An Assessment of Patients with Dopamine Agonist Resistant Prolactinomas
Clinical Presentation, Outcome, and Management
Many patients with prolactinomas are able to successfully control their condition using dopamine agonists, such as cabergoline (CAB). Doses of CAB of up to 2.0 mg each week can usually control the levels of prolactin in the blood and help reduce the size of tumors.
Though uncommon, some people with prolactinomas show resistance to dopamine agonists. A study led by researchers at the Centre Hospitalier Universitaire de Liège in Liège, Belgium, explores the concerns of dopamine agonist-resistant patients with prolactinomas. The study, “Prolactinomas resistant to standard doses of cabergoline: a multicenter study of 92 patients,” was published in August 2012 online ahead of print in the European Journal of Endocrinology.
Researchers designed a multicenter study to collect data on patients with prolactinomas whose condition was not controlled with at least 2.0 mg of CAB each week. They examined data on 92 patients (50 women, 42 men) to better understand the clinical presentation and outcome of dopamine agonist resistant patients with prolactinomas.
The results showed that most of the patients had macroprolactinomas when they were diagnosed with the condition (82.6%). Men in the sample were significantly older than women, and they generally presented with prolactinomas that were more severe and advanced than women.
More than half of the patients in the sample underwent surgery (60.9%); 10.9% underwent multiple interventions. Post-operative radiotherapy was performed on 14.1% of patients. Late development of CAB resistance was seen in 8 (8.7%) of the study participants.
The final follow-ups showed that prolactin normalization was achieved in 28% of patients, while tumor disappearance was achieved in 19.9%. Approximately 4.8% of patients died by the last follow up due to aggressive tumors or pituitary carcinoma.
The researchers conclude that CAB-resistant prolactinomas are a serious concern. They argue that new therapies, and a push for early diagnosis, could help improve the outcomes of patients with dopamine agonist resistance.