What is the role of dopamine agonist–resistant prolactinomas (DARPs) in the treatment of prolactinomas?

Updated: Mar 25, 2018
  • Author: Venkatesh Babu Segu, MD, MBBS, DM; Chief Editor: Romesh Khardori, MD, PhD, FACP  more...
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Answer

Most prolactinomas are medically responsive to dopamine agonist therapy. Slightly less than 10% of patients with prolactinomas do not respond to such treatment. Dopamine agonist resistance consists of failure to achieve normal prolactin level on maximally tolerated doses of dopamine agonist along with a failure to achieve a 50% reduction in tumor size. [31] These patients harbor tumors that are more likely to be invasive macroadenomas, more proliferative, more angiogenic, and more likely to exhibit cellular atypia. A few of these patients have malignant prolactinomas. [32]

In those patients with DARPs having persistent hyperprolactinemia despite surgical debulking, with or without radiotherapy, temozolomide, a chemotherapeutic alkylating agent, has been recommended. [10] Several case reports have shown temozolomide to reduce prolactin level and control tumor growth. [33, 34] Despite this, treatment of malignant prolactinomas is difficult, and survival is approximately one year. [35]


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