I am going to speak on large intestine, lower GI bleeding, colorectal cancer, and diverticulosis. First question, most colonic diverticular bleeding is related to diverticulitis. True or false? So this one is a little tricky. Diverticulitis usually refers to inflammation of the diverticulum. So people present more with pain and fever perhaps. When you have diverticular bleeding, it is actually painless and not associated with inflammation. The main value of screening and surveillance colonoscopy is to prevent colon polyps. True or false? So this one is a little tricky. It's actually false because it's more to prevent colon cancer. So let's begin with colon cancer. Colorectal cancer can be located anywhere throughout the large intestine, which includes the colon as well as the most distal end, the rectum. It's one of the most common cancers in the United States. It's actually third most common cause in both men and women. So in women, it's the third most common cause after breast and lung cancer, and in men, third most common after prostate and lung cancer. Lifetime risk, about 5 percent. It's actually coming down a little bit. It's about four point something at this time. This slide was shown earlier by Bill. The most common pathway for the development of colon cancer is through adenomatous polyps. So the adenoma to carcinoma pathway occurs with a sequence of somatic mutations and either mutations under loss of oncogenes and tumor suppressor genes. And this progression to cancer in sporadic cases occurs over a long time period, believed to be about 10 to 15 years. So this gives us an ample window of opportunity to intervene, to screen these patients, to detect hopefully polyps before they develop into cancer and remove them to prevent this progression or if we do detect cancer, hopefully at an early age with a higher chance of cure. Symptom for colon cancer very commonly can be asymptomatic. Patient may have no idea that they even have an underlying cancer. Some patients present with suspicious signs or symptoms, and symptoms can include rectal bleeding, significant change in bowel function. Other potential signs might be iron deficiency, anemia, or unexplained weight loss. Some patients present with more advanced colon cancer. They may present with bowel obstruction, so blockage of a large bowel, or they may come in with nausea, vomiting, distention, inability to move their bowels, or if the tumor is so advanced that it frankly perforates and you have leakage of colonic contents into the peritoneum, which is the abdominal cavity outside of the colon, that leads to inflammation and peritonitis. Screening. Most of you are probably aware that we, over the years, have recommended starting screening an average risk population at age 50. We updated the slide this year to show that more recent national guidelines are now suggesting to start a little bit earlier at age 45. So whereas we know that the strongest evidence is to begin at age 50, there is evidence of increased incidence in colon cancer development in patients under age 50, and therefore the start age for screening has actually been lowered. There are other risk factors for colon cancer where you may start screening earlier, such as family history of colon cancer, particularly in a first-degree relative, or a personal history of inflammatory bowel disease. By the way, if you have a first-degree relative with colon cancer, we usually start screening earlier at age 40. In patients that have inflammatory bowel disease, we start screening them for colon cancer, particularly if it's ulcerative colitis or Crohn's colitis. We start about eight years after the onset of symptoms in those patients. And finally, there are patients that have inherited colon cancer syndrome. So they actually have underlying germline mutations that put them at very high risk for colon cancer due to these predisposition syndromes, the most common being Lynch syndrome and familial adenomatous polyposis, or FAP. There are many screening tests that we used to look for colon cancer, and they include stool-based tests, starting with the top three. One is guaiac-based fecal cold blood testing. So there you put a stool specimen on a card. It's impregnated with a colorless chemical called guaiac. And in the presence of blood, when you smear the stool on it, if there's hidden blood in the stool, the guaiac will turn from clear to blue color when you put the developer on. And that's because the heme component of hemoglobin has a peroxidase activity. And when you add the hydrogen peroxide and the developer, it turns blue. For recent years, we now have a high-sensitivity guaiac-based test that's a little bit more sensitive than the older hemocolt tests, and still the same type of function. Problem with guaiac-based stool testing, you can get false positives. It's not specific just for human blood. So if you've eaten red meat, perhaps, or if you eat certain fruits or vegetables that have peroxidase activity in it, you can get false positives. The advancement