After radical orchidectomy for a non-seminomatous germ cell tumour, serum tumour markers are repeated to confirm falling levels. Which pair of half lives is correct?

• A AFP 1 day, beta-hCG 12 hours
• B AFP 2 to 3 days, beta-hCG 5 to 7 days
• C AFP 14 days, beta-hCG 7 days
• D AFP 5 to 7 days, beta-hCG 2 to 3 days ✓

Explanation

Alpha fetoprotein has a half life of 5 to 7 days and beta-hCG has a half life of 2 to 3 days. Markers should be rechecked after orchidectomy using these intervals; failure of markers to fall according to the expected half life implies residual metastatic disease even if imaging is normal, and mandates chemotherapy rather than surveillance. LDH reflects tumour bulk but its half life is short and it is less specific, being raised in many non-malignant conditions.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.