Patients with cancer found at the end of the large intestine called the rectum who receive one week of radiation therapy before surgery have a 50 percent reduction in chance that their cancer will return after 10 years, according to a large, randomized study presented at the plenary session, November 1, 2010, at the 52nd Annual Meeting of the American Society for Radiation Oncology (ASTRO).
"We believe that this short course of radiation will open a new window of opportunities in the treatment of rectal cancer," Corrie Marijnen M.D., lead author of the study and a radiation oncologist at the Leiden University Medical Center, in Leiden, Netherlands, said.
Cancer coming back to its original tumor site and surrounding area, called a local recurrence, is a major problem in the treatment of rectal cancer patients. The mesorectum is the fatty tissue near the rectum that contains blood vessels and lymph nodes. When rectal cancer recurs, it is often in these lymph nodes. Therefore, a better surgical technique called total mesorectal excision (TME) was introduced worldwide. It removes the entire mesorectum and lymph nodes and is most successful when all of the tumor and surrounding area is removed and no cancer cells remain. In this study, it was demonstrated that preoperative radiotherapy is still beneficial in these optimally operated patients.
The study involved more than 1,800 rectal cancer patients who were eligible for total mesorectal excision surgery and whose disease had spread outside of its original location but not to other parts of the body. Patients were randomly selected to receive short-term radiation before surgery or surgery alone. Researchers wanted to examine the effectiveness of adding radiation to TME surgery to control local recurrence among these patients.
Findings show that patients who underwent radiation before surgery had a significant decrease (6 percent) in their chances of local recurrence after 10 years of treatment, compared to those who had did not have radiation (11 percent).
Dr. Marijnen said, "Our study suggests that tumors in the middle rectum and stage III rectal cancer patients will most greatly benefit from receiving radiation before surgery."
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