Intraindividual comparison of 68Ga-DOTATATE PET/CT vs. 11C-choline PET/CT in patients with prostate cancer in biochemical relapse: In vivo evaluation of the expression of somatostatin receptors

Abstract

BACKGROUND AND OBJECTIVES: To prospectively compare the detection rate of 68Ga-DOTATATE versus 11C-choline PET/CT in patients with prostate cancer in biochemical relapse, and to evaluate somatostatin receptor expression in vivo to plan targeted therapies (177Lu-DOTATATE). MATERIAL AND METHODS: We prospectively analysed 64 patients with biochemical relapse (median PSA: 4.25 ng/mL). A PET/CT was performed with 11C-choline, and another with 68Ga-DOTATATE. The SUVmax was measured in all lesions. The correlative images, histopathology and/or clinical and biochemical follow-up were taken as the reference standard. RESULTS: The overall detection rate per patient was 48.43% for 68Ga-DOTATATE and 46.87% for 11C-choline. The results were concordant in 53 cases (82.81%). The maximum SUV of 11C-choline was significantly higher than that of 68Ga-DOTATATE for all the concordant lesions (n=130): 6.17 (1.7-15.5) versus 4.38 (1.37-26.7), median (range) for each radiotracer, respectively (p < .0001). The sensitivity and specificity values per patient were the same for both techniques: 0.82 (0.65-0.93) and 0.9 (0.73-0.98), respectively. Although the difference was not significant, the sensitivity was lower in patients with lower PSA levels: 0.63 vs. 0.89; p=.13. A significant correlation was found between the SUVmax of both tracers (r = 0.41, n = 130, p <.0001). CONCLUSIONS: 68Ga-DOTATATE PET/CT and 11C-choline PET/CT seem to have a high capacity to detect pathological lesions in the assessment of patients with prostate cancer with biochemical relapse. Further studies are required to test the potential complementary value of these PET/CT techniques, and to evaluate the potential role of 8Ga-DOTATATE for planning somostatin receptor-mediated therapies (177Lu-DOTATATE).