Screening for Colorectal Cancer: Optimizing Quality (CME). Endoscopist Version Part 1

By: Centers for Disease Control and Prevention (CDC)

[silence] My name is David Lieberman. I'm the Chief of Gastroenterology at Oregon Health and Science University, and I am honored to participate in this effort by the Centers for Disease Control and Prevention to improve the quality of colorectal cancer screening. For those of you who do not know me, I am a past president of the American Society for Gastrointestinal Endoscopy and a current member of the governing board of the American Gastroenterological Association, or the AGA. I have been a participant in the National Colorectal Cancer Roundtable for many years. I served as Chair of the Multisociety Task Force on Colorectal Cancer for six years and participated in the development of colorectal cancer screening and surveillance guidelines. My research has focused on colorectal cancer screening, surveillance, and quality. We now have compelling evidence that colon cancer screening works.

It reduces the incidence and mortality of colorectal cancer but only if it's performed with high quality. This slide presentation will discuss the current guidelines and recommendations for colorectal cancer screening and emphasize important elements of quality. We hope that these slides and the various links that we provide to primary-source information will be of value to you in your clinical practice and provide tools that will help you optimize colon cancer screening with your patients. This is going to be a two-part presentation. Each of the presentations will have links to other documents, including additional slides and source documents that will provide additional information about guidelines and clinical practice recommendations.

So we encourage you to use these links, and we'll demonstrate some of these links during the course of the presentation. I want to acknowledge the work of many people who participated in this effort, including gastroenterologists, public health experts, and primary care physicians who all participated in the development of this course. So to begin, we have evidence now that colon cancer screening works, that it saves lives.

We know that screening is a complex process that achieves its maximum benefit for the patient when all steps are implemented appropriately, and we know that there are some problems with screening implementation that have been well documented in the medical literature for each of the screening options. So, for example, what are some of these implementation problems? Well, with colonoscopy, we know that sometimes polyps are not detected. Sometimes a complete exam to the cecum is not achieved. The bowel prep may be suboptimal. The colonoscopy report may be missing key elements that would help guide future management. The recommendations for screening and surveillance intervals that are made after procedures are sometimes not consistent with practice guidelines, and some endoscopists do not monitor their performance, so they're really not aware when they are not meeting quality standards.

Screening for Colorectal Cancer: Optimizing Quality (CME). Endoscopist Version Part 1

There are also implementation problems with the fecal occult blood testing programs. First, sometimes the tests are just not offered as a good option for average-risk individuals. Patient preferences for fecal testing are not taken into account. Some physicians still use tests that are no longer recommended-- the old guaiac-based test. Some individuals perform in-office rectal exams and use that as their primary screening test, and that is really not a substitute for in-home screening. And most important, fecal occult blood testing is a program which involves having a colonoscopy if the test is positive, and if that's not done, it's going to impact the effectiveness of the program, and if the test is negative, exams need to be repeated annually. So these are elements of implementation that are key to achieving a high-quality fecal occult blood test program. The goal of this presentation is to improve screening quality by providing up-to-date guidance on ways to optimize the screening process with a strong emphasis on the areas where current practices may fall short.

Upon completion of this course, the learner should be able to recommend the appropriate testing for each patient consistent with the guidelines for screening and surveillance for different populations and recognize high-risk groups, understand ways to achieve a good bowel preparation, identify the elements required for a complete colonoscopy report that will be a strong communication tool to primary care providers, and explain which quality indicators should be monitored to improve colonoscopy performance. We know that screening works but that many eligible patients are not being screened. With this in mind, the National Colorectal Cancer Roundtable has proposed a goal of screening more than 80% of individuals by 2018. More than 150 organizations have signed a pledge to help achieve this goal. This goal should be achieved with attention to the quality of examinations and testing performed. This presentation is going to focus on providing high-quality testing for those who are screened.

The topics we're going to be covering in Part 1 will include colorectal cancer, some information about colorectal cancer and the value of screening, and we will review some of the screening and surveillance guidelines: who should receive screening, how they should get it, and when and which groups need to be stratified as higher-risk individuals. In Part 2, we will talk about colonoscopy and ensuring that the performance of colonoscopy is appropriate, the importance of a good bowel prep, the importance of complete documentation of the colonoscopy results, and recommending appropriate follow-up and the need to perform and improve the quality of colonoscopy. So to begin with Part 1, a few facts about colorectal cancer.

