Abstract
BACKGROUND: CA-125 alone is widely used to diagnose progressive disease (PD) in platinum-sensitive recurrent ovarian cancer (PSROC) on chemotherapy. However, there are increasing concerns regarding its accuracy. We assessed concordance between progression defined by CA-125 and RECIST using data from the CALYPSO trial. METHODS: We computed concordance rates for PD by CA-125 and RECIST to determine the positive (PPV) and negative predictive values (NPV). RESULTS: Of 769 (79%) evaluable participants, 387 had CA-125 PD, where only 276 had concordant RECIST PD (PPV 71%, 95% CI 67-76%). For 382 without CA-125 PD, 255 had RECIST PD but 127 did not (NPV 33%, 95% CI 29-38). There were significant differences in NPV according to baseline CA-125 (≤100 vs >100: 42% vs 25%, P < 0.001); non-measurable vs measurable disease (51% vs 26%, P < 0.001); and platinum-free-interval (>12 vs 6-12 months: 41% vs 14%, P < 0.001). We observed falling CA-125 levels in 78% of patients with RECIST PD and CA-125 non-PD. CONCLUSION: Approximately 2 in 3 women with PSROC have RECIST PD but not CA-125 PD by GCIG criteria. Monitoring CA-125 levels alone is not reliable for detecting PD. Further research is required to investigate the survival impact of local therapy in radiological detected early asymptomatic PD.