user: What are the treatments for Rectal Cancer ?

assistant: Key Points
                    - There are different types of treatment for patients with rectal cancer.    - Five types of standard treatment are used:         - Surgery     - Radiation therapy     - Chemotherapy     - Active surveillance     - Targeted therapy        - Other types of treatment are being tested in clinical trials.    - Patients may want to think about taking part in a clinical trial.    - Patients can enter clinical trials before, during, or after starting their cancer treatment.    - Follow-up tests may be needed.
                
                
                    There are different types of treatment for patients with rectal cancer.
                    Different types of treatment are available for patients with rectal cancer. Some treatments are standard (the currently used treatment), and some are being tested in clinical trials. A treatment clinical trial is a research study meant to help improve current treatments or obtain information on new treatments for patients with cancer. When clinical trials show that a new treatment is better than the standard treatment, the new treatment may become the standard treatment. Patients may want to think about taking part in a clinical trial. Some clinical trials are open only to patients who have not started treatment.
                
                
                    Five types of standard treatment are used:
                    Surgery     Surgery is the most common treatment for all stages of rectal cancer. The cancer is removed using one of the following types of surgery:            -  Polypectomy: If the cancer is found in a polyp (a small piece of bulging tissue), the polyp is often removed during a colonoscopy.     -  Local excision: If the cancer is found on the inside surface of the rectum and has not spread into the wall of the rectum, the cancer and a small amount of surrounding healthy tissue is removed.     -  Resection: If the cancer has spread into the wall of the rectum, the section of the rectum with cancer and nearby healthy tissue is removed. Sometimes the tissue between the rectum and the abdominal wall is also removed. The lymph nodes near the rectum are removed and checked under a microscope for signs of cancer.      -  Radiofrequency ablation: The use of a special probe with tiny electrodes that kill cancer cells. Sometimes the probe is inserted directly through the skin and only local anesthesia is needed. In other cases, the probe is inserted through an incision in the abdomen. This is done in the hospital with general anesthesia.     -  Cryosurgery: A treatment that uses an instrument to freeze and destroy abnormal tissue. This type of treatment is also called cryotherapy.     -  Pelvic exenteration: If the cancer has spread to other organs near the rectum, the lower colon, rectum, and bladder are removed. In women, the cervix, vagina, ovaries, and nearby lymph nodes may be removed. In men, the prostate may be removed. Artificial openings (stoma) are made for urine and stool to flow from the body to a collection bag.           After the cancer is removed, the surgeon will either:            - do an anastomosis (sew the healthy parts of the rectum together, sew the remaining rectum to the colon, or sew the colon to the anus); or     - make a stoma (an opening) from the rectum to the outside of the body for waste to pass through. This procedure is done if the cancer is too close to the anus and is called a colostomy. A bag is placed around the stoma to collect the waste. Sometimes the colostomy is needed only until the rectum has healed, and then it can be reversed. If the entire rectum is removed, however, the colostomy may be permanent.            Radiation therapy and/or chemotherapy may be given before surgery to shrink the tumor, make it easier to remove the cancer, and help with bowel control after surgery. Treatment given before surgery is called neoadjuvant therapy. Even if all the cancer that can be seen at the time of the operation is removed, some patients may be given radiation therapy and/or chemotherapy after surgery to kill any cancer cells that are left. Treatment given after the surgery, to lower the risk that the cancer will come back, is called adjuvant therapy.       Radiation therapy    Radiation therapy is a cancer treatment that uses high-energy x-rays or other types of radiation to kill cancer cells or keep them from growing. There are two types of radiation therapy:            -  External radiation therapy uses a machine outside the body to send radiation toward the cancer.     -  Internal radiation therapy uses a radioactive substance sealed in needles, seeds, wires, or catheters that are placed directly into or near the cancer.           The way the radiation therapy is given depends on the type and stage of the cancer being treated. External radiation therapy is used to treat rectal cancer.     Short-course preoperative radiation therapy is used in some types of rectal cancer. This treatment uses fewer and lower doses of radiation than standard treatment, followed by surgery several days after the last dose.       Chemotherapy    Chemotherapy is a cancer treatment that uses drugs to stop the growth of cancer cells, either by killing the cells or by stopping the cells from dividing. When chemotherapy is taken by mouth or injected into a vein or muscle, the drugs enter the bloodstream and can reach cancer cells throughout the body (systemic chemotherapy). When chemotherapy is placed directly in the cerebrospinal fluid, an organ, or a body cavity such as the abdomen, the drugs mainly affect cancer cells in those areas (regional chemotherapy).      