Recurrence rates for colorectal polyps

Novel Pixelwise Co-Registered Hematoxylin-Eosin and Multiphoton Microscopy Image Dataset for Human Colon Lesion Diagnosis

Colorectal cancer presents one of the most elevated incidences of cancer worldwide. Colonoscopy relies on histopathology analysis of hematoxylin-eosin (H&E) images of the removed tissue. Novel techniques such as multi-photon microscopy (MPM) show promising results for performing real-time optical biopsies. However, clinicians are not used to this imaging modality and correlation between MPM and H&E information is not clear. The objective of this paper is to describe and make publicly available an extensive dataset of fully co-registered H&E and MPM images that allows the research community to analyze the relationship between MPM and H&E histopathological images and the effect of the semantic gap that prevents clinicians from correctly diagnosing MPM images. The dataset provides a fully scanned tissue images at 10x optical resolution (0.5 µm/px) from 50 samples of lesions obtained by colonoscopies and colectomies. Diagnostics capabilities of TPF and H&E images were compared. Additionally, TPF tiles were virtually stained into H&E images by means of a deep-learning model. A panel of 5 expert pathologists evaluated the different modalities into three classes (healthy, adenoma/hyperplastic, and adenocarcinoma). Results showed that the performance of the pathologists over MPM images was 65% of the H&E performance while the virtual staining method achieved 90%. MPM imaging can provide appropriate information for diagnosing colorectal cancer without the need for H&E staining. However, the existing semantic gap among modalities needs to be corrected.

Aspirin and colorectal cancer: the promise of precision chemoprevention

Aspirin (acetylsalicylic acid) has become one of the most commonly used drugs, given its role as an analgesic, antipyretic and agent for cardiovascular prophylaxis. Several decades of research have provided considerable evidence demonstrating its potential for the prevention of cancer, particularly colorectal cancer. Broader clinical recommendations for aspirin-based chemoprevention strategies have recently been established; however, given the known hazards of long-term aspirin use, larger-scale adoption of an aspirin chemoprevention strategy is likely to require improved identification of individuals for whom the protective benefits outweigh the harms. Such a precision medicine approach may emerge through further clarification of aspirin's mechanism of action.

What clinicians wish to know about benign colorectal polyps: an operative classification

INTRODUCTION

In recent years we assisted to a real "boom" of colorectal polyps, mainly due to the diffusion of screening procedures and of colonoscopy. This new "Polyp Epidemic" raises a series of problems and challenges. It became clear that many syndromes are defined by the number, histological type and location of polyps, together with extraintestinal manifestations and, in most cases, specific molecular changes. This paper discusses some of the above mentioned points, focusing on the relative role of endoscopists and pathologists. The objective is to reach an operative classification of the most common polyps observed in daily practice which might be of help for the identification of inherited syndromes.

METHODS AND RESULTS

Six main histological types of polyps are defined and underlined: Adenoma, hyperplastic/serrated, hamartoma, ganglioneuroma, mixed, inflammatory. The importance of a brief description, in pathology reports, of each type of polyps is fundamental for a correct diagnosis. Each of the defined polyps is associated with inherited syndromes whose genetic basis has recently been elucidated. Relevant information should be given, and separated from additional (and not strictly necessary) information.

RECOMMENDATIONS

A correct polyp analysis is a valuable element for identifying specific inherited syndromes. Polyps represent a precious tool for planning screening and follow-up in a given individual. In addition, these lesions focus the interest of clinicians toward syndrome which were considered as rare diseases; indeed, the explosion of molecular biology and the diffusion of colonoscopy revealed that these conditions are frequent and amenable of treatment.

Aspirin in the chemoprevention of colorectal neoplasia: an overview

Considerable evidence supports the effectiveness of aspirin for chemoprevention of colorectal cancer (CRC) in addition to its well-established benefits in the prevention of vascular disease. Epidemiologic studies have consistently observed an inverse association between aspirin use and risk of CRC. A recent pooled analysis of a long-term posttrial follow-up of nearly 14,000 patients from four randomized, cardiovascular disease prevention trials showed that daily aspirin treatment for about five years was associated with a 34% reduction in 20-year CRC mortality. A separate metaanalysis of nearly 3,000 patients with a history of colorectal adenoma or cancer in four randomized adenoma prevention trials showed that aspirin reduced the occurrence of advanced adenomas by 28% and any adenoma by 17%. Aspirin has also been shown to be beneficial in a clinical trial of patients with Lynch syndrome, a hereditary CRC syndrome; in those treated with aspirin for at least two years, there was a 50% or more reduction in the risk of CRC commencing five years after randomization and after aspirin had been discontinued. A few observational studies have shown an increase in survival among patients with CRC who use aspirin. Taken together, these findings strengthen the case for consideration of long-term aspirin use in CRC prevention. Despite these compelling data, there is a lack of consensus about the balance of risks and benefits associated with long-term aspirin use, particularly in low-risk populations. The optimal dose to use for cancer prevention and the precise mechanism underlying aspirin's anticancer effect require further investigation.

Metabolic syndrome is associated with increased risk of recurrent colorectal adenomas in Korean men

OBJECTIVE

Because of the high incidence of recurrent colorectal adenomas, regular surveillance by colonoscopy is recommended. However, there is still a shortage of information on the factors that influence the incidence of recurrent colorectal adenomas in patients with a history of these lesions. The aim of this study was to determine the association between the development of recurrent colorectal adenomas, metabolic syndrome and obesity.

