Travaini Laura L, Zampino Maria G, Colandrea Marzia, Ferrari Mahila E, Gilardi Laura, Leonardi Maria C, Santoro Luigi, Orecchia Roberto, Grana Chiara M
European Institute of Oncology, Via Ripamonti, 435 20141, Milan, Italy.
Ecancermedicalscience. 2016 Mar 29;10:629. doi: 10.3332/ecancer.2016.629. eCollection 2016.
The aim of the present study is to evaluate the accuracy of Positron Emission Tomography/Computed Tomography (PET/CT) with Fluorodeoxyglucose ([18F]FDG) to predict treatment response in patients with locally advanced rectal cancer (LARC) during neoadjuvant chemoradiotherapy.
Forty-one LARC patients performed [18F]FDG-PET/CT at baseline (PET0). All patients received continuous capecitabine concomitant to radiotherapy on the pelvis, followed by intermittent capecitabine until two weeks before curative surgery. [18F]FDG-PET/CT was also carried out at 40 Gy-time (PET1) and at the end of neoadjuvant therapy (PET2). PET imaging was analysed semi-quantitatively through the measurement of maximal standardised uptake value (SUVmax) and the tumour volume (TV). Histology was expressed through pTNM and Dworak tumor regression grading. Patients were categorised into responder (downstaging or downsizing) and non-responder (stable or progressive disease by comparison pretreatment parameters with clinical/pathological characteristics posttreatment/after surgery). Logistic regression was used to evaluate SUVmax and TV absolute and percent reduction as predictors of response rate using gender, age, and CEA as covariates. Progression-free survival (PFS) and overall survival (OS) were estimated by the Kaplan-Meier method. Survivals were compared by the Log-Rank test.
Twenty-three responders (9 ypCR, 14 with downstaged disease) and 18 non-responders showed differences in terms of both early and posttreatment SUVmax percent reduction (median comparison: responder = 63.2%, non-responder = 44.2%, p = 0.04 and responder = 76.9%, non-responder = 61.6%, p = 0.06 respectively). The best predictive cut-offs of treatment response for early and posttreatment SUVmax percent reduction were ≥57% and ≥66% from baseline (p = 0.02 and p = 0.01 respectively).
[18F]FDG-PET/CT is a reliable technique for evaluating therapy response during neoadjuvant treatment in LARC, through a categorical classification of the SUV max reduction during treatment.
本研究旨在评估氟脱氧葡萄糖（[18F]FDG）正电子发射断层扫描/计算机断层扫描（PET/CT）预测局部晚期直肠癌（LARC）患者新辅助放化疗期间治疗反应的准确性。
41例LARC患者在基线时（PET0）进行了[18F]FDG-PET/CT检查。所有患者在盆腔放疗期间持续接受卡培他滨治疗，随后间歇性接受卡培他滨治疗直至根治性手术前两周。在40 Gy时（PET1）和新辅助治疗结束时（PET2）也进行了[18F]FDG-PET/CT检查。通过测量最大标准化摄取值（SUVmax）和肿瘤体积（TV）对PET图像进行半定量分析。组织学通过pTNM和Dworak肿瘤消退分级表示。根据治疗前参数与治疗后/手术后的临床/病理特征比较，将患者分为反应者（降期或缩小）和无反应者（疾病稳定或进展）。使用逻辑回归评估SUVmax和TV的绝对及百分比降低作为反应率的预测指标，将性别、年龄和癌胚抗原（CEA）作为协变量。采用Kaplan-Meier法估计无进展生存期（PFS）和总生存期（OS）。通过对数秩检验比较生存期。
23例反应者（9例达到ypCR，14例疾病降期）和18例无反应者在治疗早期和治疗后SUVmax百分比降低方面均存在差异（中位数比较：反应者=63.2%，无反应者=44.2%，p = 0.04；反应者=76.9%，无反应者=61.6%，p = 0.06）。治疗早期和治疗后SUVmax百分比降低对治疗反应的最佳预测临界值分别为相对于基线降低≥57%和≥66%（分别为p = 0.02和p = 0.01）。
[18F]FDG-PET/CT是一种可靠的技术，可通过对治疗期间SUV max降低进行分类来评估LARC新辅助治疗期间的治疗反应。
