Distribution of colonic polyps: increased incidence of proximal lesions in older patients

[Standardized and structured histopathological evaluation of colorectal polyps: a practical checklist against the background of the new WHO classification]

Gastroenterologists removing colorectal polyps expect standardized and well-structured pathological reports, providing them with all relevant data for the further clinical management of the patient. Over the last year, a task force of clinicians and pathologists has developed a checklist to improve and harmonize endoscopic and pathological reporting of colorectal polyps. This checklist concentrates more on concrete recommendations from evidence-based guidelines and established international classifications for daily practice rather than detailed molecular pathological pathways of carcinogenesis. These recommendations are based on the current S3 guidelines for colorectal cancer (the chapter entitled "Management of colorectal polyps"), the histomorphological consensus manuscript of the GI working group of the German Society for Pathology, as well as the current WHO classification for tumors of the digestive system.

A shift from distal to proximal neoplasia in the colon: a decade of polyps and CRC in Italy

Background

In the last years a trend towards proximalization of colorectal carcinomas (CRC) has been reported. This study aims to evaluate the distribution of CRC and adenomatous polyps (ADP) to establish the presence of proximalization and to assess the potential predictors.

Methods

We retrieved histology reports of colonic specimens excised during colonoscopy, considering the exams performed between 1997 and 2006 at Cuneo Hospital, Italy. We compared the proportion of proximal lesions in the period 1997-2001 and in the period 2002-2006.

Results

Neoplastic lesions were detected in 3087 people. Proximal CRC moved from 25.9% (1997-2001) to 30.0% (2002-2006). Adjusting for sex and age, the difference was not significant (OR 1.23; 95% CI: 0,95-1,58). The proximal ADP proportion increased from 19.2% (1997-2001) to 26.0% (2002-2006) (OR: 1.43; 95% CI: 1.17-1.89). The corresponding figures for advanced proximal ADP were 6.6% and 9.5% (OR: 1.48; 95% CI: 1.02-2.17). Adjusting for gender, age, diagnostic period, symptoms and number of polyps the prevalence of proximal advanced ADP was increased among people ≥ 70 years compared to those aged 55-69 years (OR 1.49; 95% CI: 1.032.16). The main predictor of proximal advanced neoplasia was the number of polyps detected per exam (> 1 polyp versus 1 polyp: considering all ADP: OR 2.16; 95% CI: 1.59-2.93; considering advanced ADP OR 1.63; 95% CI: 1.08-2.46). Adjusting for these factors, the difference between the two periods was no longer significant.

Conclusions

CRC do not proximalize while a trend towards a proximal shift in adenomas was observed among people ≥ 70 years.

Proximalisation of colorectal carcinoma: a 10-year study in Italy

INTRODUCTION

Proximalisation of colon carcinoma has been reported over the course of the last 60 years. Changes in site distribution are receiving increasing attention on account of their implications for screening programmes.

OBJECTIVE

A retrospective observational study to determine whether the site distribution of colorectal carcinoma in Italy has varied in the last years and whether changes have been influenced by age and sex.

METHODS

Findings of colonscopies conducted at Turin University from 1992 to 2001 were examined. Inclusion criteria were: outpatients, screening, presence of anaemia or gastrointestinal bleeding, weight loss, constipation or changes in evacuation frequency. Exclusion criteria were: uncompleted, surgical endoscopies or conducted for positive flexible sigmoidoscopy, with doubtful findings. Carcinomas and benign polyps were diagnosed histologically. Age, sex, date of examination, nature and location of lesions were recorded. Lesions were classed as carcinoma, and polyps <1 and >/=1 cm. Data were grouped into different year periods and compared with the chi square test. We compared 1992-1993 vs. 2000-2001 and 1992-1996 vs. 1997-2001.

RESULTS

Of the 8,132 colonoscopies performed, 7,342 were included in the study. Proximal carcinomas moved from 12.2% in 1992-1993 to 14.9% in 2000-2001 (P = 0.57), proximal polyps rose from 16.6% to 22.1% (P < 0.0001). Furthermore proximal carcinomas moved from 16.5% in 1992-1996 to 14.4% in 1997-2001 (P = 0.48); proximal polyps rose from 18.4% to 27.8% (P < 0.005). In the period 1996-2001 there was higher female prevalence (P = 0.0011) and older age (P = 0.0191).

