Sigmoid adenocarcinoma: symptoms and causes, stages, diagnosis, treatment, predictions
The sigmoid colon, which is S-shaped and located on the left side of the lower abdomen, is the penultimate part of the large intestine and the link between the colon and rectum.
The sigmoid colon is designed to perform vital life functions: it produces the final formation of feces and the absorption of all nutrients from food processed by the body.
Unfortunately, the anatomical structure of this organ is such that it is susceptible to the development of both benign and malignant neoplasms.
As the process of thickening of stool is quite long, the mucous membranes of the sigmoid colon are forced to contact the carcinogenic and toxic substances contained for a long time.
The result of this interaction is the occurrence of benign neoplasms - polyps, and permanent traumatization with calves can provoke their malignancy and degeneration into cancer tumors.
Almost 80% of cases of malignant tumors of the sigmoid colon are represented by adenocarcinomas - neoplasms, developed from the tissues of glandular epi
Causes of pathology
The main factor that provokes the occurrence of adenocarcinoma is the anatomical structure of the sigmoid colon described above.
In addition to this, a whole set of factors can become the trigger for the launch of the pathological process:
- Genetic predisposition.
- Exposure to radiation and adverse environmental conditions.
- An unbalanced diet characterized by the predominance of proteins and animal fats over plant fiber.This picture is typical for patients who prefer meat products and ignore raw vegetables and fruits.
- Eating food that is full of carcinogens and chemicals.
- Food that is abundant in genetically modified foods.
- Abuse of smoking and alcoholic beverages.
- A sedentary lifestyle characterized by a lack of physical activity, leading to stagnant food masses, impaired blood supply to the colon and intestinal peristalsis.
- Propensity to chronic constipation( any etiology).Dry and hard feces, traumatizing the mucous membrane of the sigmoid colon, provoke the appearance of malignant neoplasms.
- Diseases of the sigmoid colon.Most adenocarcinomas occur against precancerous conditions: nonspecific ulcerative colitis, terminal ileitis, polyposis, Crohn's disease, diverticulosis of the large intestine.
- Stary atony of the intestine: a decrease in muscle tone due to age-related changes occurring in the body of elderly patients.
- Exposure to carcinogens contained in household chemicals.
- Influence of permanent nervous stress.
- Abuse of certain medications.
- Work on a woodworking plant or asbestos production: the workers of these industries have the highest risk of developing sigmoid cancer.
The most important characteristic of a cancer that determines the characteristics of a clinical picture and affects the prognosis of a patient's life is the so-called Glisson index - the level of differentiation of abnormal cells.
Depending on the value of this indicator, obtained by histological examination of tumor tissues, adenocarcinomas are divided into:
- highly differentiated;
- moderately differentiated;
- are low-grade;
Adenocarcinoma of the sigmoid colon of this type is a low-aggressive tumor, which is perfectly treatable.
Because the structure and properties of cells of highly differentiated adenocarcinoma are almost identical to those of healthy tissues, they are characterized by a low level of pathogenicity - the ability to involve healthy cells in the tumor process.
Due to the increased size of nuclei, tumor cells of highly differentiated neoplasms are clearly visible against the background of healthy glandular epithelial tissue lining the sigmoid colon from the inside.
In the treatment of highly differentiated sigmoid adenocarcinoma, it is rare to resort to auxiliary therapeutic methods: radiotherapy and chemotherapy.
Despite a very low percentage of relapses, the patient( especially at risk for this disease) who underwent an operation to remove adenocarcinoma should remain under the strictest supervision of the treating specialist.
Moderately differentiated adenocarcinoma cells have more pronounced differences from healthy epithelial cells, but they may not be enough to accurately determine the source of the pathological process.
The intensity of growth of moderately differentiated neoplasms of the sigmoid colon is not too high;The probability of metastasis formation in the initial stages of the disease is just as insignificant.
However, one should not think that treatment of a moderately differentiated tumor can be carried out in a sparing mode or postponed indefinitely: such a decision would be the greatest mistake that directly threatens the life of a sick person, and that's why:
- despite the relative(In comparison with low-grade neoplasms) the slow development of the pathological process, tumor growth nevertheless occurs;
- risk of metastatic adenocarcinoma is quite large;The cause of metastasis can be the influence of provoking factors: external stresses, concomitant diseases, old age, wrong treatment tactics.
The most aggressive type of adenocarcinoma of the sigmoid colon is a tumor of a low-grade type.Their rapid growth leaves no time for reflection and requires immediate medical action.
The main difficulty in treating poorly differentiated adenocarcinomas is the practical impossibility of determining which organ or tissue the tumor process has started to develop.Equally difficult is the problem of determining the boundaries of tumor sites that merge with the tissues of healthy epithelium.
This is a case of patients in whom the growth of a low-grade neoplasm in the sigmoid colon is slow enough, while a surgical operation can trigger the spread of metastases throughout the body.
