Gluck Iris, Vineberg Karen A, Ten Haken Randall K, Sandler Howard M
Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, USA.
Int J Radiat Oncol Biol Phys. 2009 Feb 1;73(2):334-40. doi: 10.1016/j.ijrobp.2008.09.025.
To compare dose-volume consequences of the inclusion of various portions of the seminal vesicles (SVs) in the clinical target volume (CTV) in intensity-modulated radiotherapy (IMRT) for patients with prostate cancer.
For 10 patients with prostate cancer, three matched IMRT plans were generated, including 1 cm, 2 cm, or the entire SVs (SV1, SV2, or SVtotal, respectively) in the CTV. Prescription dose (79.2 Gy) and IMRT planning were according to the high-dose arm of the Radiation Therapy Oncology Group (RTOG) 0126 protocol. We compared plans for percentage of rectal volume receiving minimum doses of 60-80 Gy and for rectal normal tissue complication probability (NTCP[R]).
There was a detectable increase in rectal dose in SV2 and SVtotal compared with SV1. The magnitude of difference between plans was modest in the high-dose range. In 2 patients, there was underdosing of the planning target volume (PTV) because of constraints on rectal dose in the SVtotal plans. All other plans were compliant with RTOG 0126 protocol requirements. Mean NTCP increased from 14% to 17% and 18% for SV1, SV2, and SV total, respectively. The NTCP correlated with the size of PTV-rectum volume overlap (Pearson's r = 0.86; p < 0.0001), but not with SV volume.
Doubling (1 to 2 cm) or comprehensively increasing (1 cm to full SVs) SV volume included in the CTV for patients with prostate IMRT is achievable in the majority of cases without exceeding RTOG dose-volume limits or underdosing the PTV and results in only a moderate increase in NTCP.
比较在前列腺癌患者的调强放射治疗（IMRT）中，将精囊（SVs）不同部分纳入临床靶区（CTV）后的剂量体积结果。
对10例前列腺癌患者生成了三个匹配的IMRT计划，CTV分别纳入1 cm、2 cm或整个SVs（分别为SV1、SV2或SVtotal）。处方剂量（79.2 Gy）和IMRT计划依据放射治疗肿瘤学组（RTOG）0126方案的高剂量组。我们比较了直肠接受60 - 80 Gy最小剂量的体积百分比计划以及直肠正常组织并发症概率（NTCP[R]）。
与SV1相比，SV2和SVtotal中直肠剂量有可检测到的增加。在高剂量范围内，各计划之间的差异幅度较小。在2例患者中，由于SVtotal计划中对直肠剂量的限制，计划靶区（PTV）出现剂量不足。所有其他计划均符合RTOG 0126方案要求。SV1、SV2和SVtotal的平均NTCP分别从14%增至17%和18%。NTCP与PTV - 直肠体积重叠大小相关（Pearson相关系数r = 0.86；p < 0.0001），但与SV体积无关。
对于前列腺IMRT患者，在大多数情况下，将CTV中纳入的SV体积翻倍（从1 cm到2 cm）或全面增加（从1 cm到整个SVs）是可行的，不会超过RTOG剂量体积限制或导致PTV剂量不足，且仅使NTCP适度增加。