In 2011, there were more than 135,000 new cases and over 50,000 deaths due to colorectal cancer in the United States. We have a link to the Centers for Disease Control Web site which provides some colon cancer screening statistics, and you'll see that, if you go to the site, that you can look for information on colon cancer rates by race and ethnicity. You can look at the rates of cancer and screening in your state.

You can look at risk according to age, and you can look at trends over time. So there is a wealth of information here, and I encourage you to use these links as shown here to further investigate this subject. As I mentioned, colon cancer remains the second-leading cause of cancer death overall after lung cancer, and we have evidence that it can be prevented or detected through screening. The good news about colon cancer is that both the incidence and mortality have been declining in the United States so that over the ten-year period between 2000 and 2010, there was a 30% decrease in both incidence and mortality among adults age 50 and older. So this is exciting news, and we believe that some portion of this decrease has been directly attributed to increased rates of screening in the United States. Hence, screening becomes an important element of trying to further reduce incidence and mortality from this cancer.

Most colon cancers develop over time from preexisting adenomas or serrated polyps. These polyps are very common, and it's estimated that 30% to 50% of us will develop adenomas in our lifetime. Most do not progress to cancer, but some acquire additional mutations, become larger, develop more serious histologic changes such as villous histology or high-grade dysplasia, and in those cases, there is a higher risk of progression to cancer.

The estimate of polyp dwell time for a small polyp to developing into an invasive cancer is at least ten years. So this process takes a long time in most individuals. We have learned that screening can impact this natural history in a couple of important ways. First, that if we can detect and remove significant cancer precursor lesions, adenomatous polyps, that we can decrease both incidence and mortality of colorectal cancer. If we can detect early-stage cancer that is amenable to treatment, then we can also decrease mortality. So screening offers us two exciting opportunities for reducing mortality from colorectal cancer. Screening for colorectal cancer has been strongly urged by the United States Preventive Services Task Force, which is an expert panel that produces guidelines related to screening and prevention. This is a group that advises Congress and the Centers for Medicare and Medicaid.

They've strongly recommended colorectal cancer screening for all adults beginning at age 50 until at least age 75 with a Grade A recommendation, and what they mean by a Grade A recommendation is that there is high certainty that the net benefit is substantial and substantially outweighs the risk. Therefore, based on this recommendation, all practices should be offering and providing this service. Let's talk about some of the risk factors that one should consider when deciding to screen an individual patient. So we need to know what the risk level is, what the prior screening and surveillance history is, the age and comorbidities, and patient preferences should be weighed into the decision making.

We understand that there are different levels of risk. The most common group is average risk, and I want to emphasize that average risk is not low risk, that an average-risk individual with no other risk factors has about a one in twenty chance of developing colon cancer in their lifetime. So, therefore, screening is recommended for so-called average risk because they are not low risk. The higher-risk individuals are those that have a family history of colon cancer or large adenomas in a first-degree relative or colon cancer in other relatives, and first-degree relatives are father, mother, sister, brother, or child. It's estimated that the risk of developing colon cancer with this history may double, so that if average risk is about a 5% lifetime risk, for those with a family history, the risk may be 10%. Also, patients that have a personal history of adenomas in the past or certain serrated polyps or cancer are at risk to develop these lesions again, and they are also at increased risk.

At higher risk are individuals that have chronic inflammatory bowel disease. That would be patients with chronic ulcerative colitis or Crohn's colitis. It's thought that inflammation of the bowel may induce mutations in the cells of the bowel that could lead to the development of cancer. And so these individuals need more intensive follow-up beginning at about eight years after the onset of their disease.

The very highest-risk groups are those that have suspected genetic syndromes. That would be familial polyposis or hereditary nonpolyposis colorectal cancer, otherwise known as Lynch syndrome. And these patients have extremely high risk of developing cancer at a very young age. The suspicion for these families should be if there is any family member with colon cancer before age 50, we should at least think about the possibility that this could be an inherited syndrome and take a very careful history of all family members in that kindred to determine if they need to be referred for genetic counseling. So let's talk about screening in average-risk individuals, and I'm going to pose a few questions for you to think about as we go into this discussion. First, what is the best colorectal cancer screening test for average-risk subjects? Second, when should an average-risk patient with a normal colonoscopy be screened next after they've had a normal exam? And at what age should patients no longer be screened? So we'll try to address some of these questions. In 2016 the United States Preventive Services Task Force issued new guidelines and recommendations for average risk screening.

They included multiple screening strategies with different levels of evidence to support their effectiveness. They point out that each strategy has some advantages and some limitations and there was no empiric data that demonstrated that any one of those strategies would provide a greater net benefit than the other. The primary goal of this new recommendation is to maximize the number of individuals who get screened. The screening tests, the specific tests, are outlined on the next slide.