Before deciding to surgical removal of the low-grade adenocarcinoma of the sigmoid colon, the treating specialist carefully analyzes the entire set of patient data: a medical history, complete medical examination data, the presence of co-morbidities, general health, possible contraindications to various types of treatment.
Stages of adenocarcinoma of the sigmoid colon
The development of adenocarcinoma of the sigmoid colon is divided into the following stages:
- Stage I is characterized by the formation of neoplasm on the surface of the mucosa and tissues of the submucosa: its diameter does not exceed one and half centimeters, metastases are absent.
- Tumor II stage slightly increases in size, but it takes less than 50% of the intestinal lumen.
- Stage III adenocarcinoma sprouts the thickness of the intestinal wall and occupies more than half of the intestinal lumen.From this point on, the tumor begins to metastasize into the nearby lymph nodes and internal organs.
- Malignant neoplasm of IV stage blocks the lumen of the sigmoid colon, gives a large number of distant metastases, germinating into the walls of neighboring organs.
Symptoms of a tumor
The guile of adenocarcinoma of the sigmoid colon lies in the absolute absence of characteristic symptoms in the early stages of the disease.
Absence of specific symptoms can show flesh until late stages of the pathological process.
Clinical manifestations of the disease can be so blurred that many general practitioners generally do not see in them the prerequisites of an oncological disease.That is why the precious time necessary for the successful healing of the patient is often missed.
- In the initial stage of the disease, patients complain of increased flatulence, they are concerned about rumbling in the abdomen and instability of the stool, characterized by alternating diarrhea and constipation.
- Progressing, adenocarcinoma provokes the occurrence of persistent and prolonged constipation.Due to the permanent traumatization of the tumor by the solid calves, ulceration takes place, as a result of which an admixture of bloody, mucous or purulent discharge appears in the excrements.
- Tumor process, which reached the II-III stage, is characterized by the appearance of blunt or cramping pain in the left ileal zone, caused by the germination of adenocarcinoma into the intestinal wall and partial overlap of the intestinal lumen by the tissues of the enlarged growth( up to the occurrence of intestinal obstruction).
- All patients suffering from adenocarcinoma of the sigmoid colon are noted to have dyspeptic disorders: regular eructations, constant nausea, and debilitating attacks of vomiting.
- Cancer intoxication causes the emergence of a whole group of symptoms: increased weakness, rapid fatigue, grayish, yellow or pale skin color, lack of appetite, a sharp decrease in body weight, persistent fever, increased abdominal circumference.
- Intestinal obstruction is accompanied by bouts of cramping pains, tormenting the patient every ten to fifteen minutes.At the same time he has a bloating, a persistent retention of gases and stools.
- The destruction of the intestinal wall is fraught with the development of peritonitis( inflammation of the peritoneum, accompanied by severe abscesses of the abdominal cavity).
- In the last stages of adenocarcinoma of the rectum, the patient develops cachexia( limiting exhaustion), the liver is greatly enlarged, jaundice and anemia develop.
In the presence of alarming symptoms, a number of laboratory and instrumental diagnostic studies are assigned to the patient, allowing to identify the disease at the earliest stages of its development.
The most effective diagnostic methods are:
- Palpation is a procedure for manual examination of the sigmoid and rectum, performed at the first visit of the patient to the doctor.Wearing gloves, the expert to the greatest possible depth probes the mucous lining of intestinal walls.In the presence of tumor nodes, sometimes even such an examination is enough.
- Recto-manoscopy is a technique for visual examination of the condition of the lumen of the rectum and the lower sigmoid region with the help of a special device called a sigmoidoscope.Equipped with a backlight, miniature video camera, air supply and biopsy forceps, this device allows you to view and evaluate the state of the intestinal walls, as well as take tissue samples from the surface of detected neoplasms.
- Colonoscopy is a more informative method.Practically identical to the above described technique of sigmoidoscopy, the procedure of colonoscopy allows to examine the condition of the whole large intestine due to the longer length of the diagnostic device.In addition to identifying neoplasms, colonoscopy can be used for the rapid removal of small malignant tumors if the result of histological examination of the biopsy specimen confirms the presence of cancer cells.Given the extreme painfulness of the procedure, it is carried out under general anesthesia.
- Irrigoscopy is a technique for X-ray examination of the intestine by filling the intestinal lumen with an aqueous solution of barium sulfate, in color and consistency resembling a milkshake.In modern clinics, the procedure of double contrasting is very popular, providing for( in addition to introducing an X-ray contrast substance into the patient's body) also the injection of air into the cavity of the intestine.During the irrigoscopy, several sighting and sighting images are performed, which allow to detect the presence of even minor tumors on the intestinal wall, to establish the degree of narrowing of the intestinal lumen, or to establish the fact of complete intestinal obstruction.
- Ultrasonic diagnosis of the intestine( ultrasound endorectal examination).With the help of this diagnostic technique, a specialist can detect the presence of distant metastases, perifocal inflammation( if any) and the degree of spread of the tumor process.
