Presurgical Medical Treatment in Prolactinomas: Surgical Implications and Pathological Characteristics From 290 Cases

To review experience regarding the treatment of prolactinomas by endoscopic endonasal surgery (EES) focusing on the association between presurgical dopamine agonist (DA) treatment and perioperative outcomes, surgical morbidities, endocrine outcomes and pathological characteristics.A single-center series of 290 cases were analyzed retrospectively and clinical data were collected. Intratumoural collagen content was assessed by Masson's trichrome staining.Tenacious tumor consistency (27.8% vs 9.8%, p < 0.001) was more common in DA pretreated patients compared to patients who prefer initial surgery. Moreover, DA pretreated macroadenomas presented more intraoperative blood loss (200 [100-400] ml vs 175 [100-300] ml, p = 0.014), longer surgical duration (177±95 mins vs 154±57 mins, p = 0.043) and more surgical morbidities (19.4% vs 8.9%, p = 0.034). Additionally, DA pretreated macroadenomas presented higher collagen volume fraction (CVF) than that of the initial surgery group (23.6 ± 2.2% vs 13.2 ± 2.1%, p = 0.001). Correlation analysis revealed a close correlation between CVF and the cumulative dose of bromocriptine (BRC) in macroadenomas (r = 0.438, p < 0.001). Regarding to endocrine outcomes, DA pretreated microadenomas showed lower proportion of initial remission compared to microadenomas who prefer initial surgery (86.7% vs 100%, p = 0.047).This study described increased surgical difficulty and inferior endocrine outcomes which associated with tumor fibrosis secondary to presurgical BRC treatment in prolactinomas. Neurosurgeons should be noticed that presurgical BRC treatment may render subsequent surgery more challenging.