ESTRO 37: Brachytherapy for Patients With Cervical Cancer Does Not Increase Risk of Ureteral Stricture
A rare but potentially serious complication following radiation treatment for cervical cancer is a narrowing of the tube that takes urine from the kidneys to the bladder (the ureter), which can lead to kidney damage and sometimes life-threatening infections. This is called ureteral stricture and, until now, there have been concerns that brachytherapy might increase the risk, although the treatment itself is associated with better survival.
Symptoms of a ureteral stricture include back pain, loss of kidney function, and a risk of severe kidney or urinary tract infection. It is treated either by widening the blocked tube and inserting a stent to keep it open, or by inserting a tube directly into the kidney through the skin that is connected to a urine collection bag secured to the patient’s back. Some patients will need this for a short time, but for some, it may be permanent.
However, new research presented at the European Society for Radiotherapy & Oncology (ESTRO) 37 Conference (Abstract OC-0072) from two large international trials showed that intracavitary and interstitial (IC/IS) brachytherapy for the treatment of cervical cancer is safe and does not increase the risk of ureteral stricture. Intracavitary (IC) brachytherapy involves placing an applicator in the uterus, while interstitial (IS) brachytherapy involves inserting needles directly into the tumor. The appropriate radiation dose is delivered to the cancer via one or both of these approaches. The procedure is performed after a computed tomography (CT) or magnetic resonance imaging (MRI) scan has pinpointed the exact position of the cancer, so that the radiation treatment can be targeted precisely—this is called image-guided brachytherapy (IGBT).
Lars Fokdal, MD, PhD, a consultant at Aarhus University Hospital, Denmark, who led the study, said, “These results show that image-guided brachytherapy using intracavitary combined with interstitial techniques is safe and is not associated with more cases of ureteral stricture afterwards compared to using intracavitary techniques alone.”
EMBRACE and RetroEMBRACE Findings
Dr. Fokdal and his colleagues looked at data from 1,772 patients with locally advanced cervical cancer who were enrolled in two trials of the treatment—EMBRACE and RetroEMBRACE—that were being carried out in 12 countries. IC/IS IGBT was delivered to 36% of the patients.
After following the patients for between 1 and 163 months (median number of months = 29), 36 patients were diagnosed with the more severe form of ureteral stricture (grade 3–4). The overall risk of developing grade 3–4 ureteral stricture was 2% after 3 years and 3.2% after 5 years. The risk was lowest (1.3%) among the 1,370 patients with small tumors, and highest among the 130 patients with more advanced cancer and who had ureters swollen due to a build-up of urine (hydronephrosis) at the time of diagnosis. In these patients, the risk of ureteral stricture was 13.6% after 3 years and 23.4% after 5 years.
“The incidence of ureteral stricture in cervical cancer patients generally is between 2% to 3%, so the overall risk of developing the complication after IC/IS image-guided brachytherapy compares well. It is good to know that the interstitial component of IGBT does not increase the risk of this relatively rare but sometimes serious complication. However, the risk is more pronounced in patients with advanced stage and hydronephrosis at diagnosis,” said Dr. Fokdal.
Avoidance Strategies
“There are different strategies that can be used to avoid ureteral stricture in the subset of patients who are at higher risk. One strategy could be closer observation following IC/IS IGBT so that ureteral strictures could be spotted earlier before they become too severe. Another strategy could be insertion of ureteral stents before radiotherapy in order to visualize the organ on imaging and reduce the dose delivered during brachytherapy,” suggested Dr. Fokdal.
He continued, “Results from the RetroEMBRACE and EMBRACE trials have also shown that IC/IS image-guided brachytherapy is associated with a better outcome for patients in terms of survival and adverse side effects. The increased but targeted radiation dose to the tumors controls the cancer better without adversely affecting nearby organs and tissues. Taking all these results together, we have growing evidence in favor of IC/IS IGBT for treating cervical cancer.”
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
