Screening and surveillance for colorectal carcinoma

Matrix metalloproteases expression in different histological types of colorectal polyps

INTRODUCTION

Colorectal carcinoma (CC) may begin as benign polyps, which may be classified in different histological types with a different risk to develop cancer. Matrix metalloproteases (MMPs) are able to degrade all components in the extracellular matrix and are important tissue-remodeling enzymes and key elements in tumor invasion and metastasis. The aim of this study was to investigate the expression and clinical relevance of MMPs in different histological types of colorectal polyps.

METHODS

The expression levels of MMP-1, 2, 7, 9, 11, 13 and 14 were analyzed by real-time PCR, Western-blot and immunohistochemistry in 50 patients with different histological types of colorectal polyps, 28 of which developed CC.

RESULTS

The results indicate that hyperplastic polyps had the lowest levels of MMP-1 and MMP-7, tubular polyps showed higher levels of both MMP-7 and MMP-14, and tubulovillous adenoma showed higher levels of MMP-1, MMP-7 and MMP-14.

CONCLUSION

MMP expression was decreased in hyperplastic, tubular and tubulovillous adenoma polyps from patients who developed CC. Our findings suggest that MMP expression may be a pathological marker of colorectal polyps and for cancer susceptibility, which may improve strategies for CC prevention based on screening colonoscopy.

African Americans should be screened at an earlier age for colorectal cancer

BACKGROUND

African Americans (AAs) have been shown to exhibit a higher incidence of colorectal cancer and experience lower survival compared with whites. There is disagreement regarding the age at which to initiate screening in AAs.

OBJECTIVES

To calculate the age-specific incidence in AAs compared with whites while controlling for differences in socioeconomic status (SES) and to calculate the joinpoint at which the incidence begins to increase in each race.

DESIGN

Retrospective database review.

SETTING

Surveillance, Epidemiology, and End Results database.

PATIENTS

All patients with adenocarcinoma of the colon or rectum from 2000 through 2011 in the SEER 18 database.

INTERVENTIONS

We calculated the joinpoint of the upward trend of the age-adjusted incidence rate to determine the age at which the slope of the incidence curve began to increase in each race, while controlling for differences in SES by using a composite socioeconomic index.

MAIN OUTCOME MEASUREMENTS

Age-adjusted incidence of colon and rectal cancer.

RESULTS

The age-specific incidence of colorectal cancer (cases per 100,000 population) was 0.3 versus 0.4 in whites compared with AAs at 20 years of age. At 50 years of age, the incidence was 44.2 compared with 62.6 in whites compared with AAs. The model indicated a joinpoint at 47 years of age for whites (95% confidence interval, 45-49) and 43 for AAs (95% confidence interval, 42-45) (P < .001.) When SES was considered in stratification, joinpoints for whites were 48, 47, and 46 at high, middle, and low SES, respectively. Conversely, joinpoints of 43, 44, and 42 in the corresponding SES for AAs were noted (P ≤ .001).

LIMITATIONS

There was no intervention, and we cannot conclude that changing screening policy would affect this disparity.

CONCLUSION

There is a disparity in the age-specific incidence of colorectal cancer in AAs compared with whites beginning at 45 years of age. These differences persist across socioeconomic strata.

Study of the expression of toll-like receptors in different histological types of colorectal polyps and their relationship with colorectal cancer

PURPOSE

Dysregulation of toll-like receptors (TLR) signaling can result in chronic inflammatory and over-exuberant repair responses. The aim of this study was to investigate the expression and clinical relevance of TLR in colorectal polyps.

METHODS

The expression levels of six TLR were analyzed in 70 patients with different histological types of colorectal polyps, 38 of which developed colorectal carcinoma (CC). These analyses were performed by real-time polymerase chain reaction, western blot, and immunohistochemistry.

RESULTS

TLR9 expression was higher in hyperplastic or adenomatous polyps compared to other polyp types. Hyperplastic polyps also showed increased TLR7 levels compared to the other polyp types. TLR7 expression was lower in both hyperplastic and tubulovillous adenoma polyps from patients who developed CC. TLR9 expression was decreased in hyperplastic and villous polyps from patients who developed CC.

CONCLUSIONS

Our findings suggest a possible protective role of TLR expression against malignant transformation in the colorectal mucosa. TLR may represent a pathological marker of CC risk in colorectal polyps. The role of these factors in the pathology of colorectal polyps deserves further investigation.