DISCUSSION

We can suppose that proximalisation of carcinoma has not yet appeared in Italy.

CT colonography: an update

Computed tomographic (CT) colonography (CTC)--also known as "virtual colonoscopy"--was first described more than a decade ago. As advancements in scanner technology and three-dimensional (3D) postprocessing helped develop this method to mature into a potential option in screening for colorectal cancer, the fundamentals of the examination remained the same. It is a minimally invasive, CT-based procedure that simulates conventional colonoscopy using 2D and 3D computerized reconstructions. The primary aim of CTC is the detection of colorectal polyps and carcinomas. However, studies reveal a wide performance variety in regard to polyp detection, especially for smaller polyps. This article reviews the available literature, discusses established indications as well as open issues and highlights potential future developments of CTC.

Colorectal cancer screening: results of a 5-year program in asymptomatic subjects at increased risk

BACKGROUND AND AIMS

The province of Ferrara has one of the highest incidences of colorectal cancer (CRC) in Italy. In January 2000, we set up a colonoscopy screening program focussing on first-degree relatives of CRC patients. We now report the results 5 years after the beginning of the project. SCREENEES AND METHODS: In October 1999, we started a campaign stressing the usefulness of colonoscopy for the first-degree relatives of CRC patients. Subjects included in the screening program were aged between 45 and 75 years with at least one first-degree relative affected by CRC. They were invited to an interview where a physician suggested colonoscopy as a screening option.

RESULTS

In 5 years, 776 subjects were interviewed and 733 (94.4%) agreed to an endoscopic examination (M/F:375/401; mean age 55 years): 562 colonoscopies were performed. Adenomas and cancers were found in 122 (21.7%) and 12 (2.1%) subjects, respectively. Histological examination in 181 persons with lesions (32.8%) showed (most serious lesion quoted) 47 hyperplastic polyps (26% of all lesions), 2 serrated adenomas (1.1%), 68 tubular adenomas (48%), 24 tubulovillous adenomas (13.3%), 9 adenomas with high grade dysplasia (5%) and 12 adenocarcinomas (6.6%). The majority of the cancers were at an early stage (8 Dukes A and 3 Dukes B). Sedation was used in only 42 colonoscopies (7.5%).

CONCLUSIONS

A colonoscopy-based screening in this selected high-risk population is feasible. Even without sedation subjects readily agreed to the endoscopic procedure. We identified a significant number of advanced neoplasms and cancers at an early stage suggesting that this could be a useful tool in early identification of CRC.

Colorectal Cancer: Screening Double-Contrast Barium Enema Examination in Average-Risk Adults Older Than 50 Years

PURPOSE

To retrospectively determine the diagnostic yield of double-contrast barium enema examinations performed for colorectal cancer screening of neoplasms 1 cm or larger or advanced neoplastic lesions of any size in average-risk adults older than 50 years.

MATERIALS AND METHODS

The Institutional Review Board at the affiliated Veterans Affairs Medical Center approved this HIPAA-compliant study protocol and did not require informed consent from patients. Computerized databases revealed 276 double-contrast barium enema examinations performed for colorectal cancer screening in average-risk adults older than 50 years. Radiographic and pathologic reports were reviewed to determine the number of patients who had polypoid lesions 1 cm or larger, polyps smaller than 1 cm, or advanced neoplastic lesions of any size. Forty-five (16.3%) of the 276 patients underwent follow-up sigmoidoscopy or colonoscopy. Medical, endoscopic, and pathologic records were reviewed and compared with radiographic findings.

