Colon cancer

Colon cancer is a malignant neoplasm of the large intestine that comes from the epithelial tissue (most often account is  adenocarcinoma).

Colon cancer is usually present with the presence of blood in the stool or with complaints of gastrointestinal symptoms. The screening method of examination of the colon is the determine traces of blood in the faeces. Colon cancers is often diagnosed with the help of a colonoscopy and biopsy. The most effective method for treatment of colon cancers is surgery.  Chemotherapy is used after surgery in the presence of metastasis in the lymph nodes.

• Epidemiology of the colon

About  3-5% of world population is diagnosed of colorectal cancer (CRC) during their life time. According to the World Health Organization, 940,000 people fall ill every year and 500,000 of them die from colon cancer.  Statistics show that men get cancer of the rectum 1.5 times more often than women. In screening for colon cancer of the rectum and large intestine in age group above 60 years, the result shows that the greatest portion cancer was observed in men.

Age is a risk factor for the development of colon cancer, and the risk of developing the disease increases in people older than 40 years. It is believed that with age, the epithelial cells of the intestines undergo changes, resulting to the development of cancer.

In people who have a hereditary predisposition to the development of this disease, cancer develops at a young age. For example, patients with familial adenomatous polyposis can develop colon cancer at the age of about 20-30 years, unless surgical treatment is performed.

• Classification of colon cancer

Usually, three classifications of colon cancer are used in clinical practice: the TNM classification, the Deux classification and the classification according to the degree of differentiation of cancer cells.
read more

• Classification of TNM

 T (tumor) - the size of the primary tumor, N (node) - metastasis in the regional lymph nodes, M (metastasis) - distant metastases).

Stage	Primary tumor (T)	Regional Nodes (N)	Remote metastases (M)
Stage 0	Carcinoma in situ	N	M
Step I	The tumor penetrates the submucosal T 1 or the muscle envelope T 2	N	M
Stage II	The tumor penetrates into the muscular membrane (T 3 ) or peri-rectal tissues (T 4 )	N	M
Stage IIIA	T 1-4	N 1	M
Stage IIIB	T 1-4	N 2-3	M
Stage IV	T 1-4	N 1-3	M 1

Stage 0 - Carcinoma in situ. Cancer cells are found only in the mucosa (inner lining) of the colon and rectum. In most cases, colorectal cancer at this stage can be cured with polypectomy (removal of tumor formation inside the wall)

Stage I. Cancer grows through the mucous membrane and penetrates the muscular membrane of the rectum and large intestine. Does not spread to adjacent tissues and lymph nodes.

Stage IIA. The tumor grows through the wall of the intestine or rectum and can spread into adjacent tissues. Does not penetrate into the adjacent lymph nodes (T _3, N _0, M).

Stage IIB. Cancer penetrates the thick or rectum into the adjacent organs. Does not spread into the adjacent lymph nodes.

Stage IIIA. Cancer spread through the inner lining or through the muscular layers of the intestine and in 1-3 adjacent lymph nodes, but there are no distant metastases.

Stage IIIB. Cancer grows through the intestinal wall or into surrounding tissues, and in 1-3 adjacent lymph nodes, but there are no distant metastases.

Stage IIIC. A tumor (of any size) penetrates into 4 or more lymph nodes, but there are no distant metastases.

Stage IV. Cancer metastasizes to distant parts of the body. Any T, any N, M _1.

The Deux Classification

Stage	Characteristics
Stage A	Carcinoma in situ, limited by the mucosa and submucosa (T1, N , M )
Stage B	Cancer that penetrates the muscle shell (stage B 1 ), or into the serous membrane (B2 )
Step C	Cancer that penetrates the regional lymph nodes (T 1-4 , N 1 , M )
Step D	Cancer with distant metastases (T1-4 , N 1-3 , M 1)

There is a clear correlation between the stage of the disease and 5-year survival rates.

