Lymph node detection in prostate cancer is challenging and critical for determining treatment policy. Choline PET/CT (positron emission tomography/computed tomography) and magnetic resonance imaging (MRI) have been used for the evaluation of lymph node metastasis in patients with prostate cancer for the past decade. However, only limited patients underwent direct comparison studies.

Metastasis is a pathogenic agent's spread from an initial or primary site to a different or secondary place within the host's body it is typically spoken of as such spread by a cancerous tumor. The newly pathological sites, then, are metastases. It is generally distinguished from cancer invasion, which is the direct extension and penetration by cancer cells into neighboring tissues.  

Lymph Node

To evaluate the diagnostic performance of choline PET/CT compared with MRI imaging for detecting lymph node metastases in prostate cancer patients. Relevant English-language articles published before February 2018 were searched in PubMed database, Embase database, and Cochrane Library databases search using the keywords: (Prostate Neoplasm OR Prostate Cancer OR prostate carcinoma) and (Lymph Node) and (PET/CT OR positron emission tomography/computed tomography) and (choline or 2-hydroxy-N, N,N-trimethylethanaminium) and (magnetic resonance imaging OR MRI).

PET/CT

Articles were included that directly compare the diagnostic performance and clinical utility of choline PET/CT and MRI for detecting lymph node metastases in prostate cancer patients. Study quality was assessed with QUADAS criteria.

Analyses were performed on a per patient and a per node basis. The pooled sensitivity, specificity, diagnostic odds ratio (DOR), positive likelihood ratio (LR+), and negative likelihood ratio (LR-) were calculated using Meta-Disc 1.4 software. Summary receiver-operating characteristic (SROC) curves constructed. A total of 362 patients from 8 studies involving fulfilled the inclusion criteria.

On patient-based analysis, the pooled sensitivity, specificity, and DOR with a 95% confidence interval (CI) for choline PET/CT imaging were 0.59 (95%CI, 0.50-0.67), 0.92 (95%CI, 0.87-0.96), 17.37 (95%CI, 4.42-68.33), and for MRI imaging, they were 0.52 (95%CI, 0.44-0.61), 0.87 (95%CI, 0.81-0.92), 6.05 (95%CI, 3.09-11.85), respectively.

On node-based, the corresponding values for choline PET/CT imaging were 0.51 (95%CI, 0.46-0.57), 0.99 (95%CI, 0.98-0.99), 65.55 (95%CI, 23.55-182.45), and for MRI imaging, they were 0.39 (95%CI, 0.34-0.44), 0.97 (95%CI, 0.96-0.97), 15.86 (95%CI, 8.96-28.05), respectively. Choline PET/CT performed better than MRI imaging in evaluating the lymph nodes metastasis of prostate cancer patients and had the potential to be broadly applied in clinical practice.