title: Locally advanced prostate cancer: three-dimensional magnetic resonance spectroscopy to monitor prostate response to therapy.
abstract: OBJECTIVE
  To correlate results of three-dimensional magnetic resonance spectroscopic imaging (MRSI) with prostate-specific antigen (PSA) levels and time since external beam irradiation (EBRT) in patients treated with long-term hormone therapy (HT) and EBRT for locally advanced disease to verify successful treatment by documenting the achievement of metabolic atrophy (MA).
  
  
  METHODS
  Between 2006 and 2008, 109 patients were consecutively enrolled. MA was assessed by choline and citrate peak area-to-noise-ratio <5:1. Cancerous metabolism (CM) was defined by choline-to-creatine ratio >1.5:1 or choline signal-to-noise-ratio >5:1. To test the strength of association between MRSI results and the time elapsed since EBRT (TEFRT), PSA levels, Gleason score (GS), and stage, logistic regression (LR) was performed. p value <0.05 was statistically significant. The patients' outcomes were verified in 2011.
  
  
  RESULTS
  MRSI documented MA in 84 of 109 and CM in 25 of 109 cases. LR showed that age, GS, stage, and initial and recent PSA had no significant impact on MRSI results which were significantly related to PSA values at the time of MRSI and to TEFRT. Patients were divided into three groups according to TEFRT: <1 year, 1-2 years, and >2 years. MA was detected in 54.1% of patients of group 1, 88.9% of group 2, and in 94.5% of group 3 (100% when PSA nadir was reached). CM was detected in 50% of patients with reached PSA nadir in group 1. Local relapse was found in 3 patients previously showing CM at long TEFRT.
  
  
  CONCLUSIONS
  MA detection, indicative of successful treatment because growth of normal or abnormal cells cannot occur without metabolism, increases with decreasing PSA levels and increasing time on HT after EBRT. This supports long-term HT in advanced prostate cancer. Larger study series are needed to assess whether MRSI could predict local relapse by detecting CM at long TEFRT.
authors.affiliation: Department of Bioimaging and Radiological Sciences, Section of Radiology, Università Cattolica del Sacro Cuore di Roma, Milan, Italy. alvalentini@rm.unicatt.it
authors.forename: Anna Lia
authors.initials: AL
authors.lastname: Valentini
authors.forename: Benedetta
authors.initials: B
authors.lastname: Gui
authors.forename: Giuseppe Roberto
authors.initials: GR
authors.lastname: D'Agostino
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Mattiucci
authors.forename: Valeria
authors.initials: V
authors.lastname: Clementi
authors.forename: Ippolita Valentina
authors.initials: IV
authors.lastname: Di Molfetta
authors.forename: Pierluigi
authors.initials: P
authors.lastname: Bonomo
authors.forename: Giovanna
authors.initials: G
authors.lastname: Mantini
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D018931:Antineoplastic Agents, Hormonal / Q000627:therapeutic use; D002794:Choline / Q000378:metabolism; D003131:Combined Modality Therapy / Q000379:methods; D003401:Creatine / Q000378:metabolism; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009364:Neoplasm Recurrence, Local / Q000097:blood; D009367:Neoplasm Staging; D011446:Prospective Studies; D017430:Prostate-Specific Antigen / Q000378:metabolism*; D011471:Prostatic Neoplasms / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology / Q000532:radiotherapy*; D013997:Time Factors
chemical_list: D018931:Antineoplastic Agents, Hormonal; D017430:Prostate-Specific Antigen; D003401:Creatine; D002794:Choline