Published online Oct 28, 2017. doi: 10.4329/wjr.v9.i10.389
Peer-review started: February 15, 2017
First decision: May 7, 2017
Revised: May 26, 2017
Accepted: July 14, 2017
Article in press: July 17, 2017
Published online: October 28, 2017
Accurate nodal staging at the time of diagnosis of prostate cancer is crucial in determining a treatment plan for the patient. Pelvic lymph node dissection is the most reliable method, but is less than perfect and has increased morbidity. Cross sectional imaging with computed tomography (CT) and magnetic resonance imaging (MRI) are non-invasive tools that rely on morphologic characteristics such as shape and size of the lymph nodes. However, lymph nodes harboring metastatic disease may be normal sized and non-metastatic lymph nodes may be enlarged due to reactive hyperplasia. The optimal strategy for preoperative staging remains a topic of ongoing research. Advanced imaging techniques to assess lymph nodes in the setting of prostate cancer utilizing novel MRI contrast agents as well as positron emission tomography (PET) tracers have been developed and continue to be studied. Magnetic resonance lymphography utilizing ultra-small super paramagnetic iron oxide has shown promising results in detection of metastatic lymph nodes. Combining MRL with diffusion-weighted imaging may also improve accuracy. Considerable efforts are being made to develop effective PET radiotracers that are performed using hybrid-imaging systems that combine PET with CT or MRI. PET tracers that will be reviewed in this article include [18F]fluoro-D-glucose, sodium [18F]fluoride, [18F]choline, [11C]choline, prostate specific membrane antigen binding ligands, [11C]acetate, [18F]fluciclovine, gastrin releasing peptide receptor ligands, and androgen binding receptors. This article will review these advanced imaging modalities and ability to detect prostate cancer metastasis to lymph nodes. While more research is needed, these novel techniques to image lymph nodes in the setting of prostate cancer show a promising future in improving initial lymph node staging.
Core tip: Accurate nodal staging at time of prostate cancer diagnosis is crucial in determining a treatment plan for the patient. This review article highlights the newest imaging techniques that have been and are being developed for imaging of lymph nodes in the initial staging of prostate cancer. Magnetic resonance lymphography utilizing ultra-small super paramagnetic iron oxide has shown to detect metastatic disease in normal sized lymph nodes. Considerable efforts are being made in molecular imaging to develop effective positron emission tomography radiotracers that may be combined with computed tomography or magnetic resonance to detect prostate metastasis as well as potential therapeutic applications.