Seroprevalence of Helicobacter pylori in patients with colorectal polyps and colorectal carcinoma

OBJECTIVES

The role of Helicobacter pylori in the pathogenesis of colorectal polyps and colorectal carcinoma is unknown. H. pylori infection causes fasting and meal stimulated hypergastrinemia. Gastrin increases colorectal mucosal proliferation and promotes tumor growth. We performed a prospective study to determine the seroprevalence of H. pylori in patients with colorectal polyps and colorectal carcinoma and in controls.

METHODS

Blood samples were collected from 189 patients with colorectal carcinoma, 57 patients with colorectal polyps, and 179 controls. H. pylori serology was determined by an ELISA assay.

RESULTS

Logistic regression showed no difference in seroprevalence of H. pylori between patients with colorectal cancer and controls (odds ratio, 1.1; 95% confidence interval, 0.7 to 1.8) or between patients with colorectal polyps and controls (odds ratio 1.3; 95% confidence interval, 0.7 to 2.5). Age and sex were not found to be associated with H. pylori infection. Patients in social classes IV and V were 2.3 times more likely to have H. pylori infection than those in social classes I, II, and III (95% confidence interval, 1.3 to 4.2).

CONCLUSIONS

This study shows that there is no increase in the seroprevalence of H. pylori in patients with colorectal polyps or colorectal carcinoma compared with controls. These results do not support the hypothesis that there is a relationship between H. pylori infection and the development of colorectal neoplasia.

Colonic neoplasia in patients with nonspecific GI symptoms

BACKGROUND

The purpose of this study was to determine the prevalence rate of colonic polyps or masses 1 cm or greater in diameter in patients with nonspecific abdominal symptoms, from diverse practice settings, using a national endoscopic database.

METHODS

Consecutive patients undergoing colonoscopy were included based on procedure indication. Endoscopic data were generated with a computer database at each practice site, transmitted to a central data bank and merged with data from multiple sites for analysis. Group 1 patients had nonspecific abdominal symptoms, which were defined as pain, constipation and diarrhea. Group 2 patients had a positive fecal occult blood test. Group 3 patients were asymptomatic, undergoing screening colonoscopy. Serious colon pathology was defined as a polyp or mass greater than 9 mm in size.

RESULTS

Data were collected from 31 practice sites in 21 states during a period of 18 months. Of the 20,745 colonoscopy examinations, 9.2% were performed to evaluate patients with nonspecific abdominal symptoms, excluding other indications. Among patients with nonspecific symptoms 7.27% had polyp(s) 1 cm or greater in diameter compared with 17.05% of patients with positive fecal occult blood test (odds ratio 2.12: CI [1.73, 2.60]; p < 0.001). Patients with nonspecific symptoms had similar rates of large polyps as asymptomatic patients (7.27% vs. 6.45%, p = 0.32). Multivariate analysis identified several independent variables including increasing age, male gender and practice site at a Veterans Affairs Medical Center.

CONCLUSIONS

In diverse, practice-based settings, patients with nonspecific abdominal symptoms who are referred for colonoscopy do not have a higher risk of serious colonic pathology than asymptomatic patients.

Incidence of neoplastic polyps in the ileal pouch of patients with familial adenomatous polyposis after restorative proctocolectomy

PURPOSE

Although adenomatous polyps and even adenocarcinomas have been found in the terminal ileum of patients with familial adenomatous polyposis, the prevalence of neoplastic changes in the pouches of patients who have undergone restorative proctocolectomy is unknown. The objective of this study was to determine the frequency of pelvic pouch neoplasia in familial adenomatous polyposis patients after restorative proctocolectomy.

METHODS

Patients in a polyposis registry who had undergone restorative proctocolectomy were recruited. Demographic, surgical, pathologic, and endoscopic data were obtained from patient records. Video pouchoscopy was done after two enemas and representative biopsies were taken.

RESULTS

Of 102 eligible patients, 26 (17 males and 9 females) participated. Median age at ileal pouch-anal anastomosis was 31 (range, 12-58) years. Median follow-up period was 66 (11-156) months. Adenomas were found in the pouch of 11 (42 percent) patients, in the terminal ileum above the pouch in 1 patient, and in the anal canal of 4 patients. Among patients with pouch polyps, three patients had one lesion, three patients had two lesions, and five patients had more than ten lesions. The incidence of polyps increased steadily with time from restorative proctocolectomy. There was no relation between the incidence of pouch polyposis and the severity of colonic or duodenal disease.

CONCLUSIONS

Proctocolectomy and ileal pouch-anal anastomosis is associated with a significant risk of pouch neoplasia in familial adenomatous polyposis patients. The severity of pouch adenomas was not related either to the severity of colonic or duodenal disease. The pelvic pouches of all patients with familial adenomatous polyposis who have undergone restorative proctocolectomy should be examined periodically.

A sigmoidoscopy-based case-control study of polyps: macronutrients, fiber and meat consumption

We conducted a large, sigmoidoscopy-based case-control study to examine the relation of intake of macronutrients, meat, and fiber to occurrence of adenomas of the large bowel. Cases were subjects diagnosed for the first time with one or more histologically confirmed adenomas. Controls had no polyps of any type at sigmoidoscopy, had no history of polyps, and were individually matched to cases by gender, age, date of sigmoidoscopy, and Kaiser Center. The response rate was 84% for cases and 82% for controls. Complete dietary data for 488 matched pairs were available. All odds ratios are from matched analyses adjusted for energy. We observed positive associations with risk of adenomas for calories, animal fat, saturated fat, red meat, and the ratio of red meat to poultry and fish. Protective effects were observed for vegetable protein, carbohydrates, and dietary fiber. The fiber effects diminished after adjusting for fruits and vegetables. Results after mutually adjusting for the effects of saturated fat, fiber and the ratio of red meat to chicken and fish suggest that each of these variables has an effect on risk of adenomas that is independent of the other 2 exposures.

