Radiation Medicine Program, Princess Margaret Hospital, Toronto, ON, Canada.
Int J Radiat Oncol Biol Phys. 2010 Jun 1;77(2):477-83. doi: 10.1016/j.ijrobp.2009.05.006. Epub 2009 Sep 3.
To report the feasibility and early toxicity of dose-escalated image-guided IMRT to the pelvic lymph nodes (LN), prostate (P), and seminal vesicles (SV).
A total of 103 high-risk prostate cancer patients received two-phase, dose-escalated, image-guided IMRT with 3 years of androgen deprivation therapy. Clinical target volumes (CTVs) were delineated using computed tomography/magnetic resonance co-registration and included the prostate, portions of the SV, and the LN. Planning target volume margins (PTV) used were as follows: P (10 mm, 7 mm posteriorly), SV (10 mm), and LN (5 mm). Organs at risk (OaR) were the rectal and bladder walls, femoral heads, and large and small bowel. The IMRT was planned with an intended dose of 55.1 Gy in 29 fractions to all CTVs (Phase 1), with P+SV consecutive boost of 24.7 Gy in 13 fractions. Daily online image guidance was performed using bony landmarks and intraprostatic markers. Feasibility criteria included delivery of intended doses in 80% of patients, 95% of CTV displacements incorporated within PTV during Phase 1, and acute toxicity rate comparable to that of lower-dose pelvic techniques.
A total of 91 patients (88%) received the total prescription dose. All patients received at least 72 Gy. In Phase 1, 63 patients (61%) received the intended 55.1 Gy, whereas 87% of patients received at least 50 Gy. Dose reductions were caused by small bowel and rectal wall constraints. All CTVs received the planned dose in >95% of treatment fractions. There were no Radiation Therapy Oncology Group acute toxicities greater than Grade 3, although there were five incidences equivalent to Grade 3 within a median follow-up of 23 months.
These results suggest that dose escalation to the PLN+P+SV using IMRT is feasible, with acceptable rates of acute toxicity.
报告盆腔淋巴结（LN）、前列腺（P）和精囊（SV）的剂量递增图像引导调强放疗（IMRT）的可行性和早期毒性。
共 103 例高危前列腺癌患者接受了两阶段、剂量递增、图像引导的 IMRT 治疗，并辅以 3 年雄激素剥夺治疗。使用计算机断层扫描/磁共振共配准来勾画临床靶区（CTV），包括前列腺、部分 SV 和 LN。采用以下计划靶区体积（PTV）边界：P（10mm，后缘 7mm）、SV（10mm）和 LN（5mm）。危及器官（OaR）包括直肠和膀胱壁、股骨头以及大、小肠。采用 55.1Gy/29 次的全 CTV 初始剂量进行 IMRT 计划（第 1 阶段），并在第 1 阶段后进行 P+SV 连续 24.7Gy/13 次的推量。每天使用骨性标志和前列腺内标记物进行在线图像引导。可行性标准包括 80%的患者接受了计划剂量、95%的 CTV 位移在 PTV 内，以及急性毒性发生率与低剂量盆腔技术相当。
共 91 例患者（88%）接受了总处方剂量。所有患者均接受了至少 72Gy 的治疗。在第 1 阶段，63 例患者（61%）接受了计划的 55.1Gy，而 87%的患者接受了至少 50Gy。剂量减少是由于小肠和直肠壁的限制。所有 CTV 在>95%的治疗分数中都接受了计划剂量。没有发生≥3 级的放射治疗肿瘤学组急性毒性，尽管在中位随访 23 个月时，有 5 例发生了相当于 3 级的毒性。
这些结果表明，采用 IMRT 对 PLN+P+SV 进行剂量递增是可行的，并且具有可接受的急性毒性发生率。
