The purpose of this study was to determine the relationship of ¹⁸F-FDG uptake in the primary tumor at diagnosis, during therapy, and after therapy with a histologic response and event-free survival in pediatric and young adult patients with osteosarcoma (OS). Methods: Serial (baseline and 5 and 10 wk after start of therapy) ¹⁸F-FDG PET/CT imaging was performed in patients with newly diagnosed OS treated uniformly in a therapeutic trial at a single institution. Whole-body images were obtained approximately 1 h after injection of ¹⁸F-FDG. Logistic regression was used to study the association of tumor uptake and changes in SUV_max between 0, 5, and 10 wk for both clinical endpoints. Results: Thirty-four patients (17 males; median age, 12.2 y; age range, 6.8–19.1 y) underwent PET imaging; 25 (74%) had localized disease. Primary tumor locations included the femur (n = 17; 50%), tibia (n = 9; 26%), and humerus (n = 5; 15%). Logistic regression showed that SUV_max at 5 wk (P = 0.034) and 10 wk (P = 0.022) and percentage change from baseline at 10 wk (P = 0.021) were highly predictive of a histologic response. Using SUV_max of 4.04 at week 5, SUV_max of 3.15 at week 10, and 60% decrease from baseline at week 10 as cutoff values, we determined that the respective sensitivities were 0.93, 0.93, and 0.79 and that the respective specificities were 0.53, 0.71, and 0.76. Conclusion: SUV_max on routine images at 5 or 10 wk and percentage change in SUV_max from baseline to week 10 were metabolic predictors of a histologic response in OS. These findings may be useful in the early identification of patients who are responding poorly to therapy and may benefit from a change in treatment.

这项研究的目的是确定儿童和年轻成人骨肉瘤（OS）患者在诊断，治疗期间和治疗后¹⁸ F-FDG摄取与组织学应答和无事件生存的关系。方法：连续（基线以及开始治疗后的第5周和第10周）在单一机构进行的治疗试验中，对新诊断OS均经过统一治疗的患者进行¹⁸ F-FDG PET / CT成像。注射¹⁸ F-FDG约1小时后获得全身图像。Logistic回归用于研究两个临床终点的肿瘤摄取与SUV _max在0、5和10 wk之间变化之间的关系。结果：34例患者（17例男性；中位年龄为12.2岁；年龄范围为6.8-19.1岁）接受了PET显像。25（74％）人患有局部疾病。原发肿瘤的位置包括股骨（n = 17； 50％），胫骨（n = 9； 26％）和肱骨（n = 5； 15％）。Logistic回归显示，SUV_最大在5 wk（P = 0.034）和10 wk（P = 0.022）以及在10 wk（P = 0.021）时相对于基线的变化百分率可以高度预测组织学反应。使用SUV_最大值的4.04在第5周，SUV_最大值在第10周时3.15的临界值和在第10周时比基线降低60％的临界值，我们确定各自的灵敏度分别为0.93、0.93和0.79，特异性分别为0.53、0.71和0.76。结论： SUV_最大的常规图像在SUV 5或10周和百分比变化_最大，从基线到10本周共在OS组织学反应的代谢预测。这些发现可能有助于早期识别对治疗反应较差的患者，并且可能会受益于治疗方法的改变。