The single-center study evaluated the number of tests per patient over 12 months and the maximum number of tests each patient had each month. The analysis included data for 928 patients with advanced cancer who had outpatient visits at Columbia University Medical Center between July 1, 2013, and June 30, 2014.
“Patients with cancers other than advanced breast, colorectal, ovarian, lung (both small cell and non–small cell), pancreatic, and hepatobiliary cancers were excluded from the study sample. Advanced stage was defined as metastatic and/or unresectable disease,” the authors explained. The most common types of cancer among patients in the study were hepatobiliary (34.8%), pancreatic (24.1%), breast (15.7%), and colorectal (12%).
CA 19-9 and CEA Most Commonly Overused
For each patient, researchers recorded the dates of testing for the following tumor markers: CA-125, CA 15-3, CA 19-9, CA 27-29, and carcinoembryonic antigen (CEA).
“The mean number of any individual test per patient was seven tests, and the maximum number was 35 tests; the mean number of total tests per patient was 12 tests, and the maximum number was 70 tests; 16.3% of patients had more than 12 individual tests per year,” the researchers reported. “In a 1-month span, 34.3% of patients had more than one individual test. CA 19-9 and carcinoembryonic antigen were the most commonly overused tests.”
Overuse was defined as “the number of patients with more than 12 of any individual test per year,” the investigators noted. This occurred in 151 patients. “Because some patients died during the study period, we also evaluated monthly use,” the researchers wrote. “Overuse defined as any patient with more than one individual test per month occurred in 318 patients (34.3%). The most commonly overused tests (> one test per month) were CA 19-9 (45.9%), CEA (40.9%), and CA-125 (25.8%). Extreme overuse (> three individual tests per month) occurred in 215 patients (23.2%).” Topping the list once again were CA 19-9 (38.2%) and CEA (27.9%).
Limited Evidence of Efficacy
“The only evidence-based guidelines for tumor marker testing are for patients with metastatic colorectal cancer, where early detection of isolated metastases followed by metastasectomy improves outcome,” the authors noted. “ASCO recommends CEA surveillance in patients with metastatic colorectal every 2 to 3 months, along with abdominal imaging during active therapy; however, the National Comprehensive Cancer Network does not recommend routine monitoring of CEA in these patients. Currently, there are no guidelines regarding the use of serum tumor markers in patients with metastatic lung cancer. There are no guidelines for optimal tumor marker frequency in patients with metastatic breast, advanced liver, hepatobiliary, or pancreatic cancer.”
This lack of evidence about the effectiveness of frequent tumor marker testing “suggests that additional studies are needed to inform practice,” the researchers wrote. “Future research should define the minimal frequency of testing and determine whether response can help reduce more expensive radiologic tumor imaging. In the meantime, efforts should be made to limit use of tumor marker testing in patients with unresectable and/or metastatic solid tumors.”
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.