Parity and other reproductive factors and risk of adenomatous polyps of the distal colorectum (United States)

Evidence for an effect of reproductive factors on colorectal carcinogenesis is inconsistent and little is known about their role in development of precursor adenomatous polyps. We evaluated the relation between reproductive factors and distal colorectal adenomas (n = 982) during 14 years of follow up of 26,983 participants in the Nurses' Health Study (United States). The women were free of diagnosed cancer or polyps in 1980, underwent endoscopy 1980-94, and had reported on their parity, oral contraceptive (OC) use, and ages at menarche, first term-pregnancy, and menopause. We calculated relative risks (RR) and 95 percent confidence intervals (CI) using multiple logistic regression. Women with higher parity had an increased risk of adenomas of the distal colorectum (P trend = 0.004; 6+ cf 0 parity: RR = 1.3, CI = 0.9-1.8) or distal colon (P trend = 0.002, RR = 1.7, CI = 1.2-2.6). This association was significantly stronger among women with a family history of colorectal cancer (P interaction = 0.03); comparing 6+ term-pregnancies with nulliparity, among those with a family history, the RR for distal colon adenoma was 3.2 (CI = 1.4-7.2), while among those without a family history, the RR was 1.3 (CI = 0.8-2.2). We observed no association for distal colorectal adenoma and age at menarche, age at first term-pregnancy, ever use of OCs, or menopausal status. Further work is needed to clarify the relation of parity with colon adenoma risk.

Colorectal polyps and their relationship to cancer

Autosomal dominant, familial forms of colorectal adenocarcinoma are recognized, but more than 90% of cases are sporadic. Most familial and sporadic cases arise through malignant transformation of benign adenomas in a process known as the adenoma-to-carcinoma sequence. Adenomas are classified histologically as tubular, tubulovillous, or villous. As a neoplasm, adenomas all manifest mild, moderate, or severe dysplasia. The majority (> 90%) of adenomas are small (< 1 cm in diameter) and do not progress. Risk factors for carcinomatous progression include the presence of multiple adenomas, size greater than or equal to 1 cm, and villous histology or severe dysplasia in adenomas of any size. The adenoma-to-carcinoma sequence advances through the accumulation of lesions involving multiple genes. It appears that similar molecular genetic mechanisms are involved in familial and sporadic forms of colorectal neoplasia.

Benign colorectal polyps. Endoscopic surveillance guidelines and effects on colorectal cancer risk

In the past several years, there have been major advances in the understanding of colorectal cancer from both the clinical and basic science level. Although there are various techniques for colorectal cancer screening and surveillance, the most cost-effective approach has yet to be determined. As molecular biology techniques are improved and incorporated into clinical practice, identification of high-risk populations seems possible. With future advances in endoscopy and imaging, patient compliance can be improved. With the proper combination of both clinical and basic science techniques, it seems reasonable that a further reduction in the mortality from colorectal cancer can be accomplished.

Epidemiology of gastrointestinal polyps

Associations between polyps and cancer of the gastrointestinal tract have been fully documented for adenomatous polyps and cancer of the large bowel. The geographic, gender, and age distribution of colorectal adenomas parallels that of colorectal cancer incidence, and individuals with a history of adenomas are at increased risk for metachronous adenomas and cancer. Observational studies of risk factors for incident adenomas have found elevated risk associated with dietary variables including: high fat, low fiber, and low vegetable intake; family history; obesity; smoking; and other exposures, some of which also are associated with cancer. Dietary intervention trials with adenoma recurrence as an endpoint, however, have had little success. Screening with polypectomy has proved effective in reducing cancer incidence and may change the epidemiology of colorectal cancer.

Correlation of polypoid lesions in the distal colorectum and proximal colon in asymptomatic screening subjects

OBJECTIVE

Knowledge of a possible correlation between distal polyps found at screening sigmoidoscopy and proximal colonic lesions is important for deciding whether to perform total colonoscopy or not.

PATIENTS

A prospective analysis of 2439 consecutive patients with colorectal polyps. Of these, 304 were asymptomatic subjects who underwent complete colonoscopy for screening and were found to have adenomatous or hyperplastic polyps in the distal colorectum.

RESULTS

Ten (15%) out of 65 patients with distal hyperplastic polyps only and 86 (36%) out of 239 with distal adenomatous polyps were found to have adenomatous polyps in the proximal colon as well (P < 0.001). The frequency of synchronous proximal adenomas in patients with small (< or = 5 mm) or large distal adenomas (> 5 mm) was comparable (37% and 35%, respectively). However, patients with small distal adenomas had significantly smaller proximal adenomas (P = 0.004) containing less villous component (P = 0.017) than those with large distal adenomas. Neither the patient's age nor the presence of multiple distal adenomas increased the prevalence of proximal adenomas.

CONCLUSION

Hyperplastic polyps found on rectosigmoidoscopy do not indicate a need for a complete colorectal examination, as 15% of patients with distal hyperplastic polyps will have proximal adenomatous polyps, a figure that is comparable with that of asymptomatic patients having no distal polyps, either hyperplastic or adenomatous. When only small distal adenomas are found at screening sigmoidoscopy in asymptomatic persons the decision to do a total colonoscopy should be based on individual considerations, as in such cases only small polyps are to be expected in the proximal colon.

