Short Course of Radiation Fights Rectal Cancer

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Nov. 2, 2010 (San Diego) — A short, five-day course of radiation therapy followed by surgery more than halves the risk that cancer will come back in some people with rectal cancer, a Dutch study suggests.

The researchers studied more than 1,800 people with locally advanced rectal cancer — meaning cancer had spread to the pelvic area surrounding the rectum, but not to other parts of the body.

By about 12 years after treatment, 5.1% of those who got radiation and surgery had a return of cancer in the area where their tumor used to be (called a local recurrence), compared with 11.1% of those who only had surgery to remove the tumor.

“Local recurrences are very disabling and difficult to treat so we assume they affect quality of life,” says researcher Corrie Marijnen, MD, of Leiden University Medical Center in the Netherlands.

Patients with Stage III rectal cancer, in which cancer has spread to the lymph nodes, benefited the most, she says. In this group, the addition of radiation cut the risk of local recurrence to 8.9%, compared with 19.2% for those who got surgery alone.

The short course of radiation therapy also reduced the odds of having cancer come back anywhere in the body, from 28% for surgery alone to 25%. However, just over half of patients in both groups died, she says.

“The short course of radiation is convenient for patients since it requires less than a week of daily radiation treatments, followed by surgery the next week,” Marijnen tells WebMD.

Marijnen presented the findings here at the American Society for Radiation Oncology meeting.

Standard Treatment in the U.S.

In the U.S., the standard therapy for people with locally advanced rectal cancer is 25 to 28 radiation treatments over a period of about six weeks, with the patients receiving chemotherapy at the same time. Then doctors wait six to eight weeks before operating, says Christopher Willett, MD, chair of radiation oncology at Duke University in Durham, N.C.

Willett tells WebMD he doubts American doctors will switch to the shorter course of radiation, as the U.S. approach is associated with better outcomes.

“Waiting lets the tumor shrink” so less surrounding tissue needs to be removed, he says. Also, the longer course of radiation means a lower dose is given at each visit, he says.

“We’re concerned the higher dose [used in The Netherlands] may lead to more long-term side effects such as bowel dysfunction that requires more surgery to fix the injured tissue,” Willett says.

Nonetheless, “this is an important trial because it has stimulated a lot of other trials looking at different radiation schedules. It’s getting us closer to the optimal way to treating locally advanced rectal cancer,” he says.

New Surgical Technique

Marijnen says the introduction of a new surgical technique that is being used more and more in both the U.S. and Europe prompted the study.

In the past, “surgeons pulled out just the rectum. Then studies showed total mesorectal excision (TME), in which surgeons remove the whole rectum plus the fat around it, reduces the risk of local recurrence even further,” she says.

However, the impact of giving radiation prior to TME had not been examined, Marijnen says.

“These results demonstrate that good surgery absolutely is necessary and then radiotherapy can definitely add to the prevention of local recurrence,” she says.

Willett says the findings “show the need for continuing education so TME is integrated into standard practice.”

Radiation therapy does carry risks, chiefly temporary fatigue and transient skin reactions similar to sunburns during treatment. Later, there is a very small risk of secondary cancer or radiation-induced heart or lung disease.

This study was presented at a medical conference. The findings should be considered preliminary as they have not yet undergone the “peer review” process, in which outside experts scrutinize the data prior to publication in a medical journal.

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