Belohlavek Otakar, Fencl Pavel, Majovsky Martin, Jaruskova Monika, Benes Vladimir
PET Centre, Na Homolce Hospital, Prague, Czech Republic.
Nucl Med Rev Cent East Eur. 2014;17(1):7-12. doi: 10.5603/NMR.2014.0003.
Low-grade gliomas (LGG) of the brain have an uncertain prognosis, as many of them show continuous growth or upgrade over the course of time. We retrospectively investigated the role of positron emission tomography with 3'-deoxy-3'-[18F]fluorothymidine (FLT-PET) in the prediction of overall survival and event free survival in patients with untreated LGG. No such information is yet available in the literature.
Forty-one patients with previously untreated LGG underwent 55 FLT-PET investigations during their follow-up because of subjective complaints, objective worsening of clinical conditions, equivocal findings or progression on magnetic resonance imaging. The time interval before referral for neurosurgical or radiation treatment was considered to be event free survival, the interval until death as overall survival, respectively. Standardized uptake values (SUV) were measured, and a 3-point scale of subjective assessment was also applied. ROC analysis was used to define cut-off values. The log rank test was used for comparison of Kaplan-Meier survival curves.
Eight patients (a total of 9 FLT-PET studies performed) died during follow-up. Progression leading to referral to therapy was recorded in 24 patients (a total of 33 FLT-PET studies). With a cut-off value of SUV(mean) = 0.236, a median overall survival of 1.007 days was observed in the test positive subgroup while median overall survival for the test negative subgroup was not achieved (p = 0.0002), hazard ratio = 17.6. Subjective assessment resulted in hazard ratio 11.5 (p = 0.0001). Only marginal significance (p=0.0562) was achieved in prediction of event free survival.
Increased FLT uptake in previously untreated patients with LGG is a strong predictor of overall survival. On the other hand, prediction of event free survival was not successful in our cohort, probably because of high prevalence of patients who needed treatment due to symptoms caused by a space-occupying lesion without respect to the proliferative activity of the tumour.
脑低级别胶质瘤（LGG）的预后不确定，因为其中许多在病程中会持续生长或升级。我们回顾性研究了3'-脱氧-3'-[18F]氟胸苷正电子发射断层扫描（FLT-PET）在预测未经治疗的LGG患者总生存期和无事件生存期方面的作用。文献中尚无此类信息。
41例先前未经治疗的LGG患者在随访期间因主观症状、临床状况客观恶化、磁共振成像结果不明确或进展而接受了55次FLT-PET检查。转诊接受神经外科或放射治疗前的时间间隔被视为无事件生存期，直至死亡的间隔分别视为总生存期。测量了标准化摄取值（SUV），并应用了主观评估的3分制。采用ROC分析确定临界值。使用对数秩检验比较Kaplan-Meier生存曲线。
8例患者（共进行了9次FLT-PET研究）在随访期间死亡。24例患者（共进行了33次FLT-PET研究）记录到导致转诊治疗的进展。SUV（均值）=0.236作为临界值时，检测阳性亚组的中位总生存期为1.007天，而检测阴性亚组未达到中位总生存期（p = 0.0002），风险比=17.6。主观评估的风险比为11.5（p = 0.0001）。在预测无事件生存期方面仅达到边缘显著性（p=0.0562）。
未经治疗的LGG患者中FLT摄取增加是总生存期的有力预测指标。另一方面，在我们的队列中无事件生存期的预测未成功，可能是因为因占位性病变引起的症状而需要治疗的患者比例较高，而不考虑肿瘤的增殖活性。
