The term "colorectal cancer" conceals a very dangerous ailment, most often affecting epithelial tissues lining the walls of the colon and rectum.
The localization of malignant neoplasms is indicated by the very name of the disease, formed by the fusion of Latin designations for these parts of the large intestine: "column" is a colon and "rectum" is the rectum.
Concept of the disease
Malignant neoplasms, denoted by the term "colorectal cancer", represent a rather large and very heterogeneous group of tumors characterized by different localization, shape and histological structure of tissues.
In addition to the colon and rectum, malignant epithelial tumors, called colorectal cancer, can affect the walls of the cecum and anal canal.
Prevalence of
Colorectal cancer is one of the most common ailments, with every decade affecting an increasing number of patients.
Two decades ago it belonged to the sixth place in the structure of Russian oncological diseases. Now he moved to the fourth position in female oncology and the third - to the male.
The regions most affected by colorectal cancer include the countries of North America, New Zealand, Australia and various parts of Europe.
Oncologists of Japan, whose population until recently was not affected by this disease, say that by the end of this century, colorectal cancer can become the main cause of death of citizens of this country.
Classification of
The nature of the growth of malignant tumors with colorectal cancer allows them to be divided into three forms:
- exophyte , spreading into the lumen of the affected bowel;
- endophytic , sprouting intestinal wall and developing in the thickness of its tissues;
- saucer-like , having a flat bottom, raised edges and an oval shape elongated along the gut.
The variety of the cellular structure of malignant tumors affecting the colon tissues gives grounds for subdividing them into:
- adenocarcinomas( occurring in 80% of colorectal cancer cases);
- mucocutaneous adenocarcinomas represented by mucoid, colloidal and mucosal cancers( account for 12% of all tumors);
- mucocellular( ring-like-cell) cancer;
- cancer of undifferentiated type( having trabecular and medullary forms);
- cancer of unclassifiable type.
Malignant tumors of the rectum in addition to the above types are represented by structures that have:
- squamous;
- basal cell;
- glandular-squamous cell structure.
Risk Factors
Colorectal cancer is a poly-ietic disease that can develop due to a variety of causes( both external and internal):
- Genetic predisposition. Detection of colorectal cancer in one of the next of kin automatically assigns to the risk group of all members of his family.
- Presence of precancerous conditions: of Gardner and Türko syndromes, Crohn's disease, familial adenomatous polyposis, ulcerative colitis. The longer the inflammatory process - the higher the likelihood of malignancy( malignancy).
- Accessories for the age category over fifty years. Presence of obesity and diabetes.
- Commitment to the consumption of meat and products, almost free of vegetable fibers. In combination with a sedentary lifestyle, this factor is the culprit in slowing intestinal motility. As a result, the exposure time of carcinogenic substances that enter the intestine increases, on the mucosa of its walls, which provokes the development of cancer.
- Addiction to smoking and drinking alcoholic beverages.
- Weakened immunity of due to the presence of chronic diseases.
- Lack of calcium and pronounced hypovitaminosis.
What is colorectal cancer screening?
Screening of colorectal cancer is commonly referred to as a set of diagnostic procedures performed to actively identify patients with asymptomatic disease or having a high risk of developing it due to the influence of the genetic factor.
Photo screening for colorectal cancer
Detecting colorectal cancer at an early stage is helped by screening tests consisting of:
- study of feces for occult blood;
- examination of the walls of the rectum using a sigmoidoscope( sigmoidoscopy);
- performing colonoscopy procedure;
- rectal palpation of the rectum;
- performing a general blood test;
- in taking a blood sample for oncomarkers, helping to determine the number of cancer cells in the intestinal tissues.
First signs of
Colorectal cancer at the initial stages of its development is most often asymptomatic. As the malignancy grows, the following symptoms appear:
- unusual weakness, lethargy, a feeling of constant malaise;
- sleep disorder;
- increased irritability;
- decreased appetite;
- appearance of an unpleasant odor in the oral cavity;
- pain in the abdominal cavity, the degree of intensity and nature of which are due to the localization of the tumor process;
- sensation of gastrointestinal discomfort( eructation, frequent vomiting and nausea, a feeling of heaviness in the epigastric region, rumbling and bloating);
- irregular stool character, characterized by alternating diarrhea and constipation.
Despite a fairly wide range of manifestations, the early symptomatology of colorectal cancer does not give a specific picture.
General symptoms of
In the later stages of , colorectal cancer , characterized by disruption of many internal organs and systems, a number of common symptoms are attached:
- Appearance of pathological discharge( blood, pus and mucus) from the anus.
- Different degree of intestinal patency( from chronic to acute), fraught with the development of constipation.
- The development of anemia, leading to dryness and pallor of the skin, brittle nails and brittle hair.