- Magnetic resonance imaging of the intestine is a modern diagnostic procedure involving the use of high-tech equipment that does not require any special preparation from the patient and does not cause him any inconvenience.The MRI procedure can be prescribed instead of colonoscopy for patients suffering from diverticulosis of the thick and sigmoid colon, since they are contraindicated in any endoscopic examinations conducted through the lumen of the rectum.With the help of MRI it is possible not only to detect the presence of neoplasms, but also to establish their approximate etiology.
During the complex medical examination the patient is obliged to pass:
- Analysis of feces for occult blood.
- General( clinical) blood test.
- Blood on oncomarkers.
Treatment of adenocarcinoma of the sigmoid colon is most often combined, involving surgery, chemotherapy and radiotherapy.
The leading importance is attached to surgical treatment consisting in the radical removal of malignant neoplasm:
- The scope of a surgical operation depends on how far the tumor process has gone.Removal of adenocarcinomas, detected in the early( I-II) stages of development, is carried out by using minimally invasive endoscopic surgical techniques.
- When a more mature tumor is removed, resection of the affected bowel is performed along with a part of the mesentery and a number of adjacent lymph nodes.To prevent relapse, the affected area of the sigmoid colon is removed along with five centimeters of healthy tissue.
Video shows laparoscopic resection of the sigmoid colon:
- Surgical operations for resection of the sigmoid colon can be performed in one or two stages.In the absence of intestinal obstruction, one-step surgery is performed, at the end of which the surgeon restores the continuity of the large intestine by applying an anastomosis( stitching the ends of the hollow organs).If the adenocarcinoma led to the development of intestinal obstruction, the surgeon forms a colostomy: it displays the nearest site of the intestine on the abdominal wall.Through this hole, connected with the kalopriememnikom, the body of the operated patient will receive stool.A few months later, a second stage of the operation can be performed, aimed at restoring the natural anus.Unfortunately, repeated surgery is not always possible: some patients are doomed to wearing a kalopriemnika until the end of their days.
- Sometimes, with adenocarcinoma of the sigmoid colon, emergency surgical operations are carried out: to sanitize the abdominal cavity after peritonitis or to eliminate acute intestinal obstruction.
- Terminally ill patients suffering from severe pain caused by intestinal obstruction can undergo a surgical operation aimed at restoring this patency by applying a bypass anastomosis( without removing the tumor).Similar operations are conducted within the framework of palliative treatment aimed at improving the quality of life of hopeless patients.
Chemotherapy, involving the use of both one and several medications, can be used during both the preoperative and postoperative period.
Radiotherapy for the treatment of adenocarcinoma of the sigmoid colon is applied very narrowly and cautiously, as the tissues of cancerous tumors of this type have a low level of sensitivity to the effects of radioactive radiation.
There is also a high probability that the flow of radioactive rays can trigger the perforation of the walls of the affected organ.
Prognosis and prevention
The prognosis of five-year survival of patients suffering from sigmoid adenocarcinoma depends on a number of factors:
- timeliness of seeking medical help;
- the stage at which the disease was detected;
- of the patient's age;
- qualification of the treating specialist;
- level of equipping the medical institution with modern diagnostic and surgical equipment.
The survival prognosis( depending on the stage of adenocarcinoma) is presented in this list:
- In case of adenocarcinoma of the 1st stage sigmoid colon, 95-96% of patients have a chance of successful recovery.
- In patients with stage II tumor, occupying a smaller part of the intestinal lumen, the five-year survival rate is 75%.If neoplasm has already germinated in the tissues of the intestinal wall, this indicator decreases to 67%.
- In stage III adenocarcinoma, which has not yet begun to metastasize, 45% of patients survive for five years.If the tumor managed to give metastases to the regional lymph nodes, the chance for five-year survival remains in 35% of cases.
- When metastasizing an adenocarcinoma that has reached stage IV, no more than 10% of successfully operated patients survive in the adjacent organs.
The main preventive factor that can prevent the onset of adenocarcinoma of the sigmoid colon is a series of measures to avoid traumatization of the mucous membranes of this organ by improving intestinal peristalsis.
For this, each person must:
- To lead an active lifestyle, making physical activities a part of your daily routine of the day.
- Eat a large amount of vegetable fiber found in fresh vegetables, root vegetables, fruits, leafy greens.To do this, in a daily diet should be present salads containing the above products only in raw form.
- Given the inability of the human body to independently process plant fiber, it is necessary to resort to the help of a symbiotic microflora inhabiting the large intestine.To successfully maintain the balance of useful microflora, it is necessary to use sour-milk products, to observe the correct drinking regime( drinking at least 1.5 liters of clean water) and to normalize the food ration, enriching it with useful products and limiting the consumption of meat.
As for common factors that are of great preventive importance, each person should:
- avoid stressful situations;
- to abandon bad habits( smoking and alcohol abuse);
- to control the amount of food eaten, avoiding overeating, negatively affecting the functioning of the internal organs and large intestine.
The main measure for the prevention of bowel cancer is regular( at least once a year) screening - a comprehensive examination of the internal organs.