Chen Chien P, Johnson Julian, Seo Youngho, Weinberg Vivian K, Shinohara Katsuto, Hsu I-Chow J, Roach Mack
Department of Radiation Oncology, Scripps Health, San Diego, California.
Department of Radiation Oncology, University of California, San Francisco, San Francisco, California.
Adv Radiat Oncol. 2015 Dec 17;1(1):51-58. doi: 10.1016/j.adro.2015.11.004. eCollection 2016 Jan-Mar.
PURPOSE/OBJECTIVES: Current Radiation Therapy Oncology Group (RTOG) guidelines for pelvic radiation therapy are based on general anatomic boundaries. Sentinel lymph node (SLN) imaging can identify potential sites of lymph node involvement. We sought to determine how tailored radiation therapy fields for prostate cancer would compare to standard RTOG-based fields. Such individualized radiation therapy could prioritize the most important areas to irradiate while potentially avoiding coverage in areas where critical structures would be overdosed. Individualized radiation therapy could therefore increase the therapeutic index of pelvic radiation therapy.
Ten intermediate or high-risk prostate cancer patients received androgen deprivation therapy with definitive radiation therapy, including an SLN imaging-tailored elective nodal volume (ENV). For dosimetric analyses, the ENV was recontoured using RTOG guidelines (RTOG_ENV) and on SLNs alone (SLN_ENV). Separate intensity modulated radiation therapy (IMRT) plans were optimized using RTOG_ENV and SLN_ENV for each patient. Dosimetric comparisons for these IMRT plans were performed for each patient. Dose differences to targets and critical structures among the different IMRT plans were calculated. Distributions of dose parameters were analyzed using non-parametric methods.
Sixty percent of patients had SLNs outside of the RTOG_ENV. The larger volume IMRT plans covering SLN imaging-tailored elective nodal volume exhibited no significant dose differences versus plans covering RTOG_ENV. IMRT plans covering only the SLNs had significantly lower doses to bowel and femoral heads.
SLN-guided pelvic radiation therapy can be used to either treat the most critical nodes only or as an addition to RTOG guided pelvic radiation therapy to ensure that the most important nodes are included.
目的/目标：当前放射治疗肿瘤学组（RTOG）的盆腔放射治疗指南基于一般解剖边界。前哨淋巴结（SLN）成像可识别淋巴结受累的潜在部位。我们试图确定针对前列腺癌的定制放射治疗野与基于RTOG标准的野相比如何。这种个体化放射治疗可以优先照射最重要的区域，同时有可能避免在关键结构会接受过量照射的区域进行覆盖。因此，个体化放射治疗可以提高盆腔放射治疗的治疗指数。
10例中高危前列腺癌患者接受雄激素剥夺治疗并进行确定性放射治疗，包括SLN成像定制的选择性淋巴结体积（ENV）。为进行剂量分析，使用RTOG指南（RTOG_ENV）并仅基于SLN重新勾勒ENV轮廓（SLN_ENV）。为每位患者分别使用RTOG_ENV和SLN_ENV优化调强放射治疗（IMRT）计划。对每位患者的这些IMRT计划进行剂量比较。计算不同IMRT计划对靶区和关键结构的剂量差异。使用非参数方法分析剂量参数分布。
60%的患者SLN位于RTOG_ENV之外。覆盖SLN成像定制的选择性淋巴结体积的较大体积IMRT计划与覆盖RTOG_ENV的计划相比，剂量无显著差异。仅覆盖SLN的IMRT计划对肠道和股骨头的剂量显著较低。
SLN引导的盆腔放射治疗可用于仅治疗最关键的淋巴结，或作为RTOG引导的盆腔放射治疗的补充，以确保纳入最重要的淋巴结。
