The English-language sources, like many Russian-speaking, cancer of the colon and rectum is called colorectal cancer. Of course, the tumor arises in any particular section of the bowel, but between cancer of the colon and rectum so common, that these types of tumors are described, usually together. There will be no exception, and
this article, in which we will tell you about colorectal cancer almost everything.
As colorectal cancer is born
Most colorectal tumors develop long-term, for many years. It all begins with a benign polyp on the mucous membrane of the colon or rectum.
But not every polyp is subsequently converted into a malignant tumor, everything here depends on its type:
- adenomatous polyp (adenoma) – these are the “unreliable” from the point of view of cancer polyps. That’s why is called precancerous adenoma;
- inflammatory and hyperplastic polyps – in general, do not tend to malignancy.
However, some sources hyperplastic polyps are also referred to, shall we say, risky tumors.
Another is a precancerous condition dysplasia. It refers to the large area and direct intestinal epithelium, where the cells under a microscope looks suspiciously not like cancer, but not like normal cells respectable. Dysplasia is characteristic of individuals suffering from chronic ulcerative colitis or Crohn’s disease. Over time, chronic inflammation of the intestinal wall caused by these diseases can lead to irreversible changes in cell structure and cause the emergence of cancer.
Types of colorectal cancer
Colon and rectum can become a place of several types of cancer. In the vast (95%) of cases this adenocarcinoma. This cancer starts in the glandular cells that produce mucus for lubricating the inner surface of the intestine. When oncologists talk about colorectal cancer, it is almost always it is a adenocarcinoma . In this article you will learn exactly about it, but, for the sake of completeness, we list other possible types of cancer localized in the direct or colon:
- carcinoid tumor (formed from specific hormone producing cells of the intestine);
- gastrointestinal stromal tumor (develops from specialized cells of the colon wall, called interstitial cells of Cajal);
- lymphoma (a cancer of the immune system, which usually begins in the lymph nodes, but sometimes it can also develop in the rectum and large intestine);
- sarcoma (may occur in the blood vessels and the muscular wall of the colon and rectum intestine).
Risk factors and causes of colorectal cancer
All risk factors can be divided into 3 groups: modifiable (which can affect a person), and non-modifiable factors with unproven or disputed the degree of influence on pathological processes.
By the unmodified factors for colorectal cancer risk include:
- Age. This type of cancer can certainly develop at a young age, but usually it affects people older than 50;
- Inflammatory bowel disease (e.g., ulcerative colitis or Crohn’s disease);
- Family history (the presence of a family history of colorectal cancer or adenomatous polyps);
- Inherited syndromes (Turco syndrome, syndrome Peutz – Jeghers associated with MUTYH polyposis gene). From 5 to 10% of patients with colorectal cancer have inherited gene defects (mutations) that cause disease. In such cases, the cancer usually develops at a young age;
- Racial and ethnic factors (usually colorectal cancer affects African American and Eastern European Jews);
- Diabetes mellitus type II (neinsulinozavisimy).
Factors related to lifestyle (modified):
- Certain types of diets. A diet rich in red meat (beef, lamb, liver), hot dogs and sausages, can cause colorectal cancer. In contrast, a diet with emphasis on vegetables, fruits and cereals helps to reduce this risk. As for the other components of the diet, for example, certain types of fats, their impact on koloretkalny cancer is not fully understood;
- Physical inactivity;
- Alcohol abuse. In some ways, this is due to a low content in the body of folic acid, which are prone to active lovers of drink.
By the controversial factors include, for example, work on the night shift. The results of one study, work in a similar fashion at least 3 times a month for 15 years may increase the risk of colorectal cancer in women. Scientists attribute this to the change in the level of melatonin in the body. Some studies suggest that men who have had testicular cancer and prostate cancer is possible and the subsequent development of colorectal cancer. Most likely, this is due to radiotherapy to patients during treatment. However, at the moment these factors remain controversial.
Symptoms of colorectal cancer
Colorectal cancer may cause one or more of the following symptoms, the presence of which is strictly recommended to consult a doctor in order to find out what all the same thing:
- changes in the normal rhythm of defecation. It diarrhea, constipation or a decrease in faecal matter, lasting more than a few days;
- feeling the need to go “in the large”, which does not go away after the materialization of this goal;
- bleeding from the rectum, darkening or blood in the stool (often – in their normal appearance);
- cramps, or drawing pains in the stomach;
- weakness and exhaustion;
- unexplained weight loss.
Of course (and fortunately), that in most cases these symptoms are not directly linked to colorectal cancer and other conditions caused by – an intestinal infection, hemorrhoids , syndrome irritable bowel , or inflammatory bowel disease. Nevertheless, the existence of such problems should guard and encourage the patient to immediate trip to the doctor.
Stages of Colorectal Cancer
Stage 0 – Cancer is still only preparing for the conquest of the human body, not extending beyond direct or mucosa of the colon. This stage is called intraepithelial or preinvasive cancer.
Stage I – Tumor invades the muscle layer of the mucous membrane and reaches the submucosal layer, and more – in fact, the muscular system cancer. Lymph nodes remain unaffected.
Stage II – The tumor reaches the outer layer of the gut and then grows through it. At the finish of this stage, it grows into the surrounding organs and tissues (but not regional lymph nodes).
Stage III – depending on the direction of growth of the tumor affected regional lymph nodes (7) or the fatty tissue in the area of their location.
Stage IV – the cancer spreads to remote distant organs (liver, lung) and lymph nodes and to distant
areas of the peritoneum.
Colorectal Cancer Treatment
Today, medicine has all opportunities for early diagnosis of cancer: in fact this is the main condition for successful treatment. And in the case of colorectal cancer is not appropriate to talk about it, even the early diagnosis and prevention of. Search and Destroy polyp – that is a task that will insure against further trouble in the future.
