['Serum levels of CA19-9 have been shown to correlate with both recurrence and survival in patients with pancreatic cancer. However, little is known about the prognosis for patients with undetectable levels of serum CA19-9.', 'One hundred twenty-nine patients with pancreatic cancer who underwent preoperative assessment of serum CA19-9 followed by resection with curative intent between 1990 and 2002 were retrospectively analyzed. Data collected included preoperative serum CA19-9 level (U/mL), age, pathologic staging, and survival. Data were analyzed with the SAS system according to four distinct preoperative serum CA19-9 levels: undetectable, normal (<37), 38-200, and >200 U/mL.', 'Serum CA19-9 levels ranged from undetectable to 16,300 U/mL. Stage III/IV disease accounted for 86%, 67%, 59%, and 53% of patients in the four CA19-9 groups. The overall median and 5-year survivals were 19 months and 11%, respectively. Survival was similar between nonsecretors and those with normal CA 19-9 levels. However, both groups had statistically significant prolonged survival compared with the two groups with elevated CA 19-9 levels (P =.003). The only factors that were significant on univariate and multivariate analysis for overall survival were lymph node positivity (P =.015 and.002) and CA 19-9 grouping (P =.003 and P <.0001). Although this group of patients presented with predominately advanced-stage disease, their overall survival was superior.'] Do undetectable preoperative levels of serum CA 19-9 correlate with improved survival for patients with resectable pancreatic adenocarcinoma?