Lujan Anthony E, Mundt Arno J, Yamada S Diane, Rotmensch Jacob, Roeske John C
Department of Radiation and Cellular Oncology, University of Chicago Pritzker School of Medicine, Chicago, IL 60637, USA.
Int J Radiat Oncol Biol Phys. 2003 Oct 1;57(2):516-21. doi: 10.1016/s0360-3016(03)00521-2.
To evaluate intensity-modulated whole pelvis radiotherapy (IM-WPRT) (with bone marrow [BM] as a planning constraint) as a means to reduce the volume of pelvic BM irradiated.
Ten women with cervical or endometrial cancer previously treated using IM-WPRT were selected for this analysis. Using the treatment planning CT scan, the clinical target volume was defined to encompass the gross tumor, parametrial tissues, uterus (if present), and regional lymph nodes. The clinical target volume was expanded by a 1-cm margin to form the planning target volume (PTV). The bladder, rectum, small bowel, and pelvic BM were delineated in each patient. Three plans were created for each patient: a standard four-field WPRT plan, an IM-WPRT treatment plan designed to conform the dose to the PTV while minimizing dose to the normal tissues (excluding BM), and a BM-sparing (BMS) IM-WPRT plan that included the BM as an additional treatment planning constraint. Dose-volume histograms for the PTV, small bowel, and BM were compared for each patient.
For each of the 10 patients, BMS IM-WPRT treatment plans demonstrated a significant reduction of the volume of BM receiving >40% (18 Gy) of the prescription dose (45 Gy) compared with both IM-WPRT and four-field treatment. On average, BMS IM-WPRT resulted in only 60% of the BM volume irradiated to >50% of the dose compared with 87.4% (p <0.001) of the BM volume in a four-field plan and 75.7% (p < 0.003) of the volume in an IM-WPRT plan. Furthermore, the BMS IM-WPRT plans resulted in significant sparing of all other normal tissues that was comparable to the original IM-WPRT. In all 10 cases, the BMS IM-WPRT treatment plan did not result in any significant differences in the PTV and small bowel dose-volume histograms compared with the IM-WPRT treatment plans.
BMS IM-WPRT significantly reduces the volume of pelvic BM irradiated compared with conventional WPRT. In addition, BMS IM-WPRT did not compromise the improvements previously seen in IM-WPRT treatment plans that did not consider BM. Clinical studies are necessary to assess the significance of BMS IM-WPRT in reducing hematologic toxicity.
评估调强全盆腔放疗（IM-WPRT）（以骨髓[BM]作为计划约束条件）作为减少盆腔照射骨髓体积的一种方法。
选择10例先前接受IM-WPRT治疗的宫颈癌或子宫内膜癌女性进行此项分析。利用治疗计划CT扫描，将临床靶区定义为包括大体肿瘤、宫旁组织、子宫（如有）和区域淋巴结。临床靶区外放1 cm边界形成计划靶区（PTV）。在每位患者中勾画膀胱、直肠、小肠和盆腔骨髓。为每位患者制定三个计划：一个标准的四野WPRT计划、一个旨在使剂量适形于PTV同时将对正常组织（不包括BM）的剂量降至最低的IM-WPRT治疗计划，以及一个将BM作为额外治疗计划约束条件的骨髓保护（BMS）IM-WPRT计划。比较每位患者PTV、小肠和BM的剂量体积直方图。
对于10例患者中的每一例，与IM-WPRT和四野治疗相比，BMS IM-WPRT治疗计划均显示接受＞40%（18 Gy）处方剂量（45 Gy）的骨髓体积显著减少。平均而言，BMS IM-WPRT导致接受＞50%剂量照射的骨髓体积仅为四野计划中骨髓体积的60%（p＜0.001），为IM-WPRT计划中骨髓体积的75.7%（p＜0.003）。此外，BMS IM-WPRT计划使所有其他正常组织得到显著保护，与原始IM-WPRT相当。在所有10例病例中，与IM-WPRT治疗计划相比，BMS IM-WPRT治疗计划在PTV和小肠剂量体积直方图上未产生任何显著差异。
与传统WPRT相比，BMS IM-WPRT显著减少了盆腔照射骨髓的体积。此外，BMS IM-WPRT并未损害先前在未考虑BM的IM-WPRT治疗计划中所见到的改善。有必要进行临床研究以评估BMS IM-WPRT在降低血液学毒性方面的意义。
