title: Radiation Treatment of Lymph Node Recurrence from Prostate Cancer: Is 11C-Choline PET/CT Predictive of Survival Outcomes?
abstract: 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.
  
  
  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 (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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  (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.
authors.affiliation: Department of Nuclear Medicine, IRCCS San Raffaele Scientific Institute, Milan, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Incerti
authors.affiliation: Department of Radiotherapy, IRCCS San Raffaele Scientific Institute, Milan, Italy.
authors.forename: Andrei
authors.initials: A
authors.lastname: Fodor
authors.affiliation: Department of Nuclear Medicine, IRCCS San Raffaele Scientific Institute, Milan, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Mapelli
authors.affiliation: Department of Medical Physics, IRCCS San Raffaele Scientific Institute, Milan, Italy.
authors.forename: Claudio
authors.initials: C
authors.lastname: Fiorino
authors.affiliation: Department of Nuclear Medicine, IRCCS San Raffaele Scientific Institute, Milan, Italy.
authors.forename: Pierpaolo
authors.initials: P
authors.lastname: Alongi
authors.affiliation: University of Milano-Bicocca, Milan, Italy; and.
authors.forename: Margarita
authors.initials: M
authors.lastname: Kirienko
authors.affiliation: Department of Radiology and Nuclear Medicine, Stadtspital Triemli, Zurich, Switzerland.
authors.forename: Giampiero
authors.initials: G
authors.lastname: Giovacchini
authors.affiliation: Department of Nuclear Medicine, IRCCS San Raffaele Scientific Institute, Milan, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Busnardo
authors.affiliation: Department of Nuclear Medicine, IRCCS San Raffaele Scientific Institute, Milan, Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Gianolli
authors.affiliation: Department of Radiotherapy, IRCCS San Raffaele Scientific Institute, Milan, Italy.
authors.forename: Nadia
authors.initials: N
authors.lastname: Di Muzio
authors.affiliation: Department of Nuclear Medicine, IRCCS San Raffaele Scientific Institute, Milan, Italy picchio.maria@hsr.it.
authors.forename: Maria
authors.initials: M
authors.lastname: Picchio
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002250:Carbon Radioisotopes; D002794:Choline; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008207:Lymphatic Metastasis / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D049268:Positron-Emission Tomography / Q000379:methods*; D011237:Predictive Value of Tests; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D012372:ROC Curve; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D016019:Survival Analysis; D036542:Tomography, Spiral Computed; D016896:Treatment Outcome
chemical_list: D002250:Carbon Radioisotopes; D019275:Radiopharmaceuticals; D002794:Choline
keywords: 11C-choline PET/CT; imaging parameters; lymph node recurrence; prostate cancer; survival outcomes