Distance From the Root of the Splenic Artery to the Tumor as a Predictor of Para-Aortic Lymph Node Metastasis in Left-Sided Pancreatic Cancer.

[BACKGROUND/PURPOSE] Preoperative diagnosis of para-aortic lymph node (PALN) metastasis, particularly at station 16b1-a contraindication to pancreatic ductal adenocarcinoma (PDAC) resection-remains challenging. We investigated whether the distance from the root of the splenic artery (SPA) to the tumor (DST) is an objective predictor of PALN metastasis.

[METHODS] We retrospectively analyzed 130 patients who underwent distal pancreatectomy with PALN sampling for PDAC from 2012 to 2022. DST was measured using preoperative contrast-enhanced computed tomography. Receiver operating characteristic (ROC) analysis was performed, and clinicopathological factors were analyzed.

[RESULTS] PALN metastasis occurred in 7/130 (5.4%) patients. DST was significantly shorter in the PALN-positive group (median: 12.0 vs. 18.0 mm, p = 0.0001). ROC analysis indicated that the optimal cutoff value was 20.0 mm. In univariate and multivariate analyses, DST ≤ 20.0 mm was the only factor significantly associated with PALN metastasis (p = 0.0042 and p = 0.0093, respectively). All PALN-positive cases had DST ≤ 20.0 mm.

[CONCLUSIONS] DST is a clinically useful metric for predicting PALN metastasis in left-sided PDAC. In patients with DST > 20 mm, the likelihood of PALN involvement appeared extremely low, suggesting that intraoperative lymph node sampling may be omitted in selected patients.