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Bowel Cancer
Overview
Bowel cancer or Colorectal cancer is a malignant tumor of the large intestine. At the initial stage, it is asymptomatic. Subsequently, it manifests itself as weakness, malaise, loss of appetite, abdominal pain, dyspepsia, flatulence and intestinal disorders. Possible symptoms of intestinal obstruction. Ulceration of the neoplasm is accompanied by bleeding, however, the admixture of blood in the feces in colorectal cancer of the upper intestine may not be visually determined
Symptoms
In stages I-II, the disease may be asymptomatic. Subsequent manifestations depend on the location and characteristics of the growth of the neoplasm. There is weakness, malaise, fatigue, loss of appetite, an unpleasant aftertaste in the mouth, belching, nausea, vomiting, flatulence and a feeling of heaviness in the epigastrium. One of the first signs of colorectal cancer is often abdominal pain, more pronounced with tumors of the left half of the intestine (especially the colon).
Such neoplasms are characterized by stenosing or infiltrative growth, which quickly leads to chronic, and then to acute intestinal obstruction. Pain in intestinal obstruction is sharp, sudden, cramping, recurring after 10-15 minutes. Another manifestation of colorectal cancer, more pronounced when the colon is affected, are intestinal disorders, which can manifest themselves in the form of constipation, diarrhea or alternating constipation and diarrhea, flatulence.
Colorectal cancer, located in the right part of the large intestine, often grows exophytically and does not create serious obstacles to the progress of chyme. Constant contact with intestinal contents and insufficient blood supply, due to the inferiority of the vessels of the neoplasm, provoke frequent necrosis, followed by ulceration and inflammation. With such tumors, occult blood and pus in the stool are especially often detected. There are signs of intoxication associated with the absorption of decay products of the neoplasm during their passage through the intestines.
Colorectal cancer of the ampulla of the rectum also often ulcerates and becomes inflamed, however, in such cases, impurities of blood and pus in the feces are easily determined visually, and the symptoms of intoxication are less pronounced, since the necrotic masses do not have time to be absorbed through the intestinal wall. Unlike hemorrhoids , blood in colorectal cancer appears at the beginning, not at the end of a bowel movement. A typical manifestation of a malignant lesion of the rectum is a feeling of incomplete emptying of the intestine. With neoplasms of the anal region, pain during defecation and a ribbon-like stool are observed.
Anemia can develop due to repeated bleeding. With the localization of colorectal cancer in the right half of the large intestine, signs of anemia often appear already at the initial stage of the disease. External examination data depend on the location and size of the tumor. Neoplasms of a sufficiently large size, located in the upper intestine, can be felt by palpation of the abdomen. Colorectal cancer of the rectum is detected during a rectal examination.
Causes
The etiology of colorectal cancer has not been clearly established. Most researchers believe that pathology is one of the polyetiological diseases that occur under the influence of various external and internal factors, the main of which are genetic predisposition, the presence of chronic diseases of the large intestine, diet and lifestyle.
1. Nutritional errors. Modern specialists are increasingly focusing on the role of nutrition in the development of malignant tumors of the colon. It has been established that colorectal cancer is more often diagnosed in people who eat a lot of meat and little fiber. In the process of digestion of meat products in the intestines, a large amount of fatty acids are formed, which turn into carcinogens.
2. Violation of the evacuation function of the intestine. A small amount of fiber and insufficient physical activity lead to a slowdown in intestinal motility. As a result, a large number of carcinogenic agents contact the intestinal wall for a long time, provoking the development of colorectal cancer. A factor aggravating this circumstance is improper processing of meat, which further increases the amount of carcinogens in food. Smoking and alcohol intake is all time risk factor.
3. Inflammatory bowel disease. According to statistics, patients with chronic inflammatory diseases of the large intestine suffer from colorectal cancer more often than people who do not have such a pathology. The highest risk is observed in patients with ulcerative colitis and Crohn's disease . The likelihood of colorectal cancer is directly correlated with the duration of the inflammatory process. With a disease duration of less than 5 years, the probability of malignancy is approximately 5%, with a duration of more than 20 years - about 50%.
4. Intestinal polyps. In patients with polyposis of the large intestine, colorectal cancer is detected more often than the average for the population. Single polyps are reborn in 2-4% of cases, multiple - in 20% of cases, villous - in 40% of cases. The chance of polyp development into colorectal cancer is determined not only by the quantity of polyps, but also by their size. Polyps less than 0.5 cm in size are practically never cancerous. The bigger the polyp, the greater the risk of cancer.
