Normal serum CA125 half-life and normal serum nadir CA125 level in patients with ovarian cancers

The normal serum CA125 half-life and distribution of the normal serum nadir CA125 value in patients with epithelial ovarian carcinoma (EOC) have not been determined yet. Among patients with EOC, 41 patients met the inclusion criteria of the present study: the patients that underwent complete cytoreductive surgery and six cycles of platinum-containing chemotherapy, and who had no recurrent disease more than five years. Serum CA125 half-life (T1/2) during primary surgery and primary chemotherapy was calculated and serum nadir CA125 level was evaluated by logarithmic-transformed serum CA125. Median value of nadir CA125 was 7 U/ml (range 3-20 U/ml), and the mean ln (serum nadir CA125) was 1.96 +/- 0.45. Mean T1/2 was 10.4 days in all patients, and T1/2 value was associated with the preoperative serum levels of CA125. Predicted slope of CA125 regression curve was also influenced by the preoperative CA125 value. The present study provides fundamental information with regard to normal half-life time and normal nadir of CA125 in EOC patients.