title: Is a stable or decreasing prolactin level in a patient with prolactinoma a surrogate marker for lack of tumor growth?
abstract: The optimal interval for follow-up imaging of patients with prolactinomas is unclear. We wish to determine the likelihood of tumor enlargement in patients with prolactinomas who have a stable or reduced prolactin (PRL) level over time, whether or not they are treated with a dopamine agonist (DA). We identified 80 patients with prolactinomas (34 men, 46 women) who had at least two paired sets of serum PRL levels and pituitary MRIs, 3 or more months apart. Patients with hyperprolactinemia due to drug or stalk effects were excluded. The median (range) age was 45 (25-77) years. Sixty-three patients (78.8%) were treated with DA. PRL levels (ng/mL) at the initial and latest sets were 114 (0.3-15,732) and 16 (0.3-1,204), respectively. In patients with identifiable tumors, the maximum tumor diameters (mm) at the initial and latest MRI studies were 12.5 (2-60) and 12.5 (2-39) respectively, with an interval of 2.9 (0.3-9.7) years. Sixty percent of patients (n = 48) had a macroadenoma. Forty-two (52.5%) patients had either disappearance of the tumor (n = 22) or reduction (n = 20) in tumor size. In the remainder, tumor size was stable in 35 but increased in 3 patients. One of these patients, observed off therapy had a concomitant rise in PRL level. The other 2 had evidence of pituitary hemorrhage with no PRL increase. Tumor growth in prolactinoma patients with a stable or decreasing PRL level, regardless of size, is a rare event. Repetitive pituitary imaging in these patients may not be warranted.
authors.affiliation: Department of Endocrinology, Diabetes and Metabolism, Cleveland Clinic, 9500 Euclid Avenue/F-20, Cleveland, OH, 44195, USA.
authors.forename: Abdulrahman G
authors.initials: AG
authors.lastname: Alkabbani
authors.forename: Sann Y
authors.initials: SY
authors.lastname: Mon
authors.forename: Betul
authors.initials: B
authors.lastname: Hatipoglu
authors.forename: Laurence
authors.initials: L
authors.lastname: Kennedy
authors.forename: Charles
authors.initials: C
authors.lastname: Faiman
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Weil
authors.forename: Amir H
authors.initials: AH
authors.lastname: Hamrahian
mesh_terms: D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000097:blood*; D049109:Cell Proliferation / Q000187:drug effects; D018450:Disease Progression; D018491:Dopamine Agonists / Q000494:pharmacology / Q000627:therapeutic use; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010911:Pituitary Neoplasms / Q000097:blood* / Q000188:drug therapy / Q000473:pathology*; D011237:Predictive Value of Tests; D011388:Prolactin / Q000097:blood*; D015175:Prolactinoma / Q000097:blood* / Q000188:drug therapy / Q000473:pathology*; D012189:Retrospective Studies; D013997:Time Factors; D016896:Treatment Outcome; D047368:Tumor Burden / Q000187:drug effects
chemical_list: D014408:Biomarkers, Tumor; D018491:Dopamine Agonists; D011388:Prolactin