Purpose: For ovarian cancer patients receiving maintenance treatment after complete clinical response to primary therapy, we tested the predictive value of the following early signal of progressive disease (EPD) criterion based on serum CA-125: for patients with CA-125 nadir <or= 10 U/mL, a confirmed value of >or= 20 U/mL serves as an early signal of CA-125 progression; for patients with nadir more than 10 U/mL, a value >or= 2x nadir that is confirmed predicts progression. PATIENTS AND METHODS The EPD criterion was tested on Southwest Oncology Group trial 9701/Gynecologic Oncology Group trial 178 patients (n = 288) and compared with Gynecologic Cancer Intergroup criterion.
Results: For 204 patients with known progressive disease, the progression date was predated by EPD by <or= 60 days in 31%, 61 to 180 days in 15%, and more than 180 days in 10% (median, 56 days early). Of 84 progression-free patients, nine EPDs were found. Overall, 135 patients met the EPD criterion. True disease progression status was undeterminable for two patients and nine were potentially false signals, for a conservative positive predictive value of 93% (95% CI, 88% to 97%).
Conclusion: Initial testing of the proposed CA-125 criterion resulted in a low false-positive rate and early prediction of disease progression in more than 50% of the patients tested. The proposed criterion may better reflect the timing of disease progression and should be investigated further.