RESULTS

The results of double-contrast barium enema examination revealed 74 (26.8%) of 276 patients with 104 polypoid lesions in the colon, including 32 patients (11.6%) with 41 polypoid lesions 1 cm or larger, 15 patients (5.4%) with 19 polyps 6-9 mm, and 27 patients (9.8%) with 44 polyps 5 mm or smaller. Endoscopy was performed in 24 (75%) of 32 patients, the results of which confirmed 23 (72%) of 32 radiographically diagnosed lesions 1 cm or larger in 16 (67%) of 24 patients. In two of these individuals, the polyps were hyperplastic. The remaining 14 patients had a total of 21 neoplastic lesions 1 cm or larger, including 11 tubular adenomas, seven tubulovillous adenomas, one villous adenoma with marked dysplasia, and two cancers. The diagnostic yield of screening double-contrast barium enema examination was 5.1% (14 of 276 patients) for neoplastic lesions 1 cm or larger and 6.2% (17 of 276 patients) for advanced neoplastic lesions of any size.

CONCLUSION

Double-contrast barium enema examinations performed in average-risk adults older than 50 years have a diagnostic yield of 5.1% for neoplastic lesions 1 cm or larger and 6.2% for advanced neoplastic lesions, regardless of size.

Right-side shift of colorectal adenomas with aging

BACKGROUND

Although it is known that right-side colon cancers increase with aging, the location of adenomas according to age has been controversial. Adenomas found at initial colonoscopies may be a mixture of polyps that arose at various earlier ages.

OBJECTIVES

To elucidate the relationship between location and age at which adenomas actually developed.

DESIGN

Prospective cohort study.

SETTING

A large-scale health appraisal institution in Japan.

PATIENTS

A total of 23,444 consecutive, asymptomatic Japanese who underwent total colonoscopy at their annual medical health check-up.

INTERVENTIONS

We analyzed newly developed adenomas after confirmation of the absence of colorectal neoplasms by two serial total colonoscopies.

MAIN OUTCOME MEASUREMENTS

The results of follow-up colonoscopies in 6304 subjects with no colorectal neoplasms at 2 initial colonoscopies were analyzed. The locations were separated into right-side colon and left-side colon from the splenic flexure. The locations of new adenomas found for the first time during the follow-up term were analyzed.

RESULTS

A total of 1472 subjects developed new colorectal adenomas. In 1255 cases with single adenomas, the ratios of number of cases with right-side lesions to that with left-side lesions at the ages of <40 years, 40 to 49 years, 50 to 59 years, 60 to 69 years, and > or =70 years were 1.18, 1.00, 1.29, 1.31, and 1.89, respectively. In 217 cases with multiple adenomas found concurrently, the percentage of cases with adenomas only on the right side at the ages of <40 years, 40 to 49 years, 50 to 59 years, 60 to 69 years, and > or =70 years were 0%, 25%, 34%, 37%, and 63%, respectively.

LIMITATIONS

Small lesions might have been missed even by 2 serial colonoscopies.

CONCLUSIONS

Adenomas on the right-side colon increased with aging.

Colorectal cancer prevention

Colorectal cancer is the second leading cause of mortality in the United States. In the United States, the cumulative lifetime risk of developing colorectal cancer for both men and women is 6%. Despite advances in the management of this disease, the 5-year survival rate in the United States in only 62%. Because only 38% of patients are diagnosed when the cancers are localized to the bowel wall, it is likely that widespread implementation of screening could significantly improve the outcome. Colorectal cancer screening is cost effective, irrespective of the methods used. In addition to currently available methods (fecal occult blood, flexible sigmoidoscopy, colonoscopy, and double contrast barium enema), computed tomographic colonography (virtual colonoscopy) and stool-based molecular screening are under development. Four classes of chemopreventive compounds have demonstrated efficacy in reducing recurrent colorectal adenomas and/or cancer in randomized, controlled trials. They are selenium, calcium carbonate, hormone replacement therapy, and nonsteroidal anti-inflammatory drugs. The mechanisms of action of nonsteroidal anti-inflammatory drugs include inhibition of the cyclooxygenase system as well as cyclooxygenase-independent effects. Considerable effort is being expended to define chemopreventive activity, optimal dose, administration schedule, and toxicity for the coxibs in adenoma recurrence prevention trials. The threshold for tolerating toxicities is very low in asymptomatic individuals at minimally increased risk for colorectal neoplasia.