The role of colonoscopy in screening persons with family history of colorectal cancer

First-degree relatives of colorectal cancer patients are at increased risk for developing colorectal neoplasms. In order to assess the potentiality of colonoscopy screening in this high-risk population, 213 asymptomatic family members (age range 30-69 years, mean 42.8 years) of those patients with colorectal cancer received colonoscopic examination at Chang-Gung Memorial Hospital from April 1992 to May 1994. Twenty-eight persons with 42 lesions (polyps or cancer) were identified, including 28 adenomas, nine hyperplastic polyps and five adenocarcinomas. The positive detection rate was 9.9% for adenoma and 2.3% for cancer. Colorectal neoplasms afflicted males more frequently than females (16.7 vs 5.7%, P < 0.05) and occurred less frequently in those < 40 years of age (5.5 vs 17.2%, P < 0.05). Forty-two per cent of the detected neoplastic lesions were beyond the reach of 60 cm flexible sigmoidoscopy and 36% of adenomas were < 0.5 cm in size and would be missed if patients were screened by air contrast barium enema. Cost analysis revealed that the charges of both screening colonoscopy and screening flexible sigmoidoscopy/air contrast barium enema were approximate. Colonoscopy also has a high acceptability and safety. It appears appropriate to use colonoscopy, rather than flexible sigmoidoscopy or air contrast barium enema, as an initial screening procedure for persons with a family history of colorectal cancer, especially those > 40 years of age.

[Colorectal polyps in a hospital of Metropolitan Lima]

A prospective study concerning colorectal polyps in symptomatic patients was held at Lima, Perú, an area considered of low incidence for colorectal neoplasia. In 137 patients, 272 polyps were resected by colonoscopic polypectomy or surgery. 55.9% were adenomas, 40.4% non neoplastic polyps and 3.7% polypoid carcinomas. The distribution of polyps, and the incidence of dysplasia and malignant changes in the adenomas, were similar of that reported in areas with high incidence of colorectal cancer. A high proportion of patients with adenomas (21.4% had a synchronous advanced carcinoma, specially if there were multiple adenomas. The figure was lower in patients with only non neoplastic polyps (7.5%). There were no cases of "de novo" carcinoma. This evidence suggest that adenomas play an essential role in colorectal cancer histogenesis, even in areas of low incidence of this neoplasia.

Cronkhite-Canada syndrome: epidemiological study of 110 cases reported in Japan

One hundred and ten cases of Cronkhite-Canada Syndrome (C-C-S) reported in Japan were reviewed in this epidemiologic study. Seventy-five percent of all C-C-S cases reported in the world in literature have been reported from Japan. There has been no special occupation associated with an increased incidence of C-C-S. Mental and physical stress have been confirmed as among the most important risk factors for this syndrome. Hypogeusia is the dominant initial symptom which usually is followed by diarrhea and ectodermal changes including alopecia, nail dystrophy and skin pigmentation. Gastrointestinal polyposis is closely related to the malabsorption which induced these ectodermal changes. However, there is a small number of cases in which alopecia precedes to the diarrhea in the disease course.

Endoscopic mucosal resection for colorectal neoplastic lesions

PURPOSE

Endoscopic mucosal resection, which is a new option for endoscopic polypectomy of colorectal polyps without stalks, was evaluated on its usefulness in polypectomy.

METHODS

Three hundred thirty-seven lesions, which were removed by endoscopic mucosal resection between January 1990 and January 1993, were studied. The endoscopic configuration of neoplastic lesions were classified into four types: flat, sessile, large sessile with distinct lobulations, and semipedunculated.

RESULTS

The 337 lesions included 243 adenomas, 30 mucosal cancers, 13 submucosal cancers, 3 carcinoids, 43 hyperplastic polyps, and 5 inflammatory polyps. Of the 286 neoplastic lesions, excluding 3 carcinoids, 137 were flat, 81 were sessile, 18 were large sessile, and 50 were semipedunculated. The 137 flat lesions consisted of 125 adenomas, 10 mucosal cancers, and 2 submucosal cancers. The rate of complete removal was related to their size and configuration and was 87 percent in flat neoplastic lesions. Lesion diameters of greater than 20 mm and the large sessile-type configurations were factors that were associated with incomplete removal. Two (0.7 percent) cases were complicated by perforations, and one (0.4 percent) case was complicated by bleeding.

CONCLUSION

Endoscopic mucosal resection is an useful option for complete removal of colorectal nonpolypoid adenomas and cancers.

Applications of gastrointestinal endoscopy in infants and children

Gastrointestinal endoscopy has become an integral part of defining and treating gastrointestinal disease in children. Premalignant conditions that have been identified by endoscopy with histologic evaluation include Barrett's esophagus, juvenile polyposis coli, generalized juvenile polyposis, familial polyposis, Gardner's syndrome, and Turcot's syndrome. Advances in endoscopic instrumentation has allowed successful endoscopic retrograde cholangiopancreatography (ERCP) to be performed in infants and children. Therapeutic ERCP has been performed to remove stones, ligate strictures, and place stents. This review focuses on selected advances in gastrointestinal endoscopy and related diseases.

Prospective study of prevalence and endoscopic and histopathologic characteristics of duodenal polyps in patients submitted to upper endoscopy

BACKGROUND

Retrospective studies of duodenal polyps have shown a prevalence of 0.3%-1.5% in patients referred to upper endoscopy, and histopathologic classifications have been inconsistent.

METHODS

A prospective consecutive study was carried out in 584 patients referred to diagnostic upper endoscopy. Symptoms were registered on a questionnaire, endoscopic and histopathologic findings on standard forms. The same pathologist evaluated all biopsy specimens.

RESULTS

Twenty-seven patients had polyps in the first and/or second part of the duodenum, for a prevalence 4.6%. Sixteen polyps were either inflammatory (nine polyps) or ectopic gastric mucosa (seven polyps). Both of these polyp types were practically always non-solitary, sessile, small, and located in the duodenal bulb. Seven polyps were covered by normal mucosa, three being endoscopically typical lipomas. Two polyps were adenomas (0.4% of all the patients and 7% of the polyps), and both were found in the descending part. One hyperplastic polyp of the gastric type and one case of fibrosis were found.

