Levels of CA 19-9 Following Treatment Not Indicative of Survival in P.C.
Among patients with pancreatic cancer, levels of a specific component of certain carbohydrates (CA19-9) during and following treatment are not associated with survival outcomes. These results were recently published in The Lancet Oncology.
The pancreas is an organ surrounded by the stomach, small intestine, bile ducts (tubes that connect the liver to the small intestine), gallbladder, liver, and spleen. The pancreas helps the body break down food and produces hormones, such as insulin, to regulate the body’s storage and use of food.
CA 19-9 is associated with pancreatic cancer. It can be found circulating in the blood. Physicians have often used CA 19-9 levels to determine whether a patient is responding to therapy. Typically, CA 19-9 levels are measured from a blood sample prior to therapy, as well as during and following therapy. If levels fall while on therapy, it is considered an indication of anticancer responses to treatment. Conversely, if CA 19-9 levels do not change during therapy or became elevated, it is thought to indicate that therapy is not producing anticancer responses.
Although results from several studies have suggested that patients with pancreatic cancer who have a reduced level of CA 19-9 during therapy experience improved survival compared with patients who have higher levels, researchers from England recently conducted a study to test this theory. The study questioned whether early decreases in CA 19-9 levels during therapy were associated with increased survival. As well, they evaluated whether a decrease of at least 50% in CA 19-9 levels during therapy has any relation to survival outcomes.
This study included 247 patients with advanced pancreatic cancer who were enrolled in a clinical trial to compare chemotherapy regimens including Gemzar® (gemcitabine) plus Xeloda® (capecitabine) to Gemzar only. Levels of CA 19-9 were measured before therapy began. Of these patients 157 also had CA 19-9 levels tested during treatment.
- Patients with a CA 19-9 level prior to therapy that was at least 59 times higher that normal had a median overall survival of 5.8 months.
- In comparison, patients with a CA 19-9 level prior to therapy that was less than 59 times higher that normal had a greater median overall survival of 10.3 months.
- Neither a decrease in CA 19-9 levels early in treatment nor a decrease in levels of at least 50% during therapy were associated with survival.
The researchers concluded that higher levels of CA 19-9 prior to therapy are associated with reduced overall survival among patients with pancreatic cancer. However, reductions in CA 19-9 in response to therapy were not associated with survival and therefore do not provide a valid marker for survival once a patient begins therapy.
Reference: Hess V, Glimelius B, Grawe P, et al. CA 19-9 tumour-marker response to chemotherapy in patients with advanced pancreatic cancer enrolled in a randomised controlled trial. The LancetOncology. 2008; 9:132-138.
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