SUBJECTS AND METHODS

The hospital-based cohort was composed of 193 patients who had recurrent colorectal adenomas removed between January 2002 and December 2003. The Cox proportional hazard model was used to determine hazard ratio (HR) and 95% confidence interval (CI) between obesity, metabolic syndrome and other factors, and the incidence of recurrent adenomatous polyps.

RESULTS

The mean follow-up period was 4.8 person-years. In all, 78 of the patients (40.4%) had recurrent colorectal adenomas. In the overall recurrent adenoma group, significant associations between metabolic syndrome (HR, 1.33; 95% CI, 1.02-1.73), waist circumference (WC) ≥ 90 cm (HR, 1.42; 95% CI, 1.06-1.90) and waist-hip ratio (WHR) ≥ 0.9 (HR, 2.03; 95% CI, 1.55-2.68) were found. Moreover, advanced adenomas were significantly associated with metabolic syndrome (HR, 2.81; 95% CI, 1.86-4.25), body mass index ≥ 25 kg m(-2) (HR, 2.69; 95% CI, 1.64-4.42), WC (HR, 2.16; 95% CI, 1.31-3.54) and WHR (HR, 1.99; 95% CI, 1.28-3.11). In addition, current smoking (HR, 2.60; 95% CI, 1.09-6.25) and alcohol consumption (HR, 2.20; 95% CI, 1.10-4.39) were also significantly associated with recurrent advanced adenoma.

CONCLUSION

Metabolic syndrome and obesity were significantly associated with the development of recurrent colorectal adenomas in Korean adult males. Furthermore, these associations were more strongly associated with advanced adenomas.

Metachronous colorectal malignancies

Colorectal cancers (CRC) diagnosed 6 months after primary surgery for colorectal tumors are defined as metachronous CRC. Colonoscopy is the only reliable investigation for diagnosis. Favourable prognosis and survival is seen after conservative resection for metachronous CRCs. Clear guidelines are available for identification of CRCs after primary resection, and many questions remain unanswered regarding the development, management and prevention of CRC. We report here two cases of CRCs.

Characteristics of metachronous colorectal adenomas found during long-term follow-up: analysis of four subsequent generations of adenoma recurrence

OBJECTIVE

Because of the high recurrence rates of colorectal adenomas, regular surveillance by colonoscopy has been recommended, but there is still a dearth of information on the long-term results of follow-up colonoscopy after polypectomy. The aims of this study were to determine the differences between initial adenomas and metachronous lesions, to evaluate the effect of long-term surveillance and to describe the hypothetical origin of the colorectal adenoma-carcinoma sequence.

MATERIAL AND METHODS

Between 1978 and 2003 a total of 1091 patients undergoing periodic surveillance examinations were prospectively documented at the Erlangen Registry of Colorectal Polyps. Differences between initial and metachronous lesions found during long-term follow-up were studied. Statistical analysis using chi(2) testing of adenoma characteristics found in four subsequent recurrence periods was carried out, and the relative risk (RR) for the development of metachronous adenomas of advanced pathology was calculated.

RESULTS

In comparison with the initial findings, metachronous adenomas are generally significantly smaller lesions (p<0.00001), usually tubular in shape (p<0.00001) and bearing high-grade dysplasia less often (p<0.00001) and are usually located in the right colon (p<0.00001). These differences are found between the initial and four subsequent generations of metachronous adenomas. The number of synchronous adenomas is reduced only in the first recurrence (p<0.001); in the further generations equal proportions of multiplicity are found, as in the baseline examination. Patients with adenomas of advanced pathology, i.e. large, tubulovillous or villous adenomas at baseline, have a significantly higher risk for large (RR 2.73; 95% CI 1.77-4.20), tubulovillous or villous (RR 1.55; 95% CI 1.06-2.25) or multiple (RR 2.45; 95% CI 1.83-3.29) metachronous adenomas at the first recurrence.

CONCLUSIONS

Metachronous adenomas show the uniform characteristics of being small tubular lesions rarely bearing high-grade dysplasia, usually located in the right colon. Thus regular follow-up colonoscopy can provide sufficient colorectal carcinoma prevention.

Risk of advanced metachronous colorectal adenoma during long-term follow-up

BACKGROUND

According to the adenoma-carcinoma concept, all colorectal adenomas are to be removed and all patients have to undergo regular surveillance examinations. But there is still shortage on information on the long-term results of follow-up colonoscopy after polypectomy.

METHODS

Between 1978 and 2003, more than 20,000 polyps were prospectively documented at the Erlangen Registry of Colorectal Polyps. A total of 1,091 patients undergoing periodic surveillance examinations are studied for differences between initial and metachronous lesions of the colorectum. Statistical analysis using chi (2)-testing of adenoma characteristics found in four subsequent recurrence periods and calculation of the relative risk (RR) for the development of metachronous adenomas of advanced pathology was performed.

RESULTS

In comparison with the initial findings, metachronous adenomas are, in general, significantly smaller ones (p < 0.00001), more frequently tubular lesions (p < 0.00001) and bearing less often high-grade dysplasia (p < 0.00001). Adenomas of advanced pathology were significantly less often found during follow-up than at baseline examination (p < 0.0001). These differences are found between the initial and four subsequent generations of metachronous adenomas. Patients with adenomas of advanced pathology at baseline have a significantly higher risk for metachronous adenomas of advanced pathology (RR 1.51; 95%CI 1.04-1.93) at the first recurrence.