• In stage I, or in D-stage A, the 5-year survival is more than 90% after resection.
• In stage II or stage B, Dewux, a 5-year survival rate of 70-85%.
• With Stage III or D-stage C, 5-year survival is 30-60%.
• In Stage IV or D-stage D, the 5-year survival rates are low (approximately 5%).

 Classification by degree of differentiation of cancer cells

• Gx - the degree of differentiation is not determined.
• G1- Cells look almost like healthy cells (well differentiated)
• G2 - Cells differ from normal cells (medium-differentiated).
• G3 - Cells remotely resemble normal (slightly differentiated).
• G4 - Cells have no similarity to normal (undifferentiated).

              ICD codes -10

• C 18 Malignant neoplasm of the colon.
• C 18.0 Malignant neoplasm of the cecum.
• C 18.1 Malignant neoplasm of appendix.
• C 18.2 Malignant neoplasm of an ascending colon.
• С 18.3 Malignant neoplasm of hepatic flexure of the colon.
• From 18.4 Malignant neoplasm of transverse colon.
• Since 18.5. Malignant neoplasm of splenic flexure of the colon.
• From 18.6 Malignant neoplasm of descending colon.
• From 18.7 Malignant neoplasm of sigmoid colon.
• C 18.8 Colon lesion that extends beyond one or more of the above locations.
• C 18.9 Malignant neoplasm of unspecified site of colon.
• C 19 Malignant neoplasm of rectosigmoid junction.
• C 20 Malignant neoplasm of the rectum.

Aetiology and pathogenesis

Aetiology of colorectal cancer

Clearly identify the causes of colorectal cancer is not possible. However, there are a number of factors predisposing to the development of colorectal cancer.

• Polyps of the large intestine, usually developing in old age, increase the risk of developing colon cancer.
• Inflammatory diseases of the large intestine. Cancer of the colon is more common in patients with ulcerative colitis and Crohn's disease.
• Heredity. Familial adenomatous polyposis, in which a mutated copy of the  gene tumor is inherited. Family nonpolyposis colon cancer, representing 1-5% of all neoplasms of the colon, develops as a result of hereditary mutations of genes that restore the structure of DNA.
• Nutrition factors. Alcohol abuse and eating high-fat foods predispose to the development of colon cancer.
• Tobacco smoking is a predisposing factor in the development of colorectal cancer.

 The following diseases are related to precancerous diseases:

• Chronic colitis, in particular chronic ulcerative colitis and granulomatous colitis (Crohn's disease), which constitute the main group of facultative precancerous diseases.
• Diverticular disease  of the colon complicated by diverticulitis, is a precancerous disease.
• Polyposis lesion of the colon (obligate pre-cancer), which can be in the form of:
• Single polyps (adenomatous, villous), which are malignant in 45-50% of cases, especially polyps that are more than 2 cm in size; villous polyps are more often malignant.
• Multiple polyposis of the colon, which in turn, can have the following forms:


• Genetically determined polyposis (family-hereditary diffuse polyposis, Peutz-Jeghers syndrome(benign hamaetomatous polyps in the gastrointestinal tract and hyperpigmented macules on the lips and oral mucosa -melanosis, Turcot syndrome- multiple adenomatous colon polyps).
• Non-hereditary polyposis (sporadic polyposis, combined polyposis, cronkhite-canada syndrome-multiple polyps of the digestive tract).

• Pathophysiology of colorectal cancer
  In most cases, colon cancer is an adenocarcinoma that develops from a previous adenomatous polyp. The degeneration of adenoma into carcinoma occurs in connection with the development of genetic changes at the molecular level.

A large number of genetic changes have been identified that lead to the development of colon cancer. At a young age, colon cancer develops when the APC gene (the colon adenomatous polyposis gene) is involved, in people who have a gene of the hereditary adenomatous polyposis. There is a degradation of beta-catenin, a protein entering the complex, leading to activation of oncogenes, such as cyclin D` or c-myc.

