P <0.04). Similar trends were seen using computer-assisted image analysis. CONCLUSIONS: These results indicate that in presence of an established metastasis, there is a weak angiogenic relationship between a primary tumor and its metastasis. Heterogeneity in metastatic lesions cannot be explained solely by studying angiogenesis in primary tumors. Microvessel density in a primary tumor may not be useful as an independent prognostic indicator in late stages of disease. In such cases, assessment of microvessel density in a metastatic tumor whenever possible may be an indicator of prognosis.Funded by the Bowman Research Fund.Read at the meeting of The American Society of Colon and Rectal Surgeons, Montreal, Quebec, Canada, May 7 to 12, 1995.     

Lectin staining of neoplastic and normal background colorectal mucosa in nonpolyposis and polyposis patients

A lectin histochemistry approach was adopted for comparative assessment of a colon cancer risk. Binding of Ulex europaeus agglutinin-I (UEA-I), peanut agglutinin (PNA), Griffonia simplicifolia agglutinin-II (GSA-II), and Dolichos biflorus agglutinin (DBA) was investigated in tumor and background tissue from a total of 34 adenoma and 44 cancer patients and compared with reaction patterns in control and familial adenomatous pplyposis (FAP) patients. Adenoma patients with UEA-I positive rectal mucosa were found to have a 33.3 percent familial history of large bowel cancer, which was significantly higher (P <0.05) than the respective 4.0 percent figure for patients with negative rectal mucosa. In the cancer patients, an even stronger correlation was noted, with a 63.2 percent UEA-I positive family history association being recorded, as opposed to 4.0 percent in the negative rectal mucosa patients (P <0.01). Thus, the results suggest that, apparently, normal rectal background mucosa of individuals genetically at high risk for colon and rectal cancer demonstrates a specific lectin binding ability similar to that of FAP patients and that the simple method using UEA-I staining of rectal biopsy specimens can be of practical use in identification of high-risk colorectal cancer.     

Adjuvant chemotherapy in colorectal carcinoma

Despite the National Institutes of Health consensus regarding use of adjuvant chemotherapy in colorectal carcinoma, many general surgeons question the efficacy of this approach when considering costs involved for both the individual patient and society at large. PURPOSE: This study was designed to determine the real impact of adjuvant chemotherapy on five-year survival rates of patients. METHOD: A qualitative and quantitative meta-analysis of results from 39 randomized clinical trials published from 1959 to 1993 is described. RESULTS: Design quality of clinical trials had a mean score of 48.6 percent (±6.2 standard deviation). A small benefit of therapy in terms of overall survival was noted, with a mortality odds ratio (OR) of 0.91 (confidence interval (CI) 95 percent, 0.83–0.99). For the group of colon carcinomas, the OR was 0.81 (CI 95 percent, 0.69–0.94) with an OR of 0.64 (CI 95 percent, 0.48–0.85) for the group of rectal carcinomas. The effect size was 0.09 for the colon group and 0.20 for the rectal group. For those patients who receive chemotherapy, this effect size implies that we can expect an increase of 5 percent in the survival rate in the group with colon carcinoma and a 9 percent increase in the survival rate in the group with rectal carcinoma. CONCLUSION: Given the high incidence of colorectal carcinoma, the small benefit observed for those patients receiving chemotherapy is far from negligible. However, indications for adjuvant chemotherapy warrant further discussion.Read at the meeting of The American Society of Colon and Rectal Surgeons, Montreal, Quebec, Canada, May 7 to 12, 1995.     

DNA ploidy pattern in rectal carcinoid tumors

The nuclear DNA pattern of 22 rectal carcinoids was determined by cytophotometry of paraffin embedded tissues. The results were compared with clinical as well as histopathologic features of the tumor. Three of the carcinoids with synchronous or metachronous metastasis had aneuploid DNA pattern, whereas 19 tumors with no metastasis showed diploid DNA pattern. No other single clinical or pathologic feature of the tumor could predict more accurately the malignant potential and the subsequent course of the rectal carcinoid. It is concluded that DNA aneuploidy in rectal carcinoid tumors is not so rare as indicated by earlier studies and that it is a factor of significant prognostic value.Dr. George Tsioulias is a recipient of the Monbusho Scholarship (Japanese Ministry of Education).     

