Radiation therapy for colon cancer
What is radiation therapy for colon cancer?
In addition to chemotherapy and the surgical removal of a cancer, radiation therapy represents the third pillar and thus an important therapeutic measure in the treatment of various types of cancer.
Colon cancer, also known as "colorectal cancer", can be located in the large intestine, the so-called "colon" or the rectum, the so-called "rectum". Colon cancer in the colon is usually not irradiated. Depending on the stage, therapy consists of surgery alone or surgery with subsequent chemotherapy. In palliative situations, chemotherapy alone can also be used.
However, radiation therapy can play several roles in the treatment of rectal cancer. Radiation therapy can be carried out both before and after the operation and can perform different tasks. The most important goals of radiation therapy are to reduce the size of tumors and prevent so-called local recurrences, the recurrence of smaller tumors in the intestine after the operation.
When colon cancer is irradiated, X-rays are aimed specifically at the tumor so that the cancer cells' cell division is inhibited. In order to protect the rest of the tissue, the entire dose of the rays is distributed over several sessions so that healthy cells can recover. Nevertheless, severe side effects of radiation therapy can occur in the short and long term.
A distinction is made between 3 forms of radiation therapy: Radiation therapy is carried out either before the operation, after the operation or as the sole therapy.
For general information on radiation therapy read also Treatment with radiation therapy
Radiotherapy before the operation
In the treatment of rectal cancer (Rectal cancer) radiation therapy can play a crucial role before the final operation. Together with chemotherapy, it can be carried out as so-called "neoadjuvant radiochemotherapy". Neoadjuvant describes a supportive therapy that is carried out before the operation. It is performed when the colon cancer is difficult to operate, has grown particularly large, or is already in cancer stage 2 or 3.
The goal of radiation is to shrink the tumor and reduce the tumor mass to make surgery easier. In combination with chemotherapy, the tumor cells become more sensitive and more susceptible to x-rays.
In addition, radiation therapy for colon cancer before the operation means that the tumor is less likely to recur in the bowel even after the operation. The recurrence rate in the intestine is reduced by up to 50%.
Inquire about the topic as well Rectal cancer
Radiation therapy after the operation
Even after the operation, radiation therapy is only used for colon cancer of the rectum, the rectal carcinoma. In most cases, this is also carried out together with chemotherapy. After an operation has already taken place, one speaks of “adjuvant chemoradiotherapy”. Its aim is to kill microscopic colon cancer colonies as well as individual remaining cells in the body and on the intestine and thus prevent later metastasis or recurrence in the intestine. If radiation therapy has already taken place, chemotherapy must be carried out after the operation. Further irradiations must be made dependent on the radiation dose and the damage to surrounding tissues. If no neoadjuvant therapy was carried out before the operation, irradiation of the rectum can be started a few weeks after the operation.
Read the article on this Radiation therapy planning
Use of radiation therapy without surgery
Radiation therapy on its own without surgery is usually not performed with the intention of healing. In advanced stages, when the tumor is difficult to operate or has grown very large, radiation therapy can be used to relieve pain and treat other symptoms of the cancer. The radiation can shrink the tumor and, under certain circumstances, extend survival.
In rare cases, if the colon cancer responds well to radiation, an operation with removal of the tumor can even be carried out afterwards. Radiation therapy alone for colon cancer can relieve digestive problems in the intestine, stabilize bone metastases so that there are no fractures, and relieve numerous other disease-related symptoms
More information about "Metastases " do you think ...? Find here
What are the side effects of radiation therapy?
The function of radiation therapy is to treat malignant tissue with so-called "ionizing" radiation so that the cell division of the cancer cells is interrupted and the cells are thus destroyed. Since the cancer cells are sometimes between healthy tissues and the radiation is not limited to the tumor, there are reactions and side effects to the X-rays at the location of the radiation and in the entire body.
Immediate side effects immediately after treatment are vomiting, nausea and reddening of the skin at the site of the irradiation. Mucous membranes and other tissues that divide quickly and frequently are particularly affected by the rays. This can cause inflammation of the mucous membranes of the intestines and esophagus as well as infections. Organ-dependent side effects occur depending on which organ is being irradiated. If blood-forming bones are irradiated, this can be anemia or changes in the blood count.
Read more on the subject at: Side effects of radiation
Can you prevent side effects?
The most important measure to minimize acute side effects of radiation therapy in colon cancer is the fractionation of the radiation dose. This means dividing the radiation therapy into many sessions in order to give the tissue time to regenerate. After the irradiation, rest and rest should be observed if possible. The body needs a lot of energy to be able to react to the stimuli of radiation therapy.
In order to minimize skin irritation, loose clothing should be worn and the skin should be protected from the sun, detergents and perfumes and from dryness. To prevent infections, malnutrition and pain in the intestines, nutritional advice can be given in advance. Anti-inflammatory drugs may also be necessary for radiation therapy to the bowel. If food intake is too restricted due to pain, pain medication can also be taken temporarily.
You can find more about this at: Behavior during radiation therapy
What can you do if the radiation therapy does not work?
In some cases, colon cancer may not be sensitive to radiation therapy. The result is invisible shrinkage of the tumor or even further local growth. In these cases, radiation therapy should be interrupted and, depending on the stage of the disease, an alternative therapy should be considered. If the radiation therapy does not work before the operation, the operation can be brought forward and carried out immediately. Otherwise, chemotherapy can be used instead of radiation, with goals similar to radiation therapy. In palliative therapy, unsuccessful radiation therapy can also be interrupted. In these cases, the side effects and symptoms of the radiation often outweigh the success of the therapy.
Is colon cancer curable at all? Read about this "Is Colon Cancer Curable?"
Long-term effects of radiation therapy in colon cancer
In addition to inflammation and local reactions to the harmful rays, numerous long-term complications can also arise after radiation therapy for colon cancer. It is important here which area of the body was irradiated, since in addition to the tumor in the intestine, organs with colon cancer colonies can also be irradiated.
In general, all tissues often develop connective tissue after exposure to radiation. This also develops sensitivities and fragility of the irradiated tissue. This can be a serious obstacle for subsequent operations, but it can also cause diseases such as pulmonary fibrosis, a pathological remodeling of the lung tissue. In the intestine, various damage to the mucous membranes, muscles and nerve tracts can lead to significant long-term functional disorders. Due to the proximity to other abdominal organs and the sexual organs, radiation therapy can damage the upper abdominal organs, the bladder, the sexual organs and lead to fertility disorders.
A rare complication of radiation therapy to the intestine can be a second tumor. Due to the structural changes in the cells during the radiation, another malignant cancer can develop over the years.
