Minimal percentage of dose received by 90% of the urethra (%UD90) is the most significant predictor of PSA bounce in patients who underwent low-dose-rate brachytherapy (LDR-brachytherapy) for prostate cancer

Abstract

BackgroundTo clarify the significant clinicopathological and postdosimetric parameters to predict PSA bounce in patients who underwent low-dose-rate brachytherapy (LDR-brachytherapy) for prostate cancer.MethodsWe studied 200 consecutive patients who received LDR-brachytherapy between July 2004 and November 2008. Of them, 137 patients did not receive neoadjuvant or adjuvant androgen deprivation therapy. One hundred and forty-two patients were treated with LDR-brachytherapy alone, and 58 were treated with LDR-brachytherapy in combination with external beam radiation therapy. The cut-off value of PSA bounce was 0.1 ng/mL. The incidence, time, height, and duration of PSA bounce were investigated. Clinicopathological and postdosimetric parameters were evaluated to elucidate independent factors to predict PSA bounce in hormone-naïve patients who underwent LDR-brachytherapy alone.ResultsFifty patients (25%) showed PSA bounce and 10 patients (5%) showed PSA failure. The median time, height, and duration of PSA bounce were 17 months, 0.29 ng/mL, and 7.0 months, respectively. In 103 hormone-naïve patients treated with LDR-brachytherapy alone, and univariate Cox proportional regression hazard model indicated that age and minimal percentage of the dose received by 30% and 90% of the urethra were independent predictors of PSA bounce. With a multivariate Cox proportional regression hazard model, minimal percentage of the dose received by 90% of the urethra was the most significant parameter of PSA bounce.ConclusionsMinimal percentage of the dose received by 90% of the urethra was the most significant predictor of PSA bounce in hormone-naïve patients treated with LDR-brachytherapy alone.

Acute and late toxicities in localized prostate cancer patients treated with low-dose 125I brachytherapy (110 Gy) in combination with external beam radiation therapy versus brachytherapy alone (160 Gy)

“…There have been several reports to compare the treatment outcomes and GU or GI toxicities [ 8 , 9 , 10 , 11 , 12 , 13 , 14 ]. However, they included a variety of LDR-BT modalities or sources, or different prescribed doses such as mixed 125 I and 103 Pb [ 8 , 15 , 16 ].…”

“…Stones et al . reported, even at a high grade, if the tumor was confined to the prostate gland, BT only is adaptive, but there are also reports with opposite results [ 9 , 10 , 24 , 25 , 26 ].…”

Prostate-specific antigen bounce predicts for a favorable prognosis following brachytherapy: a meta-analysis

“…Our findings are consistent with a recent publication that analyzed the clinicopathological and post-dosimetric parameters predictors of PSA bounce. In that report, no patient with PSA bounce after low-dose rate brachytherapy experienced biochemical recurrence, while 10/150 patients that did not meet the criteria for bounce were diagnosed with biochemical recurrence [ 16 ].…”

PSA bounce after 125I-brachytherapy for prostate cancer as a favorable prognosticator

“…This might explain the suspected association between bounce phenomenon and bDFS. Other authors have suggested that inflammatory processes or a greater prostate size cause higher PSA secretion from the residual healthy prostate [18]. These theories, however, fail to explain the correlation between PSA bounce and bDFS.…”