in stool testing is fecal immunochemical test, or FIT test. And this uses an antibody specific for human hemoglobin. So you only have to do one specimen. It's more sensitive than the older guaiac-based stool testing. By the way, if any of these tests are positive, the patient needs to go on to have a colonoscopy. Abnormal FIT DNA test is the most basic way of describing the test that is commercially known as ColoGuard. And this test is actually a combination of both looking for occult blood with the fit component of the test, as well as looking for abnormal DNA. And that includes abnormal KRAS, as well as methylated biomarkers. If either of those are positive, you get back a positive test result, and that person needs to go on to colonoscopy. We include flexible sigmoidoscopy because it's still included as an option in national guidelines, but it's not as commonly used. Colonoscopy is currently still felt to be the gold standard in that it gives us direct visualization of the entire colon and rectum, and allows both diagnostic as well as potential therapeutics to allow us to biopsy or remove polyps. And finally, CT colonography is the term that's used to describe what is often referred to as virtual colonoscopy. This is done in the radiology department. A person still needs a bowel preparation, it uses CT scan technology, and with specialized computer software, you can actually come up with a virtual, both two-dimensional as well as three-dimensional fly-through image of the colon. If something is detected on that, then the person goes on to colonoscopy. These are some endoscopic images of actual colon cancers in all of these different frames here. Now what's the treatment for colon cancer? If the tumor is localized, meaning if it's limited to the colon area, then the person meaning the absence of advanced disease, distance spread, for example to the lungs, to the liver. If the person has localized disease, primary treatment would be to go on to surgery, and depending on where the tumor is located, that determines what type of operation they get. So if the tumor is in the sigmoid colon in this example, then they will have an anterior sigmoid resection and just remove that part and reconnect the rest of the colon to the rectum, and this can be done in one procedure. So when people go on to have curative colon resections, they don't necessarily have to have an ostomy, which could, in some cases, for certain type of operations, they need a permanent one. But most of the time, they do not require that. They have a primary resection, a primary connection. Whether or not you need additional treatment after that colon resection, if you think it's localized, depends on the outcome of the pathology. If up front, it looks like it's a localized tumor, you undergo operation, then the decision of whether to get adjuvant chemotherapy after surgery depends on whether it's in the lymph nodes or not. So if the lymph nodes are positive after an operation, they'll get adjuvant chemotherapy to try to decrease the risk of recurrent disease. If, however, the person presents up front with metastatic disease and they're not a surgical candidate, then the primary treatment might be systemic chemotherapy. And if they have very advanced disease and they're near the end of life, then it might be more supportive care, which is palliative, just to make them more comfortable. Move on to lower GI bleeding. Earlier, Brooke talked about upper GI bleeding being proximal to the ligament of trite. Lower GI bleeding is technically defined as anything beyond the ligament of trite. So again, the ligament of trite is a ligament at the junction between the duodenum, the first segment of the small bowel, and the jejunum, the second segment. Here are some percentages. So for lower GI bleeding, 85% will be in the colon, 5% in the small bowel distal to the ligament of trite. Symptoms of lower GI bleed include hematochesia. Again, that's bright red blood correctum, as well as melanin, which is black, tarry-colored stool. So in a lower GI bleed, as Brooke mentioned earlier, it would have to come either from somewhere in the more distal small bowel or the proximal colon so that by the time it makes it out to the out your bottom, it's black, tarry, sticky. Patients can also present with symptomatic anemia. If it's mild anemia, they might just be lightheaded. If it's more significant and or if they have underlying coronary artery disease, they may present with chest pain, as well as shortness of breath. And if it's significant anemia, then they might actually lose consciousness. That's syncope. Causes of lower GI bleeding are variable. Anatomic can be a diverticular bleed, which was our first question on the top left. Vascular causes include angio-dysplasia. These are blood vessels in the superficial surface of the colon that could bleed. Ischemic colitis. If you have lack of blood supply to the colon for a period of time, it can get ischemic and get bleeding. Hemorrhoidal bleeding, probably the most common cause