Rectal Cancer Outcomes Best With Short-Course Radiation
THURSDAY March 5, 2009 -- For people with operable rectal cancer, the most effective treatment is a short course of radiation therapy followed by "high-quality surgery," according to a new study.
Surgery is the standard treatment for rectal cancer, but just removing the tumor leaves a risk of cancer recurrence in the same area, according to background information. Previous research has shown that radiotherapy and chemotherapy after surgery can reduce the risk of recurrence. However, radiotherapy is costly and can cause long-term complications such as impaired bowel function, incontinence and sexual dysfunction.
The study involved 1,350 rectal cancer patients in the United Kingdom, Canada, South Africa and New Zealand. Professor Robert Steele, of Ninewells Hospital in Dundee, Scotland, and his colleagues randomly assigned the participants to receive five daily treatments of radiotherapy followed by surgery, or to have surgery followed by 25 treatments of chemo-radiotherapy.
Three years after treatment, 4.4 percent of those who had received radiotherapy before surgery had a local recurrence of the cancer, compared with 10.6 percent of those who had received radiotherapy after surgery. The disease-free survival rate after three years was 77.5 percent for people who had received pre-surgery radiotherapy and 72 percent for those who had gotten post-surgery radiotherapy. There was no significant difference in overall survival -- 157 deaths in the pre-surgery radiotherapy group and 173 deaths in the post-surgery group.
The findings were published in this week's issue of The Lancet.
Another study in the same issue of the journal found that recent improvements in surgical techniques have improved rectal cancer patient outcomes. Professor Phil Quirke, of the University of Leeds, in the United Kingdom, and his colleagues assessed how circumferential resection margin and the plane of surgery (the amount of tissue removed around the tumor) affected cancer recurrence risk in 1,156 people.
Of that group, 128 (11 percent) had involvement of the circumferential resection margin -- the presence of a tumor within 1 millimeter of the circumferential margin, which is associated with a high risk of local recurrence and poor survival. The plane of surgery was good (mesorectal) in 604 patients (52 percent), intermediate (intramesorectal) in 398 (34 percent) and poor (muscularis propria plane) in 154 (13 percent).
Three years after surgery, cancer had recurred locally in 6 percent of those with a negative circumferential margin and in 17 percent who had a positive circumferential margin. Local recurrence occurred in 4 percent of people in the mesorectal group, 7 percent in the intramesorectal group and 13 percent in the muscularis propria plane group.
For any plane of surgery achieved, short-course radiotherapy before surgery reduced local recurrence by about half, the study found.
"At present, only 50 percent of rectal cancer surgery is done in the mesorectal plane, suggesting that a further decrease in local recurrence rates might be obtained by improving the plane of surgery achieved," the researchers concluded. "[This could] be achieved through education and surgical tuition."
The findings of these studies show that "perioperative radiation can mitigate but not eliminate the adverse effects of imperfect surgery," Dr. Robert Madoff, of the University of Minnesota, wrote in an accompanying comment in the journal. "The best outcomes occurred when preoperative radiation was followed by optimum surgery. … The next challenge is to understand which patient needs what therapy to maximize his or her chances for a cure."
Posted: March 2009