CONCLUSIONS

Metachronous adenomas show uniform characteristics of being small tubular lesions rarely bearing high-grade dysplasia. Thus, regular surveillance examinations can provide sufficient colorectal carcinoma prevention.

Study of full-thickness endoluminal segmental resection of colon in a porcine colon model (with videos)

BACKGROUND

Entrapment injury of the adjacent bowel is frequently encountered during full-thickness endoluminal colon suction-resection.

OBJECTIVE

Our purpose was to develop a technique that can create a full-thickness resection of the colon without the risk of entrapment injury to adjacent viscera.

DESIGN

Pilot study.

SETTING

University medical center.

PATIENTS

Five pigs.

INTERVENTIONS

Traction-resection of the colon was created by using a grasping forceps to pull the colon into a band ligator loaded on a double-channel endoscope, followed by the application of a band, and subsequent snare resection (n = 14). Suction-resection of the colon was created by using a double-channel endoscope loaded with a band ligator (n = 12) and a single-channel endoscope with a band ligator (n = 6).

MAIN OUTCOME MEASUREMENTS

Number of full-thickness colon resections, frequency of the adjacent bowel and mesenteric injury, and the size of the resections were measured.

RESULTS

The suction-resection technique resulted in significant injury to adjacent viscera compared with the traction-resection technique (56% vs 0%, P = .0013). The traction-resection method resulted in a significantly larger resection compared with the suction-resection method (mean +/- SEM: 2.91 +/- 0.3 cm vs 2.1 +/- 0.1 cm, P = .024). A double-channel endoscope suction-resection method resulted in a significantly larger resection compared with a single channel suction-resection technique (mean +/- SEM: 2.1 +/- 0.1 cm vs 0.91 +/- 0.2 cm, P = .0022).

LIMITATIONS

None.

CONCLUSIONS

The traction-resection technique is safer than the suction-resection method in removing larger specimens of the colon. In addition, the traction-resection technique reduces the risk of injury of the mesentery or adjacent small intestine.

The colorectal adenoma-carcinoma sequence

BACKGROUND

It is widely accepted that the adenoma-carcinoma sequence represents the process by which most, if not all, colorectal cancers arise. The evidence supporting this hypothesis has increased rapidly in recent years and the purpose of this article is to review this evidence critically and highlight its clinical significance.

METHODS

Medline searches were used to identify recent key articles relating to the adenoma-carcinoma sequence. Further pertinent articles were obtained by manual scanning of the reference lists of identified papers.

RESULTS

The evidence supporting the adenoma-carcinoma sequence can be classified as epidemiological, clinicopathological and genetic. The most recent and largest body of data relates to molecular genetic events and their cellular effects; however, many other approaches, such as cytogenetics, molecular cytogenetics and cytometry, have also yielded valuable information.

CONCLUSION

Recent work continues to support the adenoma-carcinoma sequence, but there is a paucity of data on the interrelationship between different genetic mutations and on the relationship between molecular and other types of genetic abnormalities. The clinical utility of the observations described has yet to be fully realized and global genetic analysis of colorectal tumours may prove to be central in rational adenoma management.

First endoluminal system for transmural resection of colorectal tissue with a prototype full-thickness resection device in a porcine model

BACKGROUND

Endoluminal transmural resection of colorectal lesions is a pivotal advance in endoscopic technology. A full-thickness resection device has been developed that functions through a combination of tissue grasping, stapling, and cutting under endoscopic guidance. This preclinical study evaluated the performance, safety, and effectiveness of the full-thickness resection device in a porcine model.

METHODS

The full-thickness resection device consists of an operative handle, flexible shaft, and a resection chamber head. Eight pigs were randomized to 2 survival groups (4 each) of 14 and 28 days. The mucosa was marked electrosurgically to delineate target areas in the distal colon. A gastroscope inserted through the channel of the full-thickness resection device was advanced together with the device to the target. Targeted tissue was pulled into the resection chamber with a forceps, staples were deployed, and the isolated specimen was resected with a cutting blade. Histologic and radiographic evaluations were performed.

RESULTS

All resections were transmural. Mean resected tissue diameter was 3.6 cm (1.4-5.2 cm). Mean procedure time was 30.2 (15) minutes. Minor mechanical problems required the use of replacement devices to complete 3 procedures. Resection sites were identified endoscopically and radiographically at sacrifice. In one animal, local adhesions were present. Histology evaluation disclosed resection line mucosal ulceration in 4 animals with fibroinflammatory changes consistent with healing.

CONCLUSIONS

The full-thickness resection device can be used for endoluminal transmural localized resection of colorectal tissue in an animal model.

Recurrence and malignancy rates in a benign colorectal neoplasm patient cohort: results of a 5-year analysis in a managed care environment

OBJECTIVE

To estimate the apparent recurrence rates of benign neoplasms and the development of malignant colorectal neoplasms over a 5-yr period in a high risk managed care population.

METHODS

Using the CPT and ICD-9 CM codes, a cohort of subjects with benign neoplasms were identified with a colonoscopy in 1992 from a longitudinal claims database (MarketScan). Three groups of subjects (benign neoplasms with polypectomy, benign neoplasms without polypectomy, and no neoplasms) were evaluated. Five-year recurrence rates of benign or new malignant colorectal neoplasms were determined for the baseline benign neoplasms with polypectomy and no neoplasm groups. For the benign neoplasm without polypectomy, only rates for malignancy were evaluated.

