Neural invasion (NI) is a hallmark feature of pancreatic ductal adenocarcinoma (PDAC), detected in up to 90% of intrapancreatic specimens. However, its binary presence alone has limited prognostic value. This study aimed to refine the prognostic assessment of NI in PDAC through detailed analysis of intrapancreatic NI (IPNI) and extrapancreatic perineural invasion (EPNI). Patients undergoing radical pancreatectomy for PDAC between July 2018 and December 2022 were enrolled and divided into training and internal test cohorts. IPNI was characterized using binary classification, enumeration of invaded nerve fascicles, and a novel NI severity score. EPNI was diagnosed preoperatively on CT. Cox regression analysis identified parameters associated with poor prognosis in the training cohort, which were subsequently validated in the internal test cohort. Among 195 patients, the overall detection rates of IPNI and EPNI were 97.4% and 42.0%, respectively. EPNI ( p = 0.01), pathological N2 stage ( p = 0.001), and NI severity score ( p = 0.04) were independently associated with shorter recurrence-free survival (RFS). For overall survival (OS), significant independent prognostic factors included increased age ( p = 0.009), EPNI ( p = 0.001), pathological N2 stage ( p = 0.003), poor tumor differentiation ( p = 0.022), and NI severity score ( p = 0.032). A NI severity score >10.5 was identified as the optimal cutoff for stratifying patients with different prognoses. Kaplan-Meier analysis demonstrated that NI severity scores >10.5 were associated with significantly poorer RFS (10 vs. 24 months, p = 0.001) and OS (19 vs. 27 months, p = 0.001). Similarly, EPNI was associated with shorter RFS (8 vs. 18.5 months, p = 0.001) and OS (17 vs. 25 months, p = 0.001). These findings were validated in the internal test cohort. Furthermore, NI severity scores >10.5 were significantly associated with early recurrence within 6 months post-pancreatectomy. EPNI and an NI severity score exceeding 10.5 are significant independent prognostic indicators in resectable PDAC and can serve as predictors of tumor recurrence following detailed pathological assessment. No. 2023-161-01, approved by the Ethics Committee of the Drum Tower Hospital, affiliated with Nanjing University Medical School.
Abaydulla et al. (2026) studied this question.