Vaginal Radioactive Cylinder as Effective as External-Beam Radiation for Endometrial Cancer, With Less Toxicity

The first phase III study of its kind has found that vaginal brachytherapy-in which a radioactive cylinder is inserted into the vagina-is as effective at preventing the recurrence of higher-risk endometrial cancer as external-beam radiation therapy, has fewer side effects, and results in a better quality of life for patients (abstract LBA5503).

“Based on this study, we expect that vaginal brachytherapy will be adopted as the new standard of care for patients with this type of endometrial cancer,” said Remi A. Nout, md, a resident in radiation oncology in the department of clinical oncology at Leiden University Medical Center in the Netherlands and the study’s lead author. “This treatment is simpler and just as effective as external-beam radiation, and it allows patients to have a better quality of life both during and after treatment. This new strategy will make treatment and recovery for many patients much more manageable moving forward.”

Endometrial cancer is the most common type of uterine cancer. For high-intermediate risk disease-which is determined by the tumor’s grade and stage and the patient’s age-the standard treatment has been surgery followed by external-beam radiation therapy. Brachytherapy is currently used in combination with external-beam radiation for more advanced disease. Patients with low-risk disease are treated with surgery alone.

Fewer Side Effects in Brachytherapy Group

This multicenter Dutch study randomized 427 patients with high-intermediate risk endometrial cancer into two arms: 214 patients received external-beam pelvic radiotherapy and 213 received vaginal brachytherapy. All patients had previously undergone surgery to remove their uteruses and ovaries. At 3 years of follow-up, rates of vaginal, pelvic, and distant relapse were 0%, 1.3%, and 6.4% in the brachytherapy group and 1.6%, 0.7%, and 6.0% in the external-beam radiotherapy group. There were no significant differences in overall survival (90.4% vs 90.8%) or progression-free survival (89.5% vs 89.1%).

Patients who received brachytherapy, however, reported a lower level of side effects than patients who received external-beam radiotherapy. The most common side effect was diarrhea. After completion of radiotherapy, 22% of external-beam radiotherapy patients reported moderate to severe diarrhea, compared to 6% in the vaginal brachytherapy group. As a result, 13% of external-beam radiotherapy patients reported moderate to severe limitation in their daily activities due to bowel problems, compared to 5% in the vaginal brachytherapy group. Although these side effects gradually decreased over time, 2 years after treatment 6% of external-beam radiotherapy patients still reported moderate to severe diarrhea, compared to 1% in the vaginal brachytherapy group, which resulted in 5% and 2% moderate to severe limitation in daily activities due to bowel problems, respectively.

Physicians reported significantly higher rates of gastrointestinal toxicity during external-beam radiotherapy: 35% had mild diarrhea or cramping and 19% had moderate diarrhea greater than five times a day during external-beam radiation therapy, compared to 12% and 1% for brachytherapy.