- Deterioration of the general condition of patients manifested in increased weakness, frequent dizziness, headache and a significant decrease in performance.
- Complete loss of appetite.
- A sharp decrease in body weight.
- Increased body temperature to subfebrile values.
Metastasis
Colorectal cancer gives metastases:
- Into the liver. This is the main( at least 50% of the cases) of cancer cells metastasis, due to the peculiarities of the blood supply to the liver, which receives most of the blood from the portal vein fed by internal organs. A patient with metastases in the liver has a high degree of exhaustion, persistent nausea and vomiting, severe jaundice and itching of the skin, the presence of ascites( accumulation of fluid in the abdomen), and severe pain in the abdomen.
- Into the peritoneum - a film of connective tissue covering the surface of all internal organs and lining the walls of the abdominal cavity. Cancer cells that have sprouted through the walls of the affected intestine, first form foci in separate areas of the peritoneum, and, having captured it entirely, spread to neighboring organs covered by it.
- Into the lungs. A patient with metastases in the lungs suffers from shortness of breath, pain in the lungs, a persistent cough accompanied by hemoptysis.
Screening and Diagnosis
An assay for screening colorectal cancer is performed using:
- Finger examination of the rectum. This simple method allows to detect up to 70% of carcinomas localized in it.
- Recto-manoscopy. The use of a rigid sigmoidoscope makes it possible to examine the condition of the walls of the rectum and the distal sigmoid colon. When detecting suspicious neoplasms, a biopsy of their tissues is performed.
- Irrigoscopy is a procedure consisting of performing a barium enema and injecting air to expand the lumen of the intestine. X-rays taken during this survey can detect polyps and malignant neoplasms.
- Fibrocolonoscopy. The use of a flexible fibrocolonoscope equipped with a fiber optic system allows to study the state of the large intestine throughout its extent. Being the most accurate and expensive method of research, fibrocolonoscopy is performed at the final stage of the patient's examination.
In addition to the above-mentioned examination methods considered to be the main ones, a number of additional methods are applied to the patient:
- ultrasound;
- computed tomography;
- MRI;
- angiography;
- laparoscopy;
- test for the presence of oncomarkers.
What are the markers for colorectal cancer?
In colorectal cancer, two tumor markers are most commonly detected in the serum of a person who is ill:
- The marker CA-19-9, which has a prognostic value. The level exceeding 37 ng / ml indicates that the risk of death in operated patients with this result is 4 times higher than in patients with a lower or negative index.
- REA( cancer embryonic antigen). As a rule, elevated levels of CEA are observed with already started disease, and high - with metastasis of the tumor into the liver.
Stages and treatment options for
- The site of the localization of a colorectal tumor of stage I, occupying a smaller part of the circumference of the affected bowel, is its mucosa and submucosa. There are no metastases to the lymph nodes.
- Malignant neoplasm IIa of the stage occupies approximately half of the lumen of the gut and is confined to its walls. Regional lymph nodes are not affected.
- A tumor that has reached stage IIb and germinates throughout the intestinal wall begins to metastasize to the nearest regional lymph nodes.
- Malignant tumor of stage III occupies more than half of the intestinal lumen and gives multiple metastases to the lymph nodes.
- The IV stage tumor is called metastatic colorectal cancer and is characterized by a significant size and distant metastasis.
Treatment of colorectal cancer is carried out:
- By surgical intervention of consisting of removal of malignant neoplasm( during colectomy or hemicolectomy surgery) and affected lymph nodes( lymphadenectomy surgery).Operations can be open, that is, performed by cutting the abdominal wall, and laparoscopic - performed through micro cuts( using manipulators and miniature video systems).
- The method of chemotherapy - the use of medicines that can stop the division of cancer cells. Chemotherapy for colorectal intestinal cancer can precede surgery, it is often used in the postoperative period. If the tumor is inoperable, chemotherapy remains the only method of treatment that can improve the patient's quality of life.
- The method of radiotherapy , using the power of X-rays to destroy cancer cells. Radiotherapy is used both as an independent method of treatment, and in combination with chemotherapy.
Forecast
The prognosis for colorectal cancer is directly dependent on the stage at which the malignant tumor was detected.
- Treatment of tumors caught at the very beginning of education results in a five-year survival rate of 95% of patients.
- Colorectal cancer of stage III, metastasized into the lymph nodes, is characterized by a five-year survival rate of 45% of patients.
- Malignant intestinal tumor removed at stage IV, gives a chance of survival of less than 5% of patients.
Prevention
Primary prevention of colorectal cancer includes:
- Rational nutrition containing a large number of fruits, vegetables and foods high in fiber.
- Limited use of red meat and animal fats.
- Abstaining from alcohol and smoking.
- Active way of life.
- Body weight control.
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