OS predicted by CA 19-9 levels in resected pancreatic cancer

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.