GTN Updates

Gestational trophoblastic neoplasia (GTN) refers to a group of malignant neoplasms thatconsist of abnormal proliferation of trophoblastic tissue, and may follow a hydatidiform moleor a nonmolar pregnancy. GTN is comprised of the following histologic types: invasive mole,choriocarcinoma, placental site trophoblastic tumor (PSTT), and epithelioid trophoblastictumor (ETT). Approximately 50 percent of cases of GTN arise from molar pregnancy, 25 percentfrom miscarriages or tubal pregnancy, and 25 percent from term or preterm pregnancy. Theestimated incidence of GTN after a term pregnancy is 1 per 150,000 pregnancies and after aspontaneous miscarriage is 1 in 15,000 pregnancies. The main risk factors for the developmentof GTN are prior molar pregnancy, advanced maternal age (> 40 years), and Asian and AmericanIndian ancestry.Presenting symptoms and signs of GTN depend upon whether the antecedent pregnancy wasmolar or nonmolar. The clinical presentation may include: elevated serum human chorionicgonadotropin (hCG), hyperthyroidism, ovarian theca lutein cysts, abnormal uterine bleeding,pelvic pain or pressure, or symptoms of metastatic disease.The key elements of the diagnostic evaluation are to confirm an elevated hCG and evaluate formetastatic disease or hCG stimulation effects. The vagina and lungs are the most commonmetastatic sites. Uterine curettage or other biopsies have a limited role in the diagnosis of GTN.All patients should have a chest imaging to evaluate for lung metastases.GTN is a clinical diagnosis made based upon elevation of serum hCG, after a nonmolarpregnancy and other etiologies of an elevated hCG have been excluded. Imaging findings ofuterine enlargement or pathology consistent with GTN, bilateral ovarian theca lutein cysts, ormetastatic disease support the diagnosis. Unlike other solid tumors, a tissue diagnosis is notrequired prior to treatment.