title: Temozolomide in the management of dopamine agonist-resistant prolactinomas.
abstract: BACKGROUND
  The majority of prolactinomas respond to dopamine agonist therapy, but a proportion are resistant, requiring other treatments including surgery and/or radiotherapy. Temozolomide is an oral chemotherapy agent, which has been used as a salvage therapy to treat aggressive pituitary adenomas and carcinomas, including prolactinomas, unresponsive to all conventional treatment.
  
  
  METHODS
  We report three patients where temozolomide was used in the treatment of refractory prolactinomas. Case 1 describes a patient with a highly invasive prolactinoma, resistant to all conventional therapy, which responded dramatically to temozolomide used as a salvage treatment. In case 2, temozolomide was used after incomplete surgical resection to relieve chiasmal compression and avoid chiasm exposure to radiotherapy. In case 3, temozolomide enabled radiotherapy to be deferred in a 16-year old with a resistant prolactinoma. In all three cases, the tumours were negative by immunostaining for methylguanine methyltransferase (MGMT).
  
  
  BACKGROUND
  A review of the published literature reveals 51 reported cases of temozolomide treatment for pituitary tumours, including 20 prolactinomas. Fifteen of the 20 prolactinomas showed a good response to temozolomide. Our analysis demonstrates a strong association between MGMT-negative staining and a good response to temozolomide (OR 9.35, P = 0.0030). Current clinical practice is to use temozolomide as a salvage therapy after all conventional modalities of treatment have failed. We suggest that, in selected cases, consideration should be given to using temozolomide earlier in the treatment algorithm.
authors.affiliation: Department of Endocrinology, King's College Hospital, London, SE5 9RS, UK. benjamin.whitelaw@nhs.net
authors.forename: B C
authors.initials: BC
authors.lastname: Whitelaw
authors.forename: D
authors.initials: D
authors.lastname: Dworakowska
authors.forename: N W
authors.initials: NW
authors.lastname: Thomas
authors.forename: S
authors.initials: S
authors.lastname: Barazi
authors.forename: P
authors.initials: P
authors.lastname: Riordan-Eva
authors.forename: A P
authors.initials: AP
authors.lastname: King
authors.forename: T
authors.initials: T
authors.lastname: Hampton
authors.forename: D B
authors.initials: DB
authors.lastname: Landau
authors.forename: D
authors.initials: D
authors.lastname: Lipscomb
authors.forename: C R
authors.initials: CR
authors.lastname: Buchanan
authors.forename: J A
authors.initials: JA
authors.lastname: Gilbert
authors.forename: S J B
authors.initials: SJ
authors.lastname: Aylwin
mesh_terms: D000293:Adolescent; D000328:Adult; D003606:Dacarbazine / Q000031:analogs & derivatives* / Q000627:therapeutic use; D018491:Dopamine Agonists / Q000627:therapeutic use*; D019008:Drug Resistance, Neoplasm / Q000187:drug effects*; D006801:Humans; D008297:Male; D015175:Prolactinoma / Q000188:drug therapy*; D000077204:Temozolomide
chemical_list: D018491:Dopamine Agonists; D003606:Dacarbazine; D000077204:Temozolomide