Combined analysis of serum lactic dehydrogenase levels and isozyme patterns in ovarian neoplasms

A total of 65 cases of ovarian tumor admitted for surgical intervention were prospectively enrolled in this study, including 40 cases with benign ovarian tumors and 25 cases of ovarian cancer. The 25 malignancies were comprised of 22 cases of common epithelial origin and three cases with Krukenberg tumors. Serum total LDH level and its isozyme activity were measured preoperatively in each patient. The mean value (+/-SD of serum LDH in the malignant group was 876.3 (+/- 450.4) IU/1, which was significantly higher than 364.8 (+/- 87.9) IU/1 in the benign group. Twenty-two cases of ovarian malignancy (88%) and 6 cases of the benign group (15%) had elevated serum LDH levels above 450 IU/1. Analysis of the LDH isozyme pattern demonstrated that there was a significant shift to LDH-4 and LDH-5 fractions in ovarian malignancy when compared to the benign group (with the mean value of 9.5%, 14.6% vs. 6.5% and 4.6%, respectively). The elevated LDH level could yield 88% and 85% in sensitivity and specificity for detecting ovarian malignancy, while the abnormal isozyme pattern could yield 84% and 77.5%, respectively. From combined analysis of total LDH levels and isozyme patterns, the true positive detection rate and true negative detection rate could both reach 100%. In conclusion, the present findings imply that total serum LDH level and isozyme activity measurement may provide significant aids in evaluation and detection of human ovarian cancers among patients with ovarian tumors.