Chemoembolization of the hepatic artery is a type of regional chemotherapy that may be used to treat cancer that has spread to the liver. This is done by blocking the hepatic artery (the main artery that supplies blood to the liver) and injecting anticancer drugs between the blockage and the liver. The livers arteries then carry the drugs into the liver. Only a small amount of the drug reaches other parts of the body. The blockage may be temporary or permanent, depending on what is used to block the artery. The liver continues to receive some blood from the hepatic portal vein, which carries blood from the stomach and intestine.    The way the chemotherapy is given depends on the type and stage of the cancer being treated.    See Drugs Approved for Rectal Cancer for more information.       Active surveillance     Active surveillance is closely following a patient's condition without giving any treatment unless there are changes in test results. It is used to find early signs that the condition is getting worse. In active surveillance, patients are given certain exams and tests to check if the cancer is growing. When the cancer begins to grow, treatment is given to cure the cancer. Tests include the following:            -  Digital rectal exam.     -  MRI.     -  Endoscopy.     -  Sigmoidoscopy.     -  CT scan.     -  Carcinoembryonic antigen (CEA) assay.              Targeted therapy     Targeted therapy is a type of treatment that uses drugs or other substances to identify and attack specific cancer cells without harming normal cells.    Types of targeted therapies used in the treatment of rectal cancer include the following:            -  Monoclonal antibodies: Monoclonal antibody therapy is a type of targeted therapy being used for the treatment of rectal cancer. Monoclonal antibody therapy uses antibodies made in the laboratory from a single type of immune system cell. These antibodies can identify substances on cancer cells or normal substances that may help cancer cells grow. The antibodies attach to the substances and kill the cancer cells, block their growth, or keep them from spreading. Monoclonal antibodies are given by infusion. They may be used alone or to carry drugs, toxins, or radioactive material directly to cancer cells.                   -  Bevacizumab and ramucirumab are types of monoclonal antibodies that bind to a protein called vascular endothelial growth factor (VEGF). This may prevent the growth of new blood vessels that tumors need to grow.        -  Cetuximab and panitumumab are types of monoclonal antibodies that bind to a protein called epidermal growth factor receptor (EGFR) on the surface of some types of cancer cells. This may stop cancer cells from growing and dividing.                -  Angiogenesis inhibitors: Angiogenesis inhibitors stop the growth of new blood vessels that tumors need to grow.                   -  Ziv-aflibercept is a vascular endothelial growth factor trap that blocks an enzyme needed for the growth of new blood vessels in tumors.       -  Regorafenib is used to treat colorectal cancer that has spread to other parts of the body and has not gotten better with other treatment. It blocks the action of certain proteins, including vascular endothelial growth factor. This may help keep cancer cells from growing and may kill them. It may also prevent the growth of new blood vessels that tumors need to grow.                      See Drugs Approved for Rectal Cancer for more information.
                
                
                    Other types of treatment are being tested in clinical trials.
                    Information about clinical trials is available from the NCI website.
                
                
                    Patients may want to think about taking part in a clinical trial.
                    For some patients, taking part in a clinical trial may be the best treatment choice. Clinical trials are part of the cancer research process. Clinical trials are done to find out if new cancer treatments are safe and effective or better than the standard treatment.   Many of today's standard treatments for cancer are based on earlier clinical trials. Patients who take part in a clinical trial may receive the standard treatment or be among the first to receive a new treatment.   Patients who take part in clinical trials also help improve the way cancer will be treated in the future. Even when clinical trials do not lead to effective new treatments, they often answer important questions and help move research forward.
                
                
                    Patients can enter clinical trials before, during, or after starting their cancer treatment.
                    Some clinical trials only include patients who have not yet received treatment. Other trials test treatments for patients whose cancer has not gotten better. There are also clinical trials that test new ways to stop cancer from recurring (coming back) or reduce the side effects of cancer treatment.   Clinical trials are taking place in many parts of the country. See the Treatment Options section that follows for links to current treatment clinical trials. These have been retrieved from NCI's listing of clinical trials.
                
