Once a patient has been diagnosed with bowel cancer and the extent of the cancer has been determined, the doctor discusses with the patient what treatment should be given.
- Radiation therapy
- Combination of radiation therapy and chemotherapy (radio-chemotherapy)
- Targeted therapy, immunotherapy
- Physical methods of treatment (cryo-, thermo-, high-frequency and laser therapy)
Since the treatment of rectal carcinoma is very different from that of colon carcinoma, they will be considered separately from each other.
For colon carcinoma after a successful operation, there is a risk of the appearance of daughter tumors (metastases) in other organs in subsequent years. This occurs primarily in patients whose lymphatic glands contained tumor tissue at the time of surgery. For this reason, it is recommended that in the presence of lymphatic gland involvement, so-called adjuvant chemotherapy, an additional therapy that helps to achieve recovery, as well as in cases where all visible tumor tissue has been removed during surgery, is recommended. In colon carcinoma, adjuvant therapy is carried out in the form of chemotherapy in regular courses with interruptions over a long period of time (six months) for the best possible effect in the body. The aim of this therapy is to destroy any remaining cancer cells in the body after the operation, and thus to consolidate the success of the operation, in other words, to improve the long-term prognosis of the disease after a successful operation.
For rectal carcinoma the prognosis depends not only on the appearance of daughter tumors in other organs, but first of all on whether the tumor appears in the same place again or not. After the introduction of a special operating technique (TME, total mesorectal excision), it became possible to reduce this risk by about 10%. Once again, the risk is reduced by half with radiation therapy or combined radiation and chemotherapy. Chemotherapy drugs enhance the effect of radiation therapy at the site of radiation and improve the response of tumors to radiation. This leads to an improvement in the local recurrence rate in the pelvis. The combination of radiation therapy and chemotherapy after surgery has recently been increasingly replaced by radiation therapy and chemotherapy before surgery. They can shrink large rectal carcinomas to such an extent that the tumors can be removed completely. This form of therapy is called neoadjuvant therapy.
The only method that can achieve a complete recovery from bowel cancer is currently surgery. This applies to both colon carcinoma and rectal carcinoma. Complementary measures such as chemotherapy or radiochemotherapy can enhance the success of the operation, in other words, improve the long-term prognosis of the disease after a successful operation.
The operation remains, as before, the most important method in the treatment of bowel cancer. Its outcome is decisive for the prognosis. If during the operation it is possible to completely remove the tumor along with the adjacent lymph nodes, then the chances of a complete recovery are high.
And at advanced stages of the disease, the possibility of surgical treatment should be checked. The basic principle is that the tumor must be completely removed. If the tumor cannot be completely removed, then the task of maintaining intestinal patency comes to the fore. Under certain conditions, it is possible to remove metastases from the lungs, liver or abdominal cavity.
When the tumor grows extensively in the rectum, it is first reduced in size using the so-called neoadjuvant therapy (before surgery, radiation therapy or chemotherapy, or a combination of them is performed). Thus, the tumor will be easier to remove, and in some cases, surgical treatment becomes possible only after this therapy.
Low-lying rectal carcinoma due to its proximity to the anus can affect the rectal sphincter and cause stool incontinence. In this case, the rectal sphincter must be completely removed and an artificial anus (colostomy) created.
Chemotherapy and Radiation Therapy
Classical chemotherapy for bowel cancer consists of the following substances: 5-fluorouracil and folinic acid (5-FU/FA), oxaliplatin and irinotecan. They are used intravenously. Recently, there are active ingredients that can be taken in the form of tablets and which only in the body are converted into 5-FU (capecitabine). The effectiveness of chemotherapy can be improved by combining 5-FU with oxaliplatin or irinotecan. The combination of active substances, their dosage, duration of use is determined in each case individually, taking into account the stage of the tumor and the patient's health.
Most often, bowel cancer metastasizes to the liver and lungs. These metastases are usually treated with palliative chemotherapy. Only in about 25% patients does it make sense to use surgical removal of metastases for the purpose of recovery.
If metastases cause bone pain, they can be well treated with radiation. Consideration needs to be given to the choice between administering a single high-dose irradiation, which is less costly for the patient, or administering multiple, low-dose irradiations.
New drugs and methods
For decades, scientists have been working hard on drugs and methods that could cure cancer, or at least alleviate the patient's associated suffering. There is no cure for bowel cancer or other types of cancer. But new research offers hope that even with advanced bowel cancer, life will be better and longer. Of course, all new medicines and methods receive final evaluation only after the completion of trials in studios on a large number of patients.
