Gestational trophoblastic neoplasia — structured oral station (12 minutes)

Opening prompt — "What is the diagnosis, and what is your first action?"

Model response: [1][3]

• "This is post-molar gestational trophoblastic neoplasia. The hCG has plateaued across four weekly values, meeting the FIGO plateau criterion for post-molar GTN."
• "My first action is to confirm the hCG is real with a urine test — to exclude a phantom hCG — and to exclude a new pregnancy with ultrasound, since she is on contraception. Then I register her with the regional trophoblast centre and stage and score her."

Probe 1 — "Reproduce the FIGO 2000 anatomic staging."

• "Stage I, disease confined to the uterine corpus; Stage II, disease extending outside the uterus but limited to the genital tract structures; Stage III, disease extending to the lungs with or without genital tract involvement; Stage IV, all other metastatic sites. The stage and the WHO score are written together as a single figure."[1][2]

Probe 2 — "Reproduce the WHO score variables and the cut-off."

• "Eight variables: age; antecedent pregnancy; interval in months from the index pregnancy; pre-treatment serum hCG; largest tumour size including uterus; site of metastases; number of metastases identified; and previous failed chemotherapy. Each is scored 0, 1, 2 or 4."[2][3]
• "A total of 6 or below is low-risk and gets single-agent chemotherapy; 7 or above is high-risk and gets multi-agent EMA-CO. The Charing Cross convention scores 0 to 8 as low-risk."[4]

Probe 3 — "She is FIGO stage I with a WHO score of 3. What treatment do you give, and what do you tell her about the outcome?"

• "Low-risk disease. I give the Charing Cross 8-day methotrexate-folinic acid regimen: methotrexate 50 mg intramuscularly on days 1, 3, 5 and 7, with folinic acid rescue on days 2, 4, 6 and 8, repeated every two weeks until hCG normalises and then for consolidation."[4][5]
• "The McNeish Charing Cross cohort of 485 women reported 100% overall survival with this regimen; about two-thirds normalise on methotrexate alone. Actinomycin-D 1.25 mg per square metre every two weeks is the alternative if methotrexate is resisted or contraindicated."[4][5]

Probe 4 — "She is frightened and asks whether she will die, and whether she can have more children."

Counsel with the numbers — this is a scored domain: [3]

• "This is one of the most curable cancers we treat — overall cure exceeds 95%, and your form is essentially always cured. Treatment preserves fertility, and most women conceive afterwards. I will keep a close eye on your hCG and support you through it."
• Acknowledge her fear, give the numbers plainly, confirm she has understood, and arrange a point of contact.

Probe 5 — "What if her score had been 14, with liver metastases?"

• "High-risk, ultra-high-risk disease. I would not start full-dose EMA-CO directly — I would begin with low-dose induction etoposide 100 mg per square metre and cisplatin 20 mg per square metre on days 1 and 2 weekly, to avoid fatal tumour lysis, then proceed to EMA-CO. The Alifrangis cohort showed induction cut the early-death rate from 7.2% to 0.7%, with 94.3% overall survival in high-risk disease."[6]