CONCLUSIONS

1) Duodenal polyps are found in 4.6% of patients referred to upper endoscopy and should therefore be looked for. 2) Multiple, small polyps in the duodenal bulb are always benign and need neither biopsy nor treatment (in patients with familial polyposis biopsy is recommended). 3) In the descending duodenum polyps are rare, but a substantial number of them are adenomas. Biopsy is therefore mandatory in this localization.

Cigarette smoking and other behavioral risk factors for recurrence of colorectal adenomatous polyps (New York City, NY, USA)

Adenomatous polyps (hereinafter referred to as adenomas) are known precursors of colorectal cancer. Cigarette smoking has been associated with adenomas but not with colorectal cancer, while alcohol and fat intake have been associated with both adenomas and cancer in some studies. Approximately 30 percent of patients with resected adenomas develop another adenoma within three years. This case-control study explores the association of cigarette smoking with adenoma recurrence. Between April 1986 and March 1988, we administered a questionnaire to colonoscoped patients aged 35 to 84 years in three New York City (NY, USA) practices. We compared 186 recurrent polyp cases (130 males, 56 females) and 330 controls (187 males, 143 females) who had a history of polypectomy but normal follow-up colonoscopy, by cigarette-smoking pack-years adjusted for possible confounders. Risk for a metachronous or recurrent adenoma was significantly greater in the highest quartile of smokers than in never-smokers among both men (odds ratio [OR] = 1.8, 95 percent confidence interval [CI] = 1.0-3.4) and women (OR = 3.6, CI = 1.7-7.6). Adjustment for time since smoking cessation reduced risk only slightly, as did adjustment for dietary fat intake, which itself remained significant. No association was found between alcohol intake and risk of recurrence. Cigarette smokers appear to have an elevated risk of adenoma recurrence that is not eliminated entirely by smoking cessation. Intervention trials that use adenoma recurrence as an endpoint should take smoking into account.

Small rectosigmoid polyps as markers of proximal neoplasms

PURPOSE

The aim of this study was to determine the spatial distribution and histotype of small colorectal polyps and to determine the validity of distal-small colorectal polyps as markers of proximal neoplasms.

METHODS

In 366 patients who underwent total colonoscopy and removal of all polyps, the presence and features of polyps were recorded. The relationship between proximal neoplasms and distal polyps was investigated in 216 of 366 subjects who had no personal or familial history of colorectal neoplasia.

RESULTS

Of 366 patients, 96 were free from polyps. A total of 733 small colorectal neoplasms was removed from the remainder: 79.9 percent neoplastic and 20.1 percent hyperplastic, inflammatory, or hamartomatous. High-grade dysplasia was noted in 2.7 percent of the neoplastic polyps. One adenoma containing invasive carcinoma was observed. In the subset of 216 patients, proximal neoplasms were found in 11.4 percent of those with no distal polyps, 33.8 percent of those with distal-small colorectal polyps only (P < 0.01), and 58.8 percent of those with at least one polyp > 5 mm in diameter (P = 0.001). The proximal neoplasm percentage was the same in patients with at least one adenomatous-small polyp and those with only hyperplastic-small polyps.

CONCLUSIONS

A distal-small colorectal polyp, whether adenomatous or hyperplastic, may be a proximal neoplasm marker. Total colonoscopy is thus justified in all patients with distal polyps, regardless of their size and histotype.

Polyp guideline: diagnosis, treatment, and surveillance for patients with nonfamilial colorectal polyps. The Practice Parameters Committee of the American College of Gastroenterology

OBJECTIVE

To outline the preferable approach to the management of patients with nonfamilial colorectal polyps.

DATA SOURCES

The human subject English language literature for the past 15 years, searched using MEDLINE and the terms "polyp-," "adenoma-," and "polypectomy-colorectal."

STUDY SELECTION

The titles and abstracts of all pertinent articles were reviewed. All randomized controlled trials and large case-control and cohort studies related to colorectal polyps were reviewed in depth.

DATA SYNTHESIS

Evidence was evaluated along a hierarchy with randomized controlled trials receiving the greatest weight. Conclusions and recommendations were reviewed by a large group of experts in gastroenterology, radiology, and pathology and were circulated for comment to primary care medical societies.

CONCLUSIONS

Most patients with polyps should undergo colonoscopy to excise the polyp and search for synchronous neoplasms. Small polyps (< 0.5 cm) require individualization. A hyperplastic polyp found during proctosigmoidoscopy is not an indication for colonoscopy. Large sessile polyps require careful follow-up to ensure complete resection. The need for further treatment of a resected polyp with invasive carcinoma depends on several well-defined clinical and pathologic criteria. Follow-up surveillance after polypectomy should be tailored to the individual risk assessment for each patient. Initial follow-up should be performed at 3 years for most postpolypectomy patients. After one negative result of a 3-year examination, the interval can be increased to 5 years. Patients with one small tubular adenoma do not have an increased risk for cancer, and therefore follow-up surveillance may not be indicated. Adoption of these recommendations should substantially reduce the cost of postpolypectomy surveillance and of screening for colorectal cancer.

