Gestational Trophoblastic Disease

Regarding the pathophysiology and clinical features of gestational trophoblastic disease (GTD), all of the following statements are TRUE EXCEPT:

Which of the following is the most common type of gestational trophoblastic disease?

A 28-year-old woman from rural Maharashtra presents to the gynaecology outpatient department with vaginal bleeding and lower abdominal pain for 3 weeks. She reports amenorrhoea for 2 months. On examination, the uterus is enlarged disproportionately (size consistent with 16 weeks gestation) but soft. Serum β-hCG is markedly elevated at 450,000 mIU/mL. Transvaginal ultrasound shows a heterogeneous echogenic mass filling the uterine cavity with multiple small cystic spaces ('bunch of grapes' appearance) and no fetal parts. There is no evidence of theca lutein cysts. What is the most likely diagnosis?

A 32-year-old woman from Delhi underwent suction evacuation 6 weeks ago for a histologically confirmed complete hydatidiform mole. She had an uncomplicated post-evacuation course. Today she presents with persistent vaginal bleeding and mild lower abdominal pain. Her β-hCG at evacuation was 280,000 mIU/mL; repeat β-hCG today is 18,000 mIU/mL. Pelvic ultrasound shows a heterogeneous mass within the myometrium (2 cm × 1.5 cm) with colour Doppler showing increased vascularity. What is the most appropriate next step in management?

A 28-year-old woman presents with vaginal bleeding and a markedly elevated β-hCG level of 450,000 mIU/mL. Ultrasound shows a molar pregnancy with no fetal parts. After suction evacuation, she develops persistent gestational trophoblastic neoplasia with pulmonary metastases and an FIGO score of 8. What is the drug of choice for this high-risk molar pregnancy?