RESULTS

Of 16,293 subjects at baseline, 39.50% were diagnosed with benign and 5.50% with malignant neoplasms. The 5-yr cumulative incidence of benign neoplasms in subjects without an index neoplasm (n = 8,967) was 7.92% compared to the recurrence of 40.93% in subjects with a benign neoplasm and polypectomy (n = 4,046) at baseline (p < 0.001). The 5-yr cumulative incidence rates of malignant colorectal neoplasms in the no neoplasm (n = 8,967) and benign neoplasm groups (n = 6,438) were 1.81% and 2.55%, respectively (p < 0.005). A lower 5-yr malignancy rate was observed in benign neoplasm group with polypectomy (2.17%) compared to the benign neoplasm group without polypectomy (3.18%) (p < 0.05).

CONCLUSION

The high recurrence rate of benign colorectal neoplasms and a higher incidence of colorectal cancer in subjects at high risk (history of benign colorectal neoplasm) highlight a healthcare opportunity for surveillance and/or interventions to reduce the morbidity associated with colorectal neoplasms.

The effect of attending a flexible sigmoidoscopic screening program on the prevalence of colorectal adenomas at 13-year follow-up

OBJECTIVES

Understanding the epidemiology of colorectal adenomas is a prerequisite for designing follow-up programs after polypectomy. The aim of the study was to investigate the effect of polypectomy on the long-term prevalence of adenomas.

METHODS

In 1983, a total of 799 men and women aged 50-59 yr were drawn from the general population register. Of these, 400 comprised a screening group and 399 a matched control group. The screenees were invited to undergo a once-only flexible sigmoidoscopy. Persons with polyps had a baseline colonoscopy with follow-ups in 1985 and 1989. In 1996, both the screenees and the controls were invited to a colonoscopic examination.

RESULTS

In 1996, a total of 451 (71%) individuals attended. Adenomas were found in 78 (37%) individuals in the screening group and 103 (43%) in the control group, relative risk (95% confidence interval): 0.9 (0.7-1.1), p = 0.3, and high-risk adenomas (severe dysplasia, adenomas > or = 10 mm, villous components) were found in 16 (8%) and 32 (13%), respectively; relative risk (95% confidence interval): 0.6 (0.3-1.0), p = 0.07.

CONCLUSIONS

There was no significant difference in adenoma prevalence between the group after the screening program and the controls after the usual care. There was a trend toward more high-risk adenomas in the control group. This suggests a very limited effect of one-time screening sigmoidoscopy with surveillance colonoscopy on the prevalence of adenomas, but a preventive effect on the development of high-risk adenomas consistent with the reported effect on cancer prevention.

The prognostic value of cell proliferation in colorectal adenomas assessed with tritiated thymidine and anti-proliferating cell nuclear antigen

We analyze the cell kinetics of colorectal adenomas by tritiated thymidine (3HTdR) autoradiographic method and anti-proliferating cell nuclear antigen (PCNA) antibodies. A total of 46 patients who underwent prior endoscopic polypectomy for colorectal adenomas were reevaluated by colonoscopy for 4 years. Thymidine labeling index (T-LI) in index adenomas ranged from 1.40 to 38.0% (median value: 10. 75%); PCNA labeling index (PCNA-LI) in index adenomas ranged from 0 to 27.0% (median value: 1.95%). Among the 46 patients studied, 16 developed recurrent adenomas (Group A) and 30 were free of recurrent adenomas (Group B). The T-LI and PCNA-LI comparisons between Groups A and B were statistically significant (p < 0.0001, chi2 test). These results demonstrate that T-LI and PCNA-LI in colorectal adenomas might be helpful to predict the development of metachronous adenomas and hence to plan the follow-up of patients with adenomatous polyps after polypectomy.

Growth of colorectal polyps: redetection and evaluation of unresected polyps for a period of three years

BACKGROUND, AIMS, AND PATIENTS: In a prospective follow up and intervention study of colorectal polyps, leaving all polyps less than 10 mm in situ for three years, analysis of redetection rate, growth, and new polyp formation was carried out in 116 patients undergoing annual colonoscopy. The findings in relation to growth and new polyp formation were applied to 58 subjects who received placebo.

RESULTS

Redetection rate varied from 75-90% for each year, and was highest in the rectum and sigmoid colon. There was no net change in size of all polyps in the placebo group, however, polyps less than 5 mm showed a tendency to net growth, and polyps 5-9 mm a tendency to net regression in size, both for adenomas and hyperplastic polyps. This pattern was verified by computerised image analysis. Patients between 50 and 60 years showed evidence of adenoma size increase compared with the older patients, and the same was true for those with multiple adenomas (four to five) compared with those with a single adenoma. The new adenomas were significantly smaller and 71% were located in the right side of the colon. Patients with multiple adenomas had more new polyps at all the follow up examinations than patients with a single adenoma. One patient developed an invasive colorectal carcinoma, which may be evolved from a previously overlooked polyp. Two polyps, showing intramucosal carcinoma after follow up for three years, were completely removed, as judged by endoscopy and histological examination.