                
                    Follow-up tests may be needed.
                    Some of the tests that were done to diagnose the cancer or to find out the stage of the cancer may be repeated. Some tests will be repeated in order to see how well the treatment is working. Decisions about whether to continue, change, or stop treatment may be based on the results of these tests.   Some of the tests will continue to be done from time to time after treatment has ended. The results of these tests can show if your condition has changed or if the cancer has recurred (come back). These tests are sometimes called follow-up tests or check-ups.   After treatment for rectal cancer, a blood test to measure amounts of carcinoembryonic antigen (a substance in the blood that may be increased when cancer is present) may be done to see if the cancer has come back.
                
        		
            		Treatment Options by Stage
            		
                		
                    		Stage 0 (Carcinoma in Situ)
                    		Treatment of stage 0 may include the following:          - Simple polypectomy.    -  Local excision.     -  Resection (when the tumor is too large to remove by local excision).         Check the list of NCI-supported cancer clinical trials that are now accepting patients with stage 0 rectal cancer. For more specific results, refine the search by using other search features, such as the location of the trial, the type of treatment, or the name of the drug. Talk with your doctor about clinical trials that may be right for you. General information about clinical trials is available from the NCI website.
                		
                		
                    		Stage I Rectal Cancer
                    		Treatment of stage I rectal cancer may include the following:         -  Local excision.    -  Resection.    -  Resection with radiation therapy and chemotherapy after surgery.        Check the list of NCI-supported cancer clinical trials that are now accepting patients with stage I rectal cancer. For more specific results, refine the search by using other search features, such as the location of the trial, the type of treatment, or the name of the drug. Talk with your doctor about clinical trials that may be right for you. General information about clinical trials is available from the NCI website.
                		
                		
                    		Stages II and III Rectal Cancer
                    		Treatment of stage II and stage III rectal cancer may include the following:         -  Surgery.    -  Chemotherapy combined with radiation therapy, followed by surgery.    - Short-course radiation therapy followed by surgery and chemotherapy.    -  Resection followed by chemotherapy combined with radiation therapy.    - Chemotherapy combined with radiation therapy, followed by active surveillance. Surgery may be done if the cancer recurs (comes back).    - A clinical trial of a new treatment.         Check the list of NCI-supported cancer clinical trials that are now accepting patients with stage II rectal cancer. For more specific results, refine the search by using other search features, such as the location of the trial, the type of treatment, or the name of the drug. Talk with your doctor about clinical trials that may be right for you. General information about clinical trials is available from the NCI website.
                		
                		
                    		Stage IV and Recurrent Rectal Cancer
                    		Treatment of stage IV and recurrent rectal cancer may include the following:         -  Surgery with or without chemotherapy or radiation therapy.    -  Systemic chemotherapy with or without targeted therapy (a monoclonal antibody or angiogenesis inhibitor).    - Chemotherapy to control the growth of the tumor.    - Radiation therapy, chemotherapy, or a combination of both, as palliative therapy to relieve symptoms and improve the quality of life.    - Placement of a stent to help keep the rectum open if it is partly blocked by the tumor, as palliative therapy to relieve symptoms and improve the quality of life.    - A clinical trial of a new anticancer drug.        Treatment of rectal cancer that has spread to other organs depends on where the cancer has spread.         - Treatment for areas of cancer that have spread to the liver includes the following:               - Surgery to remove the tumor. Chemotherapy may be given before surgery, to shrink the tumor.      -  Cryosurgery or radiofrequency ablation.      -  Chemoembolization and/or systemic chemotherapy.      - A clinical trial of chemoembolization combined with radiation therapy to the tumors in the liver.                  Check the list of NCI-supported cancer clinical trials that are now accepting patients with stage IV rectal cancer and recurrent rectal cancer. For more specific results, refine the search by using other search features, such as the location of the trial, the type of treatment, or the name of the drug. Talk with your doctor about clinical trials that may be right for you. General information about clinical trials is available from the NCI website.