The use of three-dimensional geometrical models to assess the influence of tumor morphometry on outcomes of endoscopic treatment of giant pituitary neuroendocrine tumors.

Abstract

The extent of resection (EOR) in giant pituitary adenomas (PAs) is influenced by multiple anatomical and morphological factors. While conventional radiological assessment relies primarily on tumor size and invasion, the role of three-dimensional tumor geometry remains unclear. This study evaluated tumor shape irregularity and its association with surgical outcomes following endoscopic transsphenoidal surgery (ETSS). A retrospective analysis was conducted on 26 patients who underwent ETSS for giant PA between 2009 and 2016. Giant PA was defined as a tumor > 3 cm on preoperative MRI. Tumor volume was assessed using an ellipsoid model and segmentation-based volumetry. Tumor shape irregularity was quantified as the relative volume difference (VD%). Residual tumor volume (RV), its proportion relative to preoperative tumor volume (RV%), and EOR were assessed on postoperative MRI. Mean tumor volume was 17 ± 9 cm³ using the ellipsoid model and 18 ± 9 cm³ using segmentation-based volumetry (p = 0.316). Gross total resection was achieved in 19%. Higher Knosp grade was associated with increased RV (p = 0.006) and RV% (p = 0.027). After adjustment for anteroposterior (AP) dimension and Knosp grade, higher VD% was associated with greater RV (B = 0.124; 95% CI, 0.022-0.225; p = 0.019). Visual improvement occurred in 67% of patients with preoperative visual impairment, while the complication rate was 23%. Higher VD% was associated with greater RV after adjustment for AP dimension and Knosp grade. VD% may complement established radiological measures in the preoperative assessment of giant PAs, although validation is required.