PDF(Pubmed)
Abstract：
UNASSIGNED: Neoadjuvant stereotactic radiosurgery (NaSRS) of brain metastases has gained importance, but it is not routinely performed. While awaiting the results of prospective studies, we aimed to analyze the changes in the volume of brain metastases irradiated pre- and postoperatively and the resulting dosimetric effects on normal brain tissue (NBT).
UNASSIGNED: We identified patients treated with SRS at our institution to compare hypothetical preoperative gross tumor and planning target volumes (pre-GTV and pre-PTV) with original postoperative resection cavity volumes (post-GTV and post-PTV) as well as with a standardized-hypothetical PTV with 2.0 mm margin. We used Pearson correlation to assess the association between the GTV and PTV changes with the pre-GTV. A multiple linear regression analysis was established to predict the GTV change. Hypothetical planning for the selected cases was created to assess the volume effect on the NBT exposure. We performed a literature review on NaSRS and searched for ongoing prospective trials.
UNASSIGNED: We included 30 patients in the analysis. The pre-/post-GTV and pre-/post-PTV did not differ significantly. We observed a negative correlation between pre-GTV and GTV-change, which was also a predictor of volume change in the regression analysis, in terms of a larger volume change for a smaller pre-GTV. In total, 62.5% of cases with an enlargement greater than 5.0 cm3 were smaller tumors (pre-GTV < 15.0 cm3), whereas larger tumors greater than 25.0 cm3 showed only a decrease in post-GTV. Hypothetical planning for the selected cases to evaluate the volume effect resulted in a median NBT exposure of only 67.6% (range: 33.2-84.5%) relative to the dose received by the NBT in the postoperative SRS setting. Nine published studies and twenty ongoing studies are listed as an overview.
UNASSIGNED: Patients with smaller brain metastases may have a higher risk of volume increase when irradiated postoperatively. Target volume delineation is of great importance because the PTV directly affects the exposure of NBT, but it is a challenge when contouring resection cavities. Further studies should identify patients at risk of relevant volume increase to be preferably treated with NaSRS in routine practice. Ongoing clinical trials will evaluate additional benefits of NaSRS.
UNASSIGNED: We identified patients treated with SRS at our institution to compare hypothetical preoperative gross tumor and planning target volumes (pre-GTV and pre-PTV) with original postoperative resection cavity volumes (post-GTV and post-PTV) as well as with a standardized-hypothetical PTV with 2.0 mm margin. We used Pearson correlation to assess the association between the GTV and PTV changes with the pre-GTV. A multiple linear regression analysis was established to predict the GTV change. Hypothetical planning for the selected cases was created to assess the volume effect on the NBT exposure. We performed a literature review on NaSRS and searched for ongoing prospective trials.
UNASSIGNED: We included 30 patients in the analysis. The pre-/post-GTV and pre-/post-PTV did not differ significantly. We observed a negative correlation between pre-GTV and GTV-change, which was also a predictor of volume change in the regression analysis, in terms of a larger volume change for a smaller pre-GTV. In total, 62.5% of cases with an enlargement greater than 5.0 cm3 were smaller tumors (pre-GTV < 15.0 cm3), whereas larger tumors greater than 25.0 cm3 showed only a decrease in post-GTV. Hypothetical planning for the selected cases to evaluate the volume effect resulted in a median NBT exposure of only 67.6% (range: 33.2-84.5%) relative to the dose received by the NBT in the postoperative SRS setting. Nine published studies and twenty ongoing studies are listed as an overview.
UNASSIGNED: Patients with smaller brain metastases may have a higher risk of volume increase when irradiated postoperatively. Target volume delineation is of great importance because the PTV directly affects the exposure of NBT, but it is a challenge when contouring resection cavities. Further studies should identify patients at risk of relevant volume increase to be preferably treated with NaSRS in routine practice. Ongoing clinical trials will evaluate additional benefits of NaSRS.
摘要：
■脑转移瘤的新辅助立体定向放射外科（NaSRS）已变得重要，但它不是例行执行。在等待前瞻性研究结果的同时，我们旨在分析术前和术后脑转移瘤照射量的变化,以及由此产生的对正常脑组织(NBT)的剂量学效应.
■我们确定了在我们机构接受SRS治疗的患者，以比较假设的术前大体肿瘤和计划目标体积（GTV前和PTV前）与原始术后切除腔体积（GTV后和PTV后）以及具有2.0mm边缘的标准化假设PTV。我们使用Pearson相关性来评估GTV和PTV变化与前GTV之间的关联。建立多元线性回归分析来预测GTV变化。创建选定病例的假设计划以评估对NBT暴露的体积影响。我们对NaSRS进行了文献综述，并搜索了正在进行的前瞻性试验。
■我们在分析中纳入了30名患者。前/后GTV和前/后PTV没有显着差异。我们观察到前GTV和GTV变化之间存在负相关，这也是回归分析中体积变化的预测因子，就较小的pre-GTV而言，体积变化较大。总的来说,增大大于5.0cm3的病例中有62.5%是较小的肿瘤（前GTV<15.0cm3），而大于25.0cm3的较大肿瘤仅显示GTV后的减少。对选定病例进行假设规划以评估体积效应，导致相对于术后SRS设置中NBT接收的剂量，NBT暴露中位数仅为67.6％（范围：33.2-84.5％）。列出了9项已发表的研究和20项正在进行的研究作为概述。
■脑转移较小者术后照射时体积增大的风险较高。由于PTV直接影响NBT的暴露，因此目标体积的划定非常重要，但它是一个挑战，当轮廓切除腔。进一步的研究应该确定有相关体积增加风险的患者，在常规实践中最好用NaSRS治疗。正在进行的临床试验将评估NaSRS的额外益处。
■我们确定了在我们机构接受SRS治疗的患者，以比较假设的术前大体肿瘤和计划目标体积（GTV前和PTV前）与原始术后切除腔体积（GTV后和PTV后）以及具有2.0mm边缘的标准化假设PTV。我们使用Pearson相关性来评估GTV和PTV变化与前GTV之间的关联。建立多元线性回归分析来预测GTV变化。创建选定病例的假设计划以评估对NBT暴露的体积影响。我们对NaSRS进行了文献综述，并搜索了正在进行的前瞻性试验。
■我们在分析中纳入了30名患者。前/后GTV和前/后PTV没有显着差异。我们观察到前GTV和GTV变化之间存在负相关，这也是回归分析中体积变化的预测因子，就较小的pre-GTV而言，体积变化较大。总的来说,增大大于5.0cm3的病例中有62.5%是较小的肿瘤（前GTV<15.0cm3），而大于25.0cm3的较大肿瘤仅显示GTV后的减少。对选定病例进行假设规划以评估体积效应，导致相对于术后SRS设置中NBT接收的剂量，NBT暴露中位数仅为67.6％（范围：33.2-84.5％）。列出了9项已发表的研究和20项正在进行的研究作为概述。
■脑转移较小者术后照射时体积增大的风险较高。由于PTV直接影响NBT的暴露，因此目标体积的划定非常重要，但它是一个挑战，当轮廓切除腔。进一步的研究应该确定有相关体积增加风险的患者，在常规实践中最好用NaSRS治疗。正在进行的临床试验将评估NaSRS的额外益处。