In cancer and polyposis of the colon, a decrease in DNA methylation is observed. Hypomethylation leads to activation of oncogenes. With the development of large polyps of the large intestine, mutations of the ras genes are noted.

With the development of colon cancer, a deletion of genes in the tail of chromosome 18q is associated. Frequent findings in colon cancer are a deletion in the stem of 17p and mutations of the tumor suppressor gene p53. An early finding is the overexpression of the Bcl-12 gene, leading to a reduction in signals about the planned cell death. With a deletion of 18q, the risk of recurrence after radical treatment is much higher, and such patients need stronger supportive therapy.

Another precancerous condition is hereditary nonpolyposis colon cancer, in which mutations of genes responsible for DNA repair, such as MSH2, MLH1 and PMS2, are detected. These gene mutations can be found in the study of the  patients stool, which may be useful in the future in the early diagnosis of colon cancer.

It is proved that the constant intake of non-steroidal anti-inflammatory drugs leads to an increase in the number of polyps.

The forms of colon cancer are diverse: mushroom-shaped on a flat base, circular, stricturing the lumen of the intestine, and others.

Adenocarcinoma of the large intestine is classified according to the degree of cell differentiation; Undifferentiated tumors are more invasive than differentiated tumors.

The presence of ring-secreting circular ring-like cells in the tumor indicates a high probability of their metastasis.

Clinic and complications

Characteristic clinical manifestations of colon cancer

Colorectal cancer develops slowly  and can be asymptomatic for a long time.

The most common symptoms are:

• Uneven pain in the abdomen.
• Intestinal dysfunction.
• Diarrhoea, constipation or feeling of incomplete bowel movement.
• Changes in the shape of the stool, the stool becomes bulkier or on the contrary thinner than usual.
• Weight loss for unknown reasons.
• Chronic fatigue and weakness.
• Iron deficiency anemia for no apparent reason.

Clinical complaints depending on the location of colon cancer

 Clinical forms of colorectal cancer

Dyspeptic form

This clinical form is characterized by functional disorders of the gastrointestinal tract. Initial clinical signs of dyspeptic form are manifested by pain in the abdomen and symptoms of gastrointestinal discomfort - loss of appetite, unpleasant sensations in the mouth, nausea, belching, regurgitation, periodic vomiting, feeling of heaviness and swelling in the epigastric region.

Abdominal pain and discomfort symptoms are characteristic initial clinical manifestations of right colon cancer. However, these phenomena can be in case of cancer of the left half of the transverse colon. Pain in the abdomen and the presence of intestinal discomfort are sometimes of little concern to patients. These disorders are associated with a stomach disease or a violation of the food regime. Often doctors also connect these symptoms with stomach disease. Such patients diagnosed with gastritis, peptic ulcer, stomach cancer are mostly examined, but the examination is often limited to studying the upper part of the gastrointestinal tract.

In the initial stages of the disease, the clinical picture of the dyspeptic form is characterized by "small symptoms", the frequency of individual symptoms varies. Subsequent increase in intestinal disorders or disturbance of intestinal patency leads patients to medical institutions where they undergo a clinical examination of the colon, and only then does the nature of the disease become clear.

As the disease progresses, the pain syndrome and the symptoms of intestinal discomfort become more pronounced. In the future, intestinal disorders are added and intestinal obstruction can develop. The general condition of patients also suffers, weakness and emaciation develop.

Obturation form

This clinical form is characterized by the early appearance of the symptom complex of intestinal permeability. It is observed most often in cancer of the left half of the large intestine and is due to the morphological structure of the tumor and the anatomical and physiological features of this part of the colon. Endofitnye tumors of the left half already in the early stages of the disease lead to disruption of peristalsis and narrowing of the lumen of the intestine in the site of the tumor, followed by the development of stagnation of intestinal contents.

