Yolk sac tumour in a young woman — structured SAQ (15 marks)

(a) Diagnosis and tumour markers (3 marks)

• Diagnosis: malignant ovarian germ cell tumour, most likely a yolk sac (endodermal sinus) tumour, given the markedly elevated AFP and the solid-cystic mass in a young woman. [1][2]
• AFP — yolk sac tumour (this patient's markedly elevated AFP is diagnostic). [1]
• hCG — choriocarcinoma/embryonal carcinoma (negative here, as expected for a pure yolk sac tumour). [1]
• LDH — dysgerminoma (raised here non-specifically). CA125 should also be measured. [1][2]

(b) Surgical procedure and fertility-sparing principle (4 marks)

• Fertility-sparing conservative surgery is the standard in all stages of malignant ovarian germ cell tumour, because chemotherapy cures the majority. [1]
• Preserve the uterus and the contralateral ovary. Wedge biopsy of a normal contralateral ovary is not recommended (it defeats fertility-sparing intent). [1]
• Staging components: peritoneal washings, careful inspection and biopsy of all suspicious areas, unilateral salpingo-oophorectomy, omentectomy, and limited cytoreduction. Appendicectomy is added for a mucinous tumour. [1]
• The aim is to achieve no visible residual disease, which is the key prognostic factor (the Boyraz series confirmed residual disease determines survival). [5]

(c) BEP regimen — doses and schedule (4 marks)

Per the FIGO 2021 update: [1]

• Etoposide (E): 100 mg/m2 IV per day for 5 days. [1]
• Cisplatin (P): 20 mg/m2 IV per day for 5 days. [1]
• Bleomycin (B): 30 IU IV/IM on days 1, 8 and 15 (bleomycin is dosed in International Units). [1]
• Schedule: every 3 weeks for 3 cycles. If bleomycin is omitted, 4 cycles of EP are used. [1]

(d) Stage IA dysgerminoma management (2 marks)

• Observation after complete surgical staging, with surveillance. [1]
• Rationale: dysgerminoma is exquisitely chemo- and radiosensitive; a small proportion recur but are treated successfully at recurrence with a high cure rate. Radiotherapy is effective but no longer used because of late effects and the efficacy of chemotherapy. [1]

(e) Bleomycin complications and the GOG dose adjustment (2 marks)

• Bleomycin pulmonary toxicity (pneumonitis, pulmonary fibrosis), which rises sharply in patients over 40 years; there were early bleomycin-related deaths in the GOG stromal trial. [6]
• The GOG dose adjustment for stromal tumours: bleomycin reduced to 20 units/m2 IV day 1 every 3 weeks for 4 cycles (with etoposide 75 mg/m2 days 1 to 5 and cisplatin 20 mg/m2 days 1 to 5 every 3 weeks for 4 cycles). [6]

Common errors that lose marks

• Recommending a hysterectomy and bilateral salpingo-oophorectomy — conservative surgery is standard in all stages. [1]
• Quoting the BEP doses incorrectly (e.g. carboplatin/paclitaxel, or the stromal-tumour schedule for a germ cell tumour). [1][6]
• Giving adjuvant chemotherapy for a Stage IA dysgerminoma — observation is correct. [1]
• Listing the wrong tumour marker for the subtype. [1]

Examiner notes

A high-scoring candidate names yolk sac tumour with elevated AFP, defends fertility-sparing staging surgery in all stages, reproduces the BEP regimen with exact doses (etoposide 100 mg/m2/day and cisplatin 20 mg/m2/day for 5 days, bleomycin 30 IU days 1, 8, 15, every 3 weeks for 3 cycles), states that Stage IA dysgerminoma is observed, and knows the bleomycin pulmonary toxicity and the GOG dose reduction. [1][5][6]