The large intestine, which absorbs water from undigested food and stores wastes to excrete as feces, is classified into bowel, colon, and rectum. The double rectum is the last part of the large intestine, where it collects stool and waits before excretion. Rectal cancer is a malignant tumor in the rectum. Rectal cancer has few early symptoms and symptoms are similar to hemorrhoids, so it is often diagnosed late. Haidak internal medicine consultant Park Hyeon-gyeong (Seoul Park Hyeon-gyeong Internal Medicine Clinic) explained, “Rectal cancer has similar symptoms to hemorrhoids, but there are differences when you look closely.” He learns about the symptoms, diagnosis and treatment of rectal cancer with Dr. Park Hyeon-kyung.
Director of Park Hyeon-kyungㅣSource: Seoul Park Hyeon-kyung Internal Medicine Clinic
Q. Sometimes rectal cancer is misdiagnosed as hemorrhoids or constipation and the treatment period is delayed. When you have actually been treated, what symptoms do patients usually visit the hospital and get diagnosed with rectal cancer?
In the early stages, there are usually no symptoms, then by the time symptoms appear, the cancer is often already quite advanced. You may feel some pain, but usually you don’t feel pain until you’re late.
As rectal cancer progresses, the most common symptom is “blood in the stool.” Recently, during the month of September, four patients at our hospital were diagnosed with rectal cancer and I became alert. Common symptoms of patients are a sudden worsening of constipation and changes in bowel habits, such as a feeling of residual bowel movement after defecation.
Q. What are the symptoms of rectal cancer distinct from hemorrhoids?
Rectal cancer in a rather advanced state can be said to have symptoms similar to hemorrhoids as it shows symptoms such as anal bleeding, feeling of residual stools, pain during bowel movements and changes in stool thickness. However, if you look closely, there are some differences.
First of all, it is a bleeding symptom. Hemorrhoids are bright red in color and there are many cases where there is only bleeding after bowel movements, then the stool and blood are separated. It is a pattern where only blood drips after defecation and bloody blood is smeared on the toilet paper. However, in the case of rectal cancer, the stool leaks and stimulates the tumor tissue accompanied by bleeding in the rectum, so the blood is buried in the stool and the blood is often mixed with mucus rather than bright red.
The type of pain is also slightly different. Among hemorrhoids, thrombotic external hemorrhoids cause severe pain in the anus, and the pain occurs very suddenly because blood clots occur due to capillary bleeding. On the other hand, pain caused by rectal cancer usually complains of gradually worsening pain due to the nature of the disease, progressing slowly rather than causing sudden pain. This way, even if the symptoms seem similar, it is possible to roughly estimate the cause of the disease in consultation with a specialist. Therefore, it is strongly advised not to hastily judge that it is simply a symptom of hemorrhoids and to seek treatment from a specialist in digestive disorders.
Q. What is the difference between colon cancer and rectal cancer?
The large intestine can be divided into the colon and rectum, and the rectum is the last 15cm of the large intestine passing through the cecum, ascending colon, transverse colon, descending colon, and sigmoid colon. Cancer that occurs in the colon is called colon cancer, and cancer that occurs in the rectum is called rectal cancer. Both colon and rectal cancer are malignancies, ultimately collectively referred to as colon or colorectal cancer.
In terms of treatment, there is not a big difference between the lesions in the colon and rectum and it can be seen that it depends on the stage of the cancer. Basic surgical resection and additional chemotherapy (chemotherapy, radiation therapy, etc.) are considered. However, in the case of rectal cancer, it can be close to the anal margin, so the creation of a stoma (colostomy) can be included among the surgical resection methods. In oncological surgery, in order to minimize recurrence, the distance between the edge of the cancer and the surgical resection site should be kept at least 2 cm. You will be placed in a temporary or permanent colostomy for defecation.
Q. What tests are available to diagnose rectal cancer?
First of all, if rectal cancer is suspected, a biopsy via colonoscopy or sigmoidoscopy should be done. However, because lesions in the lower rectum, which is the part connected to the anus, often go undetected, it is necessary to invert the endoscope from the lower rectum and have a good look at the anus before completing the endoscopy. If cancer cells are confirmed in a biopsy, CT (computed tomography), MRI (magnetic resonance imaging) and PET (positron emission tomography) scans are also used to determine the exact size of the tumor, depth of invasion and the degree of metastasis.
Occasionally, a blood test for cancer is desired. Carcinoembryonic antigen (CEA), a marker of colorectal cancer, is a glycoprotein normally produced during the fetal period and its production is stopped before birth. If you have high levels of CEA in your blood tests, you may have other cancers, such as colorectal or lung cancer. However, blood tests alone are not suitable for diagnosing colorectal cancer, as this level can also increase in patients with cirrhosis of the liver, liver disease, chronic lung disease, and smokers.
Rectal cancer | Getty Image Bank
Q. It is said that there are many cases of problems with bowel function after rectal cancer surgery. Is it necessary to have a colostomy?
The appropriate surgical principles for rectal cancer are resection of the distal and proximal bowel at a sufficient distance from the tumor, with extensive resection of the lymphatic pathways. In the case of early stage rectal cancer, if the depth of invasion is not deep, it can be resected through an endoscopic procedure, but basically, the entire rectum is resected leaving only an adequate distance from the anus. In this process, if the distance between the rectal cancer and the anus is too small, the function of the anus cannot be saved, so a colostomy is permanently installed. However, with the development of surgical techniques, even if the distance from the anus to rectal cancer is only 4-5 cm, it is possible to temporarily place a colostomy after surgery and then perform restorative surgery.
Q. Rectal cancer is said to have a high probability of recurrence or complications even after treatment, what is the reason?
Rectal cancer recurs in about 30-50% even after radical resection. Among cases of recurrence, not only local recurrence in the area where the original tumor was located, but also extensive recurrence accompanied by distant metastases in other organs is common. The reason is that the rectum is very close to other organs in the pelvis, such as the uterus or bladder, and there is no peritoneum in the lower rectum, so cancer cells can easily invade surrounding organs. Since there are many recurrences that directly invade the surrounding genitourinary system, there are naturally many complications, and distant metastases that spread along the blood vessels or lymph nodes are common, so liver or lung metastases, bone (bone) metastases or brain metastases are mainly observed. .
Q. What are some lifestyle habits to prevent rectal cancer?
All cancer-related prevention methods will be similar, but ultimately, primary prevention to prevent the onset of cancer will be nearly impossible. This is because it is not possible to determine a single cause of cancer, and among the many causes, there are factors that we cannot choose or avoid, such as genetic predisposition. However, secondary prevention of early detection and treatment of rectal cancer through regular screening is quite effective. Therefore, even in the low-risk group with no symptoms, regular colonoscopy is recommended after the age of 40.
Furthermore, healthy eating habits are very important in the prevention of colorectal cancer. First, many studies have shown that the higher your total calorie intake, regardless of the type of food you eat, the higher your risk of colorectal cancer. In this regard, weight management to avoid obesity can help. Additionally, red meat and diets high in protein and fat can increase the risk of rectal cancer, so excessive consumption should be avoided.
Sufficient intake of dietary fiber and calcium has been reported to reduce the risk of rectal cancer, but more research on actual calcium intake is still needed.
Help = Hydak Counseling Doctor, Director Park Hyeon-kyung (Seoul Park Hyeon-kyung Internal Medicine Clinic)
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