Low Rectal Cancer

Low Rectal Cancer Radiation Treatment

Radiation therapy, or radiotherapy, is a common way to treat Stage 3 and 4 rectal cancer. Doctors who specialize in treating cancers with radiation are  known as radiation oncologists. Radiation therapy involves the use of high-energy x-rays to kill cancer cells. For many rectal cancers, radiation therapy is used after surgery to destroy any cancer cells  that may remain in the area of the operation. In advanced stages of rectal cancer, radiation therapy is often given before surgery to shrink the cancer, or instead of surgery when an operation cannot be performed. Radiation therapy is also commonly given in combination with anti-cancer drugs (chemotherapy). Chemotherapy has the ability to kill cancer cells directly and make radiation therapy more effective in killing cancer cells.

Radiation therapy for rectal cancer is typically given by a machine that aims x-rays at the body (external beam radiation). External beam radiation therapy (EBRT) for rectal cancer is given on an outpatient basis, 5 days a week, for approximately 5 to 6 weeks. EBRT begins with a planning session, or simulation, where marks are placed on the body and measurements are taken in order to line up the radiation beam in the correct position for each treatment. A program of daily treatments is then begun where the patient lies on a couch and is treated with radiation from multiple directions to the pelvis. The radiation oncologist may perform a second planning session or simulation near the end of treatment to focus the radiation to the area where cancer cells are most likely to remain. The last 3-5 days of treatment may be directed at this area. Although patients do not feel anything while receiving a radiation treatment, the effects of radiation gradually build up over time. Many patients become somewhat fatigued as treatment continues. Loose stools or diarrhea are also common. Urination may become more frequent or uncomfortable. Some patients may experience loss of pubic hair or irritation of the skin. When radiation therapy is given with 5-fluorouracil chemotherapy, diarrhea can be worse. In a small percentage of patients, an obstruction or blockage in the small bowel can occur, which may require hospitalisation or even abdominal surgery to relieve. Radiation therapy can also cause chronic changes in bowel function, resulting in loose stools and inflammation of the prostate when severe. Some radiation oncology centers have special treatment equipment for certain circumstances. For small early cancers, a focused radiation beam can be aimed directly at the cancer in the rectum. Intra-operative radiation therapy (IORT) refers to treatment in a specially equipped operating room where a single dose of radiation is given during the surgery. The radiation doctor is able to see the area being treated directly and move sensitive normal structures, such as the small bowel, away from the radiation beam. IORT is usually administered when surgery is being performed for locally extensive cancer or stage II-IV cancer that has recurred in the pelvis.

Radiation is the most often recommended for rectal cancer patients who have Stage 3 or 4 cancer. Once the cancer cells have been detected outside of the section of the rectum that has been surgically removed, radiation is the primary tool for killing the remain cancer cells.  The decision to proceed with the recommendations of your doctor to have radiation will most likely increase your chances for eliminating the cancer or at least extending your life.  That said, there are bowel function consequences caused by the radiation treatment. Adjuvant postoperative radiotherapy after anterior resection causes severe long-term anorectal dysfunction, which is mainly the result of a weakened, less sensitive anal sphincter and an undistensible rectum with reduced capacity.  Compared to those patients who underwent only surgical treatment, patients who underwent radiation had an 80% chance of having increased bowel frequency, 37% chance of having loose or liquid stool and  52% increased chance of fecal insentience.

Educate Yourself

Bowel function effect of Radiation.   Effect of radiation on bowel function

Radiation Therapy -  Detailed Guide: Colon and Rectum Cancer

Radiation Therapy for Rectal Cancer - Overview of radiation

Adjuvant Radiation Therapy of Rectal Cancer - Summary of treatment

Pelvic Radiotherapy  Discusses the Effect of radiation

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Colorectal Cancer, Radiation, Bowel Function, Quality of Life