The clinical picture with obturative form gradually increases from the symptoms of intestinal disorders (constipation, alternation of prolonged constipation with short-term diarrhea, bloating and rumbling in the intestine, the phenomenon of coprostasis), partial obstruction before full intestinal obstruction. Among the initial clinical manifestations, the pain syndrome comes to the fore. Pain in the abdomen at first can be blunt, noisy, without definite clear localization. Pain syndrome is accompanied by the appearance of persistent constipation.

As the disease progresses, the pain in the abdomen becomes worse and becomes paroxysmal. The first attacks of abdominal pain are short-lived and usually go away on their own. Then attacks of intestinal colic become more frequent and prolonged. Such attacks of abdominal pain are accompanied by swelling of the intestines, rumbling in the abdomen, increased intestinal peristalsis and delay of gases and stools. The attack can end on its own or with the use of enemas by the abundant release of fetid stool. Gradually, the frequency of seizures and their duration increase, and chronic intestinal obstruction develops. With the course of the disease, one of the attacks develops a full intestinal obstruction.

Obstructive clinical form of colon cancer in the early stages of the disease can occur with a clinical picture of chronic spastic colitis, abdominal adhesive disease and various kinds of chronic and disease progression and the acute intestinal obstruction.

Pseudoinflammatory form

 This clinical form is characterized by the absence or low severity of symptoms of intestinal discomfort, intestinal disorders and general disorders in the patient's body - the most typical clinical manifestations of colon cancer. In pseudo-inflammatory form, among the initial clinical manifestations, the symptoms of the inflammatory process in the abdominal cavity: abdominal pain, peritoneal irritation and abdominal wall tension, fever, leukocytosis, and increased ESR. From the side of the abdominal cavity there are inflammatory changes with possible subsequent development of inflammatory infiltrates, abscesses and Phlegmon.

The above symptom complex is a clinical manifestation of the inflammatory process, often associated with colon cancer. Depending on the location of the tumor, complicated by the inflammatory process, the clinical picture may be similar to appendicitis, cholecystitis, peptic ulcer and stomach, kidney, bladder, female genital organs, as well as inflammatory processes of the abdominal wall and retroperitoneal space.

Toxico-anemic form

 his form of the clinical course of colorectal cancer is named so because of the prevalence of the symptom complex of general disorders in the patient's body. Among the initial clinical manifestations in patients are symptoms such as malaise, weakness, fatigue, loss of strength and performance, fever, pale skin and the development of progressive anemia. The pallor of the integuments with the development of the disease gradually increases; the complexion of the patient acquires an earthy tinge.

In such cases, the general condition and appearance of the patient indicate the presence of a serious disease.

The increase in symptoms of general disorders, the presence of prolonged subfebrile condition, the progression of anemia cause the doctor's suspicion of septic state, endocarditis, or B ₁₂ -defect anemia. With suspicion of all sorts of other diseases, such patients are often long-term in the examination in medical institutions, but the idea of ​​a malignant tumor of the colon is usually expressed with great delay.

Despite the increasing severity of the disease and the severity of symptoms of toxico-anemic form, the nature of the disease for a long time may remain unrecognized. The belated diagnosis is explained by an erroneous evaluation of the symptom complex by doctors and the absence of a purposeful full-scale examination.

Over time, other clinical symptoms appear and grow: nausea, periodically paroxysmal pain in the abdomen.

Enterocolitis form

This form of the clinical course of colorectal cancer is characterized by a symptomatic complex of initial clinical manifestations caused by bowel dysfunction. In the clinical picture of the enterocolitis form of the cancer, such symptoms as constipation, diarrhea, alternating constipation with diarrhea, a feeling of bursting and swelling of the intestine, rumbling in the abdomen, frustration of the act of defecation, the presence of bloody, bloody mucous and mucopurulent discharge from the posterior passage.

All of the above symptoms are accompanied by pain syndrome. Pain in the abdomen is of varying intensity - from mild pains with vague localization to significant paroxysmal, such as intestinal colic.

