Gastric Cancer Staging: Is It Time for Magnetic Resonance Imaging?

Abstract

Gastric cancer (GC) is a common cancer worldwide. Its incidence and mortality vary depending on geographic area, with the highest rates in Asian countries, particularly in China, Japan, and South Korea. Accurate imaging staging has become crucial for the application of various treatment strategies, especially for curative treatments in early stages. Unfortunately, most GCs are still diagnosed at an advanced stage, with the peritoneum (61-80%), distant lymph nodes (44-50%), and liver (26-38%) as the most common metastatic locations. Metastatic disease is limited to the peritoneum in 58% of cases; in nonperitoneal distant metastases, the most involved GC metastasization site is the liver (82%). The eighth edition of the tumor-node-metastasis staging system is the most commonly used system for determining GC prognosis. Endoscopic ultrasonography, computed tomography, and 18-fluorideoxyglucose positron emission tomography are historically the most accurate imaging techniques for GC staging. However, studies have recently shown renewed interest in magnetic resonance imaging (MRI) as a useful tool in GC staging, especially for distant metastasis assessment. The technical improvement of diffusion-weighted imaging and the increasing use of hepatobiliary contrast agents have been shown to increase the diagnostic performance of MRI, particularly for detecting peritoneal and liver metastasis. However, no principal oncological guidelines have included the use of MRI as a first-line technique for distant metastasis evaluation during the GC staging process, such as the National Comprehensive Cancer Network Guidelines. This review analyzed the role of the principal imaging techniques in GC diagnosis and staging, focusing on the potential role of MRI, especially for assessing peritoneal and liver metastases.

Keywords: diagnosis; gastric cancer; magnetic resonance imaging; treatment.

Figure 1

A 62-year-old man complaining of dysphagia and epigastric pain with advanced stage gastric cancer. Axial (A) and coronal reformatted (B) contrast-enhanced computed tomography (CT) images showed a circumferential soft-tissue thickening involving the gastroesophageal junction and the cardia of the stomach (white arrows) invading the serosa layer (T-stage: T4a). Multiple (3) enlarged lymph nodes were appreciable in the aortocaval (C) (white arrow) and celiac (D) (arrowheads) region (N-stage: N2). Axial contrast-enhanced CT scan (E) did not demonstrate liver metastasis, whereas the axial ¹⁸FDG positron emission tomography computed tomography (PET-CT) image (F) revealed two metabolically active lesions with the same uptake value (SUVmax 4.7) located in the VIII hepatic segment (dotted arrows), consistent with M1 disease. The subsequent axial gadoxetic acid-enhanced magnetic resonance imaging, performed using diffusion-weighted imaging (G) and during the hepatobiliary phase (H), confirmed only one metastatic lesion (white arrow).

Figure 2

Axial contrast-enhanced computed tomography (CT) image (A), in the same patient, did not show metastatic lesions at this liver level. The axial gadoxetic acid-enhanced magnetic resonance imaging, performed using diffusion-weighted imaging (B) and during the hepatobiliary phase (C), demonstrated a small liver metastasis in the liver segment VIII (white arrows). After six months, the axial contrast-enhanced CT image (D) confirmed the metastatic liver lesion (white arrow), enlarged.