The workup of the asymptomatic patient with a positive fecal occult blood test

Early detection of colon cancer-the kaiser permanente northwest 30-year history: how do we measure success? Is it the test, the number of tests, the stage, or the percentage of screen-detected patients?

INTRODUCTION

Colorectal cancer (CRC) is the fourth most common malignancy in the Kaiser Permanente Northwest (KPNW) Region. The goals of CRC screening are early diagnosis of cancer in the preclinical state, down-staging of tumors, and increasing survival. This historical review summarizes the screening strategies since 1980 and their impact on early diagnosis, stage, and survival. During this period, the KPNW Tumor Registry documented the stage and survival, and screen-detection status of patients. We have observed that the percentage of screen-detected case measure has provided critical information that has contributed to the present success. CRC screening efforts by the end of 2010 had provided early diagnosis for one-third of patients.

METHODS

KPNW membership has undergone more than 540,000 fecal blood tests, an estimated 130,000 flexible sigmoidoscopies (FS), and more than 100,000 colonoscopies. Since 1980 members older than age 50 years have increased from 48,627 to 137,617. This report represents a review of 5458 patients. Since 1980, 5 distinct periods of CRC screening have been compared. In 1980, the CRC screening practice was primarily office-based fecal occult blood testing (FOBT) and proctosigmoidoscopy. Data from the initial home-based FOBT testing initiative (1985), transitioning to an FS program (1995), adoption of colonoscopy (2005), and subsequent reintroduction of FOBT testing (2006) allows examination of results by period. After ever-increasing promotion of endoscopy, the goal of screening shifted from "screen detection to prevention by polypectomy."

RESULTS

By reexamining the outcomes of the CRC strategies from 1980-2005, the nature of the colonoscopy label of "gold standard" was questioned leading to a return to FOBT testing. Since then, the percentage of screen-detected patients exceeded expectations with a 6-fold increase (5% to 33%) allowing KPNW to reach its highest level of early detection.

DISCUSSION

By examining the KPNW experience, we have come to better understand the significance of effectiveness measures: number of tests, stage of disease, percentage of screen-detected cancers and their relationship to survival. We examined the measures used to assess success and conclude that the current metrics-the number of examinations and disease stage-do not accurately reflect the effectiveness of screening efforts. Early detection of CRC saves lives when a program tests the most at-risk people. Using a good test (FOBT/fecal immunochemical test) that is able to reach more people, rather than the "perfect test" that reaches fewer people, transforms an ineffective program into a successful one. A critical element was the transition of the individual testing to population screening.

Yield of dual endoscopy for positive fecal occult blood test

OBJECTIVES

Dual endoscopy is frequently performed on the same day in patients whose stools are found to be positive on fecal occult blood testing (FOBT). This is often done to localize the potential sources of GI bleed. The diagnostic yield of same day dual upper endoscopy (EGD) and lower endoscopy (colonoscopy) for the detection of positive FOBT is uncertain. In the era of cost-efficient medical practice, we investigated whether a more evidence-based and structured approach could be used to guide physicians to the workup of patients who present with positive FOBT.

METHODS

We performed a retrospective analysis of 309 patients, and 260 patients from this population met our inclusion criteria. Inclusion criteria included FOBT without acute GI hemorrhage, hematochezia, or melena. Patients were required to have had EGD and colonoscopy within the same day (<24 h).

RESULTS

Of 260 patients, a total of 135 (52%) patients had positive findings on colonoscopy and a total of 42 (16.1%) patients had positive findings on EGD. Sixteen (6.1%) had positive EGD and negative colonoscopy; 109 (42%) had positive colonoscopy and negative EGD; and 26 (10%) had positive findings on both EGD and colonoscopy.

CONCLUSIONS

Colonoscopy should be chosen as the initial procedure of choice in the evaluation of patients who present with positive FOBT. Same day dual endoscopy does not seem to be cost-effective.

Finding cancer in primary care outpatients with low back pain: a comparison of diagnostic strategies

OBJECTIVE

To compare strategies for diagnosing cancer in primary care patients with low back pain. Strategies differed in their use of clinical findings, erythrocyte sedimentation rate (ESR), and plain x-rays prior to imaging and biopsy.

DESIGN

Decision analysis and cost effectiveness analysis with sensitivity analyses. Strategies were compared in terms of sensitivity, specificity, and diagnostic cost effectiveness ratios.

SETTING

Hypothetical

MEASUREMENTS

Estimates of disease prevalence and test characteristics were taken from the literature. Costs were represented by the Medicare reimbursement for the tests and procedures employed.