CONCLUSIONS

The results show that follow up of unresected colorectal polyps up to 9 mm is safe. The consistency of growth retardation of medium sized polyps suggests extended intervals between the endoscopic follow up examinations, but the increased number of new polyps in the proximal colon indicates total colonoscopy as the examination of choice. The growth retardation of the medium sized polyps may partly explain the discrepancy between the prevalence of polyps and the incidence of colorectal cancer.

Incidence and recurrence rates of colorectal adenomas: a prospective study

BACKGROUND/AIMS

The frequency of colorectal adenomas, the precursor lesions for most cases of colorectal carcinoma, has been generally measured as prevalence rates of adenomas at autopsy or colonoscopy. The aim of this study was to estimate the incidence rate of adenomas and compare it with the adenoma recurrence rate.

METHODS

Data on colonoscopies performed in three New York City practices were collected prospectively. The cumulative rate of adenoma diagnosis on repeat colonoscopy was calculated for patients with no abnormalities on index colonoscopy ("incidence" rate) and for patients with adenomas on the index colonoscopy ("recurrence" rate).

RESULTS

The cumulative incidence rate of adenomas at 36 months was 16%, and the cumulative recurrence rate at 36 months was 42% (P < 0.004). The recurrence rate was higher in patients with multiple adenomas than in those with a single adenoma on index colonoscopy, although the increase was not statistically significant.

CONCLUSIONS

Although the recurrence rate has always been assumed to be elevated, this study is the first to compare the recurrence rate of adenomas with the incidence rate directly and to show that the recurrence rate is indeed elevated.

Growth of colorectal polyps: recovery and evaluation of unresected polyps of less than 10 mm, 1 year after detection

BACKGROUND AND METHODS

Colonoscopic 1-year control of polyps of less than 10 mm left in situ was carried out in 103 (89%) of 116 originally examined patients.

RESULTS

Analysis showed an 85% recovery: 91% and 81% for polyps of 5-9 mm and < 5 mm, respectively. The recovery was significantly related to size and localization, whereas the growth rate was inversely correlated to the originally measured diameter. A linear relationship was demonstrated between anus-to-polyp distances 1 year apart, with a normalized agreement index of 0.70. In only 1 of 189 polyps, an increase of diameter to > 10 mm was demonstrated. The 79 new polyps in 52 (50%) of the patients were significantly smaller, more often right-sided, and related to multiplicity of polyps at the initial examination but not to growth of recovered polyps or cleansing status.

CONCLUSION

An acceptable recovery and growth rate of polyps < 10 mm seems to justify the continuation of the study for the remaining 2 years.

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.

Rectal epithelial cell proliferation patterns as predictors of adenomatous colorectal polyp recurrence

To determine whether proliferative patterns in flat rectal mucosal samples can predict the recurrence of adenomatous colorectal polyps, after polypectomy, biopsy specimens from normal looking rectal mucosa were obtained at endoscopy from 55 patients diagnosed for the first time as having adenomatous colorectal polyps. Epithelial cell proliferation was assessed in biopsy specimens through 3H-thymidine autoradiography. After polypectomy, patients were followed for 24 months and underwent complete colonoscopy every 6 months to detect and remove any metachronous lesions. In 40 patients second biopsy specimens were taken during one of the follow up colonoscopies to evaluate the stability of proliferative indices over time. The ratio of labelled (S phase) to total cells (labelling index) for the entire crypt, as well as ratios for each of the five equal compartments into which the crypt had been divided longitudinally, was calculated for each patient. Mean labelling indices for upper crypt compartments 3 and 4 + 5 in the 22 patients in whom polyps recurred were significantly higher (respectively p < 0.05 and p < 0.01) than those of the 33 without recurrence suggesting that an upward shift of the crypt's replicative compartment is associated with polyp recurrence. Labelling indices remained essentially unchanged in those patients who underwent biopsy twice. Reproducible kinetic parameters such as these might be useful in planning follow up of patients with adenomatous polyps after polypectomy.

Antioxidant vitamins or lactulose for the prevention of the recurrence of colorectal adenomas. Colorectal Cancer Study Group of the University of Modena and the Health Care District 16

Colonic adenomas represent the natural precursor lesions of most colorectal cancers. The treatment of choice is endoscopic polypectomy. However, after endoscopic removal, polyps recur in a large fraction of cases. Thus, we evaluated the effect of antioxidant vitamins or lactulose on the recurrence rate of adenomatous polyps. After polypectomy, 255 individuals were randomized into three groups. Group 1 was given vitamin A (30,000 IU/day), vitamin C (1 g/day), and vitamin E (70 mg/day); Group 2 was given lactulose (20 g/day); Group 3 received no treatment. Forty-six subjects had to be excluded because the histologic diagnosis was not consistent with adenoma. The remaining 209 individuals were included in the analysis according to the "intention to treat" criterion, though 34 did not adhere to the scheduled treatment or were lost during the follow-up. Subjects were followed at regular intervals for an average of 18 months. Polyps recurring before one year from index colonoscopy were considered missed by the endoscopist. In the 209 evaluable subjects, the percentages of recurrence of adenomas were 5.7 percent, 14.7 percent, and 35.9 percent in the vitamins, lactulose, and untreated groups, respectively. The fraction of subjects remaining free of adenomas, estimated by Kaplan-Meier survival curves, was significantly different among the three groups (log-rank chi-squared = 17.138; P < 0.001). Using Cox's regression analysis, treatment was the only variable that significantly contributed to the model (regression coefficient = 0.905; P < 0.001). In conclusion, either antioxidant vitamins or, to a lesser extent, lactulose lower the recurrence rate of adenomas of the large bowel and can be proposed as chemopreventive agents, at least in high-risk individuals.

