Rectal cancer refers to the malignant tumor from the dentate line to the junction of the rectum and sigmoid colon. It is a common malignant tumor in the gastrointestinal tract. Its incidence is second only to gastric and esophageal cancer. It is the most common part of colorectal cancer (accounting for about 65%). ), it is more common in the middle and lower rectum, and the proportion of low rectal cancer is about 75%. It can be palpated through digital rectal examination. Early treatment has a good prognosis. The vast majority of patients are over 40 years old, and those under 30 years old account for about 15% of men. The ratio of male to female is 2-3:1.
Many patients have rectal cancer, but they do not know the cause of this disease. The formation of rectal cancer is mainly caused by the following five reasons, for everyone to analyze one by one.
1. Malignant transformation of benign tumors
In clinical practice, colorectal adenoma is often seen to become cancer, which shows that the etiology of rectal cancer is closely related to colorectal adenoma.
Most rectal cancers occur on the basis of polyps. In the normal population, the incidence of polyps is 5% to 10%. Among adults over 45, the incidence of polyps is 10%. The incidence of rectal polyps varies with age. Increase and increase. This is also one of the causes of rectal cancer.
3. Inflammation stimulation
Inflammation such as chronic ulcerative colitis can cause intestinal mucosal exudation and edema. Repeated destruction and repair process can cause fibrous tissue hyperplasia, thickening of the intestinal wall, narrowing of the intestinal lumen, and anaplastic epithelial cells, forming multiple polyps and chronic Granuloma. This is the more common cause of rectal cancer.
4. Eating habits
The high incidence of rectal cancer is mostly economically developed countries. This has nothing to do with regional differences and ethnic genetic factors. It is mainly due to differences in dietary habits and nutritional methods. For example, the diet contains a large amount of meat, fat, and refined carbohydrate. Lack of fine fiber components.
5. Genetic factors
Such as familial adenomatous polyposis, hereditary non-polyposis colorectal cancer, etc. are also causes of rectal cancer.
Common symptoms are:
1. Hematochezia: It is the most common symptom of rectal cancer, but it is often ignored by patients. Blood in the stool is mostly red or dark red, mixed with mucus and blood in the stool, or pus and blood in the stool, sometimes accompanied by blood clots and necrotic tissue. The above-mentioned symptoms of rectal cancer are the consequences of blood supply obstacles, tissue necrosis and erosion, ulceration, infection, and ulcer formation after cancer proliferation.
2. Changes in ambassador’s habits: due to the mass and the secretions produced, the symptoms of rectal cancer can be intestinal irritation, frequent defecation, lack of defecation, tenesmus and other symptoms, but the discharge is mostly mucus, pus and blood. Initially these "pseudo diarrhea" phenomena mostly occurred shortly after getting up in the morning, called morning diarrhea (morning diarrhea). Later, the frequency gradually increased, and I could not even fall asleep at night, which changed my bowel habits in the past.
3. Anal pain and anal incontinence: Lower rectal cancer infiltrates the anal canal and can cause local pain. If it involves the anal sphincter, it can cause anal incontinence. Pus and blood often flow out and contaminate underwear; cancer infection or metastasis, symptoms of rectal cancer It can cause enlarged lymph nodes in the groin.
4. Intestinal stenosis and obstruction: It is also a common symptom of rectal cancer. Cancer infiltrates around the circumference of the intestinal wall, narrowing the intestinal cavity, especially at the junction of the rectum and the sigmoid colon, most of which are stenotic sclerocarcinoma, which can easily cause obstruction. Rectal ampullary cancer is mostly ulcer type. It is estimated that it takes about 1 to 2 years to cause stenosis and obstruction, stool formation, difficulty in defecation, constipation, and abdominal discomfort, bloating and pain. Due to the accumulation of feces, a cord-like mass can be palpated in the upper sigmoid part of the obstruction, sometimes in the left lower abdomen.
Classification of rectal cancer:
(1) General classification of rectal cancer: It can be divided into three categories.
1) Lump type: also known as cauliflower type cancer. The cancer protrudes into the intestinal cavity, and there is little infiltration of the intestinal wall. When the cancer increases, ulcers may appear on the surface, and the prognosis is poor.