Particular hope is placed on the so-called targeted treatments. The drugs used in chemotherapy are cellular poisons, they act not only on tumor cells, but also affect healthy tissues, thereby often causing severe side effects. And targeted therapies are aimed directly at tumor cells. They act, for example, against factors that stimulate tumor growth, disrupt the tumor's blood supply, or interfere with signaling between tumor cells.
Two promising developments in this area are a growth receptor blocker and an anti-vascular drug.
In Germany, a combination of an anti-vascular drug, bevacizumab, and chemotherapy is approved for the treatment of metastatic bowel cancer. In this case, we are talking about antibodies directed against the factor VEGF (vascular endothelial growth factor). VEGF is released by the cells of the intestinal tumor, fixed on the surface of the blood vessels and gives them a signal: to grow in the direction of the tumor tissue. With the help of this, the tumor will be supplied with oxygen and nutrients, and on the other hand, it will gain access to the bloodstream, thereby it will be able to spread throughout the body. Bevacizumab blocks VEGF, thereby inhibiting the blood supply to the tumor and indirectly preventing its growth and spread. It has been proven that the use of bevacizumab in combination with chemotherapy slows down the progression of the disease, in addition, the patient's life expectancy is extended.
Approximately 90% cases on the surface of intestinal cancer cells have a junction (receptor) for the so-called epidermal growth factor (EGF). EGF stimulates the growth of cancer cells. If its junction is blocked, then EGF can no longer attach to cancer cells and thus cannot cause their reaction. This will disrupt the growth of tumor cells. EGF receptor antagonists are cetuximab and panitumumab. Before a drug is prescribed, it is necessary to check whether the so-called K-Ras gene has mutated. The K-Ras gene encodes a single molecule that plays an important role in the epidermal growth factor (EGF) signaling chain within cells. With K-Ras changes, when the K-Ras molecule is activated for a long time, the inhibitory effect of cetuximab or panitumumab is not very effective. This means that only those patients who do not have this gene mutated benefit from cetuximab or panitumumab, and only these patients are allowed to take these medications. Both of these agents are given with or without chemotherapy in cases where treatment with oxaliplatin or irinotecan has failed.
Cold, heat and laser treatment
Cold (cryotherapy), heat (hyperthermia) or laser therapy can destroy cancer cells. To ensure that healthy cells are not damaged, a temperature source or a radiation source is injected directly into the tumor tissue.
These methods are mainly used to destroy metastases, especially in the liver. First of all, when an operation on the liver is impossible or does not make sense, but with the help of a physical method of influence, the complete destruction of metastases is possible. As a new treatment for liver metastases that are resistant to chemotherapy, some clinics have what is known as selective internal radiotherapy (SIRT). In this case, the femoral artery is punctured and a catheter is inserted to the hepatic artery. Radioactive balls are injected through the boat. They block the small vessels leading to the tumor and give off their radioactive radiation in the immediate vicinity of the tumor. Slowing of tumor growth is observed when using this method in cases of liver metastases treated with chemotherapy. The method is approved for use and is used in palliative medicine.
In cases where the disease has gone too far and a full recovery cannot be expected, improving the quality of life and alleviating the suffering of the patient comes to the fore. In this situation, all possible methods of therapy are used. So, for example, it makes sense to perform an operation when it is necessary to prevent threatening intestinal obstruction.
Typically, palliative care consists of chemotherapy. With its help, most likely, you can prolong the life of the patient and alleviate his suffering. Other methods, such as cryotherapy or laser therapy, are used to stop bleeding or prevent impending bowel obstruction.
Pain can be well treated with suitable medicines and methods. Pain therapy is carried out individually, taking into account the situation of a particular patient.
Surveillance for advanced cases of bowel cancer
Naturally, there is no single concept of observation that is suitable for every patient. Therefore, the general "standards" given here are only those that can be adhered to. Reliable is only that 80% all recurrences occur in the first two years, and after five years they practically do not happen. Therefore, follow-up of such patients is limited to a maximum of five years.
The time intervals between surveys do not have constant values. They are determined by the attending physician, taking into account the situation of a particular patient. In the first two years after the operation, examinations are carried out at short intervals, after which it is sufficient to conduct follow-up examinations with a large interval of time.
During control examinations, the following is carried out: a patient questioning (anamnesis), a complete medical examination, ultrasound examination of the abdominal organs, including the liver, X-ray examination and computed tomography of the chest, and the level of the CEA tumor marker is also determined. Colonoscopy is usually performed at 6 months, 3 years and 5 years after surgery.
If a patient notices a change in his condition or has complaints that cause concern, it makes sense and is right to see a doctor.
Head of the Clinic for General, Visceral and Minimally Invasive Surgery
Head of the Clinic for General, Visceral, Thoracic and Endocrine Surgery
Head of the Clinic for General and Visceral Surgery