Selection of Lymph Node–Positive Cases Based on Perirectal and Lateral Pelvic Lymph Nodes Using Magnetic Resonance Imaging: Study of the Japanese Society for Cancer of the Colon and Rectum

• Published in: Annals of surgical oncology Vol. 23; no. 4; pp. 1187 - 1194
• Main Authors: Ogawa, Shimpei, Hida, Jin-ichi, Ike, Hideyuki, Kinugasa, Tetsushi, Ota, Mitsuyoshi, Shinto, Eiji, Itabashi, Michio, Kameoka, Shingo, Sugihara, Kenichi
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.04.2016; Springer Nature B.V
• Subjects: Adolescent; Adult; Aged; Aged, 80 and over; Colonic Neoplasms - diagnostic imaging; Colonic Neoplasms - pathology; Colonic Neoplasms - surgery; Colorectal Cancer; Female; Follow-Up Studies; Humans; Lymph Nodes - diagnostic imaging; Lymph Nodes - pathology; Lymph Nodes - surgery; Lymphatic Metastasis; Magnetic Resonance Imaging - methods; Male; Medicine; Medicine & Public Health; Middle Aged; Neoplasm Grading; Neoplasm Invasiveness; Neoplasm Staging; Oncology; Pelvic Neoplasms - diagnostic imaging; Pelvic Neoplasms - secondary; Pelvic Neoplasms - surgery; Prognosis; Rectal Neoplasms - diagnostic imaging; Rectal Neoplasms - pathology; Rectal Neoplasms - surgery; Societies, Medical; Surgery; Surgical Oncology; Young Adult; Diagnostic Performance; Positive Predictive Value; Total Mesorectal Excision; Rectal Cancer; Negative Predictive Value
• ISSN: 1068-9265; 1534-4681
• DOI: 10.1245/s10434-015-5021-2

Purpose To investigate the optimum cutoff for lymph node size to identify cases positive for perirectal lymph node (PRLN) and lateral lymph node (LPLN) metastasis of lower rectal cancer on magnetic resonance imaging (MRI). Methods The subjects were 449 patients who underwent preoperative MRI. Mesorectal excision was performed in all patients (combined with lateral pelvic lymph node [LN] dissection in 324) between 2004 and 2013 at 6 institutes. Cases were classified as cN positive and cN negative on the basis of the short axis of the largest LN being greater than or equal to a cutoff or less than a cutoff, respectively. PRLN and LPLN diagnoses using 5 and 10 mm cutoffs were compared with histologic diagnoses. Of the 449 patients, 55 received preoperative chemoradiotherapy. MRI was only performed after this therapy in all of these patients. Results For PRLNs, 5 and 10 mm cutoffs gave area under the curve (AUC) values of 0.6364 and 0.5794, respectively. The 5 mm cutoff gave a significantly higher AUC value ( P  = 0.0152), with an accuracy of 63.7 %, sensitivity of 72.6 %, and specificity of 54.7 %. For right LPLNs, the respective AUC values were 0.7418 and 0.6326 ( P  = 0.0034), and the variables (5 mm cutoff) were 77.6, 68.6, and 79.7 %. For left LPLNs, AUC values were 0.7593 and 0.6559, respectively ( P  = 0.0057), and the variables (5 mm cutoff) were 79.3, 70.8, and 81.0 %. Conclusions Identification of LN-positive cases on the basis of PRLN and LPLN sizes was superior at a short-axis 5 mm cutoff. Size-based diagnosis of LN metastasis is simple and useful, but further investigation is needed to clarify whether it is superior to diagnosis based on morphology, such as shape, border, and signal intensity.