Radiologic imaging modalities in the diagnosis and management of colorectal cancer

Colorectal carcinoma poses a serious public health threat. Detection in its early stages in the best predictor for long-term survival, which is the impetus for population-based screening programs. We believe that full-colon imaging by either DCBE or colonoscopy is necessary for colon cancer screening because flexible sigmoidoscopy, even if perfect, only detects 50% to 60% of colon cancers, a rate far worse than even the worst rate reported for single-contrast barium enema. Screening for colon cancer with flexible sigmoidoscopy is equivalent to performing a "left" mammogram for the detection of breast cancer. The role of CT colonography is still to be determined. When confronted with a symptomatic patient, barium enema is applied in conjunction with CT to detect primary colorectal carcinoma, to differentiate it from other benign and malignant processes involving the colon, and to assess for disease extent before surgery in selected high-risk patient populations. Pelvic MRI may be useful in the preoperative assessment of patients with rectal carcinoma as a means for assisting surgical planning. CT, MRI, and barium enema are used in postoperative follow-up for detecting local recurrence and distant spread. In response to known difficulty in discriminating between normal postoperative changes and tumor recurrence and in determining the nature of certain liver lesions, FDG-PET has been approved for the detection and localization of recurrent colorectal cancer in patients with rising CEA levels and indeterminate findings on standard imaging studies. Given its current promise of offering high sensitivity, specificity, and accuracy, the indications for PET may well expand in the future, but its final role in still to be determined.

[Clinical and macroscopic variables that influence the prognosis of colorectal carcinoma]

BACKGROUND AND AIMS

The paradoxical evolution of approximately one third of patients with neoplasms cataloged in Dukes stages B and C demonstrates the desirability of utilizing other prognostic criteria that are capable of broadening the information provided by these two important variables. Only a small number of investigators have dedicated themselves to the study of the prognostic value of clinical and macroscopic parameters of colorectal neoplasms, and the results obtained have been shown to be controversial. The principal aim of this work was to evaluate the prognostic importance of these parameters.

PATIENTS AND METHODS

A study was made of 320 patients with colorectal cancer who underwent curative extirpation. They had a median age of 58 years, and there were 199 females (62.2%) and 121 males (37.8%). The patients were divided into three age groups: under 40 years old, between 40 and 60 years old and over 60 years old. The tumors were distributed in three intestinal segments: right colon, left colon and rectum. The neoplasms were classified as small (diameter less than or equal to 35 mm) and large (diameter greater than 35 mm). With regard to their form, they were classified as exophytic, when characterized by luminal growth, and endophytic, when there was intramural growth. The involvement of the intestinal circumference at the site of the neoplasm was considered as partial or total.

RESULTS

Of the 320 patients, 22 (6.9%) were aged under 40 years, 159 (49.7%) from 40 to 60 years and 139 (43.4%) presented an age of over 60 years. Seventy-three (22.8%) of the neoplasms were located in the right colon, 130 (40.6%) in the left colon and 117 (36.6%) in the rectum. Regarding the size, 280 (87.5%) were large and 40 (12.5%) small; exophytic lesions predominated over endophytic ones - 173 (54.1%) vs 147 (45.9%). A greater number of tumors presented total involvement of the intestinal circumference - 216 (67.5%) - while 104 (32.5%) presented partial involvement. The 5-year survival of the patients was not influenced by their age and sex, or by the location and size of the neoplasms. Exophytic lesions conferred greater survival on their sufferers (65.9%), in comparison with endophytic lesions (49.0%). The survival of patients with lesions partially involving the intestinal circumference was greater than for those with total involvement - 72.1% vs. 51.4%.

CONCLUSIONS

Clinical variables had no influence on the patients' prognosis. Among the macroscopic variables, the form of the neoplasia and its involvement in the intestinal circumference did influence the patients' prognosis. These last two variables are important data capable of contributing to the identification of patient subpopulations with greater or lesser prognostic risk.

