In a large, randomized clinical trial of women with high-intermediate risk endometrial cancer, vaginal brachytherapy (VBT) was as effective at reducing the rate of cancer recurrence in the vagina as external-beam radiation therapy (EBRT), and VBT had fewer side effects. These results from the PORTEC-2 trial, led by Remi Nout, M.D., from Leiden University Medical Center in the Netherlands, were published March 6, 2010, in the The Lancet.
A previous trial, PORTEC-1, had shown that EBRT reduced the rate of local or regional cancer recurrence from more than 20 percent to 5 percent for women at high-intermediate risk of recurrence. However, more than a quarter of these women reported side effects in the first 2 years after treatment, mostly in the gastrointestinal tract (such as diarrhea).
To test whether VBT would be as effective as EBRT but less toxic, the researchers enrolled 427 women in the PORTEC-2 trial. After surgery to remove the uterus, ovaries, and fallopian tubes, 214 women received EBRT and 213 received VBT as low-, medium-, or high-dose-rate treatment according to the treating center’s discretion. After a median follow-up of 45 months, four women in the EBRT group and three women in the VBT group had a vaginal recurrence. The estimated 5-year vaginal recurrence rates were 1.6 percent after EBRT and 1.8 percent after VBT. No significant differences in disease-free survival or overall survival were seen between the groups.
More than four times as many women reported gastrointestinal side effects at completion of EBRT (53.8 percent) as those who received VBT (12.6 percent). This difference between groups decreased over time and was no longer statistically significant 2 years after treatment. One woman in the EBRT group and four women in the VBT group reported high-grade atrophy of the vaginal mucosa, a condition in which the skin lining the vagina becomes thin and can cause uncomfortable symptoms. Rates of sexual activity after treatment were not significantly different between the two groups.
“VBT achieves excellent vaginal control and rates of locoregional recurrence, overall survival, and disease-free survival that are similar to EBRT, and quality of life and gastrointestinal toxic effects are significantly better with VBT. VBT should be the adjuvant treatment of choice for patients with endometrial carcinoma of high-intermediate risk,” the authors concluded.