Use of [11C]choline PET-CT as a noninvasive method for detecting pelvic lymph node status from prostate cancer and relationship with choline kinase expression.

PURPOSE To evaluate the accuracy and biological basis for [(11)C]choline-PET-CT in the nodal staging of high risk localized prostate cancer patients. EXPERIMENTAL DESIGN Twenty-eight patients underwent dynamic [(11)C]choline-PET-CT of the pelvis and lower abdomen prior to extended laparoscopic pelvic lymph node dissection (eLPL). The sensitivity and specificity of [(11)C]choline PET, [(11)C]choline PET-CT, and MRI for nodal detection were calculated. Average and maximal standardized uptake values (SUV(ave), SUV(max)) were compared with choline kinase alpha (CHKα) and Ki67 immunohistochemistry scores. RESULTS Four hundred and six lymph nodes (LN), in 26 patients, were assessable. Twenty-seven (6.7%) involved pelvic nodes at eLPL were detected in 9 patients. Seventeen of the 27 involved nodes were subcentimeter. The sensitivity and specificity on a per nodal basis were 18.5% and 98.7%, 40.7% and 98.4%, and 51.9% and 98.4% for MRI, [(11)C]choline PET, and [(11)C]choline PET-CT, respectively. Sensitivity was higher for [(11)C]choline PET-CT compared with MRI (P = 0.007). A higher nodal detection rate, including subcentimeter nodes, was seen with [(11)C]choline PET-CT than MRI. Malignant lesions showed CHKα expression in both cytoplasm and nucleus. SUV(ave) and SUV(max) strongly correlated with CHKα staining intensity (r = 0.68, P < 0.0001 and r = 0.63, P = 0.0004, respectively). In contrast, Ki67 expression was generally low in all tumors. CONCLUSION This study establishes the relationship between [(11)C]choline PET-CT uptake with choline kinase expression in prostate cancer and allows it to be used as a noninvasive means of staging pelvic LNs, being highly specific and more sensitive than MRI, including the detection of subcentimeter disease.