Colorectal, prostate, and skin cancer screening among Hispanic and White non-Hispanic men, 2000-2005

BACKGROUND

Hispanic men have lower colorectal, prostate, and skin cancer screening rates than white non-Hispanic men. Programs designed to increase screening rates, including the national Screen for Life campaign specifically for promoting colorectal cancer (CRC) screening, regional educational/research programs, and state cancer control programs, have been launched. Screen for Life and some intervention programs included educational materials in Spanish as well as English.

OBJECTIVE

To assess whether CRC as well as prostate and skin cancer screening rates among Hispanic and white non-Hispanic men changed between 2000 and 2005.

METHODS

Cancer screening rates were compared between 2000 and 2005 using the National Health Interview Survey data. The age ranges of the study subjects and definitions of cancer screening were site specific and based on the American Cancer Society recommendations.

RESULTS

Hispanic men were less likely to comply with cancer screening guidelines than white non-Hispanic men. However, significant increases in CRC endoscopic screening were observed in both ethnic groups. It increased 2.1-fold and 2.4-fold for Hispanics and white non-Hispanics, respectively (P < .05). In contrast, the use of home fecal occult blood tests decreased among white non-Hispanics but remained similar among Hispanics. Prostate-specific antigen screening remained stable, while the use of skin cancer screening tended to increase among both groups.

CONCLUSION

Although cancer screening rates may be affected by multiple factors, our study suggested the intervention programs such as the Centers for Disease Control and Prevention's national Screen for Life campaign may have raised CRC screening awareness and may contributed to the increase in endoscopic screening rates among both ethnic groups.

Trends in cancer screening among Hispanic and white non-Hispanic women, 2000-2005

BACKGROUND

Hispanics are the largest and fastest growing ethnic group in the United States. Compared with white non-Hispanic women, however, Hispanic women have significantly lower cancer screening rates. Programs designed to increase cancer screening rates, including the national Screen for Life campaign, which specifically promoted colorectal cancer (CRC) screening, regional educational/research programs, and state cancer control programs, have been launched. Screen for Life and some of these other intervention programs have targeted Hispanic populations by providing educational materials in Spanish in addition to English.

METHODS

The objective of this study was to compare changes in colorectal, breast, and cervical cancer screening rates from 2000 to 2005 among Hispanic and white non-Hispanic women, using data from the National Health Interview Survey (NHIS). The age ranges of study subjects and the definitions of cancer screening were site specific and based on the American Cancer Society (ACS) screening recommendations.

RESULTS

Although overall screening rates were found to be lower among Hispanic women, CRC screening increased about 1.5-fold among both Hispanic and white non-Hispanic women, mainly driven by endoscopic screening, which increased 2.1-fold and 2.9-fold, respectively, from 2000 to 2005 (p < 0.01). Fecal occult blood testing (FOBT) for CRC declined among white non-Hispanic women and remained stable among Hispanic women during the same period. Mammogram and Pap smear screening tended to decline during the study period for both ethnic groups, especially white non-Hispanic women.

CONCLUSION

Although cancer screening rates may be affected by multiple factors, culturally sensitive and linguistically appropriate national educational programs may have contributed to the increase in endoscopic CRC screening compliance.

Perforation of the colon and rectum--a newly recognized complication of CT colonography

CT colonography (CTC) and conventional colonoscopy may have similar efficacy for detection of polyps > 6 mm. Perforation of the colon and rectum is a relatively rare, but potentially morbid complication of CTC, especially in symptomatic patients. Older age and underlying concomitant colon pathology increase the risk of perforation. This review describes the incidence, clinical features, and management of colon perforations at CTC, a study that was considered risk-free until recently.

Colonic perforation at CT colonography: assessment of risk in a multicenter large cohort

PURPOSE

To assess retrospectively the incidence, clinical features, and treatment of colonic perforation at computed tomographic (CT) colonography in a large multicenter cohort.

MATERIALS AND METHODS

The study was performed in accordance with the institutional ethics committees' requirements of a retrospective review in each of the participating centers, and no informed consent was required. A review of all patients who underwent CT colonography between January 2001 and December 2004 in 11 medical centers representing more than 95% of studies performed in a single country was performed to determine the rate of colorectal perforation. Data about patient demographics and patient- and procedure-related risk were recorded. Information about the location of the perforation, its likely mechanism, and treatment was collected. Analysis included calculation of rates of colonic perforation and surgical treatment and of 95% confidence intervals.