Use of laparoscopic techniques in colorectal surgery

PURPOSE: This study evaluated the feasibility and safety of laparoscopic bowel surgery performed by colorectal surgeons not previously experienced in laparoscopic biliary or appendiceal surgery. METHODS: Thirty-two patients underwent ileocolic resection/anastomosis (n=12), loop ileostomy (n=7), colostomy (n=4), ileostomy takedown/ileorectal anastomosis (n=3), subtotal colectomy/ileorectal anastomosis (n=2), sigmoid resection (n=2), or other procedures (n=2). No curative cancer surgery was undertaken. RESULTS: Time to first bowel movement was one to eight (median, four) days. Length of stay ranged from 4 to 11 (median, 6) days. There were no major complications seen in follow-up from 6 to 15 (median, 7) months after surgery. CONCLUSIONS: Large intestinal and distal ileal surgery using laparoscopic techniques, performed by surgeons with training only in laparoscopic intestinal surgery, is feasible and safe. Faster recovery and need for less postoperative analgesia in laparoscopic surgery compared with conventional surgery cannot be surmised from this study. A randomized study design is needed to evaluate many of the differences between conventional and laparoscopic intestinal surgery.     

Quality of life in colorectal cancer

PURPOSE: The bowel and sexual function of colorectal cancer patients undergoing either sphincter-saving or sphincter-sacrificing surgical procedures may be impaired. A legitimate question is how these different surgical techniques affect the patients' quality of life. METHODS: Seventeen studies were identified that compared at least one of four aspects of patient functioning (i.e.,physical, psychologic, social, and sexual) between stoma patients and non-stoma patients. RESULTS: Although the literature does not yield entirely consistent findings, some long-term effects of surgery can be identified: 1) both patient groups are troubled by frequent or irregular bowel movements and diarrhea; 2) stoma patients report higher levels of psychologic distress than do nonstoma patients; 3) although both stoma patients and nonstoma patients report restrictions in their level of social functioning, such problems are more prevalent among patients with a colostomy; 4) sexual functioning of male and female stoma patients is consistently more impaired than that of male and female patients with intact sphincters. Results of the current review were compared with those of other, related areas. CONCLUSIONS: Although nonstoma patients generally fare better than do stoma patients, they also suffer from physical impairments induced by sphincter-saving procedures (e.g.,impaired bowel and sexual function). These impairments may become more prevalent as ultralow anastomosis is more frequently applied, resulting in bowel and sexual dysfunction and related psychologic distress. Well-designed studies are needed that examine whether quality-of-life benefits are to be gained by use of ultralow anastomosis compared with colostomy.Supported in part by a grant from the Dutch Cancer Society, Amsterdam, The Netherlands (Project NKI 90-A).     

Gastrointestinal malignancies in Crohn's disease

The relationship between gastrointestinal neoplasms and Crohn's disease is poorly defined. The purpose of this study was to characterize the features of gastrointestinal malignancies that developed in Crohn's patients. In this retrospective review the authors identified six patients with Crohn's disease who developed such lesions over a 20-year period: four patients had colorectal cancers and two had ileal malignant neoplasms. Patients averaged 52.7 years of age (range, 21 to 61 years). Three patients were men and three women. Five of the six patients had endured Crohn's disease for more than 20 years. Only two lesions were diagnosed before surgery. The colorectal lesions were predominantly right-sided and all occurred in bowel segments with active Crohn's disease. The lesions demonstrated aggressive histologic features: three of six tumors were poorly differentiated, one of the five adenocarcinomas was mucinous, and three of the colorectal cancers were Dukes' B or C lesions. Four of six patients survived five or more years. There was a single malignant carcinoid, which represents the seventh case report of a carcinoid tumor occurring in a patient with Crohn's disease. This study indicates that patients with Crohn's disease develop a wide variety of small bowel and colorectal cancers. Furthermore, it suggests that Crohn's patients with colonic disease should periodically undergo surveillance colonoscopy.     

Clinicopathologic impact of colloid in colorectal carcinoma

The overall incidence of colloid (mucinous) carcinoma in patients with colorectal cancer is 17 percent, and its influence on patterns of failure and survival in patients with colorectal cancer varies throughout the literature. The presence of colloid carcinoma may have a real but small impact on the patterns of failure or survival in colorectal cancer. The data are conflicting and, furthermore, by proportional hazards analysis, colloid carcinoma is not an independent prognostic factor for survival. Therefore, despite it being common clinical practice, a change in treatment recommendations based solely on the presence or absence of colloid cancer is not recommended. Treatment recommendations should be based primarily on the tumor stage and site. However, given the trend toward increased failure and decreased survival compared with adenocarcinoma, colloid carcinoma should be reported separate from other histological patterns to better understand its natural history.Recipient of American Cancer Society Clinical Oncology Career Development Award.     