With enterocolitic clinical form of colon cancer from the onset of the disease, the symptomatic complex of intestinal disorders is dominant. These disorders with the development of the disease gradually progress and become more pronounced, and the frequency of individual symptoms increases. Constipation for colon cancer is particularly stubborn, long and difficult to eliminate by usual medical measures. Constipation lasts for several days and even weeks and is usually resolved by the passage of an abundant amount of feces. The diarrhea that appears after the constipation is accompanied by the liberation of a stinking, watery stool. The accumulation of gases, swelling of the intestines, rumbling in the abdomen, the replacement of constipation with diarrhea indicate a violation of the function of the intestine.

The inflammatory process in the tumor and intestinal wall, the violation of absorption processes, the presence of processes of fermentation and decay, increased secretion clinically can be manifested by the appearance of mucous, blood-mucous and purulent discharge from the intestine. Pathological discharge is usually observed with clinically expressed colon cancer, but often pathological discharge and latent bleeding are noted in the early stages.

 Tumor form

This clinical form of colorectal cancer is characterized by the presence of a palpable tumor in the abdominal cavity with a low degree of clinical symptoms of the disease.

Often, among the full well-being themselves, patients or doctors during a preventive examination find a tumor in the abdominal cavity. When examining such patients, it turns out that the tumor is related to the large intestine and, in its structure, is a cancerous tumor. In such cases, one gets the impression of asymptomatic flow, and only the palpation of the tumor makes one think of a malignant neoplasm of the large intestine. However, with a thorough questioning of the patients, it turns out that several months before the tumor was detected they had abdominal pain, decreased appetite, nausea, and a feeling of heaviness in the abdomen. In other cases, among the previous symptoms, constipation, bloating, diarrhea, mucus secretion from the intestine and other symptoms were noted.  

Colon cancer that developed against ulcerative colitis and Crohn's disease

 Colon cancer, which develops against the background of ulcerative colitis and Crohn's disease, is characterized by peculiarities of the clinical course and requires special surgical tactics in comparison with uncomplicated forms.

The development of colon cancer with ulcerative colitis is relatively common. Long-term chronic course of ulcerative colitis with severe intestinal disorders and blood-mucopurulent discharge can mask the clinical manifestations of colon cancer. In chronic forms of nonspecific ulcerative colitis, there are significant changes in the mucosa throughout the colon. The presence of multiple ulcers, pseudopolypoid growths, deformities of the intestinal wall makes it difficult to recognize the initial forms of cancer. Cancer of the large intestine, which has developed against a background of chronic ulcerative colitis, differs more expressed malignancy. When combined defeat of the colon with cancer and ulcerative colitis, the amount of surgical intervention will be different than with uncomplicated forms of cancer.

Complications of colon cancer

With colorectal cancer, the following complications can develop:

• Intestinal obstruction.
• Development of inflammatory processes in the large intestine.
• Perforation of the wall of the large intestine.
• Intestinal bleeding.

 Diagnostics

It is possible to suspect the presence of colon cancer in the presence of blood or mucus in the feces, with bowel dysfunction, a decrease in the weight of the patient, worsening overall health and in detecting iron deficiency anemia.

At the slightest suspicion of the disease, colono-rectoscopy should be prescribed.

• Diagnostic Methods
• Complaints and anamnesis

Complaints require in-depth and careful study. Very painstaking collection of anamnesis, including family one, is very important.

 Laboratory diagnostics

•  Clinical blood test.

Iron deficiency anemia can be detected.

• Biochemical examination of blood.

Hepatic tests are prescribed, but the results can be normal, even if there are metastases. The level of total cholesterol decreases.

• Study of faeces for latent blood.
• Determination of the level of the cancer embryonic antigen (CEA).

Determining the level of cancer embryonic antigen (CEA) in the preoperative period can be useful in colorectal cancer. CEA usually does not increase with mildly differentiated carcinomas of the colon or rectum. It should be remembered that 1) CEA may increase in diseases of the pancreas and liver, and the increase in the level may not necessarily be due to tumor recurrence. 2) Tumor recurrence can be without increasing the level of CEA, even if CEA was elevated in the preoperative period. To diagnose relapses, it is better to take into account the data of computed tomography and colonoscopy.

