Is adrenal insufficiency (AI) rare in acromegaly (A) compared with other pituitary adenomas (PA)?

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: SUN 88-129-Acromegaly & Prolactinoma
Sunday, June 16, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board SUN-118
Maria Fleseriu1, Nadia Hameed*2, Christine G Yedinak2, Jessica Allison Brzana2, Shirley McCartney2 and Marika Gassner3
1Northwest Pituitary Center, Oregon Health & Science University, Portland, OR, 2Oregon Health & Science University, Portland, OR, 3Henry Ford Health System, Detroit, MI
CONTEXT: Studies of hypothalamic-pituitary-adrenal (HPA) axis status in acromegaly (A) patients (pts) post transsphenoidal surgery (TSS) or adjuvant medical therapy (AMT), somatostatin receptor ligand and/or pegvisomant, are scarce and contradictory. We compare adrenal insufficiency (AI) prevalence of A pts vs control (C) pituitary adenoma (PA) pts pre and post TSS, and investigate the relationship to growth hormone (GH) excess and tumor size.

METHODS: Retrospective review of 105 A pts: post radiation and insufficient follow up pts were excluded. 87 A pts matched with 87 C pts (77 PA non-functioning & prolactin, 10 Rathke’s cleft cyst) for tumor size (59 macro/28 micro). Uniform evaluation included: cortisol, ACTH, CST, GH/IGF1 and other pituitary function tests pre/post TSS, at 6, 12 and 52 wks.

RESULTS: A pts: 34 M/53 F; mean age at diag 47±16 yrs. C pts: 41M/46F; mean age 47±15 yrs; f/u post TSS 31±37 mos. 75 A pts had TSS (56 macro/19 micro) and 26 required AMT by 52 wks postop. AI in A vs C pts preop, 6 wks postop and 52 wks postop: 40% (33 pts; 12 micro) vs 33% (29 pts; 6 micro p=0.001;micro); 40% vs 43%; and 35% vs 40%, respectively. Recovery of HPA axis at 52 wks was significant: AI 17% A vs 37% C pts (p=0.002, CI 0.0603-0.3563). Macro size was predictive of AI at 12 and 52 wks. There was a weak correlation between C & A pts for AI at baseline and at 6 wks (r=.153, p=0.018). For A pts, AI at 6 wks highly correlated with ongoing AI at 12 and 52 wks (r=.948, p=0.000; r=.928, p=0.00) and at 52 wks was < C pts (p=0.010). AI in A pts (26 AMT; 25/26 nl GH/IGF1) preop vs 52 wks was 46% vs 23% (p=0.001). Age and gender were not significant.

DISCUSSION: Studies of HPA axis function in A pts have been controversial. Some suggest that HPA axis may deteriorate over time independent of treatment while others concluded that AI is infrequent in A pts in remission post TSS. Our data shows that AI prevalence at baseline and at 52 wks is lower in A pts vs. C pts. Contrary to previous reports, A pts on AMT who were in biochemical remission also had significant HPA recovery at 52 wks.

CONCLUSION: When matched for tumor size, adrenal function is better preserved at baseline in A pts with macros vs other PAs. Moreover, HPA axis is significantly recovered at 1 yr postop, independent of AMT. Further research is required to assess exact etiology. Nevertheless, A pts require short and long-term postop HPA evaluation for progressive/resolving hormone deficiencies.

Nothing to Disclose: MF, NH, CGY, JAB, SM, MG

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