Long-term survival in patients with pancreatic ductal adenocarcinoma.

Background: Long-term survival (LTS) is uncommon for patients with pancreatic ductal adenocarcinoma (PDAC). We sought to identify factors that predict 10-year, LTS after resection of PDAC.

Methods: We identified all patients with PDAC who underwent resection at UCLA after 1990 and included all patients eligible for observed LTS (1/1/1990-12/31/2004). An independent pathologist reconfirmed the diagnosis of PDAC in patients with LTS. Logistic regression was used to predict LTS on the basis of patient and tumor characteristics.

Results: Of 173 included patients, 53% were male, median age at diagnosis was 66 years, and median survival was 23 months. The rate of observed LTS was 12.1% (n = 21). Age, sex, number of lymph nodes evaluated, margin status, lymphovascular invasion, and adjuvant chemotherapy and radiation were not associated with LTS. The following were associated with LTS on bivariate analysis: low AJCC stage (Ia, Ib, IIa) (P = .034), negative lymph node status (P = .034), low grade (well-, moderately-differentiated) (P = .001), and absence of perineural invasion (P = .019). Only low grade (odds ratio 7.17, P = .012) and absent perineural invasion (odds ratio 3.28, P = .036) were independently associated with increased odds of LTS. Our multivariate model demonstrated good discriminatory power for LTS, as indicated by a c-statistic of 0.7856.

Conclusion: Absence of perineural invasion and low tumor grade were associated with greater likelihood of LTS. Understanding the tumor biology of LTS may provide critical insight into a disease that is typically marked by aggressive behavior and limited survival.