Incidence of colorectal cancer following adenomatous polyps of the large intestine

An association between adenomatous polyps of the large bowel and colorectal cancer has been reported, in the absence, however, of population-based estimates of risk. Subjects with histologically confirmed first diagnosis of large-bowel polyps notified to the population-based Cancer Registry of the Swiss Canton of Vaud (about 600,000 inhabitants) during the calendar period 1979-1990 were actively followed up to the end of 1990 for the subsequent occurrence of malignant neoplasms. Among 2,496 individuals with intestinal polyps, followed for a total of 10,310 person-years at risk (6,201 among males and 4,109 among females), 150 malignant neoplasms were registered versus 152 expected. Thus, the standardized incidence ratio (SIR) for all cancers combined was 0.99. A significant excess was observed for colorectal cancer, with 35 cases observed (19 males, 16 females) versus 17.0 expected (SIR = 2.1; 95% CI: 1.5-3.0). There was also an excess, although not significant, for small-bowel cancer (2 cases observed vs. 0.4 expected; SIR = 5.4). In none of the other cancer sites was SIR significantly or appreciably elevated: in subjects with colorectal polyps the SIR was 1.6 for stomach, 1.0 for lung, 0.9 for breast and 1.2 for prostate. The SIR of colorectal cancer was 3.1 in the first year since polyp registration, and declined thereafter to 1.8, in the absence, however, of any further trend with time since diagnosis. The cumulative risk of colorectal cancer in subjects with colorectal polyps was 2% at 5 years and 3% at 10 years. The quantitative estimates of this study are of interest for their population-based nature, and are potentially useful for defining and targeting screening colonoscopy programmes.

Solitary juvenile polyps: not a marker for subsequent malignancy

BACKGROUND

Solitary juvenile polyps are considered benign. In contrast, juvenile polyposis is associated with malignancy and poor long-term outcome. Recent reports suggest that solitary juvenile polyps may also undergo both adenomatous and malignant change. The long-term outcome of patients with solitary juvenile polyps is unknown. Patients are treated conservatively and discharged from follow-up. The present study was designed to examine the incidence of cancer and mortality of these patients, comparing their life expectancy with that of the general population.

METHODS

The outcome of 82 patients with a solitary juvenile polyp between 1958 and 1982 was examined by life table analysis. Patients were traced through the Office of Population Censuses and Surveys for death and cancer registration. Patients were compared with an age- and sex-matched group of the general population.

RESULTS

The relative risk of dying for patients who have previously had a solitary juvenile polyp in comparison with the general population was found to be 0.66 (95% confidence interval, 0.34-1.14). There was only one case of colorectal cancer.

CONCLUSIONS

Patients with a solitary juvenile polyp are not at increased risk of dying of or developing colorectal cancer and do not require further follow-up or investigations.

Low-dose aspirin and incidence of colorectal tumors in a randomized trial

BACKGROUND

Laboratory, clinical, and epidemiologic studies have recently suggested that regular use of aspirin can reduce colorectal cancer incidence or mortality. However, observational epidemiologic analyses have had limited opportunity to control for confounding bias or to specify aspirin doses used.

PURPOSE

Our purpose was to examine the relationship between regular use of low-dose aspirin and incidence of invasive and noninvasive colorectal tumors by utilizing data from the Physicians' Health Study, a randomized, double-blinded, placebo-controlled trial of aspirin and beta carotene. We also attempted to determine whether invasive cancers among aspirin users were associated with rectal bleeding and early stage at diagnosis.

METHODS

The Physicians' Health Study includes 22071 U.S. male physicians. The aspirin arm was terminated in 1988 after a mean follow-up of 5 years. Stage at diagnosis and signs and/or symptoms during presentation were abstracted from medical records. Cox proportional hazards models were used to estimate relative risk (RR), 95% confidence intervals (CIs), and the association between aspirin and bleeding. Differences between aspirin and placebo groups in tumor risk over time were visualized with Kaplan-Meier curves. We assessed the association between aspirin and stage at diagnosis with a Mann-Whitney rank sum statistic for non-parametric comparison of two ordinal distributions.

RESULTS

The RR of developing colorectal cancer for aspirin compared with placebo was 1.15 (95% CI = 0.80-1.65). For in situ cancers and polyps, the RR was 0.86 (95% CI = 0.68-1.10). There was no significant trend for decreasing RR by year of follow-up for invasive cancers (P = .09) or noninvasive tumors (P = .96). Aspirin and placebo groups did not differ in stage or prevalence of rectal bleeding at diagnosis.

CONCLUSIONS

Regular aspirin use, at a dose adequate for preventing myocardial infarction, was not associated with a substantial reduction in the incidence of colorectal cancer during 5 years of randomized treatment and follow-up. A small decrease in polyps in the aspirin group could not be reliably distinguished from a chance association. Our results suggest that among low-dose aspirin users, (a) colorectal cancer mortality is not likely to be reduced by earlier detection and (b) incidence is not likely to be increased due to aspirin-induced gastrointestinal bleeding.

IMPLICATIONS

The potential for a benefit from higher doses of aspirin or longer duration of use should be addressed by more detailed observational epidemiologic studies and prevention trials with longer follow-up of randomized participants.

Trends in subsite distribution of colorectal cancers and polyps from the Vaud Cancer Registry

BACKGROUND

Changes in the subsite distribution of malignant and benign colorectal tumors over the last few years have been reported in several series. They may be related to changes in diagnostic accuracy or to real changes in incidence.

METHODS

Trends in incidence and subsite distribution of colorectal cancers and polyps between 1978 and 1988 have been analyzed using data from the Cancer Registry of the Canton Vaud, Switzerland (530,000 inhabitants in 1981), which has adopted standardized methods for identification and registration not only of malignant, but also of benign colorectal lesions.

