RT Journal Article SR Electronic T1 Radiation Treatment of Lymph Node Recurrence from Prostate Cancer: Is 11C-Choline PET/CT Predictive of Survival Outcomes? JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 1836 OP 1842 DO 10.2967/jnumed.115.163741 VO 56 IS 12 A1 Elena Incerti A1 Andrei Fodor A1 Paola Mapelli A1 Claudio Fiorino A1 Pierpaolo Alongi A1 Margarita Kirienko A1 Giampiero Giovacchini A1 Elena Busnardo A1 Luigi Gianolli A1 Nadia Di Muzio A1 Maria Picchio YR 2015 UL http://jnm.snmjournals.org/content/56/12/1836.abstract AB 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 11C-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. Methods: 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 11C-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. Results: The median follow-up was 20 mo (mean, 26 mo; range, 3–97 mo). 11C-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 cm3. 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. Conclusion: 11C-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.