A 50-year-old man presents with headaches, jaw widening, and ring size increase over recent years. IGF-1 is three times the upper limit of normal and GH fails to suppress below 0.4 µg/L after a 75 g oral glucose load. MRI shows a 12 mm pituitary macroadenoma. Which first-line surgical outcome indicator determines the need for adjuvant somatostatin receptor ligand therapy?
- A Random GH < 1 µg/L and IGF-1 normalisation post-surgery ✓
- B MRI showing complete tumour resection without residual enhancement
- C Return of normal GH pulsatility on 24-hour profile
- D Prolactin level normalisation
Correct answer: A. Random GH < 1 µg/L and IGF-1 normalisation post-surgery
Explanation
Biochemical remission in acromegaly after pituitary surgery is defined as random GH < 1 µg/L (or nadir GH < 0.4 µg/L on OGTT) and age-normalised IGF-1. Failure to achieve these targets warrants adjuvant somatostatin receptor ligands (octreotide, lanreotide) or pegvisomant. Anatomical cure on MRI does not guarantee biochemical cure, and prolactin normalisation is irrelevant unless a co-secreting tumour is present.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.