Exploring the potential of [11C]choline-PET/CT as a novel imaging biomarker for predicting early treatment response in prostate cancer

• Published in: Nuclear medicine communications Vol. 35; no. 1; p. 20
• Main Authors: Challapalli, Amarnath, Barwick, Tara, Tomasi, Giampaolo, O' Doherty, Michael, Contractor, Kaiyumars, Stewart, Simon, Al-Nahhas, Adil, Behan, Kevin, Coombes, Charles, Aboagye, Eric O, Mangar, Stephen
• Format: Journal Article
• Language: English
• Published: England 01.01.2014
• Subjects: Androgens - deficiency; Carbon Radioisotopes; Choline; Humans; Male; Multimodal Imaging; Neoadjuvant Therapy; Positron-Emission Tomography; Prostate-Specific Antigen - metabolism; Prostatic Neoplasms - diagnosis; Prostatic Neoplasms - metabolism; Prostatic Neoplasms - therapy; Time Factors; Tomography, X-Ray Computed; Treatment Outcome
• ISSN: 1473-5628
• DOI: 10.1097/MNM.0000000000000014

The aim of the study was to assess the effects of neoadjuvant androgen deprivation (NAD) and radical prostate radiotherapy with concurrent androgen deprivation (RT-CAD) on prostatic [C]choline kinetics and thus develop methodology for the use of [C]choline-PET/computed tomography (CT) as an early imaging biomarker. Ten patients with histologically confirmed prostate cancer underwent three sequential dynamic [C]choline-PET/CT pelvic scans: at baseline, after NAD and 4 months after RT-CAD. [C]Choline uptake was quantified using the average and maximum standardized uptake values at 60 min (SUV60,ave and SUV60,max), the tumour-to-muscle ratios (TMR60,max) and net irreversible retention of [C]choline at steady state (Kimod-pat). The combination of NAD and RT-CAD significantly decreased tumour [C]choline uptake (SUV60,ave, SUV60,max, TMR60,max or Kimod-pat) and prostate-specific antigen (PSA) levels (analysis of variance, P<0.001 for all variables). Although the magnitude of reduction in the variables was larger after NAD, there was a smaller additional reduction after RT-CAD. A wide range of reduction in tumour SUV60,ave (38-83.7%) and SUV60,max (22.2-85.3%) was seen with combined NAD and RT-CAD despite patients universally achieving PSA suppression (narrow range of 93.5-99.7%). There was good association between baseline SUV60,max and initial PSA levels (Pearson's r=0.7, P=0.04). The reduction in tumour SUV60,ave after NAD was associated with PSA reduction (r=0.7, P=0.04). This association occurred despite the larger reduction in PSA (94%) compared with SUV60,ave (58%). This feasibility study shows that [C]choline-PET/CT detects metabolic changes within tumours following NAD and RT-CAD to the prostate. A differential reduction in [C]choline uptake despite a global reduction in PSA following NAD and RT-CAD could provide prognostic information and warrants further evaluation as an imaging biomarker in this setting.