• Determination of antigen level 19-9.

The definition of oncomarker 19-9 can also be useful if its level is initially elevated. An increase in the level of cancer markers is associated with a higher risk of tumor recurrence, and a shorter survival.

Instrumental diagnostics

Colonoscopy

 Colonoscopy is used for examination of patients with rectal bleeding, polyps, revealed by sigmoidoscopy and irrigoscopy, patients with family history.

With the help of this method, polyps and neoplasms are detected in 20-30% of cases, which were not detected during irrigoscopy in patients with rectal bleeding.

Colonoscopy also makes it possible to obtain a biopsy specimen for histological examination, the result of which is often necessary for surgical treatment. However, histological examination in the preoperative period is not mandatory for patients who have received typical data from an irrigoscopy.

Recto-Humanoscopy

Recto-manoscopy (tumors of the rectum and sigmoid colon are determined in 60% of cases). The method is effective in diagnosing cancer, including its early stages, erosive and ulcerative forms and malignant polyps 30 cm from the anus.

 X-ray studies

•  Radiography of the chest.

Conducted as standard. Helps to detect metastases in the lungs.

• Contrast radiography of the large intestine with barium.

It allows to detect tumors of the colon, by injecting a contrast agent with an enema.

Irrigoscopy by the method of double contrasting (usual study with contrast little informative) is the initial study of patients with stool disruption. Sometimes it is carried out in those cases when the colonoscopy does not reveal pathological changes (and the clinical signs are sufficiently pronounced), with the narrowing of any segment of the intestine, the cause of which is unclear; for choosing the method of surgical intervention (determining the length of individual parts of the colon and the state of surrounding tissues).

X-ray signs of CRC include: irregular forms of filling in the wall of the intestine (exophytic tumor), stiffness of the wall (tumor infiltration), narrowing of the lumen of the gut by the type of the "apple core".

Radiograph of colorectal cancer.

Angiography

 After the contrast medium is injected into the blood vessel, a series of images are taken. This allows the doctor to identify the location of blood vessels in relation to tumor metastases in order to avoid serious bleeding during surgery.

Histological examination

 According to the microscopic structure, colon cancer is divided into 3 groups:

1. The glandular forms.

The glandular form of cancer, or adenocarcinoma, has the form of tubular cavities of various size and shape in its microscopic structure. The glandular tubes are lined with a comparatively high cylindrical epithelium in one or more rows. Cells are elongated, elongated. Cell nuclei are located at different levels from the base, in the form of rounded or irregularly shaped dark formations. Mitoses are markedly expressed, mostly in the apical layers of the epithelium.

2. Solid forms.

A solid cancer is an alveolar tumor, with a moderately developed stroma. Parenchyma consists mainly of cells of little differentiated cylindrical epithelium of a cubic, round or polygonal shape. There are also polymorphic epithelial cells. Cells of glandular complexes are separated by connective tissue heavy-like trabeculae into alveoli of greater or lesser dimensions. Often in the centers of cancer cells, the phenomena of necrosis and the breakdown of cellular elements are detected.

3. Mucous, or colloidal, cancer.

Mucous cancer is essentially an adenocarcinoma, the cellular elements of which have the ability to mucus.

Adenocarcinoma of the large intestine.

 

Low-grade adenocarcinoma of the large intestine.

 

Highly differentiated adenocarcinoma of the large intestine.

 

Medullary carcinoma of the large intestine with a high degree of malignancy.

 

Mucinoid (colloidal) carcinoma of the large intestine.

Ring-cell carcinoma of the large intestine.

 

Small cell carcinoma of the large intestine.

 Undifferentiated carcinoma of the large intestine.

