Introduction/Background We aim to correlate serum CA 125 values after chemotherapy with clinical findings during second-look surgery.

Methodology This study was conducted on twenty-five patients with epithelial ovarian cancers undergoing second-look operations in our hospital between 2019 and 2021.

Results The average age of the patients was 59, 2 years. Twenty-one cases of stage III (84%) and 4 cases of stage VI (16%) high serous ovarian carcinoma. The CA125 level before chemotherapy was high in all cases with a mean rate of 932, 8 UI/ml. All the patients underwent multiple courses of neoadjuvant chemotherapy. The evaluation of response was clinically, radiologically, and biologically. Eight patients who had negative second-look findings gave normal serum CA125 levels. Of the 17 patients who were positive in second-look surgery, 10 had normal CA125 levels with a false negative rate of 58, 8%. Of the patients with normal CA125 levels at the time of operation, those with persistent disease had higher mean CA125 levels (22, 21 UI/ml) than those with no disease detected (12, 2 UI/ml). All the seven patients with elevated CA125 serum levels were positive in their second-look. 70% of patients with residual tumors having the greatest diameter less than or equal to 2 cm had normal CA125 with a mean value of 21 u/ml. 42% of patients with tumors having the greatest diameter greater than 2 cm had normal CA125, while all the 8 patients with no macroscopic tumor during surgery had normal CA125 level. These results show that the residual tumor size found in the second-look was related to the serum CA125 level.

Conclusion As CA125 levels within normal limits gave more false negatives, the necessity of second-look surgery can not be judged by serum CA125 assay though elevated CA125 levels do predict the presence of tumor.