Importance  A 2009 randomized clinical trial demonstrated that using cancer antigen 125 (CA-125) tests for routine surveillance in ovarian cancer increases the use of chemotherapy and decreases patients’ quality of life without improving survival, compared with clinical observation. The Society of Gynecologic Oncology guidelines categorize CA-125 testing as optional and discourage the use of radiographic imaging for routine surveillance. To date, few studies have examined the use of CA-125 tests in clinical practice.
Objectives  To examine the use of CA-125 tests and computed tomographic (CT) scans in clinical practice before and after the 2009 randomized clinical trial and to estimate the economic effect of surveillance testing.
Design, Setting, and Participants  A prospective cohort of 1241 women with ovarian cancer in clinical remission after completion of primary cytoreductive surgery and chemotherapy at 6 National Cancer Institute–designated cancer centers between January 1, 2004, and December 31, 2011, was followed up through December 31, 2012, to study the use of CA-125 tests and CT scans before and after 2009. Data analysis was conducted from April 9, 2014, to March 28, 2016.
Main Outcomes and Measures  The use of CA-125 tests and CT scans before and after 2009. Secondary outcomes included the time from CA-125 markers doubling to retreatment among women who experienced a rise in CA-125 markers before and after 2009, and the costs associated with surveillance testing using 2015 Medicare reimbursement rates.
Results  Among 1241 women (mean [SD] age 59 [12] years; 1112 white [89.6%]), the use of CA-125 testing and CT scans was similar during the study period. During 12 months of surveillance, the cumulative incidence of patients undergoing 3 or more CA-125 tests was 86% in 2004-2009 vs 91% in 2010-2012 (P = .95), and the cumulative incidence of patients undergoing more than 1 CT scan was 81% in 2004-2009 vs 78% in 2010-2012 (P = .50). Among women whose CA-125 markers doubled (n = 511), there was no significant difference in the time to retreatment with chemotherapy before and after 2009 (median, 2.8 vs 3.5 months; P = .40). During a 12-month period, there was a mean of 4.6 CA-125 tests and 1.7 CT scans performed per patient, resulting in a US population surveillance cost estimate of $1 999 029 per year for CA-125 tests alone and $16 194 647 per year with CT scans added.
Conclusions and Relevance  CA-125 tests and CT scans are still routinely used for surveillance testing in patients with ovarian cancer, although their benefit has not been proven and their use may have significant implications for patients’ quality of life as well as costs.