Caecal carcinomas in the elderly: useful signs in minimal preparation CT

OBJECTIVE

Frail, elderly and immobile patients frequently have difficulty in tolerating formal colonic investigations. Caecal tumours may account for up to 35% of colonic tumours. Barium enema and colonoscopy have limitations in assessing this region. The aims of this study were to evaluate the accuracy of a minimal preparation CT technique (merely with prolonged oral contrast medium) in identifying caecal carcinomas and to determine helpful radiological signs.

MATERIALS AND METHODS

The CT technique involved helical acquisition following 2 days of preparation with oral contrast medium. The outcome of 4 years' experience (1995-1998) was reviewed. The gold-standards were pathological and cancer registration records, together with colonoscopy and barium enema where available, with a minimum of 15 months' follow-up.

RESULTS

CT correctly identified 27 of 30 caecal carcinomas, and missed three, in a total of 1077 CT studies in 1031 patients (median age 80 years). There were also 21 false-positive cases in which CT incorrectly raised the possibility of a caecal tumour. The sensitivity, specificity, negative predictive value (NPV) and positive predictive value (PPV) were 90%, 98%, 99% and 56%, respectively. Serosal margin blurring, tumour length, presence of abnormal peri-colic fat and terminal ileal wall thickening were identified as useful radiological signs.

CONCLUSIONS

Minimal preparation CT is able to identify caecal carcinomas with fair accuracy. Such evaluation may become important given the increasing population age and evidence of a 'proximal shift' in the site of colonic tumours in the elderly.

The use of the 130-cm colonoscope for screening flexible sigmoidoscopy

The 130-cm colonoscope was utilized to determine whether a deeper insertion could be accomplished after the usual enema preparation for routine flexible sigmoidoscopy and, if so, to what extent that would enhance the yield of neoplastic findings. Sixty-four patients were examined, and intubation was accomplished to the level of 69 cm compared with 48.1 cm for a matched control group that had flexible sigmoidoscopy with the 60-cm endoscope. Another 24 patients who had a barium enema prep had a significantly greater depth of insertion (81.4 cm). Only two polyps were found proximal to 60 cm. The 130-cm colonoscope does not offer any substantial advantage over the standard 60-cm sigmoidoscope unless a bowel preparation more thorough than enemas is given and then it would probably only be worthwhile using the colonoscope in patients who are above average risk for colorectal neoplasia.

Aberrant crypt foci of the colon as precursors of adenoma and cancer

BACKGROUND

Aberrant crypt foci of the colon are possible precursors of adenoma and cancer, but these lesions have been studied mainly in surgical specimens from patients who already had colon cancer.

METHODS

Using magnifying endoscopy, we studied the prevalence, number, size, and dysplastic features of aberrant crypt foci and their distribution according to age in 171 normal subjects, 131 patients with adenoma, and 48 patients with colorectal cancer. We also prospectively examined the prevalence of aberrant crypt foci in 11 subjects (4 normal subjects, 6 with adenoma, and 1 with cancer) before and after the administration of 100 mg of sulindac three times a day for 8 to 12 months and compared the results with those in 9 untreated subjects (4 normal subjects and 5 with adenoma). All 20 subjects had aberrant crypt foci at base line.

RESULTS

We identified 3155 aberrant crypt foci, 161 of which were dysplastic; the prevalence and number increased with age. There were significant (P<0.001) correlations between the number of aberrant crypt foci, the presence of dysplastic foci, the size of the foci, and the number of adenomas. After sulindac therapy, the number of foci decreased, disappearing in 7 of 11 subjects. In the untreated control group, the number of foci was unchanged in eight subjects and slightly increased in one (P<0.001 for the difference between the groups).

CONCLUSIONS

Aberrant crypt foci, particularly those that are large and have dysplastic features, may be precursors of adenoma and cancer.

Screening for colorectal cancer

Randomized, controlled trials have shown with certainty that screening for colorectal cancer reduces morbidity and is cost-effective. Factors that increase the risk of colorectal cancer include a personal or family history of adenomatous polyps or colorectal cancer, certain genetic syndromes and chronic inflammatory bowel disease.

