Introduction and objectives: We aimed to evaluate the diagnostic accuracy of preoperative 11 C-Choline Positron Emission Tomography-Computed Tomography (PET-CT) to detect the presence of lymph node metastases (LNM) in different subsets of Prostate Cancer (PCa) patients, in comparison with morphological imaging (MI), to identify which cases could benefit from PET-CT disease staging before surgery.
Materials and methods: We retrospectively analyzed data from 262 (14.7%) out of 1785 consecutive PCa patients at clinical intermediate (IR) or high risk (HR) according to D'Amico risk classification, who underwent radical prostatectomy with pelvic lymph node dissection between January 2006 and January 2017 at single tertiary Centre, referred to preoperative 11 C-Choline PET CT and MI before surgery. Among HR patients we selected a very high risk (VHR) patients according to multiple VHR features evidenced by NCCN. In each risk group we examined the rates of true positive, false positive, true negative and false negative concerning the detection of LNM on patient-based analysis, for both MI and PET CT. The final pathologic examination was considered as the referring standard. Then, we calculated in each risk category, the sensitivity, specificity, accuracy, positive predictive value, negative predictive value and the area under the curve (AUC) of MI and PET/CT.
Results: Overall, 107 (40.8%) and 155 (59.1%) individuals were classified as IR and HR, respectively. Among the HR group, 18 (6.9%) had a clinical stage ≥ T3a, 126 (48%) had clinical Gleason score ≥8, 40 (15.3%) had ≥5 cores with Gleason score ≥8 and 3 (2.0%) had three features of clinically HR disease. Overall, 49 men (18.7%) revealed LNM at final pathology. Among HR patients we identified 28 individuals with VHR features. Table 1 and 2 show the diagnostic performance of 11 C-Choline PET-CT and MI in terms of detection of LNM. Considering overall HR patients, sensitivity and specificity were 50% and 21.2 % for PET CT and 76.1% and 98.1% for MI, with AUC of 0.64 for both imaging tools. Among HR patients, considering the subgroup of VHR individuals the sensitivity, specificity and AUC of PET CT and MI were 71.4% vs. 25%, 92.4% vs. 79.3% and 0.86 vs. 0.69, respectively.
Conclusions: In the subgroup of PCa patients with multiple high risk features (VHR), preoperative 11 C-Choline PET CT may be considered a useful tool aimed to detect LNM, since it revealed higher diagnostic accuracy as compared to MI.
