Senile colonic polyps

　　The cause of simple gastrointestinal polyps is still unclear today. The occurrence of polyps is often related to heredity, and a few are related to immune deficiency, infection, and abnormal gastrointestinal hormones. The occurrence of colorectal polyps may be related to the following factors:

　　1. Lifestyle

　　The occurrence of polyps with a high fiber content in food is less, and vice versa. Smoking is also closely related to adenomatous polyps. Those with a smoking history of 20 years or less often develop small adenomas, while those with a smoking history of more than 20 years often have large adenomas accompanying them;

　　2. Heredity

　　The occurrence of some multiple polyps is related to heredity. Patients inherit defective tumor suppressor gene APC alleles from their parents' germ cells. The other APC allele in the colonic epithelium is normal at birth. When this allele mutates later, adenomas occur at the mutated site, which is called a somatic mutation;

　　3. Embryonic abnormality

　　Juvenile polyps are mostly hamartomas and may be related to abnormal embryonic development;

　　4. Age

　　The incidence of colorectal polyps increases with age;

　　5. Infection

　　It is reported that the occurrence of adenomatous polyps is related to viral infection.

　　If senile colorectal polyps are not treated in a timely manner, they are prone to complications such as massive hemorrhage, prolapse, intussusception, and intestinal obstruction, which seriously harm the health of the elderly and affect their lifespan. Therefore, once symptoms are detected, timely treatment is essential.

　　Most colorectal polyps have no obvious symptoms, but they can also have the following manifestations:

　　1. Hematochezia

　　Blood in stool is more common in the left colon, especially in villous adenomas, and the blood in stool is bright red, which can cause anemia in severe cases.

　　2. Characteristics of feces

　　Colorectal polyps can cause the secretion of a large amount of mucus, and sometimes, when the polyps are multiple or large in size, they can also cause diarrhea or difficulty in defecation. Some large villous adenomas can secrete a large amount of mucus, which is known as hypersecretory villous adenomas. The amount of mucus excreted daily can reach 1 to 3 liters or more, and the excreted fluid contains a high amount of sodium and potassium. Therefore, in clinical practice, it can cause symptoms such as dehydration, low sodium, and low potassium. In severe cases, it can lead to coma, shock, and even death.

　　3. Abdominal Pain

　　Less common, sometimes larger polyps can cause intussusception, leading to intestinal obstruction and abdominal pain.

　　4. Polyp Prolapse

　　Polyps with a long pedicle in the rectum can prolapse out of the anus during defecation.

　　The etiology of elderly colonic polyps is unknown. Timely treatment of colonic inflammation is necessary, and attention should be paid to diet, heredity, and other factors; patients with hematochezia, diarrhea, difficulty defecating, and abdominal pain should undergo colonoscopy promptly to clarify the diagnosis; the recurrence rate of polyps is high, and regular colonoscopy should be performed after treatment. If recurrence occurs, treatment should be carried out promptly to prevent malignancy.

 

　　Most elderly patients with colonic polyps have no specific symptoms, so the diagnosis mainly relies on clinical examination. The routine examination items are as follows:

　　1. Routine Blood and Stool Examination

　　Patients with intestinal polyps accompanied by chronic bleeding may have decreased hemoglobin, positive occult blood in feces, and sometimes feces may contain a large amount of mucus.

　　2. Rectal Digital Examination

　　Rectal polyps close to the anus can be detected by rectal digital examination, and generally, rectal polyps within 5 cm of the anus can be detected by rectal digital examination.

　　3. X-ray Examination

　　Upper gastrointestinal polyps can be detected by upper gastrointestinal barium contrast examination. The detection rate increases with the size of the polyp, and polyps with a diameter less than 1.0 cm are prone to be missed, with a detection rate of 55% to 65%. Barium meal X-ray is the main method for diagnosing small intestinal polyps. Barium enema is simple, easy to perform, and less painful, and is an important method for diagnosing lower gastrointestinal polyps. Barium enema with double contrast has a detection rate of 82% for colonic polyps larger than 1 cm. Since the canceration rate of polyps larger than 1 cm is 10%, and 50% for those larger than 2 cm, the chance of canceration for small polyps (diminutive polyp, polyps with a diameter less than 5 mm) is only 0.1%. Therefore, barium enema is meaningful for screening malignant polyps. The perforation rate of colonoscopy is 1/5000 to 1/200, and the mortality rate is 1/5000 to 1/2000, while the perforation rate of barium enema is 1/12500 to 1/2500, and the mortality rate is 1/50000. Additionally, about 43% of colonoscopies cannot reach the ileocecal region, and the missed diagnosis rate is similar to that of barium enema. Moreover, the price of barium enema is 1/5 to 1/3 of colonoscopy, so barium enema has unique advantages in the diagnosis of gastrointestinal polyps. Under barium-air double contrast, colonic polyps appear as round or elliptical translucent defects filled with barium or as soft tissue shadows in the aerated intestinal lumen. Depending on their size, polyps can be obscured by barium. When locally compressed, a filling defect (simple barium contrast) can be seen, or a polyp shadow can be observed from the side (barium-air double contrast). Pedunculated polyps can be seen with a round or elliptical filling defect, and polyps with a pedicle can be seen with pedicles of different lengths.

