A short course of preoperative radiotherapy before total mesorectal surgery significantly reduced the rate of local recurrence in patients with rectal cancer, particularly if the tumor was located in the midrectal region.
After 10 years of follow-up, however, the 50% reduction in local recurrence didn’t translate into better overall survival, Dr. Corrie Marijnen will report at the annual meeting of the American Society for Radiation Oncology. But these data from the Dutch TME (Total Mesorectal Excision) study have still been enough to change practice in the Netherlands, she said at a press briefing Oct. 25 before the meeting.
“The preoperative radiation, which we give over 5 days immediately before the surgery, is safe and typically painless,” said Dr. Marijnen, a radiation oncologist at the Leiden (the Netherlands) University Medical Center. “We have advised that in all our Nordic countries, patients with stage II and III rectal cancer will get this short course of preoperative radiotherapy before their TME surgery.”
She will report 11-year follow-up data on 1,861 patients who were enrolled in the randomized TME study. All patients had resectable stage II or III rectal cancer.
Surgeon training was a key point in the TME study, Dr. Marijnen stressed. Experts in the technique visited surgeons in all the participating centers, instructing them in how to best perform the surgery. After a level of expertise was established, patients were randomized to either TME surgery alone, or 5 days of 5-Gy radiotherapy immediately followed by TME. The primary end point was local disease control
The 10-year local recurrence rate was 6.4% in the combination therapy group and 13.3% in the surgery-only group, a significant difference (P = .001). Overall recurrence was also significantly lower in the combination therapy group, compared with the surgery-only group (28.8% vs. 33.3%; P = .042). Dr. Marijnen noted, however, that there was no difference in overall survival.
In a subgroup analysis, the benefit seemed to be confined to those patients who had negative circumferential resection margins, stage III tumors, and midrectal tumors greater than 5 cm.
“We showed that the local recurrence rate was reduced by about 50% when preoperative radiotherapy was given before surgery, with most of the benefit seen in patients with midrectal cancers,” Dr. Marijnen said at the briefing. “Also, to our surprise, we saw that the radiotherapy was even more beneficial for patients with a good surgical outcome – negative lateral margins – than it was for patients who had positive margins. This demonstrates that good surgical technique is also absolutely necessary.”
Neither Dr. Marijnen nor any of her coauthors disclosed any financial conflicts with regard to the study.