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.

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.

Primary colonoscopy

There is good evidence that colonoscopy, in expert hands, is the most accurate investigation for the diagnosis of colorectal disease, and it also allows histological confirmation and therapeutic procedures to be carried out. Furthermore, by screening high-risk groups together with regular follow-up of patients with known colorectal neoplasia and surveillance of long-standing ulcerative colitis patients, it may be possible to reduce the incidence of colorectal cancer. However, at the present time, the lack of widespread availability and the variability in the quality of examinations precludes the employment of colonoscopy as the first-line investigation in colorectal disease. Flexible sigmoidoscopy combined with good quality double contrast barium enema is a reasonable alternative in the majority of cases, reserving colonoscopy for investigation of the elderly and high-risk patients, together with surveillance of patients with premalignant conditions. Technologically, colonoscopy has probably reached its peak and it is now necessary to make provision for more widely available colonoscopy services, provided by adequately trained endoscopists who can guarantee total colonoscopy in more than 90% of cases safely and rapidly. This requires structured training programmes for gastrointestinal physicians and surgeons and ultimately changes in patterns of working practice if adequate numbers of colonoscopy sessions capable of dealing with a steadily increasing workload are to be achieved.

Usefulness of performing colonoscopy one year after endoscopic polypectomy

This retrospective study defines a population with neoplastic colonic polyps who have had colonoscopic polypectomy and, in follow-up within one year, a repeat colonoscopic evaluation. The population was broken down into two groups, one group that had polyps at the second examination and one group that did not. This study determined which factor(s) were significant among this population in distinguishing whether new polyps would be found at one year follow-up. The authors found that among the many variables studied, only polyp multiplicity was significant in predicting polyp recurrence. More than one polyp found at index colonoscopy led to a significant chance of having a new polyp after only one year. Also, it was demonstrated that these "new" polyps were unlikely to have been "missed" polyps from the initial colonoscopy. Because of the shifting location, smaller size, and fewer instances of histologic atypia in these polyps compared with those at index examination, the authors believe that polyps found after one year may be assumed to have arisen de novo. Finally, the authors show that a significant number of polyps occur beyond the reach of the flexible sigmoidoscope (approximately 60 cm). The authors recommend that patients who have polyps undergo a colonoscopic examination. When patients are re-evaluated after having colonoscopic neoplastic polypectomy, they should undergo repeat colonoscopy.

Tumor progression by DNA flow cytometry in human colorectal cancer

We wished to better understand the role of aneuploidy during the progression of human colorectal cancer. Fresh or frozen multiple samples from 221 human colorectal adenomas, 93 carcinomas, and corresponding control mucosa were investigated using high-resolution DNA flow cytometry. A total number of 164 DNA abnormal clones were observed and characterized by a quantitative index of DNA aneuploidy (DI). In precancerous lesions the vast majority of DNA abnormal clones (almost 3/4 in adenomas with mild to moderate dysplasia) was hypo- and hyper-diploid with DI values from 0.8 to 1.2 (near-diploidy). In moderately to poorly differentiated carcinomas the vast majority of abnormal clones was near-triploid and hypotetraploid with DI values from 1.4 to 1.8 (near hypertriploidy) and only 12% were near-diploid. Adenomas with foci of carcinomas, a group of special interest since they represent a link in colorectal tumor progression, had median triploid DNA content. In addition to an increase in DI values, the carcinomas had a clear increase in the proportion of cells actively synthesizing DNA (S-phase fraction). These results are interpreted as evidence for a ploidy-evolution model according to which near-diploid clones in adenomas at early stages of dysplasia would derive from abnormal mitotic cells that divide their DNA unequally between two daughter cells. Tetrapolidization of these near-diploid cells and successive DNA loss would then lead in later stages of tumor progression to near-hypertriploid clones characterized by a balance of chromosomes bearing growth-promoting and growth-suppressing genes confering a selective proliferative advantage.

The benefit of colonoscopy

In a prospective study involving 833 consecutive outpatient and open-access colonoscopies, attempts were made to characterize the benefit of colonoscopy in terms of both predicted and unpredicted findings and therapeutic procedures. The endoscopist therefore predicted the endoscopic findings before the endoscopy. The results were compared for the different indications for colonoscopy. The overall agreement between the predictions and the colonoscopic findings was 61%. Clinically significant abnormalities were found in about half the examinations. The most frequent abnormal findings were benign polyps (24%), inflammatory bowel disease (17%), and malignancy (5%). In about half the patients with a malignancy the indication for colonoscopy was rectal bleeding, and half of the malignancies were not predicted. The greatest benefit of colonoscopy was found in patients referred because of overt rectal bleeding or occult faecal blood, and abnormal barium enema or endoscopy findings. The importance of complete colonoscopy in connection with operation for colorectal carcinoma is emphasized.

Colonoscopic management of polypoid lesions

Virtually all colonic polyps may be removed endoscopically and with great safety provided the endoscopist is experienced with diagnostic colonoscopy as well as electrosurgical principles and hazards. Many polypoid protrusions will not require total removal or even sampling. Those lesions thought to need formal surgical management will require not only adequate tissue sampling but also accurate localization for the surgeon.