RESULTS

A total of 11 870 CT colonographic studies were performed in 6837 (57.6%) men and 5033 (42.4%) women (mean age, 59.9 years; range, 38-90 years) with seven cases of colorectal perforation, yielding a risk rate of 0.059% (one of 1696 studies; 95% confidence interval: one of 974, 971 of 6537). The mean age of the patients with perforation was 77.8 years. Six (84%) of seven cases of perforation occurred in symptomatic patients at high risk for colorectal neoplasia, and one (16%) occurred in an asymptomatic average-risk patient. All studies were performed after insufflation of room air. Six (84%) cases of perforation occurred in patients in whom a rectal tube was inserted, and in five of them, a balloon was inflated. Five (71%) cases of perforation occurred in the sigmoid colon; and two (29%), in the rectum. Four (57%) patients (one in 2968 patients; 95% confidence interval: 1.5 in 10 000, 14.7 in 10 000) required surgical treatment. Possible factors that contributed to perforation were left inguinal hernia containing colon (n = 4), severe diverticulosis (n = 3), and obstructive carcinoma (n = 1).

CONCLUSION

Perforation of the colon and rectum is a rare complication of CT colonography. Older age and underlying concomitant colonic disease were present in patients with perforation.

A scoring system for the strength of a family history of colorectal cancer

BACKGROUND

Family history of colorectal cancer is associated with an increased risk for the disease, although there are many combinations of family history that are hard to correlate with risk status. A scoring system for family history of colorectal cancer was designed to make risk more readily quantifiable.

METHODS

A colonoscopy database was used to test the following points system: each first-degree relative with colorectal cancer = 3 points; each second-degree relative with colorectal cancer = 1 point. Families with one or more first-degree relative affected under 50 years of age = an extra 3 points. Families with one or more second-degree relative affected under 50 years of age = an extra 1 point. Families with multiple relatives on the same side of the family = an extra 3 points (first-degree relatives), 1 point (second-degree relatives), or 2 points (first-degree and second-degree relatives). Points were added and categories defined as follows: low risk, 1 to 4 points; medium risk, 5 to 7 points; high risk, 8 to 10 points; very high risk, >10 points. A control group of average-risk patients having screening colonoscopy was used. Categories were compared in number of adenomas, hyperplastic polyps, and cancers.

RESULTS

The records of 992 patients were used to test the system. Mean adenomas per patient per group were 0.4 for controls, 1.0 for low risk, 1.0 for medium risk, 1.7 for high risk, and 1.7 for very high risk. Cancers per group were 2 of 196 for controls, 8 of 513 for low risk, 3 of 171 for medium risk, 3 of 84 for high risk, and 1 of 28 for very high risk. The score categories were combined to produce revised risk levels of low (score 1 to 7) and high (>7). Average adenomas per patient in the revised categories were 0.4 (control), 1.0 (low risk), and 1.7 (high risk). The odds ratio of having one to two adenomas was 1.73 (1.19-2.50, 95% confidence limits) in the low-risk group and 2.39 (1.41-4.01) in the high-risk group. Odds ratios for having three or more adenomas were 5.70 (2.44-13.32) in the low-risk group and 10.35 (3.97-26.97) in the high-risk group.

CONCLUSION

In the two-category system proposed here of quantifying familial risk of colorectal cancer, patients having less than 8 points were at low risk and those with 8 or more were at high risk. Surveillance and chemoprevention protocols can be designed through use of these risk categories. A scoring system for family history of colorectal cancer can make risk assessment easier and facilitate both collaborative studies and patient triage into appropriate screening programs.

Risk of perforation after colonoscopy and sigmoidoscopy: a population-based study

BACKGROUND

Although the risk of bowel perforation is often cited as a major factor in the choice between colonoscopy and sigmoidoscopy for colorectal screening, good estimates of the absolute and relative risks of perforation are lacking.

METHODS

We used a large population-based cohort that consisted of a random sample of 5% of Medicare beneficiaries living in regions of the United States covered by the Surveillance, Epidemiology, and End Results (SEER) Program registries to determine rates of perforation in people aged 65 years and older. We identified individuals who were cancer-free and had undergone colonoscopy or sigmoidoscopy between 1991 and 1998, calculated both the incidence and risk of perforation within 7 days of the procedure, and explored the impact on incidence and risk of perforation of age, race/ethnicity, sex, comorbidities, and indication for the procedure. We also estimated the risk of death after perforation. Risks were calculated with odds ratios (ORs) and 95% confidence intervals (CIs). All statistical tests were two-sided.

