Department of Nuclear Medicine, Chang-Bing Show Chwan Memorial Hospital, Changhua, Taiwan.
Clin Nucl Med. 2011 Jun;36(6):447-51. doi: 10.1097/RLU.0b013e31821738b8.
The prognostic value of CT-derived primary tumor volume in patients with nasopharyngeal carcinoma (NPC) has been demonstrated in our previous serial studies. The purpose of the present study is to compare the primary tumor volume measured by FDG PET and traditional CT in NPC, and to ascertain their prognostic value.
From 2007 to 2008, 32 patients with newly diagnosed NPC were prospectively studied. All patients underwent a CT scan, followed by a FDG PET/CT scan. CT-derived primary tumor volume (VolumeCT) was measured using the summation-of-area technique. PET-volume was measured using 3 methods: delineating the contour of tumor with the threshold of standardized uptake value (SUV) ≧2.5 (Volume2.5), ≧40% of maximal SUV (Volume40%), and ≧50% of maximal SUV (Volume50%). The primary tumor volumes derived from the 4 methods, VolumeCT, Volume2.5, Volume40%, and Volume50%, were compared. Univariate Cox regression was used to identify the above parameters as prognosticators.
The volumes derived from the VolumeCT, Volume2.5, Volume40%, and Volume50% methods were 16.48 ± 12.46 cm(3), 25.87 ± 16.96 cm(3), 13.66 ± 6.90 cm(3), and 8.25 ± 4.52 cm(3), respectively. There was decent correlation between VolumeCT and Volume2.5 (r = 0.64, P = 0.0001), and Volume2.5 was systemically larger than VolumeCT. No significant difference was noted between VolumeCT and Volume40% (P = 0.24), but the correlation was poor (r = 0.15, P = 0.39). For VolumeCT and Volume50%, the difference was significant (P = 0.0006) and the correlation was poor (r = 0.23, P = 0.20). Larger tumor volumes presented as VolumeCT, Volume2.5, and Volume50% were associated with shorter overall survival.
PET-derived primary tumor volumes are substantially different from CT-derived tumor volumes, only decent correlation is noted between VolumeCT and Volume2.5. Volume2.5 and Volume50% seem to be reasonable alternatives for VolumeCT in predicting the patient outcomes.
我们之前的系列研究已经证明，CT 检测的原发肿瘤体积在鼻咽癌（NPC）患者的预后评估中有重要价值。本研究旨在比较 NPC 中 FDG PET 和传统 CT 检测的原发肿瘤体积，并确定其预后价值。
2007 年至 2008 年，前瞻性纳入 32 例初诊 NPC 患者。所有患者均行 CT 扫描，随后行 FDG PET/CT 扫描。采用面积总和法测量 CT 检测的原发肿瘤体积（VolumeCT）。采用 3 种方法测量 PET 体积：SUV 阈值≧2.5（Volume2.5）、最大 SUV 的 40%（Volume40%）和 50%（Volume50%）的肿瘤轮廓勾画。比较 4 种方法（VolumeCT、Volume2.5、Volume40%和 Volume50%）得到的原发肿瘤体积。采用单因素 Cox 回归分析确定上述参数作为预后预测指标。
采用 VolumeCT、Volume2.5、Volume40%和 Volume50%方法得到的体积分别为 16.48±12.46 cm3、25.87±16.96 cm3、13.66±6.90 cm3和 8.25±4.52 cm3。VolumeCT 与 Volume2.5 之间存在良好的相关性（r=0.64，P=0.0001），且 Volume2.5 明显大于 VolumeCT。VolumeCT 与 Volume40%之间的差异无统计学意义（P=0.24），但相关性较差（r=0.15，P=0.39）。VolumeCT 与 Volume50%之间的差异有统计学意义（P=0.0006），相关性较差（r=0.23，P=0.20）。较大的肿瘤体积（包括 VolumeCT、Volume2.5 和 Volume50%）与总生存期较短相关。
PET 检测的原发肿瘤体积与 CT 检测的肿瘤体积有明显差异，仅 VolumeCT 与 Volume2.5 之间存在良好的相关性。Volume2.5 和 Volume50%似乎是预测患者预后的 VolumeCT 的合理替代方法。