Endoscopic screening and surveillance for gastrointestinal malignancy

In the US, the cumulative lifetime risk of developing carcinoma of the upper gastrointestinal tract is less than 1 per cent, premalignant conditions are uncommon, and esophageal and gastric malignancies are rarely curable even when identified early. Endoscopic screening of the upper gastrointestinal tract in asymptomatic persons thus cannot be justified. Surveillance of persons with certain uncommon conditions associated with a higher risk of upper gastrointestinal cancer may be of benefit. These conditions include achalasia, Barrett's esophagus, chronic atrophic gastritis with intestinal metaplasia, familial polyposis coli, gastric polyps, lye stricture, Plummer-Vinson syndrome, and tylosis. In the lower gastrointestinal tract, however, the lifetime risk of developing carcinoma is 5 per cent, premalignant conditions and lesions are common, and carcinoma is curable when detected at an early stage. Sigmoidoscopic screening of asymptomatic adults has been advocated by the American Cancer Society but has not become widely practiced because of its cost, required physician effort, low overall yield, and poor patient compliance. Surveillance by flexible sigmoidoscopy is recommended for persons at slightly increased risk of colorectal carcinoma who have prior breast or gynecologic malignancy or a family history of colorectal malignancy. Colonoscopic surveillance is recommended for patients with high risk of colorectal cancer who have had prior colorectal carcinoma or adenoma or who have inflammatory bowel disease or a ureterosigmoidostomy.

Screening for colorectal carcinoma

Colorectal carcinoma will occur in some 147,000 Americans this year. This disease accounts for 15% of all cancers and 12% of all cancer deaths. Screening for colorectal carcinoma may allow the disease process to be found earlier and, in some situations such as when polyps are found and removed, may even prevent the disease. The two main modalities of screening are fecal occult blood tests and sigmoidoscopy. By general screening of asymptomatic patients as well as by selective screening of those at high risk, there is hope that the incidence and mortality of this cancer will diminish. Absolute confirmation of this benefit is still lacking, making the evaluation of the cost-effectiveness of this screening somewhat questionable. Current educational efforts are designed to increase compliance and to help solve some of these unanswered questions.

The influence of age on colonic epithelial cell proliferation

Cancer of the large bowel is relatively rare in persons younger than 50 years of age, but its incidence increases sharply in persons older than 60 years of age. We thought that the evaluation of colonic cell proliferation, an accurate biomarker of predisposition to colorectal cancer, might help to elucidate the susceptibility of elderly persons to this common malignancy. Accordingly, 30 persons with normal lower endoscopy results were divided into three age groups (30 to 50,51 to 65, and 66 to 90 years of age; Groups 1, 2, and 3, respectively). Samples of rectal mucosa were taken at endoscopic examination, incubated with [3H]thymidine, and processed with standard autoradiographic techniques. At histologic examination, each intestinal hemicrypt was divided into five equal longitudinal compartments from the fundus (compartment 1) to the surface (compartment 5). The number and the position of labeled cells along the crypt were recorded. The total labeling index (LI) (the ratio of labeled cells to total cells) was significantly higher in Group 3 than in the two other groups. Similarly, the LI per crypt compartment in the most superficial portions of the crypts was consistently higher in persons older than 65 years of age (P less than 0.01 at least), indicating an expansion of the proliferative zone to the most superficial portion of the colonic glands. When the proliferative profiles of the three groups of subjects investigated were compared with those of patients with polyps, an almost complete overlap of values was observed between this population at increased risk for cancer and the subjects in Group 3. We conclude that aging is characterized by an overall increase of epithelial cell proliferation in colorectal mucosa and by an upwards expansion of the proliferative compartment, similar to that observed in a population at risk for cancer of the large bowel.

Follow-up of patients with colonic polyps containing severe atypia and invasive carcinoma. Compliance, recurrence, and survival

Between January 1975 and December 1984 1769 polyps were endoscopically removed from 1219 patients. Eight percent of these patients had polyps containing severe atypia and 5.0% had polyps containing invasive cancer. A close postoperative surveillance program was followed by only a few patients, but compliance improved with longer follow-up intervals. Metachronous polyps were observed with similar frequency in patients with benign polyps (34.8%) and those with polyps containing severe atypia (23.8%) or cancer (41.7%). Patients in whom malignant polyps were endoscopically removed had a 5-year survival rate of 84.3% that did not differ from that of patients' whose polyps contained severe atypia (79.0%). It was concluded that endoscopic removal of malignant polyps with favorable histologic conditions does not impair survival. The follow-up program of these patients should be adapted to that of patients with benign polyps, a procedure that may even improve patient compliance.

DNA flow cytometry of endoscopically examined colorectal adenomas and adenocarcinomas

DNA ploidy of 64 colorectal adenomas and 49 adenocarcinomas, examined endoscopically, was studied by flow cytometry. We found DNA aneuploidy in none of the 105 normal mucosa samples (0%), in 20 adenomas (31%), and in 36 adenocarcinomas (74%). DNA ploidy of adenomas correlated with size (P = 0.02) and degree of dysplasia (P less than 0.01) but not with histologic type. Adenomas had a 45% incidence of DNA aneuploid stem lines in the DNA index range of 0.80-1.20, compared with 8% in the case of adenocarcinomas. The distribution of the DNA index values of adenocarcinomas was approximately normal, with a mean value 1.63 +/- 0.28. The mean DNA index for the three cases of "carcinoma in adenoma" with invasion of the stalk of the adenoma was 1.52 +/- 0.18. These results, using DNA flow cytometry, provide evidence for the progression of colorectal adenoma to adenocarcinoma. The classification of adenomas according to DNA ploidy may be information of considerable practical value to the clinician in predicting risk of further adenomas and/or risk of cancer.