Colon cancer often develops in the presence of colorectal cancer and other malignant neoplasms in the next of kin. Such cancer is often diagnosed in patients with familial diffuse polyposis , Turcot's syndrome and Gardner's syndrome .
Other predisposing factors include:
• Age over 50
• Obesity
• Insufficient physical activity
• Diabetes
• Lack of calcium
• Hypovitaminosis
• Immunodeficiency states caused by various chronic diseases, weakening of the body and taking certain medications.
Prevention
Colon cancer is a potentially preventable disease. If you follow certain rules, you can significantly reduce the likelihood of its occurrence.
Diet:
The first step is to reconsider eating behavior . It is recommended to normalize the diet, stop overeating, control the intake of animal fats. With a lack of dietary fiber in the diet, the menu should be enriched with vegetables, fruits and cereals. From meat products, it is better to give preference to lean white meat and fish.
Physical activity:
Normal physical activity is also important . If you lead a sedentary lifestyle, try to at least take daily half-hour walks. But it is better to optimize your daily routine so that there is enough time for physical activity and rest.
Removal of polyps:
The third point is the timely detection and treatment of precancerous bowel diseases . Most often, cancer is formed from polyps, and the longer a polyp exists, the higher the likelihood of its malignant transformation. If it is removed in a timely manner, the tumor will not develop. In order to timely detect polyps or cancer at an early stage, it is recommended to perform a total colonoscopy.once every 10 years, starting at the age of 50. However, this study is quite expensive, requires special equipment, qualified personnel, as well as special patient preparation. Therefore, in many countries, the circle of persons to be examined is narrowed down with the help of a preliminary fecal occult blood test. This makes it possible to identify patients who are most at risk of having asymptomatic tumors and subject them to a more thorough examination.
Treatment
The main method of treatment of a malignant tumor of this localization is surgical. The volume of the operation is determined by the stage and localization of the neoplasm, the degree of intestinal obstruction, the severity of complications, the general condition and age of the patient. Usually, resection of a segment of the intestine is performed, while removing nearby lymph nodes and peri-intestinal tissue. In colorectal cancer of the lower intestine, depending on the location of the neoplasm, abdominoanal extirpation is performed (removal of the intestine along with the closing apparatus and the imposition of a sigmostoma ) or sphincter-preserving resection (removal of the affected intestine with bringing down the sigmoid colon while maintaining the closing apparatus).
When colorectal cancer spreads to other parts of the intestine, stomach and abdominal wall without distant metastasis, extended operations are performed. In colorectal cancer complicated by intestinal obstruction and intestinal perforation, two- or three-stage surgical interventions are performed. First, a colostomy is placed. The neoplasm is removed immediately or after some time. The colostomy is closed a few months after the first operation. Assign pre- and postoperative chemotherapy and radiotherapy.
Tests Required for Diagnosis
The diagnosis of colorectal cancer is established by an oncologist on the basis of complaints, anamnesis, general and rectal examination data, and the results of additional studies. The most accessible screening tests for colorectal cancer are fecal occult blood tests, sigmoidoscopy (if the tumor is low) or colonoscopy (if the tumor is high). When endoscopic techniques are unavailable, patients with suspected colorectal cancer are referred for barium enema . Given the lower information content of X-ray contrast studies, especially in the presence of small single tumors, in doubtful cases, irrigoscopy is repeated.
To assess the aggressiveness of local growth of colorectal cancer and to detect distant metastases , chest X- ray, ultrasound of the abdominal organs , ultrasound of the pelvic organs, cystoscopy , urography , etc. internal organs. Assign a general blood test to determine the severity of anemia and a biochemical blood test to assess liver dysfunction.
Useful info
The most common complication of colorectal cancer is bleeding, occurring in 65-90% of patients. The frequency of bleeding and the volume of blood loss vary greatly. In most cases, small, recurring blood losses are observed, gradually leading to the development of iron deficiency anemia . Rarely, in colorectal cancer, profuse bleeding occurs, which poses a threat to the life of the patient. With the defeat of the left parts of the sigmoid colon, obstructive intestinal obstruction often develops . Another severe complication of colorectal cancer is perforation of the intestinal wall.
Neoplasms of the lower parts of the large intestine can germinate neighboring organs (vagina, bladder). Local inflammation in the area of a low-lying tumor can provoke purulent lesions of the surrounding tissue. Perforation of the intestine in colorectal cancer of the upper intestine entails the development of peritonitis . In advanced cases, a combination of several complications may occur, which significantly increases the risk of surgery.