MAIN RESULTS

In the baseline analysis, using magnetic resonance imaging (MRI) as the imaging procedure prior to a single biopsy, strategies ranged in sensitivity from 0.40 to 0.73, with corresponding diagnostic costs of $14 to $241 per patient and average cost effectiveness ratios of $5,283 to $49,814 per case of cancer found. Incremental cost effectiveness ratios varied from $8,397 to $624,781; 5 strategies were dominant in the baseline analysis. Use of a higher ESR cutoff point (50 mm/hr) improved specificity and cost effectiveness for certain strategies. Imaging with MRI, or bone scan followed in series by MRI, resulted in a fewer unnecessary biopsies than imaging with bone scan alone. Cancer prevalence was an important determinant of cost effectiveness.

CONCLUSIONS

We recommend a strategy of imaging patients who have a clinical finding (history of cancer, age > or = 50 years, weight loss, or failure to improve with conservative therapy) in combination with either an elevated ESR (> 50 mm/hr) or a positive x-ray, or using the same approach but imaging directly those patients with a history of cancer.

Accuracy of double-contrast barium enema in diagnosing colorectal polyps and cancer

CRC is a common malignancy, and reduced mortality can be achieved through detection and treatment of early cancers and by removal of colonic adenomas. Although current screening recommendations, especially in the average-risk individual, typically promote the use of FOBT and FS, a substantial minority of colonic cancers and many colonic adenomas are not detected by these methods. Modalities that examine the entire colon, such as the barium enema and colonoscopy, can detect most clinically important colorectal neoplasms; however, their additional costs and potential risks have limited their use as initial screening examinations. But recent changes in governmental policies regarding reimbursement for CRC screening and increasing emphasis on total colon examinations have altered these recommendations. This review on the accuracy of the DCBE has emphasized the detection of colonic polyps and cancers and has updated the changing role of this examination in screening patients at variable risk for CRC. The efficacy of the barium enema depends on many factors that radiologists must understand and control to perform accurate examinations. Current recommendations for CRC screening and approved reimbursement of the barium enema for that purpose provide a new impetus to radiologists to maintain and improve their skills in performing and interpreting this radiologic examination. The barium enema may have a future in the new millennium.

Screening for colorectal cancer

Colorectal cancer is the third most commonly diagnosed cancer and the second leading cause of cancer deaths in the United States. Fortunately, both the incidence and mortality associated with the disease have declined during the past 2 decades. This is likely due, at least in part, to improved efforts at screening and more aggressive removal of adenomatous polyps. However, colorectal cancer screening is still generally underutilized. This article reviews the current status and future outlook for colorectal cancer screening, including a discussion of risk factors for the disease, its anatomic distribution, proposed mechanisms of development from adenomatous polyps, rationale for screening, and screening options. Published literature concerning the cost-effectiveness of colorectal cancer screening is also summarized. The article concludes with a discussion of the emerging consensus regarding the importance of and approaches to screening.

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.

Decision analysis--a helpful tool for clinicians to establish diagnostic-therapeutic guidelines?

In this paper we focus on the question: Does decision analysis provide a framework to assess the value of diagnostic tests in clinical practice and how can it be used by clinicians in establishing diagnostic-therapeutic guidelines. To study this question we performed two analyses concerning the use of pelvic lymphadenectomy and pedal lymphography for staging prostate cancer. Both analyses yielded similar results as far as the preferred strategy was concerned, yet the approach and set up of the two analyses were different. The first analysis was performed in accordance with the textbooks on decision analysis. However, using this traditional approach we encountered some difficulties: in structuring the decision tree, in eliciting values for the quality of life parameters, and in interpreting the results. These difficulties urged us to modify the approach, presented in the second analysis. In this second analysis, the decision problem was split into several consecutive decision problems which corresponded to the questions posed by the clinicians. Longevity and quality of life were considered separately and the consequences of treatment and testing, which affect the quality of life of the patients, were indicated by just two parameters. Finally, the result of the analysis was expressed in clinically meaningful terms. The second analysis is compared with different approaches presented in the literature for analyzing decision problems involving diagnostic tests. Despite some unresolved methodological problems it is concluded that decision analysis provides a good framework for clinicians to structure and analyze complex decision problems.

Innovative therapies in hematology and oncology

As one can see, there are a number of new and exciting advances in the prevention, detection, and treatment of various malignancies. We anxiously await the future to see the exact integration of the tremendous advances taking place in the cellular and molecular biopsy of disease and its application to the therapy of patients.

Filtering strategies in mass population screening for colorectal cancer: an economic evaluation

On the basis of clinical trial data, 13 strategies for initial screening (filtering) for colorectal cancer are modeled for the purpose of economic evaluation. A wide range of detection cost estimates are generated, although ranking options by detection cost ignores the important consideration of undetected cancers. Formulating the problem as one of cost-effectiveness, however, allows the authors to demonstrate that members of a subset of strategies uniquely outperform all others and that the optimum strategy can be identified by the ex ante specification of the valuation of cancers missed on screening.

