ESTRO 2017: HDR Brachytherapy in Prostate Cancer Does Not Cause Higher Toxicity, Results in High Patient Satisfaction
Treating prostate cancer with a single, high dose of radiation delivered precisely to the site of the tumor results in good quality of life and fewer trips to the hospital, with adverse side effects that are no worse than if the radiation treatment had been given in several lower doses. These findings were presented at the European Society for Radiotherapy & Oncology (ESTRO) 36 Conference (Abstract OC-0270).
Alfonso Gomez-Iturriaga, MD, PhD, of the Hospital de Cruces, Baracaldo, Spain, told the ESTRO 36 conference that results were encouraging from the phase II trial of high-dose rate (HDR) brachytherapy, delivered in a single fraction of 19 Gy to 45 patients with prostate cancer that was at low or intermediate risk of metastasizing.
“Our study demonstrates that patients do not suffer higher toxicity or a worse quality of life than might be expected with other methods of delivering radiation treatment. In fact, patients are very satisfied with this single outpatient treatment, which they find convenient and which allows them to return rapidly to normal activities. It is too early to say that this strategy can be used outside the trial setting, but it seems quite clear that the toxicity and impact on quality of live are very low. Longer follow-up for at least 5 years is needed to demonstrate definite cancer control,” said Dr. Gomez-Iturriaga.
HDR Brachytherapy
HDR brachytherapy involves the very precise positioning of catheters, with the aid of ultrasound, at the site of the tumor while the patient is under spinal or general anesthetic. A radioactive source (iridium-192) is delivered via the catheters to the target, avoiding other structures such as the bladder and the bowel, so that they deliver the maximum dose precisely to the target. The treatment usually takes about 30 minutes.
“The combination of a short lapse of time, real-time 3D visualization of the target, and needles positioning using ultrasound, and the ability to optimize the dose (high doses to target and low doses to surrounding organs at risk), allows for an extraordinary control over the dose administration. To the patient, the main advantage is to get the radiotherapy in just 1 day. Although the brachytherapy is done in an operating room, it is an outpatient procedure and the patient avoids daily radiation treatment,” said Dr. Gomez-Iturriaga.
Although it has been thought that HDR brachytherapy could be used for treating prostate cancer, until now there has been limited evidence of its safety and efficacy.
Study Findings
In this study, 45 consecutive patients received HDR brachytherapy at the Hospital de Cruces between January 2014 and July 2016. The patients had low- or intermediate-risk prostate cancer, mild to moderate symptoms, a tumor volume that was 60 cc or less, and had not yet had surgery or androgen-deprivation therapy.
After a follow-up time that ranged from 3 to 31 months (median average was 16 months), there were no grade 3 adverse side effects from the treatment; six patients had moderate (grade 2) bowel or bladder problems (diarrhea or needing to pass urine frequently or urgently).
In terms of quality of life, the need to pass urine urgently declined significantly between the first and sixth month after treatment and had returned to normal after 1 year. There were no significant changes in bowel movements or sexual or hormonal functioning. Sixty percent of patients who had normal sexual functioning before the treatment continued to function normally afterwards. Six months after the radiation therapy, 77% of patients said they were “extremely satisfied” with their treatment and quality of life and 23% were “very satisfied”.
Dr. Gomez-Iturriaga said these were excellent results in terms of patient satisfaction, quality of life, toxicity, and tolerability, as well as safety.
“The precise control over dose delivery inherent in HDR brachytherapy is not readily achievable with low-dose rate (LDR) brachytherapy because of several factors: movement of the radioactive seeds away from the target site, swelling of the prostate after the implant, and uncertain dose delivery outside the prostate, which can all contribute to less than optimal dose distributions,” he said. “With LDR brachytherapy, the actual dose distribution achieved is not known until the post-plan quality assurance is completed, several weeks after the treatment. In contrast, with HDR brachytherapy, what you plan to treat is exactly what is actually administered.”
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®.