Follow-up colonoscopy in patients with colorectal adenomatous polyps

Forty-four asymptomatic patients with adenomatous colorectal polyps were followed by repeated colonoscopies and subsequent removal of new polyps. The median follow-up time was 34 months (range, 4 to 131 months). Twenty-six patients (59 percent) developed new adenomatous polyps. The recurrence rate was 69 percent in patients with multiple polyps compared with 54 percent in patients with a single polyp. The location of new polyps was in the same colonic segment in 81 percent of the patients, but not at the same site in the colon where a previous polyp had been removed. The histopathology and size of new polyps compared with the initial polyps showed a significant improvement in histopathology toward more benign polyps (P less than 0.02) and smaller polyps (P less than 0.001). In patients who initially had single adenomatous polyps, new polyp(s) were diagnosed after a mean time of 23 months compared with 13.5 months in patients with two or more adenomatous polyps initially. Patients with atypia in initial polyp(s) developed new polyp(s) after a mean time of 11 months compared with 23 months in patients without atypia. The mean time from a colon with no polyps to the diagnosis of a new adenomatous polyp less than 5 mm in size was 11.5 months, which was a statistically significant shorter time than the 19.4 months observed for the development of polyps 5 mm or larger.

Repeat colonoscopy after endoscopic polypectomy

The records of all patients undergoing endoscopic polypectomy between December 1979 and December 1982 were reviewed. One hundred seventy-two patients underwent colonoscopic polypectomy in the absence of carcinoma or inflammatory bowel disease. Of these, the polyp could not be retrieved in 4, and 19 were lost to follow-up. One hundred forty-nine patients underwent subsequent endoscopy from one to four years after the initial polypectomy. Seventy-five (50.3 percent) of the patients developed new polyps. Although 61 of the 75 patients with new polyps were identified in the first two years, new polyps were noted throughout all four years. The presence of multiple polyps on the initial examination was statistically significant in predicting new polyps. The age and sex of the patients, size of the polyps, and the presence of atypia did not identify patients at higher risk for new polyps. The data indicate that new polyps are more likely to develop in patients who had a previous polyp. It would appear that annual examinations should be performed until two successive examinations are negative. Following a second negative examination, reexamination at two- or three-year intervals, unless symptomatic, would appear to be adequate.

Risk of colorectal cancer in adenoma-bearing individuals within a defined population

Assuming that all colorectal cancers develop from preexisting adenomas, the annual conversion rate, defined as the number of cancers occurring each year as a percentage of all adenoma-bearing individuals, was determined. The number of adenoma-bearing individuals in the living population of northern Norway was estimated in each cohort for the period 1974-76 by determining the prevalence of colorectal adenomas in an autopsy population of 271 consecutive cases, representative of the population of the area with regard to underlying causes of death. During the 10-year period 1974-1983 a total of 656 colorectal cancers were recorded among an estimated number of 26,419 adenoma-bearing individuals aged over 35 years. The annual conversion rate was found to be 0.25%, indicating that an average adenoma-bearing individual is only at a moderate risk of colorectal cancer. The annual conversion rates for individuals having large adenomas, or adenomas with villous structures, or severe dysplasia were roughly estimated to be 3%, 17% and 37% respectively, assuming that colorectal cancer develops from one of these sub-groups of adenomas only.

Colorectal adenomas. Distribution, incidence of malignant transformation, and rate of recurrence

In 282 patients, 731 colon polyps (643 adenomas and 88 hyperplastic polyps) were extirpated endoscopically or biopsied and investigated histologically. Localization of the adenomas with various degrees of atypia and the hyperplastic polyps, as well as their size distribution, were determined. In 66 patients with adenoma polypectomy on the first examination, one or more control colonoscopies were carried out (in all, 107). The median period of follow-up observation was 31 months. Thirty percent of the one-year control colonoscopies after polypectomy revealed new adenomas. The statistical analyses showed that patients with singular adenomas, on initial investigation, develop significantly fewer adenomas in the further course than patients with multiple initial findings, especially in negative results in the one-year control. The size of new adenomas found during the first 24 months after polypectomy does not exceed 10 mm. On the basis of these results and the literature data available so far, a follow-up program is presented for discussion.

The significance of synchronous carcinoma and polyps in the colon and rectum

The relationship of colorectal carcinoma with polyps was studied retrospectively in 1202 patients. The incidence of synchronous carcinoma (SC) and metachronous carcinoma (MC), prognosis, and recurrence patterns were studied. Synchronous polyps (SP) were found in 36% of the patients. SC was found in 4.4% of the patients, and MC developed in 3.5% of patients. The incidence of SC and of MC increased with SP, and varied according to number, size, and histologic features of the polyps. The adjusted 5-year survival rate was improved in patients with SP compared with those without SP, both overall (79% versus 64%, respectively) and by Dukes' Stage B (87% versus 73%, respectively) and Dukes' Stage C (56% versus 39%, respectively). The pattern of relapse was the same for the SP and non-SP groups. Subtotal colectomy is recommended for colorectal carcinoma and SP in good-risk patients.