A 35-year-old man presents with a painless, firm testicular swelling. Ultrasound confirms an intratesticular mass. Serum AFP is 1400 IU/mL and beta-hCG is 3 IU/L. Post-orchidectomy histology shows non-seminomatous germ cell tumour (NSGCT). AFP level one week later is 700 IU/mL. What does this AFP trend suggest?

• A Complete tumour resection with expected exponential decline
• B Inadequate resection with residual viable tumour
• C Liver metastasis must be present given this decline rate
• D Consistent with the expected half-life of AFP (5–7 days) suggesting no residual disease ✓

Explanation

AFP has a serum half-life of 5–7 days. A drop from 1400 to 700 IU/mL over 7 days represents a halving, which is precisely the expected decline if the tumour has been completely excised. This is a reassuring post-orchidectomy marker trajectory. If AFP did not decline appropriately, residual disease or metastases would be suspected. Beta-hCG half-life is much shorter at 1–3 days.

Reference: Bailey & Love's Short Practice of Surgery, 27th ed.

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Written and medically reviewed by the StethoPrep medical team.