Prognostic value of ploidy,cell proliferation kinetics,and conventional clinicopathologic criteria in patients with colorectal carcinoma

PURPOSE: The aim of this study was to obtain additional biologic determinants that may be of use in segregating into subgroups with different prognosis patients with similarly staged colorectal cancers. METHODS: Between 1989 and 1991, a prospective study of prognostic factors has been performed in a group of 98 consecutive, unselected patients who underwent curative resections for primary untreated large bowel carcinoma. The fate of all patients is known at three years after operation. Clinical and pathologic data were recorded at the time of presentation and operation, and patients have been the subjects of regular follow-up. Tumor DNA content was determined by flow cytometry, and cell proliferative activity was determined by autoradiography with tritiated thymidine labeling index (LI). RESULTS: Univariate analysis revealed that the most important predictors of survival (P<0.001) were the presence of positive lymph nodes, the presence of preoperative complications, Dukes stage, and LI. The multivariate analysis showed that Dukes stage (P<0.002) and LI(P<0.0001) were the only factors significantly related to survival. Disease-free survival was influenced significantly by Dukes stage (P<0.001), LI, according to the classification in the two groups of high and low proliferative activity, respectively, (P<0.0001), LI, calculated as a continuous variable (P<0.0002), and the presence of lymph node metastases (P<0.003). Outcome (favorable/unfavorable) was influenced significantly by Dukes stage (P<0.0001) and LI (P<0.0001). Concordance for each patient between Dukes stage and outcome was 73.1 percent and between LI, calculated as a continuous variable, and outcome was 74.1 percent. If, on the other hand, Dukes stage and LI are used together, concordance with outcome reaches 89.2 percent. CONCLUSION: We can conclude that, from a practical point of view, LI is an essential factor that must be combined with pathologic variables for a better prediction of patient outcome.     

Pathogenetic implications of DNA nondiploidy in colorectal cancers

PURPOSE: Several studies propose that proximal and distal colorectal cancers have a different pathogenesis. We tested the hypothesis using flow cytometric DNA analysis. METHODS: DNA analysis was performed in 719 patients with colorectal cancer. In addition, histopathologic data were re-evaluated in a blinded fashion by a single pathologist. RESULTS: Distal tumors were more often nondiploid than were proximal tumors (61 vs.49 percent;P =0.015). Compared with the proximal tumor, distal tumors were smaller ( P =0.0001) and had less desmoplastic reaction (39 vs.53 percent;P =0.0001). Tumor location had no significant associations with the remaining parameters, including mucin production, perineural invasion, blood/lymphatic vessel invasion, lymphocytic infiltration, histologic grade, tumor stage, gross appearance, age, and gender. CONCLUSIONS: The unequal distribution of ploidy suggests distinct pathogenetic mechanisms at proximal and distal sites.Poster presentation at the meeting of The American Society of Colon and Rectal Surgeons, Seattle, Washington, June 9 to 14, 1996.     

Villous component as a marker for synchronous and metachronous colorectal adenomas

To determine whether patients with colorectal adenomas containing a villous component (+vc group) have a higher incidence of synchronous or metachronous colorectal adenomas, 527 consecutive cases of completely removed colorectal adenoma were used. Synchronous adenomas were detected in 22.6 percent and 19.0 percent of the patients in the +vc and –vc groups, respectively. In the analysis of metachronous adenomas, 164 patients who had been followed for 1 to 11 years (mean, 3.31 years) were included. The cumulative adenoma-free rate according to Kaplan-Meier tended to be lower in the +vc group, the difference being statistically significant 1.0 to 1.2 years after treatment of the initial adenoma and the two curves being different based on the generalized Wilcoxon test. The numbers of newly detected adenomas annually were 1.76 and 0.86, and their annual incidences were 1.09 and 0.59 times, in the +vc and –vc groups, respectively. These results suggest the importance of the villous component as a predictor of metachronous colorectal adenomas.