2) Ulcer type: more common, accounting for 50%, growing deep into the intestinal wall, and infiltrating around, easy to bleed, low differentiation, and early metastasis.
3) Narrow type: rare, also called invasive. Cancer spreads and infiltrates along the intestinal wall, which can easily cause intestinal wall stenosis, early metastasis and poor prognosis.
(2) Histological classification of rectal cancer
1) Adenocarcinoma: the most common, accounting for about 75% to 85%.
2) Mucinous adenocarcinoma: about 10% to 20%. It is composed of cancer cells that secrete mucus, and is characterized by a large amount of mucus in the cancer tissue, which is highly malignant.
3) Undifferentiated cancer: The cancer cells are small, the shape is more consistent, and the prognosis is the worst.
4) Others: squamous cell carcinoma, etc.
Rectal cancer is easily confused and misdiagnosed with hemorrhoids. There are often cases of colon cancer and rectal cancer being misdiagnosed as hemorrhoids in the medical profession. Many early rectal cancers are transformed from rectal polyps, and early rectal polyps are easily confused with hemorrhoids and cause misdiagnosis. Hemorrhoids are the most common cause of blood in the stool. However, with the improvement of living standards, environmental pollution is getting worse. The incidence of rectal polyps is gradually increasing, and the coexistence of colon cancer, rectal cancer and hemorrhoids is also common clinically. Therefore, once suspected non-hemorrhoid bleeding, colonoscopy should be performed promptly.
1. Digital rectal examination Approximately 90% of rectal cancers, especially lower rectal cancer, can be found only by digital examination.
2. Proctoscopy or colonoscopy should be performed after the digital rectal examination, assist in the diagnosis under direct vision, observe the shape of the mass, the upper and lower edges and the distance from the anal edge, and take the mass tissue for pathological biopsy. Determine the nature of the mass and its degree of differentiation. It is located in the middle and upper part of the rectum with cancer and cannot be touched by the fingers. Colonoscopy is a better method. It is the main basis for the diagnosis of rectal cancer.
3. Barium enema and fiber colonoscopy are not very helpful in the diagnosis of rectal cancer, so they are not listed as routine examinations and are only used to rule out multiple colorectal tumors.
4. Carcinoembryonic antigen determination. Carcinoembryonic antigen (CEA) determination has been generally carried out. It is generally considered to be valuable for evaluating the treatment effect and prognosis. Continuous determination of serum CEA can be used to observe the effect of surgery or chemotherapy. A significant reduction in CEA after surgery or chemotherapy indicates a good treatment effect. Serum CEA is often maintained at a high level if surgery is not complete or chemotherapy is ineffective. If CEA drops to normal after surgery and rises again, it often indicates tumor recurrence
5. B-ultrasound examination In the case of rectal tumors, B-ultrasound can be performed in the rectal cavity. This is a non-invasive examination developed in recent years. Its advantage is that it can judge the depth and extent of the infiltration of rectal cancer. It also has a certain value for lymph node metastasis. Liver B-ultrasound is particularly important to prevent missed diagnosis of rectal cancer liver metastasis.
6. CT scan is not as accurate as intracavitary ultrasound in judging the depth of infiltration in the intestinal wall, but it has a higher diagnostic accuracy for moderate to extensive extraintestinal spread. CT scan is of great significance for the monitoring of rectal cancer recurrence after surgery.
The treatment of rectal cancer needs to be based on surgery, supplemented by comprehensive treatment of chemotherapy and radiotherapy.
(1) Surgical treatment
There are two types: radical and palliative.
1. Radical surgery
(1) Transabdominal and perineal resection (Miles operation) is suitable for lower rectal cancer less than 7cm from the anal margin. The scope of resection includes the sigmoid colon and its mesangium, rectum, anal canal, levator ani muscle, sciatic rectal fossa and around the anus The skin and blood vessels are ligated and cut below the root of the inferior mesenteric artery or the branch of the left colon artery, and the corresponding para-arterial lymph nodes are cleaned. Make a permanent colostomy (artificial anus) in the abdomen. This surgical resection is complete and the cure rate is high.