RESULTS

There were 77 perforations after 39 286 colonoscopies (incidence = 1.96/1000 procedures) and 31 perforations after 35 298 sigmoidoscopies (incidence = 0.88/1000 procedures). After adjustment, the OR for perforation from colonoscopy relative to perforation from sigmoidoscopy was 1.8 (95% CI = 1.2 to 2.8). Risk of perforation from either procedure increased in association with increasing age (P(trend)<.001 for both procedures) and the presence of two or more comorbidities (P(trend)<.001 for colonoscopy and P(trend) =.03 for sigmoidoscopy). Compared with those who were endoscopied and did not have a perforation, the risk of death was statistically significantly increased for those who had a perforation after either colonoscopy (OR = 9.0, 95% CI = 3.0 to 27.3) or sigmoidoscopy (OR = 8.8, 95% CI = 1.6 to 48.5). The risk of perforation after colonoscopy, especially for screening procedures, declined during the 8-year study period.

CONCLUSIONS

The risk of perforation after colonoscopy is approximately double that after sigmoidoscopy, but this difference appears to be decreasing. These observations should be useful to clinicians making screening and diagnostic decisions for individual patients and to policy officials setting guidelines for colorectal cancer screening programs.

Colon cancer: detection and prevention

Recent data have advanced our ability to detect, survey, and manage patients with colonic neoplasia. Current studies and consensus statements increasingly support the role of colonoscopic screening over less invasive testing such as FOBT or FS for appropriately selected individuals. There are many issues, however, that remain unresolved. What is the appropriate surveillance of an individual with a single family member who had colon cancer at an early age? How should family members of suspected HNPCC kindreds be managed? There has yet to be a prospective cohort validation of the Bethesda criteria in directing clinical practice, with the endpoint of mortality reduction. Questions regarding prophylaxis with dietary supplements and medications are exciting areas that are currently under study. As newer technologies become clinically available for molecular diagnostics and screening, and virtual colonoscopy with computed tomography and magnetic resonance disseminates, there will undoubtedly be new questions to be answered regarding their ability to aid in the detection and management of colon cancer.

The limited incorporation of economic analyses in clinical practice guidelines

BACKGROUND

Because there is increasing concern that economic data are not used in the clinical guideline development process, our objective was to evaluate the extent to which economic analyses are incorporated in guideline development.

METHODS

We searched medline and HealthSTAR databases to identify English-language clinical practice guidelines (1996-1999) and economic analyses (1990-1998). Additional guidelines were obtained from The National Guidelines Clearinghouse Internet site available at http://www.guideline.gov. Eligible guidelines met the Institute of Medicine definition and addressed a topic included in an economic analysis. Eligible economic analyses assessed interventions addressed in a guideline and predated the guideline by 1 or more years. Economic analyses were defined as incorporated in guideline development if 1) the economic analysis or the results were mentioned in the text or 2) listed as a reference. The quality of economic analyses was assessed using a structured scoring system.

RESULTS

Using guidelines as the unit of analysis, 9 of 35 (26%) incorporated at least 1 economic analysis of above-average quality in the text and 11 of 35 (31%) incorporated at least 1 in the references. Using economic analyses as the unit of analysis, 63 economic analyses of above-average quality had opportunities for incorporation in 198 instances across the 35 guidelines. Economic analyses were incorporated in the text in 13 of 198 instances (7%) and in the references in 18 of 198 instances (9%).

CONCLUSIONS

Rigorous economic analyses may be infrequently incorporated in the development of clinical practice guidelines. A systematic approach to guideline development should be used to ensure the consideration of economic analyses so that recommendations from guidelines may impact both the quality of care and the efficient allocation of resources.

Bowel surveillance patterns after a diagnosis of colorectal cancer in Medicare beneficiaries

BACKGROUND

Postoperative colon surveillance has been recommended for patients with a diagnosis of local/regional colorectal cancer. The extent to which these recommendations are followed in practice is poorly characterized. Patterns of surveillance after surgery for colorectal cancer were determined by using a large population-based database.