of mild lower GI bleeding. Malignant causes in the bottom left. So if you have a colon cancer, particularly if it's close to the bottom, close to the rectum, where you're more likely to get gross overt bleeding. Inflammatory bowel disease can cause blood loss, as well as infectious colitis. Here you can see pseudomembranes. This is probably an image of C. difficile colitis. Could potentially be associated with bleeding. And finally, iatrogenic, meaning caused by us, essentially, and a common cause can be after removal of a polyp, you might have bleeding. Definition of GI bleeding. Similar to upper GI bleeding, the first order of business is resuscitation. You want to make sure you have adequate vascular access, so two large-bore IVs, particularly if it's a significant bleed. And you begin with volume resuscitation. After giving fluids, we want to get blood in them. Further management. If somebody presents with significant bright red blood perectum and or melanoma, the question might be, is this truly a lower GI bleed or could potentially be an upper GI bleed? So if it's bright red blood, but they're hemodynamically unstable and you're suspicious that it might be an upper GI bleed, you could potentially put down a nasogastric tube and aspirate contents of the stomach. And if you get back red blood or coffee-ground material, as mentioned earlier, dark, black coffee-ground type, that might suggest it's actually an upper GI bleed. And if you suspect it's upper GI or you determine it to be upper GI by an NG tube lavage, then we would move on to upper GI endoscopy as the next step. If we're assessing somebody from below with a colonoscopy for lower GI bleed, here are potential management options to get hemostasis or to stop the bleeding. If it's a post-polypectomy bleed in the upper slide, then we detect the polypectomy site. We see either active bleeding or a visible vessel. In this case, you can apply a hemoclip to mechanically compress the area and stop the bleeding. The bottom series of images is a bleeding diverticulum. So if you scope somebody, you can actually identify the actual diverticulum where you actually have spurting of blood out of, which, by the way, is a very challenging thing to do because often when we scope somebody with a diverticular bleed, we just see so much blood and diverticula that it's hard to identify the site. But in the event you're lucky enough to detect that site, it's possibly to treat it with applying endoclips to mechanically stop the bleed. Active options for hemostasis during colonoscopy would be epinephrine injection. So that's another potential option for a post-polypectomy bleed in the upper left corner. Bottom right, it's possible to apply bands, so similar to what Bill showed earlier about doing — Bill, you showed banding, right? — to show banding that can be applied to internal hemorrhoids, release a band onto it. It kind of essentially chokes off the blood supply to it and decreases vascular supply and stops the bleeding. Additional options are argon plasma coagulation. In this case, it's a — bottom left, it's an angio-dysplasia. Here you apply coagulation through the APC. And to the bottom right, radiation proctitis. So this is a common cause of bleeding in somebody who's gotten pelvic radiation off in its men for prostate cancer. Okay, moving on to diverticulosis. These are outpouchings of colonic mucosa and submucosa, which are visualized here in the illustration to the right. Incidence increases with age. Now I will say that in doing — we all do colonoscopy, it's a very common procedure. We see diverticulosis all day long. It's extremely common. But most of these diverticulosis cases are really asymptomatic. It's really a very small percentage of people that run into problems being diverticular bleeding or diverticulitis. So they're typically located — or they can be located throughout the colon, but we most commonly see them on the left side, usually in the sigmoid area. Diverticulitis, it's usually, as I mentioned, incidental finding during colonoscopy. And in past years, if people had barimentumus, they could be picked up during them as well. And those are these little pockets of white-colored contrast that you can see. Complications, as we've talked about, is diverticulitis if they become inflamed or diverticular bleeding. First diverticulitis, it's inflammation of a diverticulum. It affects about 15 to 25 percent of patients with diverticulosis. And symptoms are most commonly left lower quadrant abdominal pain. And patients may also present with fever and an elevated white blood count. Definitive diagnosis of diverticulitis is typically by CAT scan imaging. And what you typically see, as is highlighted here by the circle, is thickening of the colonic wall in that area. Again, it's usually down in the sigmoid. You might get some pericolonic fat infiltration. And if there was some perforation, you may get little spots of free air outside of the colon or potentially even a frank fluid collection or abscess if it's