There are stool-based tests which include a highly sensitive guaiac fecal occult blood test performed every year, a fecal immunochemical test, or FIT, which is performed every year, and a multi-targeted DNA test which includes a stool DNA and FIT which can be performed every one year or every three years. There are several visualization tests which enable visualization of the colon, colonoscopy performed every ten years, CT colonography performed every five years, flexible sigmoidoscopy, alone, performed every five years and flexible sigmoidoscopy with the FIT test. The flexible Sig is performed every ten years, the FIT test is performed annually. We will highlight the two new tests that were included in this list since the 2008 guideline. The first of those tests is the multi-targeted stool DNA test, which includes a fecal immunochemical test and stool DNA. This has a higher single test cancer detection rate, and polyp detection rate than FIT alone. The test identifies several key mutations that are associated with colorectal cancer neoplasia and can also detect blood in the stool.

The key features of this test is that it does appear to be more sensitive for detection of cancer than FIT alone, but it results in a higher rate of false positive tests, and therefore, more colonoscopies would be performed if patients had colonoscopy for a positive test. There is insufficient evidence about the follow up of a positive stool DNA test and a negative colonoscopy. It's conceivable that patients could have neoplasia in their colon that might not have been detected with colonoscopy, and that could lead to overly intensive surveillance due to these concerns, after a negative colonoscopy. Currently, Medicare reimburses the multi- targeted stool DNA test every three years. The second new test introduced by the Preventive Services Task Force was CT colonography. This has been around for a long time. It's a CT scan which can be rendered in two dimensional or three dimensional images.

It requires a very thorough bowel prep prior to the procedure, so that there will be no confusion between stool versus polyps. It's quite sensitive for polyps, detection of polyps greater than six millimeters, and for detection of cancer. When CT scans are performed of the abdomen there are maybe incidental extra-colonic findings that are discovered. But most do not require additional evaluation in average risk asymptomatic individuals. However, these extra-colonic findings do have some potential for both benefit and harm. It's possible to detect occult lesions elsewhere in the abdomen, but there is also, it's also possible to detect incidental findings that could lead to over diagnosis, over treatment and potential harm to patients.

Ideally, the facility performing CT colonography should have the capacity to perform same day colonoscopy when polyps are discovered so that patients do not have to go through a second bowel prep. As of July 2016, this procedure is not yet covered for screening by Medicare, but coverage is being reconsidered. It is currently covered for screening by some private insurers.

When should screening begin and when should it end? Well, the guidelines strongly suggest that most adults between the ages of 50 and 75 should be offered colon cancer screening. In the elderly, screening may be associated with increased risk and decreased benefit, and so the U.S. Preventive Services Task Force has suggested that for individuals age 76 to 85 that the decision to continue screening should be made on case-by-case basis, that if patients have had a prior history of adequate screening that they may not need to have further screening. However, if they've not had up-to-date screening, then they may benefit from more screening provided that they have a life expectancy of at least five to ten years and would, therefore, be likely to benefit from screening. There's a strong recommendation not to screen individuals after the age of 85, and that is because the risk begins to strongly outweigh any benefit after that age group.

There's some controversy about special groups and when screening should be initiated. So one of these groups are African Americans. So we understand that African Americans have a higher risk of colorectal cancer and have a higher risk of death from colorectal cancer, and some have suggested that, perhaps, screening should begin at a younger age for this higher-risk group. However, the rationale against performing early screening is that most of the colorectal cancer cases in African Americans still occur after age 60, as they do in Caucasians, that the prevalence of large polyps greater than nine millimeters is similar for whites and African Americans before age 50, that there is really no evidence that supports the effectiveness of early screening, and, in fact, there's some modeling that has suggested that by increasing screening rates by 10% over the age of 50 that this may actually be more effective than initiation of screening at a younger age. You'll see that the guidelines do vary.

The U.S. Preventive Services Task Force recommends beginning screening at age 50 for African Americans. Other groups have opted to recommend a younger age, and the coverage for this type of screening varies depending on the state and for insurance companies. Our expert consensus, at least at this time, is to begin screening at age 50 for African Americans but to really intensify that screening effort because this is such a high-risk group.

There are also individuals that should not be screened, and these are individuals that have limited life expectancy and severe comorbidities that would increase the risk of screening so that if the life expectancy is less than five years for really any reason, we do not recommend screening, and for patients that have high-risk conditions because this is an elective procedure, we recommend that screening be delayed or not be performed if life expectancy is going to be less than five years. Let's talk a little bit about some groups that have higher risk of colorectal cancer. So the most common group are those that have a family history.