Referrals for double-contrast barium examination. Factors influencing the probability of finding polyps or cancer

Predictors of the radiologic detection of colorectal polyps or cancer were studied in 1852 patients referred from primary health care for a double-contrast barium enema. Significant polyp predictors were age 40-79 years (odds ratio (OR), 2.4-5.0) and rectal bleeding (OR, 1.8). Previous colorectal neoplasm, familial history of cancer in general, and male sex were nearly significant predictors of polyps. Significant cancer predictors were age > or = 60 years (OR, 8.6-27.8), rectal bleeding (OR, 2.7), loss of weight (OR, 2.6), and male sex (OR, 2.2). Fatigue and abdominal pain were nearly significant negative predictors for cancer. No association was found between patient delay and the detection of polyps or cancer. Physician delay was significantly shorter in patients with cancer than in cancer-free patients. Age was the most important predictor for the detection of both polyps and cancer, more important than symptoms and history, including family history.

Colorectal carcinoma: analysis of management in two medical eras

Trends in presentation, diagnosis, management, and outcome were analyzed for 503 patients with colorectal cancer seen at the UCLA Medical Center between 1960 and 1970 (Group A; n = 210) and 1980 and 1985 (Group B; n = 293). Patients in the latter group exhibited a shift in site to the right side of the colon (18% in Group A vs. 31% in Group B; P < .01), an increase in the number of primary resections without colostomy (38% vs. 61%; P < .01), a lower overall complication rate (28% vs. 18%; P = .01), and a decline in 30-day mortality (6.2% vs. 2%; P = .01). Although little difference was seen in detection of asymptomatic tumors, earlier lesions were treated in the latter group, accounting for substantially reduced rate of recurrence (69% in Group A vs. 44% in Group B; P < .01). Future management should include an emphasis on earlier detection in order to continue the trend toward enhanced survival.

The role of barium enema in detecting colorectal disease. A radiologist's perspective

The single-contrast barium enema examination remains useful for patients with acute diseases such as bowel obstruction, diverticulitis, appendicitis, and fistulas. It is also the procedure of choice for those patients who are too elderly, debilitated, or ill to cooperate with the maneuvers necessary for a double-contrast examination. The double-contrast technique is more sensitive than the single-contrast technique for detection of polyps, early inflammatory bowel disease, and lesions of the rectum. In the older population, there has been an increase in the incidence of colonic polyps and carcinomas in the right side of the colon. This emphasizes the need to examine the entire colon in these patients. The double-contrast barium enema is a safe, accurate, and cost-effective tool for accomplishing this. It is also recommended as the initial procedure in the examination of patients with positive results on fecal occult blood testing.

Age and sex: underestimated selection criteria for referral to x-ray examination of the colon?

An analysis was made of 2416 consecutive patients who underwent a double-contrast barium enema at the Central Roentgen Institute in Oslo. Age, sex, and radiological findings were registered. The age and sex distribution among patients consulting in general practice and in our study was surprisingly similar. This suggests that age as a risk factor for colorectal neoplasms did not play a prominent role among the referring doctors. Colorectal cancer was more frequent in males (4%) than females (2%) (p = 0.03). Odds ratio adjusted for age was 2.1 (1.3-3.8). This may be due to few examinations performed in old age, and different patient behaviour when experiencing colorectal symptoms. The overall polyp frequency was 11%. The frequency increased significantly from the age group 40-49.

Premalignant lesions of the gastrointestinal tract. Surveillance regimens for three treatable disorders

Barrett's esophagus, ulcerative colitis, and adenomatous colorectal polyps have been proven to be precursors of cancer. Early treatment and appropriate esophagoscopic or colonoscopic surveillance for recurrence or disease progression in these patients can save lives. Dr Schuman discusses typical regimens and special considerations in follow-up of these disorders.