complicated. Most of the time, diverticulitis is uncomplicated. And the treatment for uncomplicated or the standard treatment over years has typically been antibiotics. If the person's not sick, they can just be sent home on oral antibiotics and usually do well. If they're sicker, they might have to be admitted and get IV antibiotics for a short period of time in the discharged home. I'll just mention that in more recent years, there has been some talk and some evidence that uncomplicated diverticulitis may actually be able to be treated just with supportive care. So just to make you aware that some people are talking now about potentially treating some mild cases by just sending them home and, you know, watching them without antibiotics. Complicated diverticulitis, however, can be associated with abscess fistula. So you could fistulize into an adjacent organ in women into the vagina or men or women into the bladder. It can – diverticulitis can perforate. Again, you can get fluid collection or abscess. Or if you get swelling and constriction of the bowel lumen at the site, you can actually get frank bowel obstruction of the large bowel. Diverticular bleeding occurs when an artery erodes into the base of the diverticulum. It usually presents as painless rectal bleeding. So again, highlighting that diverticular bleeding is different than diverticulitis. Usually the person does not have abdominal pain. In most cases, diverticular bleeding is mild and self-limited, but patients can be admitted with significant bleeding and need hospitalization. Treatment for diverticular bleeding, typically it's colonoscopy. And again, if we can identify the site, you can treat it with an endoclip. However, if you look inside and there's just blood everywhere and you can't determine the actual bleeding site, if the bleeding does not stop on its own, the patient becomes more unstable or has ongoing bleeding requiring significant need for transfusion support, then the next step might be to go to interventional radiology for angiogram and embolization. And then finally, if you can't stop it either endoscopically or through IR, then the ultimate would be to do an actual surgical procedure and resection. Moving on to hemorrhoids. Hemorrhoids are swollen veins in the rectal canal. They can either be just above the junction between the rectum and the anus. Those would be internal on the rectal side. By the way, the dentate line is the line that we consider that separates the distal rectum from the anus. Or you can get hemorrhoids externally. Causes of hemorrhoids include prolonged sitting. So somebody that might have a job that requires long periods of time sitting, maybe a long haul trucker, for example, or perhaps people in office positions. People with chronic constipation, particularly with a lot of fecal straining, bearing down, spending a lot of time in the john to move your bowels. Pregnancy is a very common cause of hemorrhoids. And a person that has a large pelvic tumor that might be pressing against large vessels and decreasing vascular return might also result in hemorrhoids. Diagnosis of hemorrhoids include rectal exams. So actually looking, visualizing the perineum, the perianal skin around the anus. You can see external hemorrhoids. You may see internal hemorrhoids bulging out and prolapsing. Anoscopy, which is this image in the middle. It's a very small speculum, almost often transparent, clear-shaped. More commonly used by a rectal surgeon. But it can be placed into the rectum and you can see the anal canal better. And then finally, colonoscopy, which is the most common way we look. And at the end of colonoscopy, we always retroflex the scope tip so that we can see the distal rectum and usually see the internal hemorrhoids. Treatment for hemorrhoids, most commonly it's conservative management. Try to avoid constipation, so more physical activity, less sitting, more increased daily fluid intake, high-fiber diet, dietary fiber supplements. Topical therapies can be low-dose steroids and suppositories. Sitz baths can help soothe them. Then procedural management includes rubber band ligation. So again, putting these bands onto them, which you can see in the upper image and to the right after the band's been placed, kind of choking off the hemorrhoid. And then it becomes ischemic and it sloughs off and it scars down. In the past, people have tried sclerotherapy injection, kind of similar to what was done in the past for esophageal varices. Sometimes it can be coagulated. I don't have it listed here, but with different types of devices to coagulate. And then finally, surgery, hemorrhoidectomy. Not done as commonly anymore. We usually try to avoid surgery and treat them conservatively or with minimally invasive procedures like band ligation. And that's it. Sorry to go quickly, but I know we're trying to catch up a little bit. Time for a quick question, or we can move on to the next speaker.

large intestine

diverticulosis

colorectal cancer

hemorrhoids

lower GI bleeding

screening colonoscopy