(2) Transabdominal low resection and one-stage extraperitoneal anastomosis, also known as anterior resection of rectal cancer (Dixon operation), is suitable for upper rectal cancer more than 12cm from the anal margin. Resection of the sigmoid colon and most of the rectum in the abdominal cavity, freeing the peritoneum The rectum below the reflexed part is anastomosed with the sigmoid colon and the rectal cut end outside the peritoneum. This operation is less invasive and can retain the original anus, which is ideal. If the cancer is large and has infiltrated the surrounding tissues, it should not be used.
(3) Resection of rectal cancer with preserving anal sphincter is suitable for early rectal cancer 7 to 11 cm from the anal margin. If the cancer is large, the degree of differentiation is poor, or the upper main lymphatic vessels have been infarcted by cancer cells and there are lateral lymphatic metastases, this surgical method is not completely removed, and it is better to combine abdominal and perineal resection. The currently used anal sphincter-preserving rectal cancer resection includes anastomosis with a stapler, low abdominal resection-transanal valgus anastomosis, transabdominal free-transanal drag-out resection and anastomosis, and transabdominal transsacral resection. Specific situation selection.
2. Palliative surgery
If the cancer is locally infiltrated or extensively metastasized and cannot be cured, in order to relieve the obstruction and reduce the patient’s suffering, palliative resection is feasible. The intestinal segment with cancer is resected limitedly, the distal rectum is sutured, and the sigmoid colon is used as a stoma. (Hartma surgery). If it is not possible, only a sigmoid colostomy is performed, especially in patients with intestinal obstruction.
Radiotherapy plays an important role in the treatment of rectal cancer. At present, it is believed that the survival period of late-stage mid-to-low rectal cancer is longer than that of surgery followed by concurrent radiotherapy and chemotherapy before surgery.
For patients with postoperative pathological staging of rectal cancer as stage II and stage III, postoperative chemotherapy is recommended. The total chemotherapy time is half a year.
(4) Treatment of patients with metastasis and relapse
1. Treatment of local recurrence
If the scope of the local recurrence is limited and there is no recurrence or metastasis in other parts, surgical exploration and excision can be performed. For patients who have not received pelvic radiotherapy, radiotherapy for recurrent lesions in the pelvic cavity can temporarily relieve pain symptoms.
2. Treatment of liver metastases
In recent years, many studies have confirmed that the effect of surgical resection of rectal cancer and liver metastasis is not as pessimistic as originally thought. Liver metastasis in patients with rectal cancer, whether it is co-existed with the primary tumor or after the primary tumor is removed, if the liver metastasis can be completely removed, the survival rate can be improved. For single metastases, segmental or wedge resection is feasible. For patients with multiple liver metastases that cannot be surgically removed, systemic chemotherapy can be used first to shrink the tumor to a time when the tumor can be surgically removed, and the same effect can be achieved. For some patients, even if intense chemotherapy cannot reduce liver metastases to the extent that they can be surgically removed, palliative chemotherapy is given.
Patients who have no chance of surgical resection receive systemic chemotherapy. If there is pain, bleeding and obstruction caused by the metastatic site, corresponding palliative treatment measures, such as radiotherapy, analgesics, and fistulas, can be used.
Complications of rectal cancer
1. Colonic obstruction is one of the late complications of rectal cancer, which can occur suddenly or gradually. It is mostly caused by tumor proliferation and obstruction of the intestinal cavity or narrowing of the intestinal cavity. It can also be caused by acute inflammation, congestion, edema, and bleeding at the tumor.
2. Bowel perforation There are two cases of perforation in rectal cancer: the perforation occurs in the local area of the cancer; the proximal colon perforation is a complication of cancer obstruction. After the perforation occurs, it can be clinically manifested as diffuse peritonitis, localized peritonitis or local abscess formation. Diffuse peritonitis is often accompanied by toxic shock, and the mortality rate is extremely high.
The prognosis of rectal cancer has nothing to do with the gender and age of the patient, but it is closely related to the course of the disease, the extent of tumor invasion, the degree of differentiation and the presence or absence of metastasis.