　　4, Endoscopic examination

　　Fiberoptic endoscopy or electronic endoscopy is the most accurate and reliable method for diagnosing intestinal polyps. Due to the larger magnification of electronic endoscopy, the missed diagnosis rate of small polyps is significantly reduced. The advantage of endoscopy is that it can perform biopsy of polyps and has no false positives. Colonoscopy should strive to reach the ileocecal region to avoid missed diagnosis. In addition, the examination should be thorough to avoid missed small polyps. Since about 1/3 of lower gastrointestinal polyps are multiple, during colonoscopy, one should not be satisfied with finding a single polyp and should perform a thorough examination of the entire colon. For each polyp found larger than 1cm, multi-site biopsies should be performed to clarify its nature.

　　After treatment for elderly colonic polyps, the diet should be light, with less greasy, high-fat foods, more fibrous foods, more fresh fruits and vegetables, a reasonable diet, and attention to adequate nutrition; avoid smoking and alcohol, and avoid spicy foods.

　　The treatment of colonic polyps mainly depends on their location, whether they have a stalk, size, and malignant potential to choose the treatment method. In recent years, due to the gradual widespread application of fiberoptic colonoscopy, there has been significant progress in the treatment of polyps located above the sigmoid colon, which has greatly reduced the need for laparoscopic exploration surgery. In principle, for benign polyps or mucosal carcinomas, even invasive carcinomas with stalks, as long as the invasion has not exceeded the neck of the polyp, local resection can be performed. However, there are also reports in literature that focal invasive carcinomas can occur at the distal end of polyps with stalks. Although they are far from the stalk, lymphatic metastasis can occur occasionally. When a polyp less than 0.5cm is found during the endoscopy, it should be immediately removed with forceps, as it is often difficult to find the lesion when retracting the endoscope. For polyps larger than 0.5cm and less than 2.0cm, resection should be performed according to their shape and whether they have a stalk. For long stalked large polyps, a distance of 0.5cm should be left between the cutting section and the root of the polyp, and the method of cutting while coagulating and tightly closing the ligature device should be used. For short stalked polyps, after ligating, they should be pulled to form a尖幕状 at the root, and then coagulate. During electrocoagulation resection, the lens should maintain a distance of more than 2.0cm from the polyp, and the polyp should be kept away from the surrounding intestinal wall. Attention should be paid to ensure that the tip of the ligature device does not touch the intestinal wall and that the ligature device is tightly closed. If the lesion is too large and cannot be suspended in the intestinal lumen, the head of the polyp can be widely contacted with the intestinal mucosa, and the close contact method can be used to avoid burning the normal intestinal mucosa. As for how many polyps should be removed, some suggest removing 3 to 8 polyps at a time with ligature resection and 20 with coagulation, but we believe that the number of polyps to be removed should be considered comprehensively based on the specific condition of the patient, whether the polyps have stalks, and their size. Because whether bleeding or perforation occurs after electrocoagulation resection of polyps does not depend on the number of polyps removed, as long as there is a certain amount of normal intestinal mucosa left between the coagulated polyps, it is feasible to increase the number of polyps removed appropriately. Usually, the treatment method for colonic polyps is selected based on the following conditions.
　　1. Polyps located within 25cm from the anus can be treated through the anus or sigmoid colonoscope, and different methods are adopted depending on whether the polyp has a stalk. Polyps with stalks can be removed by electrocautery at the stalk using a snare. According to the pathological section examination, if it is benign or mucosal cancer, or invasive cancer but not beyond the neck of the polyp, further treatment may not be required. If invasive cancer has invaded the stalk but the margin of the resected specimen does not show cancer, further treatment may not be required. Broad-base polyps should be biopsied first. If they are benign or small, they can be completely removed by electrocautery through the sigmoid colonoscope. If the polyp is large or mucosal cancer, the entire mucosal layer of the intestinal wall including the polyp should be resected, and polyps located above 12cm from the anus should be removed by laparotomy. If the broad-base polyp is invasive cancer, it should be treated according to the principles of colorectal cancer surgery.
　　2. Polyps located above 25cm from the anus can be treated by colonoscopy. Depending on whether the polyp has a stalk, different treatments are adopted. Polyps with stalks are removed by electrocautery at the stalk of the polyp using a snare. In the following situations, the treatment should follow the principles of colorectal cancer surgery: ① When the cutting line only touches the cancer; ② When cancer emboli are seen in the lymphatic vessels in the sections; ③ When undifferentiated cancer is present. The biopsy of broad-base polyps is benign, and small polyps can be completely removed by electrocautery through the colonoscope. If the polyp is large or invasive cancer, it should be surgically removed by laparotomy.
　　3. For those who cannot undergo colonoscopy and have polyps located more than 25cm from the anus, laparotomy should be performed for exploration.
　　4. Optimal Treatment Plan: The optimal treatment plan is to perform polyp electrocoagulation and resection under a microscope as soon as a polyp is found.
　　5. Rehabilitation Treatment: Regular follow-up checks should be performed after the electro-resection of polyps to be vigilant against cancer transformation.