Colorectal carcinoma over 30 years at one hospital: no evidence for a shift to the right

Many recent reports in the North American literature have documented an increase in the ratio of proximal to distal colorectal cancers with an increase in right-sided lesions. In order to assess trends in the distribution of large bowel carcinoma at our hospital we reviewed the files of 1553 patients who presented with primary colorectal carcinoma over a 30-year period. Thirty-nine percent of patients were over 70 years old and 51% were in the 50-69 year age group. Seventy five percent of the carcinomas were left-sided, 22% right-sided and caecal carcinomas accounted for 18%. This distribution varied only slightly over the study period. Left-sided lesions were more common in males (55%: p less than 0.005), and right-sided lesions were more common in females (57%: p less than 0.005). Caecal carcinoma was more common in patients over 69 years old than in younger patients (p less than 0.001). In elderly females (greater than 69 years) 30% of colorectal carcinomas occurred in the caecum. These findings may have important implications for the investigation of patients with suspected colorectal disease or for screening programmes.

Cancer screening in the elderly

Cancer screening in the elderly presents several unique challenges. There are no prospective trials of any cancer screening exam that have conclusively demonstrated efficacy in this age group. Any assessment of cancer screening in the elderly must include measuring an improvement in quality of life and functional status as well as decreased mortality from early cancer detection. Older patients usually prefer improved quality over quantity of life; they may be less interested in a trade-off of months or years of life in exchange for the side effects of cancer treatment. The elderly may need more home assistance during the treatment of the detected cancers; physicians should arrange for this. All of these variables must be included in studies of cancer screening in the elderly; the need for these studies is great. The following recommendations are probably the most reasonable in view of the currently inadequate knowledge base. Screening for breast cancer has demonstrated efficacy, with growing evidence for a cumulative effect from monthly breast self-examination, yearly breast examination by a physician, and yearly or biennial mammography. There may be no need to screen for cervical cancer in women after age 65 who have had regular Pap smear screening; however, older women who have never had Pap smears should have regular Pap smears for several years. Finally, because of the high frequency of colorectal and prostate cancers in the elderly, physicians should probably perform yearly rectal examinations with stool guaiac and regular sigmoidoscopy in this age group until definitive data support continuing or discontinuing these screening examinations. Physicians should educate their elderly patients to the importance of regular cancer screening and cancer risk-factor modification and should offer cancer screening examinations and counseling to elderly patients on a regularly scheduled basis.

Spatial clustering of multiple hyperplastic, adenomatous, and malignant colonic polyps in individual patients

Analysis of relative polyp locations in 426 consecutive patients with multiple colonic polyps found on colonoscopy showed novel findings. First, synchronous and metachronous neoplastic polyps showed spatial clustering in individual patients. For example, patients with their largest neoplasm in the cecum or proximal ascending colon, had 34.3 percent +/- 4.6 percent (standard error) of their other colonic neoplasms in the same location. Second, hyperplastic polyps showed spatial clustering in individuals that was statistically significantly greater than expected from the increased hyperplastic polyp concentration in the rectum and sigmoid. Third, hyperplastic polyps showed spatial clustering with neoplastic polyps; this clustering was similar in magnitude to clustering for exclusively hyperplastic or neoplastic polyps. In contrast, lipomas were not spatially clustered with hyperplastic and neoplastic polyps. The magnitude of clustering between hyperplasia and neoplasia showed a closer association between these histologic types than previously appreciated. Because of clustering, regions with prior polyps appear to merit closer surveillance. These findings suggest clinical study, using a randomized controlled clinical trial, of whether a patient who had only rectal and sigmoid adenomas on initial and follow-up colonoscopy should have surveillance with flexible sigmoidoscopy alternating annually with colonoscopy. A patient with a prior cecal adenoma should have surveillance only with a complete colonoscopy or adequate cecal views on barium enema.

