Gross total resection in low-grade and pretreated high-grade invasive growth hormone pituitary adenomas promises favorable outcomes

Abstract

Introduction: Growth hormone (GH)-secreting pituitary tumors cause serious systemic comorbidities, necessitating the achievement of gross total resection (GTR) and biochemical remission. This study aims to identify predictors of resection status and biochemical remission.

Methods: We retrospectively reviewed the records of 54 GH adenoma patients receiving endoscopic endonasal transsphenoidal approach (EETSA). Medical records and magnetic resonance imaging were reviewed for tumor size, volume, resection status, invasion status, and Knosp and Hardy-Wilson grades. We also classified invasion status into high- and low-grade groups. Biochemical remission was defined as an insulin-like growth factor 1 value within sex- and age-adjusted reference or a random GH level < 1.0 ng/mL.

Results: The degrees of horizontal and vertical invasion based on preoperative Knosp and Hardy-Wilson grade were highly associated with intraoperative resection status (p = 0.0054, 0.0043 and 0.013 respectively). We also found more significant differences between resection status and higher-grade invasion (p = 0.0018, 0.006 and 0.0018, respectively). Hardy-Wilson grades and resection status were significantly associated with biochemical remission (p = 0.0484, 0.0252, and 0.0007, respectively). Although we observed no difference between outcomes with respect to micro- vs. macroadenoma, tumor size and volume were significantly associated with outcomes (p = 0.017, 0.0032, respectively). More significant differences were observed between biochemical remission and higher-grade Hardy-Wilson invasion grade (p = 0.0053 and 0.0075). Multivariate analysis showed that higher-grade Hardy-Wilson invasion correlated with resection status (p = 0.0481 and 0.0125); only resection status was associated with biochemical remission (p = 0.0101).

Conclusions: EETSA remains the best treatment option for GH adenomas. Biochemical remission was highly associated with invasion status and the possibility of achieving GTR. Aggressive resection for low-grade and pretreated high-grade tumors promises favorable outcomes.

Keywords: Biochemical remission; Endoscopic endonasal transsphenoidal approach; GH pituitary adenoma; Knosp and Hardy–Wilson grade; Pre-operative treatment; Resection status.

Fig. 1

Knosp system grades the parasellar extension of a tumor towards the cavernous sinus in relation to the intracavernous carotid artery [8, 18]

Fig. 2

Hardy–Wilson classification of pituitary tumors. Upper panel shows the classification of downward sphenoid bone invasion (grade 0, intact with normal contour; grade I, intact with bulging floor; grade II, intact with enlarged fossa; grade III, localized sellar destruction; grade IV, diffuse sellar destruction). Only grade III and IV tumors are considered invasive or high grade. Lower panel describes the classification of upward suprasellar extension (grade A, intrasellar location alone; grade B, recess of the third ventricle; grade C, whole anterior third ventricle; grade D, intracranial extradural; grade E, extracranial extradural) [9]

Fig. 3

A patient with higher-grade Knosp (grade 4) and Hardy–Wilson classification (grade IV, stage E). A GH adenoma; B STR was accomplished with residue in the right cavernous sinus

Fig. 4

A patient with lower-grade Knosp (grade 2) and Hardy–Wilson classification (grade II, stage B). A GH adenoma; B GTR was accomplished without residual tumor

Fig. 5

A higher-grade GH adenoma. A patient underwent STR with residual tumor mainly abutting the right cavernous sinus. B The tumor shrank significantly after SRL treatment

Fig. 6

Axial T2-weighted image showing a GH adenoma with low signal (A, arrow); Tumor shrank in size significantly from before (B) to after SRL treatment (C)