Implementation of preventive services in an HMO practice

Practice does not conform to guidelines unless the guidelines are specifically implemented and performance is monitored. Several examples of implementation in one health maintenance organization (HMO) are given. These include immunization for influenza and follow up of positive screening tests for colorectal and cervical cancer. Each implementation effort has required the development of systems, which in this HMO are automated. Several issues influencing implementation are discussed, including resource constraints and priorities for the allocation of new resources. Developers cannot expect that their guidelines will be incorporated into clinical practice. They must foster specific implementation plans.

Flexible sigmoidoscopy plus air contrast barium enema versus colonoscopy for suspected lower gastrointestinal bleeding

A randomized, controlled trial was performed to compare the diagnostic yields and cost-effectiveness of two strategies for the evaluation of nonemergent lower gastrointestinal bleeding. Three hundred eighty patients aged greater than or equal to 40 yr were randomized to undergo initial flexible sigmoidoscopy plus air contrast barium enema or colonoscopy; 332 completed the initial studies. Initial colonoscopy detected more cases of polyps less than 9 mm in size, adenomas, and arteriovenous malformations but fewer cases of diverticulosis. No significant difference was found between strategies in the number of patients detected with cancers or polyps greater than or equal to 9 mm in size. In both strategies, cancers were more common in subjects aged greater than or equal to 55 yr (8% overall) than in those aged less than 55 yr (1%). Among patients aged less than 55 yr with suspected lower gastrointestinal bleeding, initial flexible sigmoidoscopy plus air contrast barium enema is a more cost-effective strategy for the detection of colonic neoplasms than initial colonoscopy. However, initial colonoscopy is more cost effective for those aged greater than or equal to 55 yr.

Urinary tract cancers found by homescreening with hematuria dipsticks in healthy men over 50 years of age

In a homescreening study 235 asymptomatic men, 50 years of age and older without known causes of hematuria, tested their urine each week with a chemical reagent strip for the presence of blood for 1 year. Forty-four men had hematuria at least once, and 31 had a full urologic evaluation. Of these, eight were found to have urinary cancers and seven had nonmalignant diseases warranting immediate treatment. In six of these 15 men (only two with cancer) hematuria occurred in over 1/3 of the testings, and in four hematuria was found on microscopic urinalysis at the time of urologic evaluation. The degree of hematuria was unrelated to the seriousness of its cause. We conclude that in this population hematuria occurs intermittently and when found, regardless of quantity or symptoms, serious underlying pathology must be ruled out. Furthermore, regular hematuria home testing offers a promising means of detecting urinary cancers and other diseases that warrant therapy in asymptomatic men 50 years of age and older.

Strategies for screening for colorectal carcinoma

Four tests commonly used in screening strategies to detect colorectal cancer were examined from a cost-effectiveness perspective. Thirteen combinations of the tests were evaluated. Evaluating a positive fecal occult blood test with a double-contrast barium enema study, followed, if necessary, by colonoscopy, is the most cost-effective strategy for individuals at average risk. An alternative screening strategy for higher-risk individuals or for populations in which the frequency of adenomatous polyps is higher is to follow a positive fecal occult blood test directly with colonoscopy. Sensitivity analysis demonstrated that the superior cost-effectiveness of these two strategies compared with the other 11 modeled strategies is almost independent for reasonable alterations in test cost and for the sensitivities and specificities of the procedures. The major contributing factor to the diagnostic cost is the frequency of adenomatous polyps. The major contributing factor to the marginal cost per year of extended life is the frequency of cancer.

Cost effectiveness of HemoQuant versus Hemoccult for colorectal cancer screening

Initial reports on HemoQuant, a new quantitative test for occult gastrointestinal bleeding, suggest it is more sensitive than Hemoccult. Increased detection of upper gastrointestinal tract bleeding and dietary hemoglobin may reduce HemoQuant's specificity in the screening setting. The authors performed a cost effectiveness analysis comparing Hemoccult and HemoQuant for colorectal cancer screening using assumptions based on probabilities and costs in the current literature, varying the specificity of HemoQuant. The analysis showed the marginal cost effectiveness of Hemoccult versus no test to be $43,000, and HemoQuant versus Hemoccult to be $296,000 if HemoQuant specificity is 0.95. The marginal cost effectiveness ratio increased to $601,000 if three HemoQuant tests were used. Survival benefit was small and highly dependent on Hemoccult sensitivity and mortality from colonoscopy if HemoQuant specificity was less than 0.9. The authors conclude that unless the high sensitivity reported for HemoQuant is accompanied by a specificity comparable to that of Hemoccult, HemoQuant may not be an acceptable alternative for colorectal cancer screening.

Using decision analysis to communicate the importance of quality assurance studies

Decision analysis, which structures the information used by physicians in making medical decisions, has the potential for being a valuable quality assurance (QA) tool. Probability trees derived from decision analysis studies can be used to make quantitative, graphic connections between QA data and adverse medical outcomes. This article provides four hypothetical examples of how decision analysis studies can help providers understand the relationship between QA data and patient welfare.