Colorectal cancer usually refers to cancer of the large intestine (colon carcinoma) or its lower end, the rectum (rectal carcinoma). Cancerous tumors in the small intestine or anus are rare. Since colorectal cancer develops very slowly and therefore initially shows hardly any symptoms, it is often only discovered in the late stages. A colonoscopy can help to detect a tumor early and thus save lives. The most important healing option is an operation.
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Colorectal Cancer Causes And Risk Factors
Nine out of ten colorectal cancers develop from benign colon polyps. The cells in the mucous membrane of the large intestine change over a period of several years: they degenerate; they divide and multiply uncontrollably, and a malignant tumor develops. Scientists are still researching why this is so. Small bowel cancer is so rare because indigestible components of food are quickly passed on to the large intestine.
Risk factors
Age is one of the risk factors for colorectal cancer. Nine out of ten sufferers are 55 years old or older. This is why check-ups are particularly useful from this age - especially if one of the other risk factors comes into play:
- Intestinal polyps in yourself, your parents or siblings
- Colorectal cancer in parents or siblings, especially if the affected person was under 50 years old
- Other types of cancer in yourself or close relatives
- Chronic inflammatory bowel disease such as ulcerative colitis (more common with colon cancer) or Crohn's disease (more common with small bowel cancer)
- Hereditary diseases such as familial adenomatous polyposis (FAP), Gardner syndrome, Peutz-Jeghers syndrome, hereditary nonpolyposis colon carcinoma syndrome (HNPCC)
- In the case of small bowel cancer, also people with a weakened immune system (after organ transplants or with HIV disease)
There are also a number of lifestyle-related risk factors that are thought to increase the likelihood of colon cancer. This includes:
- Smoking
- High alcohol consumption
- Lack of exercise
- Unfavorable diet with lots of red meat, sausage, animal fats and too little fiber
- Overweight
Colorectal Cancer (Colon Cancer) Symptoms
Do you have alternating diarrhea and constipation?
Do you have blood in your stool?
These symptoms, which are typical of colorectal cancer, usually appear when the tumor has reached a certain size. In the early stages, colorectal cancer often goes undetected because it hardly causes any symptoms. Blood in the stool could be a sign of colon cancer: but since there is often such a small amount of blood in the stool, it is invisible to the human eye. It can only be detected with a special hemoccult test (see treatment).
Other signs of a possible cancerous tumor are changes in bowel habits. Constipation or diarrhea, or both, can be symptoms of colon cancer, especially if they last for a long time. If the tumor has grown so large that the stool builds up in front of the tumor, the stool can become as thin as a pencil and smell bad. Despite the constriction, the bowel will try to empty itself. Therefore, cramps and abdominal pain are often the result.
A cancer such as colon cancer also leads to a weakening of the entire body. This often manifests itself in a reduction in performance, a feeling of weakness and tiredness, but loss of appetite and a slight fever can also be accompanying symptoms. If people lose weight unintentionally and for no apparent reason, this can also indicate cancer.
Symptoms in detail:
- Changes in bowel habits
- Paradoxical diarrhea: alternation of constipation (constipation) and diarrhea (diarrhea)
- Foul-smelling flatulence and fetid bowel movements, including severe flatulence associated with the involuntary discharge of stool, blood and mucus
- Blood on, on or in the stool, black stool (tarry stool)
- Pencil stool: Thin stool caused by narrowing of the intestine by the tumor
- Pain in right abdomen, bowel cramps for more than a week
- Palpation of a cylindrical hardening through the abdominal wall
- For small bowel cancer: abdominal pain, nausea, vomiting, diarrhea and constipation
Accompanying symptoms:
- Unexplained, unwanted weight loss (tumor cachexia) of more than 10% of baseline weight within 6 months
- Weakness, reduced performance, tiredness, listlessness, loss of appetite
- Swollen lymph nodes
- Slight fever and night sweats
- Anemia (tumor anemia)
If a person suffers from one of these symptoms, it does not mean that they really have colon cancer. Nevertheless, these complaints should be taken seriously and should be clarified. In general, it is advisable for people over the age of 40 to pay close attention to changes in bowel habits. If these last longer than three weeks for no apparent reason, they should be examined for their cause. The prospects for a cure for colorectal carcinoma are better the earlier they are diagnosed.
Colorectal Cancer Treatment
The simplest method of screening for colon cancer is a blood test. Those affected do not even have to go to the doctor, because pharmacies also have these tests ready, give advice on how to use them and clarify whether it makes sense to go to the doctor. Specialists in intestinal disorders are gastroenterologists. They carry out palpation examinations and colonoscopies and have options for further imaging diagnostic methods. To diagnose small bowel cancer, doctors do either an ultrasound, an X-ray, or a gastrointestinal scan.
- Blood in stool test: The test also shows small amounts of blood that are not visible to the naked eye (occult, invisible blood). Blood in the stool can mean colon cancer, but it can also be due to many other causes, such as hemorrhoids and broken skin. Therefore, those affected should definitely consult a doctor after a positive occult blood test.
- Physical examination: The doctor can find tumors in the rectum (rectal carcinoma) by examining them with a finger. In men, this examination is often carried out as part of a prostate cancer check-up, in women as part of a gynecological examination. The doctor can only recognize changes in the rectum and not always these either.
