Age of onset of hereditary colorectal cancer

Colorectal cancer mainly includes colon cancer and rectal cancer. There are often no symptoms in the early stage. When non-specific symptoms such as blood in the stool, abdominal pain, and diarrhea appear, the patient is usually in the middle or late stage. The high-risk groups for colorectal cancer mainly include: symptomatic people over 40 years old in areas with high incidence of colorectal cancer; people who have received surgical treatment for colorectal cancer or colorectal polyps; people whose direct relatives have suffered from colorectal cancer or colorectal polyps.

Colorectal cancer can be preventedTall people are more likely to get colorectal cancer

Colorectal cancer is a preventable cancer. According to surveys, the peak age of colorectal cancer in my country is 50-60 years old, while in Western countries it is 60-70 years old. In comparison, the average age of onset in my country is 10 years younger. People who are prone to colorectal cancer include those who are obese, have a high-protein, high-calorie, low-fiber diet, have a family history of colorectal cancer, and have a history of colon polyps or a family history.

Adults with tall stature have an increased risk of colorectal cancer. Men taller than 185cm have a greater risk of colorectal cancer than men shorter than 165cm, and women taller than 168cm have a greater risk than shorter women. Obesity can also increase the risk of colon cancer. "Obese men have a two-fold increased risk of colon cancer, and obese women also have an increased risk of colon and rectal cancer."

Who are at high risk of colorectal cancer?

1. If one of your parents, siblings or children has colorectal cancer, your risk of developing the disease increases and you should start standard screening with sigmoidoscopy, fecal occult blood or both at the age of 40.

2. Those who have undergone radical resection for colorectal cancer have an increased risk of recurrent cancer or new cancer. Carcinoembryonic antigen (CEA) should be dynamically monitored after surgery. If CEA continues to not decrease or decreases in a short period of time and then increases again, the possibility of incomplete resection or recurrence should be considered, and a colonoscopy should be performed in time to detect the presence of tumors. If a thorough examination is not performed before colorectal cancer resection, a colonoscopy is recommended within 1 year after surgery. If the current or preoperative colonoscopy shows normal results, the next colonoscopy can be performed 3 years later, and then every 5 years.

3. Familial adenomatous polyposis is caused by congenital or acquired defects in the adenomatous polyposis coli (APC) gene. Mutations in this gene often occur between the ages of 20 and 30, which can lead to hundreds or thousands of adenomas in the colon. After the age of 40, almost 100% of people who carry this gene will develop cancer. Family members of this type should receive genetic counseling and undergo regular colonoscopy examinations from adolescence.

4. The canceration rate of adenomatous polyps is related to the size of the polyps. The larger the polyps, the more likely they are to become cancerous. If adenoma is found during the initial examination, electrosurgical biopsy is performed. If it is confirmed to be adenoma, a follow-up colonoscopy should be performed 3 years later. If the first follow-up examination shows normal results or a single small tubular adenoma is found, the next follow-up examination can be postponed to 5 years later; on the contrary, if the polyps are large in size and large in number, the interval between examinations should be shortened.

5. Hereditary non-polyposis colorectal cancer is an autosomal dominant hereditary disease in which multiple people in the same family suffer from colorectal cancer. Individuals suspected of having this disease should undergo a colonoscopy every 1 to 2 years starting at the age of 20 to 30, and once a year after the age of 40.

6. Patients with ulcerative colitis have an increased risk of colorectal cancer. This risk begins 8 years after the onset of the disease and continues to increase steadily. Patients with pancolitis should undergo a colonoscopy every 1 to 2 years, starting 8 years after the onset of the disease, and patients with left-sided colitis should undergo a colonoscopy every 1 to 2 years, starting 15 years after the onset of the disease.

7. In the past, it was believed that the polyps of patients with Peutz-Jeghers disease would not turn into cancer. However, in recent years, medical research has found that the probability of cancer in patients with Peutz-Jeghers disease is much higher than that of normal people. A survey showed that the incidence of malignant tumors in patients with Peutz-Jeghers disease is 20% to 23%. Therefore, patients with Peutz-Jeghers disease should be actively followed up and examined and treated. For patients over 10 years old, a full digestive tract radiography should be performed routinely every two years; patients over 20 years old should also undergo fiber colonoscopy every two years.

8. For polyps larger than 1 cm, especially those with abdominal symptoms, endoscopic electrocautery, elective laparotomy, or laparoscopic resection of polyps or diseased intestinal segments with the assistance of fiber colonoscopy should be performed as much as possible; after the age of 25, a comprehensive examination including the abdomen and pelvis should be performed every year; female patients should also undergo breast examination, cervical smear and pelvic B-ultrasound examination.