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Introduction
Pituitary adenomas are a type of benign intracranial endocrine tumor that account for ~10% of intracranial tumors (1,2), and prolactin-secreting adenomas (prolactinomas) account for 40–60% of pituitary adenomas (3). The treatment of prolactin-secreting adenomas primarily involves surgery and the administration of drugs such as bromocriptine (4,5). Some patients choose to undergo radiation therapy when surgery and drug therapies have been unsuccessful (6).
The aim of treatment is to eliminate the oppressive effects of pituitary adenomas on normal tissues, and to reduce or control hormone levels to their normal ranges. Clinical treatments include drug therapy, surgery and radiation therapy (7,8). In 2006, the diagnosis and treatment guidelines for pituitary prolactinoma devised at the 9th International Pituitary Congress stated that dopamine agonists are the preferred treatment for patients with prolactinoma (9). In China, the most commonly used treatment is surgery using a nasal transsphenoidal approach supplemented with the oral administration of dopamine agonists, such as bromocriptine. Prolactinomas typically occur in women of childbearing age (20–40 years old). Common symptoms are amenorrhea, lactation and infertility in female patients, and sexual dysfunction in male patients. Prolactinomas are also associated with vision disorders and hypopituitarism resulting from compression by the tumor (10–13).
Drug therapy serves a prominent role in the treatment of prolactinomas; currently, bromocriptine is the most widely used drug clinically; it is as a semi-synthetic lysergic alkaloid bromide that acts as a dopamine agonist. Bromocriptine can reduce tumor size by inhibiting the synthesis and secretion of prolactin, and inhibiting angiogenesis in the surrounding tissue (14). Prolactin levels decrease rapidly following treatment with bromocriptine (7.5–10 mg/day), and tumors quickly reduce in size or disappear (15,16). Galactorrhea may improve in female patients after 2 weeks of treatment with bromocriptine, and menstruation and ovulation can be recovered after 2 months of treatment (17). In male patients, sexual function can be recovered following several weeks of treatment and typically returns to normal within a year (18). However, the use of bromocriptine has a number of disadvantages; it can cause fibrosis or hardening of tumors, and capsule thickening, which increases the difficulty of surgical tumor removal. In addition, a number of adverse reactions can occur in patients, such as nausea, vomiting and orthostatic hypotension. Furthermore, bromocriptine is an expensive drug, requiring long-term...