Correlations of post-implant regional dosimetric parameters at 24 hours and one month, with clinical results of low-dose-rate brachytherapy for localized prostate cancer

Abstract

PurposeTo evaluate the correlations of post-implant regional dosimetrics at 24 hours (24 h) and 1 month after implant procedures, with clinical outcomes of low-dose-rate (LDR) brachytherapy for localized prostate cancer.Material and methodsBetween January 2008 and December 2014, 130 consecutive patients treated for localized prostate cancer, receiving definitive iodine-125 (125I) brachytherapy treatment were retrospectively analyzed. All patients underwent post-implant CT imaging for dosimetric analysis at 24 h and 1 month after implantation procedure. Prostate contours were divided into quadrants: anterior-superior (ASQ), posterior-superior (PSQ), anterior-inferior (AIQ), and posterior-inferior (PIQ). Predictive factors and cut-off values of biochemical failure-free survival (BFFS) and toxicities of LDR brachytherapy were analyzed.ResultsThe median follow-up time was 69.5 months. Seven patients (5.4%) had biochemical failure. The 3-year and 5-year BFFS rates were 96.7% and 93.1%, respectively. On multivariate analysis, prostate-specific antigen and Gleason score were significant prognostic factors for biochemical failure. D90 (the minimal dose received by 90% of the volume) of PSQ and PIQ at 24 h, and D90 of PSQ at 1 month were also significant factors. The cut-off values of PSQ D90 were 145 Gy at 24 h and 160 Gy at 1 month. D90 of the whole prostate was not significant at 24 h and at 1 month. D90 of PSQ at 1 month was a significant factor for rectal hemorrhage.ConclusionsPost-implant D90 of PSQ is significantly associated with BFFS for localized prostate cancer not only at 1 month, but also at 24 hours. D90 of PSQ at 1 month is also a significant factor for rectal hemorrhage.

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)

“…In this study, late GU toxicities ≥ grade 2 in the combination therapy group showed a rate of 8.3% and the BT monotherapy group 11.1%. In the previous reports of BT monotherapy, the late GU toxicity rate was 8.1-22.3% [ 17 , 18 ], and late urinary retention was reported in 0.6% [ 4 ]. By contrast, a study of BT and EBRT combination therapy reported a late GU grade 2 toxicity rate of 17% and grade 3 – 3% [ 10 ].…”

“…There have been no reports about it in combination therapy vs. BT monotherapy. In BT monotherapy, there has been one report of a late hematuria rate of 15.4% [ 17 ], and several reports of late rectal hemorrhage rates of 6-16% [ 3 , 4 , 17 ]. In our study, only one late grade 1 rectal hemorrhage in the monotherapy group was recorded.…”

Five-year effectiveness of low-dose-rate brachytherapy: comparisons with nomogram predictions in patients with non-metastatic prostate cancer presenting significant control of intra- and periprostatic disease

“…Individual risk factors (tumor stages, PSA levels, Gleason scores) however correlated less well with the observed outcomes, and thus appear to be less valuable than prognostic risk groups in the context of brachytherapy, at least in the timeframe of 5 years [ 34 ]. In particular, the tumor stage cT2c (tumor covering both lobes) was not associated with lower 5-year bPFS than cT2a or cT2b (tumor confined to ≤ 50 or > 50% of one lobe, respectively).…”

Comparison of post-implant dosimetrics between intraoperatively built custom-linked seeds and loose seeds by sector analysis at 24 hours and 1 month for localized prostate cancer

“…The prostate volume was divided into four quadrants, such as anterior-superior quadrant (ASQ), posterior-superior quadrant (PSQ), anterior-inferior quadrant (AIQ), and posterior-inferior quadrant (PIQ). The superior- inferior and anterior-posterior segments were divided by the midpoint of the prostate on reconstructed CT images ( Figure 1 ) [ 22 ].…”

“…In addition, although most previous reports refer to the dosimetric parameters of the whole prostate, some have evaluated dose distribution in different regions of the prostate [ 10 ]. We have previously reported the usefulness of sector analysis for localized prostate cancer treated with LS [ 22 ].…”