Colorectal carcinomas: diagnostic implications of their changing frequency and anatomic distribution

This retrospective review included 1,694 consecutive cases of colorectal carcinoma diagnosed at the University of Chicago Medical Center during a 25-year period (1960 through 1984). The number and percentage of tumors occurring within 7 anatomic segments of the large bowel were determined. The statistical data for a recent 5-year interval were then compared with those of the 2 preceding decades. There was a 10.2% increase in the frequency of cancers originating in the cecum or ascending colon, while rectal and rectosigmoid carcinomas declined by 15.8% during the same study period. These data provide further evidence for a progressive left-to-right shift in cancer distribution within the colon during the past quarter century. Currently, the most proximal and distal 20-25 cm segments of the large bowel (cecum or ascending colon versus rectum and rectosigmoid) each harbor approximately 25% of the tumors. Therefore, the classic medical teaching that over 50% of colorectal cancers would be detectable by digital examination and/or proctosigmoidoscopy is no longer accurate. This documented increase in proximal colon cancers and redistribution of lesions within various large bowel segments indicate the growing importance of barium enema and colonoscopy as the optimal techniques for detection of colorectal neoplasms.

Do all colorectal carcinomas arise in preexisting adenomas?

In this article, the underlying nature of the adenoma is defined and evidence in support of the adenoma-carcinoma sequence is presented. Emphasis is placed on recent findings from the field of molecular biology which fortify the concept of the adenoma as a step in the evolution of large bowel cancer. Despite the considerable body of indirect evidence in support of the adenoma-carcinoma sequence, the de novo theory still has some support. Although differences between the de novo and adenoma carcinoma concept are largely semantic, the fact that infiltrating carcinoma can arise within small, flat foci of severely dysplastic epithelium (indistinguishable from carcinoma in situ) may be of considerable clinical importance. Other routes of morphogenesis exist also, but these make a relatively small contribution to the overall incidence of colorectal cancer. Even if it is accepted that the majority of colorectal cancers develop in a preexisting adenoma, the systematic removal of adenomas would pose a number of practical difficulties. First, adenomas are extremely common, particularly in populations at high risk of colorectal cancer. A second factor is the recently recognized existence of flat or depressed adenomas which may be small and difficult to visualize endoscopically. A simple screening program based on our knowledge of the evolution of colorectal cancer is outlined.

The value of a barium enema in the investigation of patients with rectal carcinoma

A review of 545 patients with clinically diagnosed rectal carcinoma was conducted to determine the diagnostic usefulness of pre-operative barium enema and the frequency with which it was employed. Only 118 patients underwent pre-operative barium enema (21.7%). This successfully outlined the whole colon in 107 (90%). Synchronous carcinomas were detected in 9.3% of patients who underwent complete barium enema, compared to 4.3% of those who underwent laparotomy alone (P less than 0.05). Polyps were found in 23.4% of patients who had a barium enema but in only 14.7% of those who did not (P less than 0.05). Twenty-nine per cent of synchronous carcinomas and 11% of polyps were proximal to the descending colon and would have been beyond the reach of a flexible sigmoidoscope. Barium enema remains a useful investigation in patients with rectal carcinoma. It will outline the whole colon in most cases and will result in the detection of more synchronous carcinomas and polyps than if the surgeon relies on operative palpation alone.

Colorectal polyps: a correlation of radiological and pathological findings

Ninety colorectal polyps seen on double contrast barium enema were reviewed and note was made of surface and base characteristics, size, site and the presence of associated disease. Results were then correlated with the histology. The radiological characteristics of each histological type of polyp encountered are described. Because of the variation in radiological appearance of each histological type and similarities in appearance between these types, we conclude that radiology cannot accurately predict the histology of a colorectal polyp.

Screening of colorectal cancer

Colorectal cancer (CRC) remains a cancer in a disappointing location. However, its location clearly has an advantage that could theoretically permit efficient secondary prevention: the preceding of the cancer by a benign lesion, ie, the adenoma. Complete colonoscopy and its substitute, the double-contrast barium enema, and their specific limitations, must be reserved for high-risk patients: hereditary cancers and ulcerative colitis. For all the others, ie, adults of 45 years of age and with standard risks, the proposal is either to select the patients to be colonoscoped through occult blood testing of the stools or to perform a fiber sigmoidoscopy or a combination of both. Although imperfect, both methods allow the detection of polyps and cancers at a presymptomatic stage, when they are either benign or malignant, but localized and with a better prognosis. However, the absolute proof of the benefits of this strategy of screening would be the demonstration by controlled studies of a prolonged survival rate or a decrease in morbidity. Until now, this proof is not fully available.