Purpose: Accurate diagnosis of lateral lymph node metastasis is a major concern in rectal cancer. Metastasis is not only a poor prognostic factor, but it can also affect decisions about treatment options, such as preoperative chemoradiotherapy and lateral lymph node dissection. The purpose of this review was to assess the diagnostic performance of magnetic resonance imaging and computed tomography for lateral lymph node metastasis in rectal cancer.
Methods: A literature search was systematically performed using PubMed, Scopus, and the Cochrane Central Register of Controlled Trials. All studies in which preoperative magnetic resonance imaging or computed tomography findings involving the lateral lymph nodes were compared with pathologic findings were included. Two authors independently assessed the literature and extracted the data, and any disagreement was resolved by discussion. Pooled sensitivity, specificity, and diagnostic odds ratios were estimated using hierarchical summary receiver-operating characteristic curve analysis. The methodologic quality of the included studies was assessed using the QUADAS-2 tool.
Results: Nine studies were included in the meta-analysis of magnetic resonance imaging. The pooled sensitivity, specificity, and diagnostic odds ratio for magnetic resonance imaging were 0.72 [95% confidence interval (CI) 0.66-0.78], 0.80 (95% CI 0.73-0.85), and 10.2 (95% CI 6.4-16.3), respectively. Pooled analyses were not conducted for computed tomography because of the small number of studies (only three could be identified) and the wide range in diagnostic performance between these studies.
Conclusions: Magnetic resonance imaging was useful to diagnose lateral lymph node metastasis in rectal cancer, especially due to high specificity.
Keywords: Diagnostic accuracy; Lateral lymph node; Magnetic resonance imaging; Rectal neoplasms; Systematic review.