That would be a first-degree relative-- father, mother, sister, brother, child-- that has a history of colorectal cancer or large adenomas. Here, the guidelines distinguish between the age of the family member. So that if the index family member that had cancer developed cancer after age 60, the recommendation is to begin screening with any of the recommended tests at age 40 and to repeat at the usual intervals for those individuals. However, if the family member developed cancer before age 60 or if two or more first-degree relatives are diagnosed at any age, this represents a higher-risk family, and it's recommended that colonoscopy be the preferred form of screening and that colonoscopy screening begin at age 40 or ten years younger than the youngest-- than the index case in the family and then should be performed every five years instead of every ten years, and this is in recognition that this represents a higher-risk family. So a few more questions to think about. What is the recommended surveillance interval to the next colonoscopy for a patient that has a polyp, a seven millimeter tubular adenoma? And what is the recommended surveillance interval for a patient that has three small adenomas? So we'll try to address these questions about surveillance after screening in this next set of slides. So guidelines have been developed to guide physicians based on the evidence, and there's a link to this guideline that I'd like to show you that specifies some of the evidence. And this will give you an example of going to a source document.

This is a paper that was published in 2012 outlining the colonoscopy surveillance guidelines after screening had been performed and reviews all of the evidence. So I, again, encourage you to use these links, which will provide additional information. In this paper, we distinguish between several levels of risk. First are individuals that were found to have low-risk adenomas, which are defined as having one or two tubular adenomas less than ten millimeters.

This represents a very low-risk group. The recommendation is to perform colonoscopy in five or ten years with most of the evidence now leaning towards the longer interval of ten years, provided that the baseline exam was a complete exam to the cecum and had a good bowel prep. Each of these recommendations is really contingent on the assumption that the baseline exam was complete and that the prep was adequate and that all visible polyps were completely removed. The next category are patients that have high-risk adenomas. That would be three or more adenomas or adenomas greater than one centimeter with villous histology or high-grade dysplasia. These are patients that we know are more likely to develop additional high-risk adenomas in the future and have a higher risk of cancer.

These individuals should have surveillance at a three-year interval. For those few patients that have more than ten adenomas on their baseline exam, the recommendation is to go back in a shorter interval to remove any remaining polyps and to think about whether this patient might have one of the polyposis syndromes. And, finally, if a patient has any adenoma that was removed in a piecemeal fashion or possibly incomplete excision, that person should have another colonoscopy in the next two to six months to reinspect that site and confirm that all neoplastic tissue was removed on the baseline examination. We have some new information about what to do after that first surveillance examination. So patients that had a baseline colonoscopy for screening, had a surveillance examination for polyps-- what do you do after that? And what this slide highlights is a relatively simple algorithm for follow-up of these individuals. If the patient had a low-risk adenoma on their baseline examination and has no adenoma on their follow-up surveillance examination. They are low-risk and can have their next surveillance exam at ten years, which would be the same as a screening examination. Conversely, if that patient was found to have a high-risk adenoma on the surveillance examination, then they should revert back to a shorter three-year interval for surveillance.

In the next row, you see patients that have high-risk adenomas on their baseline examination. The evidence would suggest that this remains a higher-risk individual, and therefore, the follow-up in those individuals should range between three and five years, depending on what is found on the surveillance examination. Well, what about serrated adenomas? Many of you have heard about serrated polyps. Do they ever develop into cancer, and what is the recommended surveillance for these lesions? First of all, what are serrated polyps? Well, these are lesions, polyps, that are characterized histologically by having a serrated or saw-toothed appearance of the crypts in the epithelium. In the past, most of these lesions were called hyperplastic polyps because they have an appearance that is similar to hyperplastic polyps and most do not have cytological dysplasia, which is a characteristic of hyperplastic polyps. And they were thought to have little or no malignant potential.

More recently, though, we've learned that a subset of patients with serrated lesions may be a precursor for colorectal cancer in as many as 20% or 30% of lesions. These are most commonly found in the proximal colon, and they have certain genetic characteristics that seem to be associated with a higher risk. So as we think about the two types of polyps that can develop into cancer, one are polyps that go through the traditional adenoma-carcinoma pathway, which starts with the development of an adenoma. There are additional genetic mutations that lead to the development of cancer. In the serrated polyp pathway, we believe that this may start as a hyperplastic polyp, that additional mutations may occur, and then there's probably a critical step in here in the middle showing that if a serrated polyp develops cytological dysplasia, that these patients may have silencing of an important mismatch repair gene that can lead to the development of cancer, and so we believe that that is the most likely pathway that these lesions may follow. So these patients can develop cancers, and understanding the natural history of these lesions has been troublesome for two important reasons. First, these lesions are very difficult to detect at endoscopy. They're often very flat.

