Predictive Value of Preoperative Computed Tomography for Lateral Pelvic Lymph Node Metastasis in Rectal Cancer

• Published in: SN comprehensive clinical medicine 2023-06, Vol.5 (1), Article 161
• Main Authors: Emoto, Shin, Homma, Shigenori, Yoshida, Tadashi, Ichikawa, Nobuki, Matsui, Hiroki, Tani, Michio, Fujima, Noriyuki, Taketomi, Akinobu
• Format: Article
• Language: English
• Subjects: Medicine; Medicine & Public Health; Original Paper; Topical Collection on Imaging
• ISSN: 2523-8973; 2523-8973
• DOI: 10.1007/s42399-023-01490-4

Background Pretreatment diagnosis of lateral pelvic lymph node (LPLN) metastasis is critical in deciding the therapeutic strategy for locally advanced rectal cancer. We aimed to investigate computed tomography (CT) cut-off values and diagnostic and prognostic implications of lateral pelvic lymph node metastasis (LPLNM) in rectal cancer. Methods Patients with rectal cancer ( n  = 126) who underwent primary tumor resection between April 2010 and July 2020 were included. CT findings and diagnostic accuracies were analyzed. Results In this study, the cut-off values of 7 mm for long-axis diameter and 5 mm for short-axis diameter were selected. At cut-offs of 7 mm for long-axis diameter, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 88.9%, 93.8%, 34.8%, 99.6%, and 93.7%, respectively. At cut-offs of 5 mm for short-axis diameter, the values of sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 88.9%, 90.9%, 26.7%, 99.5%, and 90.9%, respectively. CT findings of ≥ 7 mm for long-axis diameter (odds ratio, 68.0) and ≥ 5 mm for short-axis diameter (odds ratio, 38.4) were strong predictors of LPLNM. In the subgroup analysis of patients with enlarged LPLN (≥ 7 mm), higher recurrence-free survival and lower local recurrence rates were found in patients who had LPLN dissection (5-year recurrence-free survival: 100% vs. 58.3%, p  = 0.17 with LPLN dissection; and 5-year local recurrence: 0% vs. 31.4%, p  = 0.27, without LPLN dissection). Conclusion Pretreatment CT at cut-off values of 7 mm for the long-axis diameter and 5 mm for the short-axis diameter of LPLN provides sufficient diagnostic accuracy for LPLNM.