Tissaverasinghe Steven, Crook Juanita, Bachand Francois, Batchelar Deidre, Hilts Michelle, Araujo Cynthia, Anderson Danielle, Bainbridge Terry, Farnquist Brenda
Radiation Oncology, BC Cancer and University of British Columbia, Vancouver, British Columbia, Canada.
Radiation Oncology, BC Cancer and University of British Columbia, Vancouver, British Columbia, Canada.
Brachytherapy. 2019 May-Jun;18(3):299-305. doi: 10.1016/j.brachy.2019.01.006. Epub 2019 Feb 20.
To present the dosimetric results of a Phase II randomized trial comparing dose escalation to the MRI-defined dominant intraprostatic lesion (DIL) using either low-dose-rate (LDR) or high-dose-rate (HDR) prostate brachytherapy.
Patients receiving prostate brachytherapy as monotherapy were randomized to LDR or HDR brachytherapy. Prostate and DILs were contoured on preoperative multiparametric MRI. These images were registered with transrectal ultrasound for treatment planning. LDR brachytherapy was preplanned using I-125 seeds. HDR brachytherapy used intraoperative transrectal ultrasound-based planning to deliver 27 Gy/2 fractions in separate implants. DIL location was classified as peripheral, central, or anterior. A student t-test compared DIL D between modalities and DIL locations.
Of 60 patients, 31 underwent LDR and 29 HDR brachytherapy. Up to three DILs were identified per patient (100 total) with 74 peripheral, six central, and 20 anterior DILs. Mean DIL volume was 1.9 cc (SD: 1.7 cc) for LDR and 1.6 cc (SD 1.3 cc) for HDR (p = 0.279). Mean DIL D was 151% (SD 30%) for LDR and 132% (SD 13%) for HDR. For LDR, mean peripheral DIL D was 159% (SD 27%) and central or anterior 127% (SD 13%). HDR peripheral DILs received 137% (SD 12%) and central or anterior 119% (SD 7%). DIL D for peripheral lesions was higher than anterior and central (p < 0.001).
DIL location affects dose escalation, particularly because of urethral proximity, such as for anterior and central DILs. HDR brachytherapy may dose escalate better when target DIL is close to critical organs.
呈现一项II期随机试验的剂量学结果，该试验比较了使用低剂量率（LDR）或高剂量率（HDR）前列腺近距离放射治疗对MRI定义的前列腺内主要病灶（DIL）进行剂量递增的情况。
接受前列腺近距离放射治疗作为单一疗法的患者被随机分为LDR或HDR近距离放射治疗组。在术前多参数MRI上勾勒出前列腺和DIL的轮廓。这些图像与经直肠超声配准用于治疗计划。LDR近距离放射治疗预先计划使用I-125种子。HDR近距离放射治疗使用基于术中经直肠超声的计划，在单独的植入物中给予27 Gy/2分次。DIL位置分为外周、中央或前部。采用学生t检验比较不同治疗方式和DIL位置之间的DIL D。
60例患者中，31例行LDR近距离放射治疗，29例行HDR近距离放射治疗。每位患者最多识别出3个DIL（共100个），其中74个外周DIL、6个中央DIL和20个前部DIL。LDR组DIL平均体积为1.9 cc（标准差：1.7 cc），HDR组为1.6 cc（标准差1.3 cc）（p = 0.279）。LDR组DIL D平均为151%（标准差30%），HDR组为132%（标准差13%）。对于LDR，外周DIL D平均为159%（标准差27%），中央或前部为127%（标准差13%）。HDR外周DIL接受137%（标准差12%），中央或前部接受119%（标准差7%）。外周病灶的DIL D高于前部和中央病灶（p < 0.001）。
DIL位置影响剂量递增，特别是因为尿道接近，如前部和中央DIL。当靶DIL靠近关键器官时，HDR近距离放射治疗可能能更好地进行剂量递增。
