Orthopaedics Oncology, Leiden University Medical Centre, Leiden, the Netherlands.
Radiology, Nuffield Orthopaedic Centre, Oxford University Hospitals NHS Trust, Oxford, United Kingdom.
Surg Oncol. 2020 Dec;35:261-267. doi: 10.1016/j.suronc.2020.08.030. Epub 2020 Aug 26.
Recurrence rates remain high after surgical treatment of diffuse-type Tenosynovial Giant Cell Tumour (TGCT). Imatinib Mesylate (IM) blocks Colony Stimulating Factor1 Receptor (CSF1R), the driver mechanism in TGCT. The aim of this study was to determine if IM reduces the tumour metabolic activity evaluated by PET-CT and to compare this response with the response seen on MR imaging.
25 Consecutive patients treated with IM (off label use) for locally advanced (N = 12) or recurrent (N = 13) diffuse-type TGCT were included, 15 male and median age at diagnosis 39 (IQR 31-47) years. The knee was most frequently affected (n = 16; 64%). The effect of IM was assessed pre- and post-IM treatment by comparing MR scans and PET-CT. MR scans were assessed by Tumour Volume Score (TVS), an estimation of the tumour volume as a percentage of the total synovial cavity. PET-CT scans were evaluated based on maximum standardized uptake value (SUV-max). Partial response was defined as more than 50% tumour reduction with TVS and a decrease of at least 30% on SUV-max.
Median duration of IM treatment was 7.0 (IQR 4.2-11.5) months. Twenty patients (80%) discontinued IM treatment for poor response or intended surgery. Twenty patients experienced an adverse event grade 1-2, three patients grade 3 (creatinine increment, neutropenic sepsis, liver dysfunction). MR assessment of all joints showed 32% (6/19) partial response and 63% (12/19) stable disease, with a mean difference of 12% (P = 0.467; CI -22.4-46.0) TVS between pre- and post-IM and a significant mean difference of 23% (P = 0.021; CI 4.2-21.6) in all knee lesions. PET-CT, all joints, showed a significantly decreased mean difference of 5.3 (P = 0.004; CI 1.9-8.7) SUV-max between pre- and post-IM treatment (58% (11/19) partial response, 37% (7/19) stable disease). No correlation between MR imaging and PET-CT could be appreciated in 15 patients with complete radiological data.
This study confirms the moderate radiological response of IM in diffuse-type TGCT. PET-CT is a valuable additional diagnostic tool to quantify response to tyrosine kinase inhibitor treatment. Its value should be assessed further to validate its efficacy in the objective measurement of biological response in targeted systemic treatment of TGCT.
弥漫型腱鞘巨细胞瘤（TGCT）经手术治疗后复发率仍然很高。甲磺酸伊马替尼（IM）可阻断集落刺激因子 1 受体（CSF1R），这是 TGCT 的驱动机制。本研究旨在确定 IM 是否能降低 PET-CT 评估的肿瘤代谢活性，并将这种反应与磁共振成像（MRI）的反应进行比较。
25 例局部晚期（n=12）或复发性（n=13）弥漫型 TGCT 患者接受 IM（标签外使用）治疗，包括 15 名男性，中位年龄为 39 岁（IQR 31-47 岁）。膝关节最常受累（n=16；64%）。通过比较 MRI 扫描和 PET-CT，评估 IM 治疗前后的效果。MRI 扫描采用肿瘤体积评分（TVS）评估，即肿瘤体积占整个滑膜腔的百分比。PET-CT 扫描根据最大标准化摄取值（SUV-max）进行评估。TVS 肿瘤减少超过 50%和 SUV-max 减少至少 30%定义为部分缓解。
IM 治疗的中位持续时间为 7.0（IQR 4.2-11.5）个月。20 名患者（80%）因疗效不佳或计划手术而停止 IM 治疗。20 名患者出现 1-2 级不良反应，3 名患者出现 3 级不良反应（肌酐升高、中性粒细胞败血症、肝功能障碍）。所有关节的 MRI 评估显示 32%（6/19）有部分缓解，63%（12/19）为稳定疾病，预 IM 和后 IM 的 TVS 平均差异为 12%（P=0.467；CI -22.4-46.0），所有膝关节病变的 SUV-max 平均差异有显著意义，为 23%（P=0.021；CI 4.2-21.6）。所有关节的 PET-CT 检查显示，IM 治疗前后 SUV-max 的平均差异显著降低 5.3（P=0.004；CI 1.9-8.7）（58%（11/19）有部分缓解，37%（7/19）为稳定疾病）。在 15 名具有完整影像学数据的患者中，无法评估 MRI 成像和 PET-CT 之间的相关性。
本研究证实了 IM 在弥漫型 TGCT 中的中等影像学反应。PET-CT 是一种有价值的附加诊断工具，可定量评估酪氨酸激酶抑制剂治疗的反应。应进一步评估其价值，以验证其在 TGCT 的靶向全身治疗中生物反应的客观测量中的疗效。
