Giant prolactinomas: are they really different from ordinary macroprolactinomas?

Abstract

Giant prolactinomas (gPRLomas) are rare tumors of the lactotroph defined by an unusually large size (>4 cm) and serum PRL levels >1000 ng/mL. The purpose of this study is to characterize the clinical spectrum of gPRLomas comparing them with non-giant prolactinomas. This is a retrospective study at a large referral center. Data from patients harboring gPRLomas and macroprolactinomas were retrieved from medical records of the Prolactinoma Clinic. Analysis was focused on clinical, biochemical, and tumor volume characteristics, as well as on the response to treatment with dopamine agonists. Among 292 patients with prolactinomas followed between 2008 and 2015, 47 (16 %) met the diagnostic criteria for gPRLomas (42 males). The most common complaint was a visual field defect; headache was reported by 79 % and sexual dysfunction was present in over half of the patients. Median basal PRL level and tumor volume were 6667 ng/mL (3750-10,000) and 32 cm(3) (20-50), respectively; hypogonadotropic hypogonadism was documented in 87 %. Cabergoline treatment resulted in the normalization of PRL levels in 68 % and in the reduction of >50 % in tumor volume in 87 % of the gPRLoma patients. The composite goal of PRL normalization and >50 % tumor reduction was achieved by 55 % (n = 26) of patients with gPRL and by 66 % (n = 100) of patients with no giant macroprolactinomas (p = 0.19). Recovery of hypogonadism and improvement of visual fields defects occurred in 32 % and 68 % of the patients, respectively. Cabergoline treatment was equally effective in patients with gPRLoma and those with macroprolactinomas in regard of achieving treatment goals, although the median CBG dose was slightly higher in the gPRLoma group (2 vs. 1.5 mg/w). Six patients required surgery. Beyond their impressive dimensions and the huge amount of PRL they secrete, the clinical behavior of gPRLoma is not different from macroprolactinomas. These tumors are highly responsive to cabergoline treatment, and pituitary surgery is seldom required.

Long-Term Clinical Outcomes of Invasive Giant Prolactinomas after a Mean Ten-Year Followup

“…Dopamine agonists have been demonstrated as a first-line therapy for IGPs, because they can significantly shrink tumor volume and control the PRL levels [2, 10–12, 14, 18–25]. As for giant prolactinomas, the overall tumor response rate to DA treatment was 47%–87% [10, 11, 14, 19, 20, 22, 25].…”

“…As for giant prolactinomas, the overall tumor response rate to DA treatment was 47%–87% [10, 11, 14, 19, 20, 22, 25]. In Maiter and Delgrange's recent review [14], the overall tumor response rate for giant prolactinomas to DA treatment was 74% (65/88 evaluable cases), and the hormonal response rate was 60% (58/97 evaluable cases), with a mean followup of 37 months.…”

Prolactinoma: Etiological, Diagnostic and Therapeutic Aspects

“…Все агрессивные пролактиномы характеризуются наличием расширения /прорастания в соседние структуры, быстрым ростом опухоли и/или наличием опухоли более 4 см в диаметре, чаще встречающиеся у мужчин [17,18,38]. Симптомы гигантских пролактином зависят не только от уровня пролактина, но и от опухолевого масс-эффекта и связанными с ним нейроофтальмологическими осложнениями [6,34].…”

“…Симптомы гигантских пролактином зависят не только от уровня пролактина, но и от опухолевого масс-эффекта и связанными с ним нейроофтальмологическими осложнениями [6,34]. Эти пациенты имеют повышенный риск апоплексии гипофиза, внутриопухолевых кровоизлияний, ликворных свищей с ринорреей [18,38]. Уровень пролактина в сыворотке крови при гигантских пролактиномах, как правило, очень высокий, обычно >1000 нг/мл, а иногда превышающий 40 000 нг/мл.…”

Giant prolactinomas: Multi-modal approach to achieve tumor control

“…Two series published recently, one with 47 (5 females, 42 males) patients with giant prolactinomas [6] and the other with 18 patients (2 females, 16 males) with giant tumors larger than 60 mm [7] reported fairly good response to cabergoline treatment with PRL normalization in 68 and 61% of patients, and recovery of gonadotrophic axis in 32 and 37%, respectively. Six (13%) and nine (50%) of the patients included in these two cohorts had pituitary surgery compared to 69% in the current series [5].…”