May 15, 2012 (Barcelona, Spain) — Survival rates with brachytherapy for the treatment of early-stage muscle-invasive cancer are comparable to the gold standard, cystectomy, and spare bladder function, according to the largest retrospective series to date.
Bradley Pieters, MD, and colleagues, from the Department of Radiation Oncology at the University of Amsterdam in the Netherlands, conducted a multicenter retrospective review of 1042 patients from 12 treatment centers from 1983 to 2000.
Dr. Pieters presented the results here at the ESTRO 31: European Society for Radiotherapy and Oncology 2012 Annual Conference.
The median age of the patients was 66 years, and 78% were male. Tumor diameter was 3 cm or less in 70% of patients; tumor stage was pT2 in 77% and poorly differentiated in 79%, he said.
Prior to brachytherapy, the majority of patients (76%) underwent cystotomy; the remainder underwent partial cystectomy.
Brachytherapy techniques were either pulsed-dose rate, consisting of low-dose external-beam radiotherapy of 10 Gy followed by 50 to 60 Gy brachytherapy, or continuous low-dose rate, consisting of high external-beam radiotherapy of 30 to 40 Gy followed by 25 to 40 Gy brachytherapy.
The 5-year local recurrence-free survival rate was 75%, the disease-free survival rate was 61%, and the overall survival rate was 62%, which is comparable to recent cystectomy results showing a 5-year recurrence-free survival rate of 60% to 70%, and 10-year overall survival rates of somewhere between 35% to 45%, said Dr. Pieters.
There were 232 local recurrences; 41% were nonmuscle invasive, 22% were muscle invasive, 13% were both invasive and noninvasive recurrence, and 24% were of unknown origin.
The majority of patients with recurrence went on to bladder-sparing treatment; 26% underwent salvage cystectomy.
On univariate and multivariate analysis, a comparison of prognostic factors showed the brachytherapy technique to be a prognostic factor for local control; patients who underwent pulsed-dose-rate brachytherapy did better than those who underwent continuous low-dose-rate brachytherapy (hazard ratio [HR], 0.46; P = .004), but this significance was lost for overall survival, said Dr. Pieters. Age, stage, grade, and tumor diameter were found to be associated with overall survival.
Asked to comment on the study, Umesh Mahantshetty, MD, a radiation oncologist at Tata Memorial Hospital in Mumbai, India, and chair of the session in which the research was presented, said that "this approach is challenging radical surgery. The results are quite good and exciting for radiation oncologists because the most important end point is cystectomy-free survival."
"The standard treatment for muscle-invasive cancers has been cystectomy across the globe; it's an established treatment modality. It is very unusual to do brachytherapy," Dr. Mahantshetty told Medscape Medical News.
"I think this is an excellent opportunity to look at it in a prospective way.... Maybe this will cause a paradigm shift in the treatment of muscle-invasive bladder cancers," he added.
Dr. Pieters and Dr. Mahantshetty have disclosed no relevant financial relationships.
ESTRO 31: European Society for Radiotherapy and Oncology 2012 Annual Conference: Abstract OC-056. Presented May 11. 2012.
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