- Colonoscopy: The best examination to detect colon cancer is a colonoscopy. To do this, the doctor inserts a thin, flexible tube with a light source and camera at the end into the anus. With this examination method, the doctor can detect even smaller polyps and tissue changes in the entire rectum and large intestine and possibly even at the beginning of the small intestine. In addition, a colonoscope allows the gastrointestinal specialist to remove polyps and take tissue samples (biopsies) from areas that are suspected of being cancerous, so that they can be examined more closely. Before the colonoscopy, people take a laxative to empty their bowels. Patients usually sleep while the endoscope is inserted into the colon.
- Gastroscopy: To diagnose small bowel cancer, the doctor can perform a gastroscopy. To do this, he guides an endoscope through the mouth and throat area via the esophagus into the stomach and duodenum. To ensure that the examination is as comfortable as possible for those affected, either the throat is numbed with a spray or the patients are given short-term anesthesia.
- Virtual colonoscopy: If a complete examination with the endoscope is not possible due to a narrowing in the intestine, for example, individual sections of the intestine can be visualized using computed tomography (CT), magnetic resonance imaging (MRI) and X-rays. An enema of contrast medium into the large intestine may be necessary for X-ray diagnosis so that the inner walls of the upper gastrointestinal tract are better visible in the X-ray image.
- Other examination options: In order to rule out that the colon cancer has already spread and secondary tumors (metastases) have formed, the abdomen can be imaged using ultrasound and the lungs using X-rays. Additional options are gynecological examinations, cystoscopy and a CT scan of the abdomen.
Therapy
The purpose of treating colorectal cancer - whether it's colorectal cancer or small bowel cancer - is to completely remove or destroy the tumor. The success of the therapy depends heavily on how far the cancer has progressed. At an early stage, there is a good chance that a tumor can be completely removed and a complete cure takes place.
In general, the treatment of colorectal cancer depends on the location, size and type of the tumor. It is also important for the therapy whether the cancer has already formed metastases. The specialist doctor has various options available to him, which he discusses in a detailed preliminary discussion with the person concerned: he can surgically remove the cancer, or destroy it with medication (chemotherapy) or with radioactive radiation. A combination of the methods is also possible if this increases the success of the treatment.
Surgery
The most important treatment method for colorectal cancer in the rectum, in other areas of the colon and in the small intestine is surgery. The surgeon cuts out the affected part of the intestine plus a safety margin of several centimeters and sews the ends together. In addition, he removes the lymph nodes in the neighborhood. The usual method for this is open surgery, in which a surgeon completely exposes the access to the intestine. As an alternative, a keyhole operation (laparoscopy) is used more and more often, which only involves a small incision in the abdominal wall.
In the case of small malignant rectal tumors in an early stage, it may be possible to operate them out through the anus (peranal endoscopic resection, transanal microsurgery, TEM). If the tumor is too close to the anus, the sphincter muscle and the entire rectum may have to be removed. The surgeon will then create an artificial anus (anus praeter, stoma).
Whenever possible, surgeons try to avoid a colostomy during bowel surgery. For a stoma, part of the bowel in front of the operated area is relocated to the outside. However, an artificial anus may be temporarily necessary so that the intestinal suture can heal more easily; it is then reversed after about six weeks.
If you have a stoma, you have to wear a special adhesive bag on your body to collect the stool. The attending physicians and nursing staff show the patients how to change and care for their ostomy bags. Many people with an artificial bowel outlet feel an additional burden. Regional self-help groups offer them opportunities to exchange ideas with other affected people.
Chemotherapy
Chemotherapy is treatment with anti-cancer drugs (cytostatics) that are intended to inhibit the growth of cancer cells or kill them completely. For colorectal cancers such as colon cancer, rectal cancer, and small bowel cancer, chemotherapy is used for a variety of reasons:
- As adjunctive therapy (adjuvant chemotherapy): to destroy residual cancer cells hidden somewhere in the body after surgery that may later lead to secondary tumors, and to reduce the risk of recurrence (remedies: oxaliplatin, irinotecan, 5-fluorouracil and folinic acid). The doctor usually administers the cytostatics through the vein. The drug capecitabine comes in tablet form and converts to 5-fluorouracil in the body. All treatments have side effects such as diarrhea, changes in the mucous membranes, painful reddening of the hands and feet, misperceptions and paraesthesia.
- As a preparatory therapy for an operation (neoadjuvant therapy): The aim of neoadjuvant therapy is to create a better starting position for an operation through chemotherapy. Large tumors are to be reduced to such an extent that an operation is then possible.
- To inhibit tumor growth and alleviate symptoms (palliative therapy): Firstly, in the case of an advanced tumor that can no longer be operated on, secondly, in those affected who do not want an operation, and thirdly, in the case of secondary tumors that are already present, the palliative therapy should keep the tumor as small as possible, to slow down the progression of the disease. The aim is to prolong the life of those affected and to alleviate the symptoms so that the quality of life can be maintained for a long time.
Radiotherapy
Radiation therapy is used to destroy cancer cells in certain areas of the body. In people with rectal cancer, radiation before surgery may shrink the tumor, making it easier for the surgeon to remove it afterwards. This treatment is often combined with chemotherapy. After surgery, it may be appropriate to continue the combination treatment to prevent the tumor from returning to the same site.
If metastases have formed, doctors may also consider radiation. In the case of bone metastases, for example, radiation is intended to relieve pain and eliminate the risk of fracture. If small and few liver metastases have formed, they can be destroyed by a treatment similar to radiotherapy, radiofrequency ablation. To do this, a probe is inserted directly into the affected part of the organ to avoid major surgery.