Podcast: Screening for Colon Cancer
The U.S. Preventive Services Task Force recommends that adults age 50 to 75 be screened for colorectal cancer. Several types of screening have proved effective in detecting evidence of colon and rectal cancer early, when cancer is in its beginning stages. In some cases, screening can include removal of polyps in the colon before they become cancerous.
In recognition of Colon Cancer Awareness Month, Einstein Perspectives recently spoke with John Leighton, MD, Division Chair of Hematology and Medical Oncology at Einstein Healthcare Network. In this podcast, Dr. Leighton discusses the importance of screening and the options available.
Bill Fantini: After lung cancer, colorectal cancer is the No. 2 killer among all cancers in the United States, but it can be caught early and even prevented with regular screening tests.
Bill Fantini: I am Bill Fantini with Einstein Perspectives. For more information we turn to John Leighton, MD, division chair of hematology and medical oncology at the Einstein health network and principal investigator for gastrointestinal malignancy clinical trials performed at the Einstein Cancer Center. To start, who should be screened for cancers of the colon and rectum and why?
Dr. Leighton: Anybody aged 50 or older, and the reason is colorectal cancer screening can either detect cancers earlier than they would be detected if you waited for symptoms, or they can detect polyps that would have become cancer had they not been removed. So by screening, we can detect earlier cancers or detect what are called precancerous lesions that can be treated, and this ultimately saves lives because colorectal cancer is treatable when diagnosed early.
Dr. Leighton: Controversies exist in the 45-50 age group, where some organizations do recommend screening at a younger age; others do not. Others would suggest possibly more for African-Americans since they seem to be more susceptible to colorectal cancer at an earlier age. Anybody with a history of colorectal cancer or polyps isn’t really screened anymore. They undergo what is called surveillance, and anyone who has a family history of colorectal cancer or polyps would be considered different than the average population and needs to discuss the appropriate screening with their physicians, but typically it would be done at an earlier age than those in the general population.
Bill Fantini: Is there proof that screening saves lives, Dr. Leighton?
Dr. Leighton: The gold standard are randomized clinical trials, and the tests that have randomized controlled trials with data to show benefit in terms of mortality are those with fecal occult blood testing, where stool samples are tested for blood. And the colonoscopy, which has become the gold standard, actually doesn’t have the mortality benefit in a randomized control study, but I think that the fact that there are screening tools that save lives allows you to work with the different screening tests and decide what is best for a particular person. Because not enough people in our country are getting screened, and part of it is the testing that is used. So while colonoscopy has become sort of the gold standard, I think the standard test is the one that the patient will participate in and complete.
Bill Fantini: The different methods of screening, tell us what they involve and how often they should be done.
Dr. Leighton: There’s the stool-based tests, which include the old standard, the occult blood test; the more recently approved fecal immunohistochemical test or FIT test; then there is the Cologuard, with evaluating for stool DNA. These are tests of stool samples. They don’t require a procedure. They can either be done in a doctor’s office or bringing in a specimen in from home, and they are effective to some extent in terms of detecting lesions, but they require a follow-up.
Dr. Leighton: For example, if you find an abnormal stool test, then the patient must have a colonoscopy to find out why the test is abnormal. And they typically need to be done on a repeated basis. For example, FIT testing is required every year. So no procedure, no anesthesia for stool tests, but pretty rigorous follow-up from year to year, and I would say that it’s not as accurate as the tests that directly visualize the colon.
Dr. Leighton: The tests that do look at the colon are the flexible sigmoidoscopy, which is a shorter scope and captures a lot of the colon but not the entire colon, and the colonoscopy, which looks at the entire colon. The flexible sigmoidoscopy needs to be done every five years unless you combine it with every-year FIT test, you can do it every 10 years. Colonoscopy, if normal, can be done every 10 years because it’s looking at more. You don’t need sedation or anesthesia for sigmoidoscopy. You do need to clean out the colon for the direct visualization test. And what they allow for is to actually look inside the colon, do biopsies of something that looks abnormal, and even remove a polyp that could be precancerous or cancerous.