  

CT scan

•  Computed tomography of the abdominal cavity and pelvis.

The study is useful in the diagnosis of colon cancer, metastasizing to the lymph nodes and liver. Cancer with multiple metastases in the liver is weakly susceptible to surgery and chemotherapy. It is also used for screening. Can give information about the prevalence of the tumor, as well as the locations of potential metastases. Before performing surgical interventions, it is advisable for all patients to undergo computed tomography, except in urgent situations. In this case, the computer tomography should be performed immediately after the intervention, before the beginning of the auxiliary therapy.

• Computed tomography of the thorax.

Computer tomography is useful in detecting metastases in the lungs. This method of research is used in the control of relapses and response to chemotherapy.

Computer tomogram of abdominal and pelvic organs with colon cancer.

Ultrasonography

 Transrectal ultrasound is currently performed for all patients with rectal carcinoma, since decisions about the appointment of treatment are made on the basis of these data (preoperative chemotherapy, or resection without preparation). Transrectal ultrasound helps to detect the exact depth of penetration of the tumor into the wall of the intestine in 80-90% of cases, as well as involvement of lymph nodes in 70-80% of cases.

Transrectal ultrasound transducer.

Ultrasonography. Cancer of the rectum T ₂ N ₁

Virtual Colonoscopy

 This method does not use a contrast agent. Only air is introduced for the expansion of the large intestine. Then spiral computed tomography is used. This method is more effective than the study with barium, but inferior to the colonoscopy in the identification of small polyps.

 Positron Emission Tomography (PET)

 Positron emission tomography (PET) is useful for determining the stage of cancer, and detecting relapses. A relatively new research method, which is carried out with radiolabelled 2-fluorodioxglucose labelled (18F). It is the most sensitive functional method of diagnosing tumors at the moment, and colon cancer in particular. In case of recurrence, hypermetabolic activity is detected even in the absence of an increase in the level of the cancer embryonic antigen and the absence of changes in the computed tomography.

Positron Emission Tomography. In the right upper quadrant of the liver, hypermetabolic activity - metastasis was revealed.

 Differential diagnosis in colon cancer

In patients with haemorrhages of the lower gastrointestinal tract, differential diagnosis between colon cancer and the following diseases is carried out:

• Inflammatory bowel diseases ( nonspecific ulcerative colitis or Crohn's disease ).
• Diverticulosis of the large intestine .
• Uraemia.
• Rendu-Osler-Weber Syndrome (Hereditary haemorrhagic telangiectasia)
• The presence of foreign bodies in the intestine.
• Polyps of the large intestine.
• Metastases of any other tumors.
• Intestinal lymphomas.
• Kaposi's sarcoma.

 Treatment

• Objectives of treatment
• Increase the survival time of patients in all cases.
• Eliminate neoplasm and prevent the occurrence of relapses with resectable tumors.
• To improve the quality of life with the help of palliative therapy in case of non-primary tumors.

Tactics of treatment

The best way to reduce mortality from colon cancer is to prevent its occurrence by diagnosing and treating precancerous conditions.

The management of a patient with colorectal cancer is determined by the localization and stage of cancer, but surgical treatment is an indispensable method for radical tumor removal, prevention of intestinal obstruction and stopping bleeding.

 Surgery

Prevention of malignancy of adenoma is the most effective method of treatment. It is performed with the help of sigmoid-colonoscopy. Obviously, it is much easier to cure a precancerous state than to treat a malignant tumor.

Polypectomy with the help of heated surgical forceps.

A classic operation for colon cancer is anterior resection with the use of non-contact insulating technology. A revision of the abdominal cavity is performed for tumor operability, and segmental resection (right-sided or left-sided hemicolectomy) with the application of an anastomosis from end to end. It is recommended to resect 10 cm from the edge of the tumor in both directions with the removal of the adjacent lymph nodes. Total resection of the large intestine is carried out in patients with hereditary polyposis and multiple polyps of the large intestine.

