Does the nadir CA125 concentration predict a long-term outcome after chemotherapy for carcinoma of the ovary?

The tumour marker CA125 is an important indicator of the clinical progress of women with carcinoma of the ovary. We have investigated the interval from the nadir CA125 value to progression defined by rising CA125 (time to biochemical progression, TBP), and overall survival of patients treated with chemotherapy for this disease in relation to the nadir CA125 value in patients in whom this was <30 U/ml following chemotherapy. The median TBP in group A (38 patients, nadir </=10 U/ml) was 2436 days, in group B (32 patients, nadir 11-20) 182 days and in group C (nine patients, nadir 21-30) 90 days, (P < 0.001). This was associated with similar differences for overall survival, the median was 2968 days in group A, 537 days in group B and 537 days in group C, (P < 0.001). Variations in the CA125 value even within the normal range carry useful information. This prognostic indicator will be useful in studying the management of patients following response to first-line chemotherapy.