RESULTS

Age-standardized incidence rates for malignant tumors of the ascending colon in men increased from 4.6/100,000 in 1978-80 to 6.4/100,000 in 1987-88, and in women from 4.9 to 6.5. Incidence was approximately stable for transverse, descending, and sigmoid colon, whereas a decline was observed for "other and unspecified" colon cancers. Rates for rectal cancer declined by over 10% in both sexes, although the trends were not linear across calendar periods in each sex. Overall colorectal cancer incidence was relatively stable in both sexes in the Vaud population. In terms of proportional distribution, the percentage of cases in the ascending colon increased from 27% in 1978-83 to 33% 1984-88 (P < 0.05). Reliable incidence data for polyps were available for 1979 and from 1982 to 1988. Rates for ascending colon polyps increased from 1.0/100,000 in 1979-83 to 5.0/100,000 in 1987-88 in men, and from 0.4 to 2.7 in women. Incidence rates were higher, although to a lesser extent, for transverse colon and for descending colon polyps in men only. As in the case of malignant tumors, incidence rates declined between the early and the late 1980s for rectal polyps as well as for "other and unspecified" colon polyps. Overall, colorectal polyp incidence was stable around 45/100,000 for men but increased from 19 to 27/100,000 for women. With reference to proportional distributions, significant increases were observed for ascending (from 8.4% to 16.8%) and, to a lower degree, transverse colon (from 8.4% to 11.0%). No appreciable change was observed for any other subsite, except a decline for "other and unspecified" colonic polyps.

CONCLUSIONS

The observation of similar changes in distribution for benign and malignant tumors may suggest the importance of improved diagnostic accuracy (particularly total colonoscopy) for lesions arising in the proximal colon.

Benign tumors of the small intestine: preoperative evaluation with a barium infusion technique

During a seven year period 18 benign small intestinal tumors were histologically documented in patients referred to us for a small bowel study, using a barium infusion technique. These included seven leiomyomas, five adenomatous polyps, two Peutz-Jeghers hamartomas, one myoepithelial hamartoma, one lipoma, one Brunner's gland adenoma and one neurilemmoma. Ten of the patients were women and eight were men, with their ages ranging from 20 to 75 years (mean age 45 years). Presenting symptoms were gastrointestinal bleeding in 12, anemia in 9, abdominal pain in 4, partial intestinal obstruction in 3 and bloody diarrhea in one. The time elapsed from onset of symptoms to radiological diagnosis ranged between one month and seven years (mean time 16 months). Multiple lesions were encountered in four cases and solitary in fourteen. The site of involvement was the duodenum in 3 patients, the jejunum in 8 and the ileum in 7 of them. Main radiological appearances included solitary or multiple intraluminal filling defects, mass effect on neighbouring loops and dilation of intestinal loops proximally to the lesion. The primary tumor, in the form of a mass or other abnormality of the small intestine was identified in all study cases. Correlation with surgical or endoscopic findings showed that radiology depicted all single lesions, whereas multiple lesions were underestimated in one case. The individual morphological changes shown on examination of the resected specimens resembled the appearances on the barium study in all cases. However, enteroclysis missed four out of seven ulcers and a stalk in one of the five pedunculated lesions. A specific tumor-type diagnosis was reached preoperatively in eleven patients, it was suggestive in five and mistaken in two of them. Our experience indicates that enteroclysis is an effective means in evaluating patients with suspected benign small bowel tumors, preoperatively.

Design and analysis of studies to reduce the incidence of colon polyps

Decisions regarding the design and analysis of a phase III study to reduce the incidence of colorectal polyps must take into account two complicating factors: the possibility that polyps are missed during screening exams, and variable lengths of follow-up. In this paper we investigate the effects due to misclassification on the power of statistical tests to detect a change in polyp recurrence rates. We also use Monte Carlo studies to examine the relative efficiency of different methods of adjusting for variable times of follow-up.

Dietary risk factors for the incidence and recurrence of colorectal adenomatous polyps. A case-control study

OBJECTIVE

To investigate the association of dietary factors with the incidence and recurrence of colorectal adenomatous polyps.

DESIGN

Two case-control studies.

SETTING

Three university-based colonoscopy practices in New York City.

PATIENTS

For the incidence study, 286 patients with pathologically confirmed incident adenomatous polyps (162 men and 124 women) were compared with 480 controls (210 men and 270 women) with no current or previous neoplasia. For the recurrence study, 186 patients with recurrent polyps (130 men and 56 women) were compared with 330 controls (187 men and 143 women). These patients had a history of polyps but no current neoplasia.

MEASUREMENTS

Structured interviews using the Block food frequency questionnaire were conducted on all participants and were compared over quartiles of crude nutrient intake of total and saturated fat; fiber; protein; carbohydrates; carotene; vitamins A, C, and E; and various food groups. Data were adjusted for age, Quetelet index, and caloric intake by multiple logistic regression for men and women separately.

RESULTS

For incident polyps, elevated adjusted odds ratios (high to low quartile) for women were found for saturated fat (odds ratio, 2.3; 95% CI, 0.9 to 5.8) and the ratio of red meat to chicken and fish intake (odds ratio, 1.9; CI, 1.0 to 3.6). Protective associations were observed for fish and chicken (odds ratio, 0.6; CI, 0.3 to 1.2) and vitamin A intake (odds ratio, 0.4; CI, 0.2 to 0.9). Among women, recurrent polyps showed an association with total dietary fat (odds ratio, 4.4; CI, 1.0 to 19.5), saturated fat (odds ratio, 3.8; CI, 1.0 to 14.9; P = 0.15 for the trend), and total fiber (odds ratio, 0.2; CI, 0.1 to 0.5; P = 0.01) and a borderline association with carbohydrates (odds ratio, 0.3; CI, 0.1 to 1.3; P = 0.10). No consistent relations were observed for men, although increased caloric intake increased the risk for incidence and recurrence in both men and women.

CONCLUSIONS

These findings are consistent with previously described relations between diet and the incidence of colon cancer and suggest that, at least in women, dietary modification may be warranted in patients diagnosed with polyps.