Laparoscopic resection of the large intestine. Currently, the level of development of technology allows for resection of the large intestine laparoscopically. Recent studies have shown good postoperative results for 5 years.

In patients with cancer recurrences and metastases, limited to the liver, partial hepatectomy is used. In many studies, an increase in the average life expectancy after this operation was noted.

Also, such methods as cryoablation and hepatic arterial infusion of chemotherapeutic drugs are used to transfer the tumor into an operable state.

To treat disseminated colon cancer, methods such as cryoablation and radiofrequency ablation are used. For example, cryoablation of metastases in the liver is performed in patients who cannot perform liver resection.

Intraoperative photo, illustrating the technique of cryoablation using liquid nitrogen under ultrasound control.

 Auxiliary therapy

Chemotherapy (usually done with 5-fluorouracil (5-fluorouracil -Ebove , fluorouracil -LENS ) and leucovorin) improves the survival of patients with positive metastases in the lymph nodes from 10 to 30%. With cancer of the rectum with metastases to the lymph nodes, there is an improvement in the lesion from 1 to 4 lymph nodes. In the event that more than 4 lymph nodes are affected, the combined therapy regimens are not as effective. Chemotherapy and radiotherapy in the preoperative period help to increase the operability of the tumor, and reduce the number of metastases in the lymph nodes.

The most common side effect of chemotherapy is diarrhoea. Other side effects are mucositis, neutropenia, hair loss, and skin reactions of hypersensitivity. Intestinal perforation and gastrointestinal bleeding occur much less frequently.

 Radiation therapy

Radiation therapy uses powerful sources of energy, such as X-rays to destroy cancer cells left after surgery, to reduce the size of the tumor before surgery, and to alleviate symptoms of cancer of the colon and rectum.

Radiation therapy is rarely used in the early stages of colon cancer, but it is an important part of colon cancer treatment in the early stages, especially when the cancer grows through the rectal wall or spreads into the adjacent lymph nodes. Radiation therapy, often combined with chemotherapy, can be used after surgery to reduce the risk of developing cancer recurrence in the same area where it first appeared.

Side effects when using radiation therapy are diarrhoea, rectal bleeding, weakness, loss of appetite and nausea.

Further management of patients

Careful observation of patients is necessary to detect recurrences and prescribe appropriate therapy in a timely manner.

In patients with tumor metastases, 5-fluorouracil-based therapy is administered as long as side effects permit. During the period of therapy, a computer tomography of the abdominal cavity and chest is usually performed every 2 months.

If there is such an opportunity, then PET is performed, which helps to identify relapses.

With the progression of the disease, intrahepatic chemotherapy is possible.

Prognosis

Histopathological criteria, tumor prevalence and some other data are important for determining the prognosis.

• With tumors confined to the intestinal wall, the five-year survival rate reaches 80%.
• In tumors that grow into the intestinal wall, but in the absence of metastases in the regional lymph nodes, the five-year survival rate reaches 60%, and when regional lymph nodes are involved it decreases to 30%.
• In patients with metastases to the lungs and liver, the prognosis is usually poor.
• At highly differentiated tumors at any stage the prognosis is more favourable.
• Other factors of the prognosis: operational mortality is higher in the elderly, but young ones are dominated by rapidly progressive tumors; women have a better prognosis than men; the forecast worsens in the presence of complications (obstruction, perforation, etc.).

Prevention

• Carrying out every 3 years of colonoscopy to people at increased risk (recurrent polyposis, familial adenomatous polyposis, immediate relatives of patients under the age of 40, total ulcerative colitis, patients who underwent resection for colon cancer).
• Rectoromanoscopy and other compulsory examinations to identify colon cancer in patients treated with complaints from the digestive tract.
• Analysis of faeces for occult blood every 2 years after 40 years, for persons with no risk factors (with a positive reaction it is recommended to repeat the test after 6 days with the exception of meat products, and if the result is positive, then instrumental studies are conducted)