Kitao Tomoka, Shiga Tohru, Hirata Kenji, Sekizawa Mitsunori, Takei Toshiki, Yamashiro Katsushige, Tamaki Nagara
Radiology Department, National Hospital Organization Hokkaido Cancer Center, 2-3-54, Kikusui-4, Shiroishi-Ku, Sapporo, 003-0804, Japan.
Department of Nuclear Medicine, Graduate School of Medicine, Hokkaido University, Kita 15 Nishi 7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan.
Ann Nucl Med. 2019 Jan;33(1):22-31. doi: 10.1007/s12149-018-1298-0. Epub 2018 Sep 8.
Soft-tissue sarcomas (STS) are rare types of tumors that have variable levels of tumor differentiation. F-18 fluorodeoxyglucose positron emission tomography (FDG PET) has been established as an useful tool for STS patients, and the metabolic tumor volume (MTV) and total lesion glycolysis (TLG) are reported to be useful in various cancers. We compared the diagnostic value of four PET parameters (maximum standardized uptake value [SUVmax], SUVmean, MTV, and TLG) from two acquisition timings for predicting the expression of the pathological marker of cell proliferation Ki-67, based on pathological investigation.
In this retrospective study, we investigated 20 patients (59 ± 19 years old, 18-87 years old) with pathologically confirmed STS who underwent FDG PET before surgical intervention. The patients fasted ≥ 6 h before the intravenous injection of FDG. The whole body was scanned twice; at an early phase (61.5 ± 2.6 min) and at a delayed phase (118.0 ± 2.1 min) post-injection. The SUVmax, SUVmean, MTV, and TLG of the primary lesion were measured with a tumor boundary determined by SUV ≥ 2.0. Ki-67 was measured using MIB-1 immunohistochemistry. We used Pearson's correlation coefficient to analyze the relationships between the PET parameters and Ki-67 expressions. The Kaplan-Meier analysis with the log-rank test was performed to compare overall survival between high-group and low-group at each of the four PET parameters and Ki-67 expression.
All four PET parameters at each phase showed significant correlations with Ki-67. Among them, the Pearson's correlation coefficient (r) was largest for TLG (r = 0.76 and 0.77 at the early and delayed phases, respectively), followed by MTV (0.70 and 0.72), SUVmax (r = 0.65 and 0.66), and SUVmean (r = 0.62 and r = 0.64). From early to delayed phases, the SUVmax and SUVmean both increased in all 20 patients, whereas the MTV and TLG increased in 13/20 (65%) and 16/20 (80%) patients, respectively. None of the %increases of the PET parameters were significantly correlated with Ki-67. The overall survival was shorter for high-SUVmax, high-SUVmean, high-TLG, and high-Ki-67 groups than the other groups, although the difference did not reach statistical significance.
The SUVmax, SUVmean, MTV, and TLG acquired at both 1 and 2 h after injection showed significant correlations with Ki-67. Among them, correlation coefficient with Ki-67 expression was highest for TLG, although the best parameter should be determined in a larger population. The delayed-phase FDG PET was equally useful as that of early-phase to predict tumor aggressiveness in STS.
软组织肉瘤（STS）是一类罕见肿瘤，其肿瘤分化程度各异。F-18氟脱氧葡萄糖正电子发射断层扫描（FDG PET）已成为STS患者的一种有用工具，据报道，代谢肿瘤体积（MTV）和总病变糖酵解（TLG）在各种癌症中都很有用。基于病理研究，我们比较了两个采集时间点的四个PET参数（最大标准化摄取值[SUVmax]、SUVmean、MTV和TLG）对预测细胞增殖病理标志物Ki-67表达的诊断价值。
在这项回顾性研究中，我们调查了20例经病理确诊的STS患者（年龄59±19岁，18 - 87岁），这些患者在手术干预前接受了FDG PET检查。患者在静脉注射FDG前禁食≥6小时。全身扫描两次，分别在注射后的早期（61.5±2.6分钟）和延迟期（118.0±2.1分钟）。通过SUV≥2.0确定肿瘤边界来测量原发灶的SUVmax、SUVmean、MTV和TLG。使用MIB-1免疫组织化学法测量Ki-67。我们采用Pearson相关系数分析PET参数与Ki-67表达之间的关系。进行Kaplan-Meier分析及对数秩检验，以比较四个PET参数及Ki-67表达的高分组和低分组之间的总生存期。
各阶段的所有四个PET参数均与Ki-67显示出显著相关性。其中，TLG的Pearson相关系数（r）最大（早期和延迟期分别为r = 0.76和0.77），其次是MTV（0.70和0.72）、SUVmax（r = 0.65和0.66）以及SUVmean（r = 0.62和r = 0.64）。从早期到延迟期，所有20例患者的SUVmax和SUVmean均升高，而MTV和TLG分别在13/20（65%）和16/20（80%）的患者中升高。PET参数的升高百分比均与Ki-67无显著相关性。高SUVmax、高SUVmean、高TLG和高Ki-67组的总生存期比其他组短，尽管差异未达到统计学意义。
注射后1小时和2小时获取的SUVmax、SUVmean、MTV和TLG均与Ki-67显示出显著相关性。其中，TLG与Ki-67表达的相关系数最高，不过最佳参数应在更大样本量人群中确定。延迟期FDG PET在预测STS肿瘤侵袭性方面与早期同样有用。