Multiple lymphomatous polyposis of the gastrointestinal tract

We report two rare cases of multiple lymphomatous polyposis of the gastrointestinal tract. Both patients had multiple polypoidal defects involving large segments of gastrointestinal tract. The histopathology in both cases was diffuse poorly differentiated lymphoma. One case had multiple relapses despite treatment and died after 58 months. The second patient died following induction chemotherapy.

Gastroduodenal polyps in patients with familial adenomatous polyposis

A review of the endoscopy reports and pathology results from esophagogastroduodenoscopy (EGD) of all patients with familial adenomatous polyposis (FAP) undergoing such an examination was performed. Two hundred forty-seven patients were identified, with an overall prevalence of duodenal adenomas of 66 percent and of fundic gland polyps of 61 percent. Analysis of our more recent experience (1986 to 1990) shows the prevalence to be 88 percent and 84 percent, respectively. A normal-appearing papilla was adenomatous in 50 percent of cases. No case of periampullary carcinoma developed in patients under surveillance. Routine EGD is indicated for patients with FAP. Duodenal adenomas and fundic gland polyps will occur in the majority of patients.

Drinking water and the prevalence of colorectal adenomas: an epidemiologic study in Telemark, Norway

This study was based on an endoscopic screening study for detection of polyps in the rectum and sigmoid colon in a randomized, normal population sample of 400 individuals aged 50-59 years. Family disposition for cancer and indicators of lifestyle (including dietary registration) were recorded. The 310 individuals received domestic drinking water from one out of four public water supplies. The participants were categorized according to the water supply connected to their house of residence. Drinking water was analysed monthly during 2 years for chloroform, total organic carbon, colour index, calcium, magnesium and chlorine. The overall prevalence of colorectal polyps was significantly higher in residents receiving chlorinated water with a high organic content when compared with recipients of water with a low organic content. There was no association between polyp prevalence and chloroform concentration in the drinking water. Multivariate analysis revealed that age, male sex, high BMI, smoking, few stools per week, high protein intake and low intake of fibre, iron and cruciferous vegetables were far more important for the presence of polyps than the total organic content in chlorinated drinking water.

Gastroduodenal polyps in familial adenomatous polyposis

A retrospective review of the medical records of 30 patients with familial adenomatous polyposis who underwent oesophagogastroduodenoscopy was performed to evaluate the spectrum of gastroduodenal polyps. Twenty-five patients (83%) had gastroduodenal polyps. Eighteen patients (60%) had gastric polyps and 21 patients (70%) had duodenal polyps. Five patients (17%) had gastric and 20 patients (67%) had duodenal adenomatous polyps. Three patients (10%) died from an upper gastrointestinal tract adenocarcinoma. Three of nine patients with periampullary adenomas had a normal-appearing papilla of Vater. Since gastroduodenal polyps are common in familial adenomatous polyposis, oesophagogastroduodenoscopy should be performed at the time of diagnosis. Biopsy of polyps as well as biopsy of a normal-appearing papilla of Vater should be performed. Due to their malignant potential, if identified, gastroduodenal adenomatous polyps should be destroyed.

Prevalence of colorectal polyps in Filipinos. An autopsy study

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.

Relationship between breast cancer and colorectal adenomatous polyps. A case-control study

Although there is a known reciprocal association between breast and colorectal cancer in women, few studies have investigated whether a similar association exists between breast cancer and colorectal adenomatous polyps, known to be precursor lesions for colon cancer. A case-control study was conducted on patients in three colonoscopy practices in New York to determine possible risk factors for adenomatous polyps. Among women studied, there were 128 patients with incident adenomatous polyps and 284 control subjects who underwent colonoscopy and had no colorectal neoplasia. No significant association between the incidence of an adenomatous polyp in the colon or rectum and a history of breast cancer was found (odds ratio, 0.71; 95% confidence interval, 0.34 to 1.64). If shared risk factors for breast and colorectal cancer are the reasons for the concurrence of these two malignant lesions, these results suggest that these factors act at the level of promoting adenomatous polyps of the colon and rectum into colorectal cancer.

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

The population based registry of digestive tract tumours established for the department of Côte d'Or, France (population 480,000) was used to study the epidemiology and management of malignant large bowel polyps. In a 10 year period (1976-85), 146 cases were recorded in the area. Age standardised incidence rates were 2.7 per 100,000 for men and 1.4 per 100,000 for women. Although incidence rates increased significantly during the study period, large bowel cancer diagnosed as a malignant polyp remained relatively rare (6.2% of all registered large bowel cancers). Two malignant polyps (1.4%) were less than 1 cm in diameter, 34 (23.3%) were more than 30 mm. Sixty patients were treated by endoscopic polypectomy, four by contact radiotherapy, 21 by surgical local excision, 58 by colectomy (10 preceded by polypectomy), and three by colotomy. Operative mortality was 8.2% after intra-abdominal surgery, 4.8% after local surgical excision, and 0% after polypectomy (p less than 0.05). All deaths occurred in patients over 65 years. The five year cumulative recurrence rates were 8.9% after surgical excision and 11.3% after endoscopic polypectomy (NS). The corresponding five year net survival rates were 86.1% and 95.9%. Endoscopic excision alone can be considered a sufficient treatment for adenomas with malignant change unless there is evidence of incomplete resection or a high risk of lymph node metastases.

