Department of Nuclear Medicine, IRCCS San Raffaele Scientific Institute, Milan, Italy.
Department of Radiotherapy, IRCCS San Raffaele Scientific Institute, Milan, Italy.
J Nucl Med. 2015 Dec;56(12):1836-42. doi: 10.2967/jnumed.115.163741. Epub 2015 Sep 24.
PET/CT is a valuable tool to detect lymph node (LN) metastases in patients with biochemical failure after primary treatment for prostate cancer (PCa). The aim was to assess the predictive role of imaging parameters derived by (11)C-choline PET/CT on survival outcomes-overall survival, locoregional relapse-free survival, clinical relapse-free survival (cRFS), and biochemical relapse-free survival (bRFS)-in patients treated with helical tomotherapy (HTT) for LN recurrence.
This retrospective study included 68 patients affected by PCa (mean age, 68 y; age range, 51-81 y) with biochemical recurrence after primary treatment (median prostate-specific antigen values obtained at the time of PET/CT scan, 2.42 ng/mL; range, 0.61-27.56 ng/mL) who underwent (11)C-choline PET/CT from January 2005 to January 2013 and were treated with HTT in correspondence of the pathologic choline LN uptake. PET-derived parameters, including maximum/mean standardized uptake value (SUVmax and SUVmean, respectively) and metabolic tumor volume (MTV) with a threshold of 40%, 50%, and 60% were calculated. The best cutoff values of PET-derived parameters discriminating between patients with and without relapse, after treatment guided by PET, were assessed by receiver-operating-characteristic (ROC) curve analysis. Univariate and multivariate Cox regression analysis including the most predictive PET-derived parameters and survival outcomes were performed.
The median follow-up was 20 mo (mean, 26 mo; range, 3-97 mo). (11)C-choline PET/CT showed pathologic LN uptake in 4 patients at the pelvic level, in 5 at the abdominal level, in 13 at both the pelvic and the abdominal level, and in 46 at the abdominal or pelvic or other sites. The 2-y overall survival, locoregional relapse-free survival, cRFS, and bRFS were 87%, 91%, 51%, and 40%, respectively. On the basis of ROC curves, the most discriminative cutoff value for MTV values was an MTV threshold of 60% (MTV60) of greater than 0.64 cm(3). No significant cutoff values were found for SUVmax or SUVmean at univariate analysis, whereas MTV60 was confirmed as an independent predictor in multivariate analysis and significantly correlated with bRFS and cRFS. MTV60 and extrapelvic disease well predict the risk of cRFS.
(11)C-choline PET/CT performed as a guide for HTT on LN recurrence is predictive of survival. In particular, MTV60 and extrapelvic disease were the best predictors of tumor response for bRFS and cRFS in PCa patients with LN recurrence after primary treatment. This information may be useful in emerging treatment strategies.
正电子发射断层扫描/计算机断层扫描（PET/CT）是一种有价值的工具，可用于检测前列腺癌（PCa）初次治疗后生化失败患者的淋巴结（LN）转移。本研究旨在评估（11）C-胆碱 PET/CT 衍生的影像学参数对接受螺旋断层放疗（HTT）治疗 LN 复发患者的生存结局（总生存、局部区域无复发生存、临床无复发生存[cRFS]和生化无复发生存[bRFS]）的预测作用。
本回顾性研究纳入了 68 例前列腺特异性抗原（PSA）水平在初次治疗后生化复发的 PCa 患者（平均年龄 68 岁；年龄范围 51-81 岁），这些患者在 PET/CT 扫描时的中位 PSA 值为 2.42ng/ml（范围 0.61-27.56ng/ml），他们在 2005 年 1 月至 2013 年 1 月期间接受了（11）C-胆碱 PET/CT 检查，并在病理胆碱 LN 摄取部位接受了 HTT 治疗。计算了最大/平均标准化摄取值（SUVmax 和 SUVmean）和代谢肿瘤体积（MTV）等 PET 衍生参数，阈值分别为 40%、50%和 60%。通过接受者操作特征（ROC）曲线分析评估了 PET 衍生参数区分有和无复发患者的最佳截断值。使用单变量和多变量 Cox 回归分析包括最具预测性的 PET 衍生参数和生存结局。
中位随访时间为 20 个月（平均 26 个月；范围 3-97 个月）。（11）C-胆碱 PET/CT 显示 4 例患者盆腔水平有病理 LN 摄取，5 例患者腹腔水平有摄取，13 例患者盆腔和腹腔水平均有摄取，46 例患者腹部、盆腔或其他部位有摄取。2 年总生存、局部区域无复发生存、cRFS 和 bRFS 分别为 87%、91%、51%和 40%。基于 ROC 曲线，MTV 值的最佳截断值为 60%（MTV60）大于 0.64cm³。SUVmax 或 SUVmean 在单变量分析中没有显著的截断值，而 MTV60 在多变量分析中被证实是独立的预测因子，并与 bRFS 和 cRFS 显著相关。MTV60 和盆腔外疾病可很好地预测 cRFS 的风险。
（11）C-胆碱 PET/CT 指导 HTT 治疗 LN 复发可预测生存。特别是，在 PCa 患者 LN 复发后接受 HTT 治疗时，MTV60 和盆腔外疾病是 bRFS 和 cRFS 的最佳肿瘤反应预测因子。这些信息可能对新出现的治疗策略有用。
