Surgical Experience of Prolactinomas at a Single Center: Outcomes of Surgery for Silent, Weakly Secreting, and Functional Tumors

Introduction: Outcomes of surgery for prolactinomas is largely limited to patient series evaluating functional tumors. However, the spectrum of prolactinomas treated surgically include silent (no hyperprolactinemia), weakly secreting (moderate hyperprolactinemia with no or minimal clinical symptoms), and functional (hyperprolactinemia with clinical symptoms). A comparative study of the surgical outcomes of the spectrum of prolactinomas is limited.

Methods: An IRB-approved, single-center, retrospective cohort study of patients undergoing surgical resection for the treatment of PitNETs with positive prolactin immunohistochemical staining at University of Washington between 2011 and 2023 was performed. The electronic medical record was queried for demographic, clinical, radiographic, pathologic, and surgical data. Patients were stratified by biochemical and clinical symptoms to include silent, weakly secreting, and functional prolactinomas. Outcomes included extent of resection and recurrence rates. Descriptive statistics were used for analysis.

Results: A total of 282 patients undergoing resection of immunohistochemically confirmed prolactin positive PitNETs during the 12-year study period were identified. Silent, weakly secreting, and functional prolactinomas were identified in 33, 8.9, and 58.1% of cases, respectively. A total of 9.2% of patients presented with pituitary apoplexy. In those patients with functional prolactinomas, all had at least trialed dopamine agonist therapy and 34% were on a dopamine agonist in the immediate preoperative period. Average tumor volume was 3.06, 6.28, and 3.70 cm³, for silent, weakly secreting, and functional prolactinomas, respectively. Radiographic gross total resection was achieved in 91.4% of silent, 80.0% of weakly secreting, and 79.3% of functional tumors (p = 0.039). Postoperatively, normalization of prolactin levels was achieved in a total of 88.2% of cases where hyperprolactinemia was present preoperatively. Subsequent biochemical and radiographic recurrence was identified in 4.3, 8.0, and 6.7% of silent, weakly secreting, and functional tumors, respectively. For those patients who had recurrence of tumor, 47.1% were treated with additional surgery while 35.3 and 17.6% of patients were treated with radiosurgery or additional dopamine agonist therapy, respectively.

Conclusion: Prolactinomas represent a challenging surgical pathology. While dopamine agonist therapy remains the gold standard of initial therapy, surgery is often required for treatment failure. Biochemical remission of functional prolactinomas occurred at lower rates than silent and weakly secreting tumors, necessitating appropriate patient counseling before surgery that additional surgical, radiosurgical, or medical therapy may be required.

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Artikel online veröffentlicht:
05. Februar 2024