Three major dietary considerations for patients with rectal cancer
The treatment period and recovery period of rectal cancer are quite long, and because of the location of the disease, if you do not control your own diet, it will greatly hinder the recovery of the disease, so pay attention to the diet after rectal cancer surgery , Let's take a look below.
Food recipes should pay attention to eating liquid food
Fasting spicy food. It is best to eat a plain diet and avoid greasy food. In the early stage after rectal surgery, the patient will have confusion in intestinal effectiveness, the most common is diarrhea, followed by constipation. Usually, it is obviously relieved after 3 to 6 months after operation, and no special treatment is required. The diet after rectal cancer surgery is a low-fiber, low-lactose, low-fat, and high-protein diet, and the amount of fiber will be increased after the bowel effect is restored.
If diarrhea occurs after the operation, the high-lactose-containing rice, bananas, applesauce and fruit juice should be stopped. People with constipation should increase the amount of fiber, eat more fruits, vegetables, grains, fruit juice, and vitamin b12 after surgery.
To reduce the intake of fat in the diet
The relationship between diet and cancer, the most studied one is fat, including saturated fat and unsaturated fat. The oil in the diet can promote the growth of cancer cells, and it can also make normal cells mutate early and form tumors. Whether it is animal fat or vegetable fat, reduce it as much as possible.
Too much oil, especially animal fat, can stimulate the secretion of bile acid in the small intestine. When the amount of bile acid in the intestine is too high, it is easy to form carcinogens and promote the growth of cancer cells. This shows that a high-fat diet is particularly closely related to the development of rectal cancer.
To increase the intake of fiber in the diet
The main function of fiber in food is to make the intestines move normally, increase the volume of feces, and reduce the time that feces stay in the rectum. The feces present in the colon can make bacteria lively and may cause carcinogens. When there is a lack of fiber in the diet, the stool in the colon will become dry and hard, coupled with the slow rate, the abdominal muscles become weak, which makes the emptying time extend. If the time is too long, the risk of colon cancer will be relatively improved. Many studies have confirmed that the fiber in food can dilute the possibly carcinogenic substances in oils and fats, and can also speed up the rate of rejection of carcinogens through the digestive system.
6 simple ways to keep you away from bowel cancer
1. Eat more berries, anthocyanins and polyphenols in raspberries and other berries can inhibit tumor growth. Black raspberry (also known as raspberry) contains 40% more anthocyanins and polyphenol anticancer substances than red raspberries. In addition, more anti-cancer substances can be obtained when the berries are frozen for several hours and eaten.
2. In the sun for 10 minutes a day, vitamin D helps to change the growth of intestinal cells and prevent cancer. Not wearing sunscreen every day, 10 minutes of sun helps the body to produce enough vitamin D. In winter, when there is less chance of sun exposure, it is best to add more vitamin D every day.
3. Active 40 minutes a day, 40 minutes of high-intensity aerobic activities (running, swimming, skiing, cycling, etc.) can help reduce insulin levels and restrain tumor growth. In addition, aerobic activities can also promote digestion, accelerate intestinal emptying, and eliminate the retention time of carcinogens. Reaching 65%-85% of the maximum heart rate during activity is the best result.
4. Eat more corn and butter. The cellulose content in corn and other foods can prevent the growth of intestinal tumors and keep the cells in a healthy state. The Karolinska Institute of Medicine in Sweden found that butter also has anti-cancer effects. Eating some high-fat dairy products every day can reduce the risk of bowel cancer by 34%. When eating corn, you can add some butter.
5. Eat curry once a week. Curry can inhibit tumor angiogenesis. When intestinal cancer cells are exposed to curry, 25% of cancer cells die every day. Therefore, it is best to eat curry chicken, curry rice or curry vegetables at least once a week. In addition, taking a small tablet of aspirin after eating curry has better anti-cancer and anti-inflammatory effects.
6. Eat marine fish and drink white tea frequently. To prevent colon cancer, there should be fish rich in omega-3 fatty acids in the refrigerator, such as sea fish such as hairtail and yellow croaker. White tea has a stronger effect on inhibiting tumor cells than green tea.