They often have the same color as the surrounding mucosa with very indistinct edges. They're often covered with adherent mucus that obscures the vascular pattern and makes it difficult to see these lesions. So these lesions are probably often missed at endoscopy. The second problem with understanding the natural history is variability in distinguishing hyperplastic from other serrated polyps histologically even among expert pathologists who disagree. So to understand the natural history of a lesion, you really need to be able to detect it accurately and you need to classify it accurately.

And those are problems with serrated polyps, and that's why the understanding of serrated polyps is still evolving, and the current management guidelines are based on weak evidence. OK, this slide discusses the surveillance of patients with serrated polyps at a prior colonoscopy. For patients that have hyperplastic polyps less than ten millimeters in the rectum or sigmoid, it's a very low-risk group. They can be rescreened in ten years with any of the recommended screening options. For those individuals that have small hyperplastic polyps proximal to the sigmoid colon less than six millimeters, the recommendation is to perform colonoscopy in about ten years.

For those that have lesions greater than five millimeters, the recommendation is to perform colonoscopy at five years based on very weak evidence. And for those that have serrated polyps less than ten millimeters in the proximal colon, the recommendation is to do colonoscopy in five years. The group that I think should be highlighted that I want you to remember are those patients that have serrated polyps that are either greater than ten millimeters or have cytological dysplasia. We believe that this may represent a higher-risk individual and should be managed like those with classic high-risk adenomas and have follow-up colonoscopy in three years. And for the unusual patients that have serrated polyposis, which are many hyperplastic polyps, some of which are greater than ten millimeters, in their colon, they should have colonoscopy at one-year intervals until all those polyps have been removed.

The next slide talks about the surveillance of patients that have had cancer resected. So these are patients that have whatever it takes to develop colorectal cancer either genetically or environmentally or lifestyle, and therefore, they are at risk to develop recurrent cancers. So for those that had colon or rectal cancer, the next examination should be within six months after their surgical resection if they were not able to have a complete bowel examination prior to surgery. This could be due to an obstructive cancer that precluded performing a complete examination. If they were able to have a preoperative complete examination, then they should have their follow-up at one year after the curative resection and then every three to five years thereafter. A possible exception to this are patients that have rectal cancer, and the concern about rectal cancer is that there is a higher risk of recurrences at the anastomosis, and for that reason, many experts recommend that these individuals have sigmoidoscopies to inspect that anastomosis every three to six months, possibly with rectal ultrasound as well over the first two to three years.

They should continue, though, to have the full colonoscopy at the one-year and then every three-to-five-year intervals because they're still at risk to develop cancers elsewhere in the colon. Finally, I'd like to spend a few minutes talking about those patients that are at higher risk. So these include patients that have chronic inflammatory bowel disease, including ulcerative colitis and Crohn's disease.

We recognize that the risk of colorectal cancer begins to increase at about eight years after the onset of disease, possibly related to the inflammation which causes mutation in the lining of the bowel. For these individuals, colonoscopy is recommended every two years, and there's some new evidence that suggests that colonoscopy with chromoendoscopy, using dyes like indigo carmine or methylene blue, may enhance our ability to detect subtle lesions that may have low- or high-grade dysplasia. So this is something for endoscopists to consider in their practice, and it's one reason to consider referral to a center that has expertise in performing surveillance for inflammatory bowel disease and its management. The highest-risk groups are those that have a genetic syndrome, and those include the patients with hereditary nonpolyposis colon cancer and familial polyposis. These syndromes should be suspected in any family who has a relative with cancer before age 50, in which case complete history of family members should be obtained, and if suspicion is there, patients should be referred for genetic counseling and testing along with counseling of the family.

For these individuals, because cancers can develop at a very young age, testing may begin in late teens and twenties. So it's very important for primary care physicians to obtain this history as part of the initial history and physical that they obtain. Thank you for viewing Part 1, in which we have tried to focus on the following subjects: who should get screened and when, who is high risk and needs more intensive screening and surveillance, and what is the appropriate follow-up of patients after they have had screening.

In Part 2, we're going to discuss issues surrounding colonoscopy and how to ensure that colonoscopy is performed with high quality. I urge you to use the links provided in this course to get additional information from some of the source materials. Thank you very much for participating in this course.

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