METHODS

This is a retrospective cohort study with cancer registry data linked to Medicare claims. Identified were 52,283 patients treated for local/regional colorectal cancer between 1986 and 1996, and surveillance patterns through 1998 were determined. Surveillance patterns were analyzed by using survival analysis and by computing the proportion of surviving patients who underwent procedures during 4 time periods after treatment: 2 to 14 months, 15 to 50 months, 51 to 86 months and more than 87 months.

RESULTS

Median times to first through fifth surveillance events were 20, 14, 15, 15, and 15 months, respectively. For 17% of the cohort there was no surveillance event. Younger patients were more likely to undergo surveillance. Surveillance patterns were not affected by stage. The proportions of the cohort that underwent no surveillance during the 4 respective time periods were 54%, 52%, 60%, and 69%. The percentages of patients who underwent surveillance annually or more frequently in the latter 3 time periods, respectively, were 19%, 10%, and 5%, or 11% overall, treating the data for the 3 events as a whole. Over the period from 1986 to 1998, the proportion of patients who had no surveillance procedures gradually decreased, whereas the proportion of those who underwent procedures annually or more frequently remained relatively constant.

CONCLUSIONS

During the period from 1986 to 1998 there was low utilization of postdiagnosis colon surveillance in a substantial proportion of elderly patients with a diagnosis of local/regional colorectal cancer. Over time there was a trend toward increasing receipt of any surveillance procedures. The percentages of patients undergoing surveillance annually or more frequently did not change between earlier and later periods.

Detection of the mutated K-Ras biomarker in colorectal carcinoma

This study describes an advantageous, effective protocol for detecting K-Ras mutations in human stool as a prototype screen for colorectal carcinoma (CRC), the third most common malignancy in the United States. A reliable screening test that detects early lesions would contribute to a decrease in mortality. Currently, the only noninvasive screen for CRC is the hemeoccult, test which has a high false-positive rate. Previously, several investigators have identified genetic biomarkers for CRC in stool DNA. The K-Ras oncogene, mutated in 46-50% of CRC tumors, serves as one molecular marker by which stool samples may be evaluated for early detection of adenocarcinomas. DNA was isolated from stool samples by a new method we specifically designed for extracting high-quality DNA using tetradecyltrimethylammonium oxalate [Catrimox-14, Iowa Biotechnology Corp., (currently Qiagen)]. This protocol produces an optimal yield of high-purity DNA, suitable for genotyping. Detection of the human gene in stool samples was enhanced by hybrid selection of the K-Ras sequences, polymerase chain reaction, and single-strand conformation polymorphism. Tumor tissue and preoperative stool samples for eight patients were K-Ras genotyped and compared; stool samples from two asymptomatic, healthy patients were also evaluated in a double-blind format. In seven of eight samples (87%), the genotypes of the stool and colon tissue DNA were the same. Both healthy patients showed wild-type K-Ras. This protocol shows promise for the development of an efficient and accurate screen for CRC.

Biomarkers as surrogates for cancer development

Biomarkers are routinely applied in the management of chronic diseases to reduce morbidity and mortality through early diagnosis, as well as to assess the necessity for, and responsiveness to, applied interventions. Biomarkers yield mechanistic insights into layers of biologic organization from molecule to organelle, to cell, and finally to cellular organization and tissue. A step-wise approach to the development of tissue-based biomarkers is presented. These biomarkers may serve as molecular targets for scientific inquiry and intervention, as well as approvable endpoints for clinical trials.

Colorectal cancer screening

Colorectal cancer (CRC) is the third most common cancer in the world, and mortality has remained the same for the past 50 years, despite advances in diagnosis and treatment. Because significant numbers of patients present with advanced or incurable stages, patients with pre-malignant lesions (adenomatous polyps) that occur as result of genetic inheritance or age should be screened, and patients with long-standing inflammatory bowel disease should undergo surveillance. There are different risk groups for CRC, as well as different screening strategies. It remains to be determined which screening protocol is the most cost-effective for each risk catagory. The objective of screening is to reduce morbidity and mortality in a target population. The purpose of this review is to analyze the results of the published CRC screening studies, with regard to the measured reduction of morbidity and mortality, due to CRC in the studied populations, following various screening procedures. The main screening techniques, used in combination or alone, include fecal occult blood tests, flexible sigmoidoscopy, and colonoscopy. Evidence from the published literature on screening methods for specific risk groups is scanty and frequently does not arise from controlled studies. Nevertheless, data from these studies, combined with recent advances in molecular genetics, certainly lead the way to greater efficacy and lower cost of CRC screening.