Pre-operatory predictors were represented by higher serum cortisol after DST and lower baseline plasma ACTH (but not all studies agreed); one study identified a cortisol (after DST) cut-off ≤ 4.7 μg/dL that predicted 6-week recovery (89.5% sensitivity and 72.7% specificity), and another study showed the lowest cortisol level after DST of 1.2 μg/dL in patients who further developed adrenal insufficiency following tumour removal (66.6% accuracy) [31,32,33,34,35,36,37,38,39,40,41,42,43,44]. Here, POMC is linked to Adrenal insufficiency.