Vanuytsel L J, Vansteenkiste J F, Stroobants S G, De Leyn P R, De Wever W, Verbeken E K, Gatti G G, Huyskens D P, Kutcher G J
Department of Oncology (Section Radiotherapy), University Hospital Gasthuisberg, Herestraat 49, B-3000, Leuven, Belgium.
Radiother Oncol. 2000 Jun;55(3):317-24. doi: 10.1016/s0167-8140(00)00138-9.
(18)F-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) combined with computer tomography (PET-CT) is superior to CT alone in mediastinal lymph node (LN) staging in non-small cell lung cancer (NSCLC). We studied the potential impact of this non-invasive LN staging procedure on the radiation treatment plan of patients with NSCLC.
The imaging and surgical pathology data from 105 patients included in two previously published prospective LN staging protocols form the basis for the present analysis. For 73 of these patients, with positive LN's on CT and/or on PET, a theoretical study was performed in which for each patient the gross tumour volume (GTV) was defined based on CT and on PET-CT data. For each GTV, the completeness of tumour coverage was assessed, using the available surgical pathology data as gold standard. A more detailed analysis was done for the first ten consecutive patients in whom the PET-CT-GTV was smaller than the CT-GTV. Theoretical radiation treatment plans were constructed based on both CT-GTV and PET-CT-GTV. Dose-volume histograms for the planning target volume (PTV), for the total lung volume and the lung volume receiving more than 20 Gy (V(lung(20))), were calculated.
Data from 988 assessed LN stations were available. In the subgroup of 73 patients with CT or PET positive LN's, tumour coverage improved from 75% when the CT-GTV was used to 89% with the PET-CT-GTV (P=0.005). In 45 patients (62%) the information obtained from PET would have led to a change of the treatment volumes. For the ten patients in the dosimetry study, the use of PET-CT to define the GTV, resulted in an average reduction of the PTV by 29+/-18% (+/-1 SD) (P=0.002) and of the V(lung(20)) of 27+/-18% (+/-1 SD) (P=0.001).
In patients with NSCLC considered for curative radiation treatment, assessment of locoregional LN tumour extension by PET will improve tumour coverage, and in selected patients, will reduce the volume of normal tissues irradiated, and thus toxicity. This subgroup of patients could then become candidates for treatment intensification.
（18）F-氟-2-脱氧-D-葡萄糖正电子发射断层扫描（FDG-PET）联合计算机断层扫描（PET-CT）在非小细胞肺癌（NSCLC）纵隔淋巴结（LN）分期方面优于单纯CT。我们研究了这种非侵入性LN分期程序对NSCLC患者放射治疗计划的潜在影响。
本分析基于之前发表的两项前瞻性LN分期方案中纳入的105例患者的影像和手术病理数据。对于其中73例CT和/或PET显示LN阳性的患者，进行了一项理论研究，即根据CT和PET-CT数据为每位患者定义大体肿瘤体积（GTV）。以可用的手术病理数据作为金标准，评估每个GTV的肿瘤覆盖完整性。对PET-CT-GTV小于CT-GTV的前十例连续患者进行了更详细的分析。基于CT-GTV和PET-CT-GTV构建理论放射治疗计划。计算计划靶体积（PTV）、全肺体积以及接受超过20 Gy照射的肺体积（V（肺（20）））的剂量体积直方图。
可获得988个评估LN站的数据。在73例CT或PET显示LN阳性的患者亚组中，当使用CT-GTV时肿瘤覆盖率为75%，使用PET-CT-GTV时提高到89%（P = 0.005）。在45例患者（62%）中，从PET获得的信息会导致治疗体积的改变。对于剂量学研究中的十例患者，使用PET-CT定义GTV导致PTV平均减少29±18%（±1标准差）（P = 0.002），V（肺（20））减少27±18%（±1标准差）（P = 0.001）。
在考虑进行根治性放射治疗的NSCLC患者中，通过PET评估局部区域LN肿瘤扩展将改善肿瘤覆盖，并且在部分患者中，将减少正常组织的照射体积，从而降低毒性。这部分患者可能成为强化治疗的候选对象。
