Postmolar choriocarcinoma: An independent risk factor for chemotherapy resistance in low-risk gestational trophoblastic neoplasia.

Objective: To evaluate the effect of a clinicopathologic diagnosis of choriocarcinoma (CCA) on clinical characteristics, extent of disease, and response to chemotherapy in low-risk gestational trophoblastic neoplasia (GTN).

Methods: We reviewed the records of 678 patients with low-risk GTN (FIGO stage I and stages IIIII, score<7) treated from 1962 to 2009. Patient and disease characteristics, treatment course, as well as clinical response and survival were analyzed retrospectively. Patients with a clinicopathologic diagnosis of CCA were compared to those with a clinical diagnosis of postmolar GTN.

Results: Of 678 women with low-risk GTN, 129 (19.0%) had a clinicopathologic diagnosis of CCA. Patients with CCA had higher parity (median 1 vs. 0, p=0.003), more pretreatment human chorionic gonadotropin (hCG) levels at >100,000mIU/mL (12.7% vs. 5.9%, p=0.009), longer duration of disease (19.6 vs. 9.9weeks, p<0.001), and higher FIGO scores (median 2 vs. 1, p<0.001) compared with those with other histology; however, patients with CCA and postmolar GTN presented with similar stage of disease (stage I, 83.1% vs 88.2%, p=0.126). Although there was no difference in survival between groups, increased resistance to first-line methotrexate chemotherapy was significantly associated with a diagnosis of postmolar CCA (OR 2.67, p=0.007)), pretreatment hCG level at >10,000mIU/mL (OR 2.62, p=0.002), and higher FIGO score (3-4: OR 2.02, p=0.027; 5-6: OR 5.56, p<0.001) on multivariate analysis.

Conclusions: Clinicopathologic diagnosis of postmolar CCA in patients with low-risk GTN is associated with higher pretreatment hCG levels, higher FIGO scores, and increased resistance to first-line single-agent methotrexate chemotherapy.