[Neoplastic polyps of the colon]

We report all patients with neoplastic polyps endoscopically excised during 10 years, performed in different hospitals in Mexico City. All ages, both sexes and socio-economic levels were seen in several endoscopy services both, public and private. We find 190 patients (100 females) with 268 polyps and a mean age of 54.5 (range 18-86). Tubulo-villous adenomas have the less frequency (8%). Villous adenomas were the largest and had a 11% frequency, almost all were confined to recto-sigmoid region its mean age was 6 years. Villous adenomas were the most frequent (69%) distributed in all colonic segments, its mean age was 54.5 years with the widest range (18-80 years); they have highest dysplasia rate (8.1%). Carcinomas arising in polyps were all located in recto-sigmoid region, with female predominance (2.3:1) and oldest mean age of presentation (66.3 years). Neoplastic polyps in Mexico City general population has a low frequency; endoscopic polypectomy is safe and had a low morbi-mortality rate.

Single-visit screening and treatment of first-degree relatives. Colon cancer pilot study

A pilot study has been carried out to evaluate three aspects of screening of first-degree relatives of patients with colon cancer in four Hamilton hospitals; yield of adenomas, feasibility of a one-visit approach to screening and treatment, and compliance. Protocol included flexible sigmoidoscopy after full bowel preparation, followed immediately by either therapeutic colonoscopy or diagnostic barium enema, depending on the flexible sigmoidoscopy findings. We found adenomas in 19 percent of 88 first-degree relatives, with a mean age of 52, compared with an expectation of 8 percent. The protocol was found to be acceptable to the relatives and workable for the various groups of physicians in three of four hospitals, despite many initial logistic difficulties. Numerous problems were encountered with compliance of referring physicians, index patients, relatives, and investigating physicians.

Ethnic differences in the anatomical location of colorectal adenomatous polyps

The ratio of right- to left-sided colonic cancer is increasing, but data on the distribution of its usual precursor lesion, the colorectal adenoma, are contradictory. Therefore, we investigated the prevalence of right- and left-sided colorectal adenomatous polyps from January 1, 1970, to September 30, 1989, using the study design of "epidemiologic necropsy" and the autopsy files of The Johns Hopkins Hospital. Compared with the decade of the 1970's, the 1980's showed a slight decrease in the overall prevalence of right-sided adenomas (6.4 per 1,000, 95% confidence limits 4.7-8.8 vs. 5.1 per 1,000, 95% CL 3.6-6.5), but a marked decrease occurred in left-sided adenomas (11.8 per 1,000, 95% CL 9.3-14.3 vs. 6.7 per 1,000, 95% CL 4.8-8.6). As a result, the ratio of right-sided to left-sided adenomas increased from 0.55 in the 1970's to 0.77 in the 1980's. This increased ratio occurred in both sexes, although prevalences were lower in females, and in whites. Unexpectedly, blacks had a ratio of right-sided to left-sided adenomas greater than unity in both the 1970's and 1980's (1.19 vs. 1.79) due to a relatively high prevalence of right-sided adenomas (5.8 per 1,000, 95% CL 3.6-8.0 in 1970's; 5.8 per 1,000, 95% CL 3.3-8.3 in 1980's), but low prevalences of left-sided adenomas (4.9 per 1,000, 95% CL 3.0-6.8 in 1970's; 3.2 per 1,000, 95% CL 1.2-5.2 in 1980's). The overall adenoma prevalence in blacks was lower than in whites. We conclude that the right-sided predominance of colorectal adenomas in blacks suggests ethnic differences in the pathogenesis of colorectal adenomas. This observation may have important implications for secondary prevention of colorectal cancer.

Prevalence and malignant potential of colorectal polyps in asymptomatic, average-risk men

Screening colonoscopy was performed on 119 asymptomatic elderly men with no other risk factors for colonic neoplasms. Ninety adenomas were detected in 49 (41%) subjects. Mean adenoma size was 6.5 mm, with 83 (92%) less than or equal to 10 mm. Forty-nine (54%) adenomas were located proximal to the splenic flexure, and 17 (19%) were classified as tubulovillous or villous. Moderate- to high-grade dysplasia was found in 29 (32%) adenomas and was associated with larger size (p less than 0.0001) and villous architecture (p = 0.0038). Two subjects harbored adenomas with invasive cancer. Seventy-one hyperplastic polyps were found in 40 (34%) subjects. The mean size of hyperplastic polyps was 3.4 mm, and 64 (90%) were located in the left colon. We conclude that, in this population, adenomas are common lesions that are frequently small. However, substantial proportions of these adenomas may be at risk for malignant degeneration due to the presence of villous architecture and higher grades of dysplasia. Because adenomas and hyperplastic polyps are endoscopically indistinguishable, all polyps found at endoscopy should be removed or ablated.

Cancer and polyps of the colorectum and lifetime consumption of beer and other alcoholic beverages

Two parallel case-control studies were conducted in the Marseilles metropolitan area of France from 1979 to 1985 on cancers and adenomatous polyps of the colorectum. All cases of cancer (n = 389) and polyps (n = 252) were incident and histologically confirmed. Controls (n = 641) matched for sex and age were selected among patients undergoing functional reeducation for injury or trauma in one of five hospital centers. Intake of alcoholic beverages was investigated by questions on daily or weekly intake of wine, beer, apéritifs, and distillates during different life periods. Questions on alcoholic beverages were integrated in a detailed diet history interview questionnaire. The risk of rectal cancer was elevated in male beer drinkers (relative risk = 1.73, 95% confidence interval 1.01-2.95) and in men and women combined (relative risk = 1.71), while beer consumption was not associated with colon cancer. Total ethanol intake and consumption of wine and distillates were not associated with the risk of cancer of the colon or rectum, nor with risk of polyps. Adjustment in the statistical analysis for energy intake and for other dietary variables (fiber from fruits and fiber from vegetables), which were found to be risk factors in the study, did not substantially change the results found for beer and other alcoholic beverages. Etiologic hypotheses related to nitrosamine content of beer are discussed in the light of growing epidemiologic evidence that beer consumption specifically increases the risk of rectal cancer.