Department of Nuclear Medicine, Ghent University Hospital, De Pintelaan 185, 9000, Ghent, Belgium,
Eur J Nucl Med Mol Imaging. 2013 Aug;40(8):1214-22. doi: 10.1007/s00259-013-2421-z. Epub 2013 May 1.
Standardized added metabolic activity (SAM) is a PET parameter for assessing the total metabolic load of malignant processes, avoiding partial volume effects and lesion segmentation. The potential role of this parameter in the assessment of response to chemotherapy and bevacizumab was tested in patients with metastatic colorectal cancer with potentially resectable liver metastases (mCRC).
(18)F-FDG PET/CT was performed in 18 mCRC patients with liver metastases before treatment and after five cycles of FOLFOX/FOLFIRI and bevacizumab. Of the 18 patients, 16 subsequently underwent resection of liver metastases. Baseline and follow-up SUVmax, and SAM as well as reduction in SUVmax (∆SUVmax) and SAM (∆SAM) of all liver metastases were correlated with morphological response, and progression-free and overall survival (PFS and OS).
A significant reduction in metabolic activity of the liver metastases was seen after chemotherapy with a median ∆SUVmax of 25.3% and ∆SAM of 94.5% (p = 0.033 and 0.003). Median baseline SUVmax and SAM values were significantly different between morphological responders and nonresponders (3.8 vs. 7.2, p = 0.021; and 34 vs. 211, p = 0.002, respectively), but neither baseline PET parameters nor morphological response was correlated with PFS or OS. Follow-up SUVmax and SAM as well as ∆SAM were found to be prognostic factors. The median PFS and OS in the patient group with a high follow-up SUVmax were 10.4 months and 32 months, compared to a median PFS of 14.7 months and a median OS which had not been reached in the group with a low follow-up SUVmax (p = 0.01 and 0.003, respectively). The patient group with a high follow-up SAM and a low ∆SAM had a median PFS and OS of 9.4 months and 32 months, whereas the other group had a median PFS of 14.7 months and a median OS which had not been reached (p = 0.002 for both PFS and OS).
(18)F-FDG PET imaging is a useful tool to assess treatment response and predict clinical outcome in patients with mCRC who undergo chemotherapy before liver metastasectomy. Follow-up SUVmax, follow-up SAM and ∆SAM were found to be significant prognostic factors for PFS and OS.
标准化摄取值（SAM）是一种 PET 参数，用于评估恶性肿瘤的总代谢负荷，避免了部分容积效应和病变分割的影响。在有潜在可切除肝转移的转移性结直肠癌（mCRC）患者中，测试了该参数在评估化疗和贝伐珠单抗反应中的作用。
对 18 例 mCRC 肝转移患者进行（18）F-FDG PET/CT 检查，在治疗前和 FOLFOX/FOLFIRI 联合贝伐珠单抗治疗 5 个周期后进行检查。这 18 例患者中有 16 例随后进行了肝转移切除术。对所有肝转移灶的基线和随访 SUVmax、SAM 以及 SUVmax（∆SUVmax）和 SAM（∆SAM）的减少与形态学反应、无进展生存（PFS）和总生存（OS）进行了相关性分析。
化疗后，肝转移灶的代谢活性明显降低，中位∆SUVmax 为 25.3%，∆SAM 为 94.5%（p=0.033 和 0.003）。形态学反应者和无反应者的基线 SUVmax 和 SAM 值中位数差异有统计学意义（3.8 比 7.2，p=0.021；34 比 211，p=0.002），但基线 PET 参数和形态学反应均与 PFS 或 OS 无相关性。随访 SUVmax 和 SAM 以及∆SAM 被发现是预后因素。高随访 SUVmax 组患者的中位 PFS 和 OS 分别为 10.4 个月和 32 个月，而低随访 SUVmax 组患者的中位 PFS 为 14.7 个月，中位 OS 尚未达到（p=0.01 和 0.003）。高随访 SAM 和低∆SAM 的患者的中位 PFS 和 OS 分别为 9.4 个月和 32 个月，而其他患者的中位 PFS 为 14.7 个月，中位 OS 尚未达到（PFS 和 OS 均为 0.002）。
（18）F-FDG PET 成像可用于评估 mCRC 患者在肝转移切除术前接受化疗后的治疗反应，并预测临床结局。随访 SUVmax、随访 SAM 和∆SAM 是 PFS 和 OS 的显著预后因素。
