Clinical significance of combined use of macrophage colony-stimulating factor and squamous cell carcinoma antigen as a selective diagnostic marker for squamous cell carcinoma arising in mature cystic teratoma of the ovary

OBJECTIVES: Mature cystic teratoma of the ovary transforms into malignant tumors, mostly squamous cell carcinomas, at an incidence of approximately 2%. Preoperative diagnosis of squamous cell carcinoma arising in mature cystic teratoma of the ovary is a difficult task. The present study aims to assess whether combined use of two serum tumor markers, macrophage colony-stimulating factor (M-CSF) and squamous cell carcinoma antigen (SCC), is effective in preoperatively diagnosing squamous cell carcinoma arising in mature cystic teratoma of the ovary, distinguishing it from mature cystic teratoma without malignant transformation. METHODS: Serum levels of M-CSF and SCC were assayed using blood samples collected preoperatively from 31 patients with squamous cell carcinoma arising in mature cystic teratoma of the ovary and 133 patients with mature cystic teratoma of the ovary without malignant transformation. RESULTS: In 22 of the 31 (71.0%) patients with squamous cell carcinoma arising in mature cystic teratoma of the ovary, the serum M-CSF levels exceeded the upper limit of the normal level (1056 U/ml). This positive incidence of the elevated serum M-CSF levels was significantly higher compared with that (13.5%, 18/133) observed in patients with benign cystic teratoma of the ovary (P < 0.0001). Regarding the serum levels of SCC, 13 of 31 (41.9%) patients with malignant tumors showed positive values exceeding the cutoff value of 2.0 ng/ml. Again, this incidence of positive cases was significantly higher compared with that (15.0%, 20/133) observed in patients with benign tumors (P < 0.01). There was no correlation between the serum levels of M-CSF and SCC among patients with squamous cell carcinoma arising in mature cystic teratoma of the ovary. Patients with malignant tumors testing positive for elevated M-CSF did not necessarily test positive for SCC. Patients with positive values for excess M-CSF and/or SCC constituted 87.1% of the total (27/31). Even when patients were restricted to those with stage I tumors, a value as high as 83.3% (15/18) was still obtained for those testing positive for elevated M-CSF and/or SCC. CONCLUSION: Serum M-CSF was proven to be useful as a tumor marker for detecting squamous cell carcinoma arising in mature cystic teratoma of the ovary. Combined use of serum M-CSF and SCC as a marker seemed to be useful in the selective diagnosis of mature cystic teratoma of the ovary harboring malignant squamous carcinoma, discriminating it from that without malignant carcinoma.