Since 50 years, both men and women are recommended every 5 years to pass sigmoidoscopy, and if positive result – a colonoscopy (every 10 years), and barium enema with double contrast (every 5 years). These studies are aimed at detecting and benign polyps and malignant neoplasms. The following tests are designed to detect exactly cancer: fecal occult blood, immunochemical fecal test, fecal DNA.
Types of surgeries on the colon and rectum are slightly different, so we will talk about each of them separately.
This is the main method of treatment in the early stages of cancer. Most routine operation is open colectomy – the removal of the colon together with regional lymph nodes through an incision in the abdominal wall. In recent years the increasing distribution receives less invasive laparoscopic colectomy, the use of which, however, limited by the size of the tumor. Instead of one large incision is made a few small, through which introduced tools and removed the cut part of the intestine to the lymph nodes. In some cases, in the early stages of cancer to use polypectomy is sufficient, even when a small tumor removed through the colonoscope, which does not require excision of the abdominal wall.
Surgery direct intestine
This method of treatment is basic, wherein before and / or after the surgery radiotherapy and chemotherapy are used. In the early stages of cancer can also be used here polypectomy through the anus. Through the anus without abdominal incision is performed and local transanal resection, when cut all the layers of the rectum and the tumor is
removed along with part of the surrounding tissue. The operation requires a local anesthetic. If the tumor is located in the farthest parts of the straight intestine and can not be removed in this way, in this case, resorting to transanal endoscopic microsurgery: the rectum endoscope is introduced, which allows the surgeon to perform all manipulations with a jeweler’s precision.
Minimally invasive surgery, referred to in the paragraph above, are effective only in the early stages of
colorectal cancer. In more advanced stages of using other types of interventions, such as low anterior resection of the rectum. The essence of this operation is to remove part of the colon containing the tumor, followed by bonding portions of the intestine so that the patient can to ease in the usual way. The operation of complete removal of the rectum is called proktoektomiya (large intestine is connected to the anus by koloanalnogo anastomosis). A more sophisticated option is intervention abdominoperineal extirpation of the rectum, when not only the excised abdominal wall, but also the area of the anus to form a colostomy (opening in the abdomen to remove feces). If the cancer has spread to nearby organs, the output can be exenteration (removal) of the pelvic organs. Removed organs such as the bladder, prostate (in men), uterus (in women). This is the most radical option of surgery.
Maybe part of the treatment of cancer as the colon and rectum. In conjunction with chemotherapy curative effect is more pronounced.
With respect to colon cancer radiation therapy is used mainly when the tumor struck any other internal organ (including bones and brain), or the peritoneum, in which case the surgeon can not be sure of complete removal of the tumor, radiation and We need to kill cancer cells that may remain in the body.
When rectal cancer radiation therapy is used before or after surgery to prevent recurrence of cancer at the site of its
initial deployment. A common phenomenon today is the irradiation of the tumor before the operation to reduce its size and to facilitate the further work of the surgeon.
When colorectal cancer using radiation therapy options such as external beam therapy, intracavitary radiation therapy, brachytherapy, microspheres embolization with Yttrium-90.
When colorectal cancer chemotherapy can not only be a system that is used to fight metastases, but also local. In the latter case, the chemotherapy drug is administered into the hepatic artery, and has less side effects on the whole organism. Although this approach is used less widely than systemic chemotherapy. Generally, chemotherapy combined with radiotherapy before and / or after surgery. The most preferred drug for colorectal cancer is 5 Fluorouracil (commonly assigned with the leucovorin), capecitabine (Xeloda) Irinotecan (Kamptosar), oxaliplatin (Eloxatin).
About targeted drugs – this new word in Oncology – we have repeatedly mentioned in our previous articles. Recall that, unlike chemotherapy drugs, these drugs “see” cancer cells at the gene level and affects only on them, without involving the cycle of adverse reactions of any innocent organs and tissues.
For example, cancer cells contained VEGF-protein, helping them to form new blood vessels for nutrient supply to the tumor. Avastin and Zaltrap have an affinity for this protein, by means of which they are the key to the tumor itself. On the surface of cancer cells are EGFR-receptors that help them grow. Erbitux and Vectibix recognize these receptors and “take out” the tumor through them. Among other targeted drugs used in colorectal cancer, we can mention also Stivargu.
The survival rate for colorectal cancer
By tradition, we give a 5-year survival rate of patients with colorectal cancer of the intestine. Given that they are slightly different from each other, do it separately.
For colon cancer:
Stage I – 74%;
Stage II – from 37 to 67%;
Stage III – from 28 to 73% (it is not a misprint: in some cases, to the survival of stage III cancer exceeds that on II);
Stage IV – 6%.
For colorectal cancer:
Stage I – 74%;
Stage II – from 32 to 65%;
Stage III – from 33 to 74%;
Stage IV – 6%.
Diagnosis and treatment of colorectal cancer:
what’s new? Research in the field of prevention and treatment of colorectal cancer are carried out continuously. To date, we have already developed specific tests to help identify people at risk for colorectal cancer: Oncotype Dx, Colon Cancer Assay, ColDx.
Another method of diagnosis of colorectal cancer, which promises to be very promising – chemoprophylaxis. Researchers tested various kinds of natural and artificial materials that can affect the cancer risk, including calcium, folic acid, vitamin D , selenium, curcumin, statins.
A new approach to colorectal cancer treatment is immunotherapy using special vaccines. In contrast to the vaccines used for prevention of infectious diseases, these vaccines are designed to spur patient immunity to deal with cancer cells.
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