CA 19-9 level may predict OS in patients with resected
pancreatic cancer, according to data from Radiation Therapy Oncology Group
trial 9704.
As a secondary endpoint of the trial, researchers
conducted a prospective evaluation of post-resectional CA 19-9 as a predictor
of OS in patients with pancreatic cancer. They examined CA 19-9 as a
dichotomized variable: <180 U/mL vs. ≥180 U/mL or ≤90 U/mL vs. >90
U/mL.
The evaluation included 385 patients with assessable CA
19-9 levels. Two-hundred and twenty patients had a CA 19-9 level <180 U/mL
and 200 patients had levels ≤90 U/mL. Thirty-four percent of patients were
Lewis antigen negative, 33 patients had levels >180 U/mL and 53 had levels
>90 U/mL.
Median survival for patients with CA 19-9 ≥180 U/mL
was nine months compared with 21 months for patients with CA 19-9 <180 U/mL
(P<.0001). Differences in OS were not significant between Lewis
antigen–negative patients and those with CA 19-9 <180 U/mL.
The researchers reported a 72% reduction in the risk for
death among patients with a CA 19-9 <180 U/mL compared with those whose
level was ≥180 U/mL (HR=3.58; 95% CI, 2.40 to 5.34). Patients with a level
≤90 U/mL were also at a lower risk for death (HR=3.4; 95% CI, 2.4-4.64).
“Multivariate analyses confirmed that CA 19-9, when
analyzed as both a continuous and a dichotomized variable, is a highly
significant predictor of OS in patients with resected pancreatic cancer,”
the researchers wrote.
J Clin Oncol. 2008;doi:10.1200/JCO.2008.18.6288.