Endoscopic endonasal transcavernous surgery for knosp grade 3-4 growth hormone-secreting pituitary neuroendocrine tumors: surgical outcomes and predictors of biochemical remission.

Achieving biochemical remission in growth hormone-secreting pituitary neuroendocrine tumors (GH-PitNETs) with cavernous sinus invasion (Knosp grade 3-4) remains a significant surgical challenge. The objective was to evaluate the outcomes of the endoscopic endonasal transcavernous approach (transcavernous-EEA) and identify predictors of postoperative biochemical remission. This retrospective study included 50 patients with Knosp grade 3-4 GH-PitNETs. Patients were divided into two cohorts: Group 1 (prior to October 2020) received conventional EEA, while Group 2 (after October 2020) underwent transcavernous-EEA. The biochemical remission rate was significantly higher in Group 2 (64.7%) than in Group 1 (31.3%) (P = 0.027), with comparable surgery-related morbidity. In Group 2, preoperative IGF-1 (OR 0.984, 95% CI 0.969-0.999) and postoperative day 1 (POD1) GH levels (OR 0.241, 95% CI 0.076-0.760) were independently associated with biochemical remission in an exploratory multivariable analysis. Receiver operating characteristic curve analysis determined preliminary cutoff values of 587 ng/ml for preoperative IGF-1 (AUC 0.739, P = 0.007; Specificity 58.3%) and 2.185 ng/ml for POD1 GH (AUC 0.898, P < 0.001; Specificity 83.3%). Transcavernous-EEA was associated with higher biochemical remission during short-term follow-up in Knosp grade 3-4 GH-PitNETs without increasing surgical morbidity. Preoperative IGF-1 and POD1 GH levels may help stratify the likelihood of postoperative remission following this approach.