Dr. Leighton: There is the one radiologic task, the CT colonography, where you do still do the prep, but it’s an imaging test. It’s sort of a way to go look at the colon with x-rays. It points out potential polyps that would need colonoscopy for follow-up. It’s noninvasive. The concerns are, since it’s not as popular as some of the other tests, could there be some learning by the radiologists who interpret it? It needs to be done every five years rather than of every 10 years. And if they find something outside the colon, it might be something that is significant, that you help the patient. But you might find something that you do a lot of testing on, including biopsies, and it turns out that it’s all okay but you have put the patient through some anxiety and some other testing.
Dr. Leighton: I think of the various tests, the colonoscopy is infrequent, it looks at the colon, it gets biopsies, and I think that’s why it’s become the gold standard. But the prep, I think, really scares a lot of people away from it.
Bill Fantini: Would that be why someone might choice to go with the sigmoidoscopy instead of a colonoscopy?
Dr. Leighton: You still have to clean out the colon. You don’t need to be sedated for it, so in theory you could go have a sigmoidoscopy and drive yourself to work. They are not looking as far, so there’ll be less risk of complications. But I have a hard time advocating for sigmoidoscopy over colonoscopy, just because it would need to be done more frequently, and if you have something on the sigmoidoscope you are obligated to look at the whole colon. But there are patients who all their polyps could be beyond the sigmoidoscope, and they could have a normal sigmoidoscopy but not be getting to the area of the colon that needs to be seen.
Bill Fantini: I understand that only about 63% of people who should be screened actually get the test. Why aren’t more people screened? Would it be because of the arduous prep or are there other reasons?
Dr. Leighton: I think there’s various reasons. I think the prep is the one that you hear the most. People just don’t want to do it. I mean, if you have a colonoscopy you are sedated, you are asleep, so the test itself is not painful and it’s fairly quick. Some people might be frightened about what is going to be found.
Dr. Leighton: For some older patients who, say, have government-based insurance, it is covered as screening, but if they find a polyp it becomes a therapeutic test and it’s not handled the same way insurance wise, so people worry about the cost of a test. Maybe they know someone who had a bad time with it.
Dr. Leighton: So I think there’s various reasons, and maybe it’s not getting reinforced enough with patients. Maybe doctors are very busy, they don’t have as much time with an individual patient as they used to have. And if patients have active problems, you spend your time managing the active problems and maybe not pushing the screening tests as hard as you might otherwise.
Bill Fantini: I wonder if you could elaborate a little bit more about the FIT test. Research indicates that it’s highly effective. It has to be done every year, but it’s easy to do. Would more people try this option if it were publicized better?
Dr. Leighton: I don’t know. I mean, it definitely is an effective screening test. It can miss lesions if they’re not bleeding enough, and that’s a downside, but it is more accurate than the typical occult blood and rather than requiring three samples it requires one. I think the downside is if that’s the method you choose to do you must have it done every single year. You can’t miss.
Dr. Leighton: And once you have a positive FIT test, then you have a have to have the colonoscopy. If somebody went 10 years and they have one positive FIT test they are still getting a colonoscopy. Again, if somebody said, “I’m not doing a colonoscopy,” and they will do this every year I think it’s a perfectly reasonable test to do. It falls within various guidelines and I think it’s appropriate.
Bill Fantini: Any final thoughts, Dr. Leighton?
Dr. Leighton: I just think it’s important for people to realize that colorectal cancer is a treatable disease, it’s a curable disease. By catching it early, you have a better chance of cure and you can achieve that cure with less treatment, so less complications from surgery, perhaps not needing chemotherapy, perhaps not needing radiation therapy. So those are additional benefits. This is the one disease where screening not only diagnoses the disease but can treat the disease.
Bill Fantini: That’s John Leighton, MD, division chair of hematology and medical oncology at Einstein Healthcare Network. For Einstein perspectives, I’m Bill Fantini. Thanks for listening.