Pinheiro‐Neto, Carlos

Abstract Prolactinomas comprise half of all pituitary adenomas. This study explores the significance of measuring intraoperative (IO) prolactin (PRL) levels in guiding surgical decision-making and predicting operative success. Retrospective cohort study design of consecutive patients with prolactinomas who underwent transsphenoidal resection from June 2021 to May 2023. IO PRL was measured after tumor resection was completed. Remission was defined as normalization of PRL levels during follow-up without medication. Outcomes included factors associated with remission, utilizing significance thresholds at p < 0.05. Thirteen patients were included with a 5.3-month median follow-up (range, 3–15 months). Most of the tumors were microadenomas (61%), with a median preoperative PRL level of 116 ng/mL (range, 25–471). Gross total resection was achieved in 69% of patients, all of whom attained remission. The median IO PRL was 19.8 ng/mL (range, 1–329), the postoperative day 1 PRL of 3.6 ng/mL (range, 1–203), and the latest PRL at 9.3 ng/mL (range, 1–137). A ≥40% decline in IO PRL from baseline was identified as the optimal cutoff for predicting biochemical remission, with 89% sensitivity, 75% specificity, and 85% accuracy. Monitoring PRL levels intraoperatively may be a useful biomarker aiding surgeon's assessment of the extent of tumor resection and guide surgical decision-making. Further refinement of the immunoassay assay and clinical testing with more extensive prospective studies are needed.