18F-FDG PET/CT代谢指标预测胃肠道间质瘤恶性危险度

目的探讨¹⁸F-脱氧葡萄糖正电子发射计算机体层显像仪（¹⁸F-FDG PET/CT）代谢指标对胃肠道间质瘤（GIST）恶性危险度的预测价值。 方法回顾性分析2010年11月至2017年12月北京大学肿瘤医院44例GIST患者¹⁸F-FDG PET/CT术前显像及手术病理结果等临床病理资料。对于¹⁸F-FDG PET/CT显像阳性和阴性患者，应用χ²检验分析患者性别、年龄、病变部位、肿瘤直径、淋巴结转移、脏器转移、核分裂象、Ki-67指数、CD117和CD34表达、美国国立卫生研究院（NIH）危险度分级以及世界卫生组织（WHO）肿瘤预后分组等临床病理参数。对于¹⁸F-FDG PET/CT显像阳性患者，应用非参数秩和检验分析不同临床特征（性别、年龄、病变部位、肿瘤直径、病变密度、淋巴结或脏器转移情况）和不同病理特征（核分裂象、CD34表达情况、Ki-67指数、NIH危险度分级以及WHO肿瘤预后分组）患者3种PET/CT代谢指标，即最大标准摄取值（SUVmax）、肿瘤代谢体积（MTV）、病灶糖酵解总量（TLG）。采用Pearson相关分析分析SUVmax、MTV、TLG与GIST恶性危险度的相关性。 结果44例GIST患者中¹⁸F-FDG PET/CT显像阳性者31例，阴性者13例，显像阳性率为70.5%。显像阳性和显像阴性患者在肿瘤直径、核分裂象、Ki-67指数、NIH危险度分级、WHO肿瘤预后分组方面的差异均有统计学意义（χ²=13.926，P=0.003；χ²=7.738，P=0.021；χ²=4.233，P=0.040；χ²=24.670，P<0.001；χ²=24.670，P<0.001），而在性别、年龄、病变部位、淋巴结转移、脏器转移、CD117和CD34表达方面差异均无统计学意义（P均>0.05）。31例¹⁸F-FDG PET/CT显像阳性者中，肿瘤直径≤5 cm患者与>5 cm患者比较，MTV（P=0.003）和TLG（P=0.004）的差异具有统计学意义，而SUVmax的差异无统计学意义（P>0.05）。核分裂象≤5/50HPF和>5/50HPF的患者，Ki-67指数≤5%和>5%的患者，以及不同NIH危险度分级、WHO肿瘤预后分组的患者，其SUVmax（P=0.022，0.023，0.016，0.016）、MTV（P=0.038，0.028，0.004，0.004）和TLG（P=0.025，0.014，0.004，0.004）的差异均具有统计学意义。不同性别患者，年龄≤60岁和>60岁患者，不同病变部位患者，不同病变密度患者，淋巴结或脏器有无转移的患者，以及不同CD34表达情况的患者，其SUVmax、MTV和TLG的差异均无统计学意义（P均>0.05）。行Pearson相关性分析显示，SUVmax（P=0.020，0.020，0.014，0.014）、MTV（P=0.037，0.026，0.003，0.003）和TLG（P=0.024，0.012，0.003，0.003）与核分裂象、Ki-67指数、NIH危险度分级、WHO肿瘤预后分组等病理学特征均具有相关性，差异具有统计学意义。SUVmax、MTV、TLG受试者工作特征曲线下面积分别为0.754、0.801和0.801。 结论¹⁸F-FDG PET/CT代谢指标SUVmax、MTV、TLG对GIST恶性危险度的分级有一定预测价值。

Predictive value of 18F-FDG PET/CT metabolic parameters in patients with gastrointestinal stromal tumors

ObjectiveTo assess the predictive value of ¹⁸F-FDG PET/CT metabolic parameters in patients with gastrointestinal stromal tumors (GISTs). MethodsThe preoperative ¹⁸F-FDG PET/CT imaging and surgical pathological data of 44 patients with GISTs treated at Beijing Cancer Hospital from November 2010 to December 2017 were analyzed retrospectively. Clinicopathological parameters such as sex, age, lesion location, tumor diameter, lymph node metastasis, organ metastasis, mitotic figure, Ki-67 index, CD117 and CD34 expression, NIH risk classification, and WHO prognosis were analyzed by the Chi-square test in patients with positive and negative ¹⁸F-FDG PET/CT imaging results. In patients with positive ¹⁸F-FDG PET/CT imaging results, three PET/CT metabolic indexes (SUVmax, MTV, and TLG) were analyzed by the non-parametric rank sum test in different groups with different clinical or pathological features. ResultsThirty-one cases had positive ¹⁸F-FDG PET/CT imaging results and 13 cases had negative results. The Chi-square test showed that there were significant differences between the two groups with regard to tumor diameter, mitotic figures, Ki-67 index, NIH risk classification, and WHO prognosis (χ²=13.926, P=0.003; χ²=7.738, P=0.021; χ²=4.233, P=0.040; χ²=24.670, P<0.001; χ²=24.670, P<0.001), but there was no significant difference in sex, age, lesion location, lymph node or organ metastasis, or expression of CD117 and CD34 (P>0.05 for all). Among the 31 ¹⁸F-FDG PET/CT positive cases, MTV and TLG differed significantly between patients with tumor diameter≤5 cm and>5 cm (P=0.003 and 0.004, respectively), but the difference of SUVmax was not significant (P>0.05). SUVmax (P=0.022, 0.023, 0.016, 0.016), MTV (P=0.038, 0.028, 0.004, 0.004), and TLG (P=0.025, 0.014, 0.004, 0.004) differed significantly between patients with different mitotic figures (≤5/50 HPF vs >5/50 HPF), Ki-67 index (≤5% vs >5%), NIH risk classification, or WHO prognosis, while no significant difference was found between patients with different sexes, age (≤60 vs >60 years old), lesion site or density, CD34 expression (presence vs absence), lymph node or organ metastasis (presence vs absence) (P>0.05 for all). Pearson correlation analysis showed that SUVmax (P=0.020, 0.020, 0.014, 0.014), MTV (P=0.037, 0.026, 0.003, 0.003), and TLG (P=0.024, 0.012, 0.003, 0.003) were significantly correlated with pathological features including mitotic figure, Ki-67 index, NIH risk classification, and WHO prognosis. The areas under the ROC curves of the three metabolic parameters (SUVmax, MTV, and TLG) were 0.754, 0.801, and 0.801, respectively. ConclusionThe metabolic parameters of ¹⁸F-FDG PET/CT have appreciated predictive value in grading the malignant risk of GISTs.