Significance of the serum CA125 level in recurrent ovarian cancer

Thirty-four recurrent cases of 89 patients with ovarian cancer treated in our department between 1985 and 1989 were examined for changes in serum CA125 level. 1) Upon confirmation of recurrence, 17 patients were positive for CA125 and 15 were negative. 2) According to the histopathological type, the rate of CA125 positivity in patients with recurrence was high for serous adenocarcinoma, suggesting that determination of CA125 is useful for detection of recurrence. In contrast, all patients with mucinous adenocarcinoma or endometrioid adenocarcinoma were negative for CA125. 3) The CA125 positivity rate upon confirmation of recurrence was 9% in patients whose CA125 was less than 1,000 U/ml on initial examination, suggesting that close management of such patients is necessary. 4) Elevation of CA125 by 3 steps or more within the normal range (less than 35 U/ml) was useful for predicting recurrence. 5) The cut-off level of CA125 during follow-up should be set at 16 U/ml. 6) It was difficult to evaluate remission with only the serum CA125 level. It is impossible to avoid second look operation at present. These results indicate that pretreatment values and changes of the parameter within the normal range (less than 35 U/ml) have to be considered when using CA125 as a marker of tumor recurrence.