Medically treated prolactin-secreting pituitary adenomas: when should we operate?

The Combination of Dopamine Agonist Treatment and Surgery May Be the Best Option in Challenging Prolactinoma Cases: A Single-Centre Experience

OBJECTIVE

To investigate the initial and long-term remission rates, factors related to remission, secondary treatments, and outcomes for patients with prolactinoma who underwent endoscopic transsphenoidal surgery (ETSS).

METHODS

The medical files of the 45 prolactinoma patients who underwent ETSS between 2015 and 2022 were retrospectively reviewed. Relevant demographic and clinical data were obtained.

RESULTS

Twenty-one (46.7%) patients were female. The median age of patients at ETSS was 35 (interquartile range, 22.5-50) years. The median clinical follow-up of patients was 28 (interquartile range 12-44) months. The initial surgical remission rate was 60%. Recurrence was detected in 7 patients (25.9%). Postoperative dopamine agonists were used in 25 patients, radiosurgery in 2, and second ETSS in 4 patients. After these secondary treatments, the long-term biochemical remission rate was 91.1%. The factors associated with failure in surgical remission are: male gender, older age, higher tumor size, advanced Knosp and Hardy stage, and elevated prolactin level at diagnosis. A prolactin level of <19 ng/mL in the first postoperative week predicted surgical remission with a sensitivity of 77.8% and a specificity of 70.6% in patients who received preoperative dopamine agonist treatment.

CONCLUSIONS

In macro adenomas and/or giant adenomas with cavernous sinus invasion, and significant suprasellar extension, which constitutes the difficult part of prolactinoma treatment, neither surgery nor medical treatment alone may be effective enough. Both treatment modalities should be carried out together by a team of neurosurgery and endocrinology in the management of these patients.

Surgical outcomes of medically failed prolactinomas: a systematic review and meta-analysis

PURPOSE

In Prolactinomas, surgery or radiation are reserved for DA failure due to tumor resistance, intolerance to medication-induced side-effects, or patient preference. This systematic review and meta-analysis summarizes the currently available literature regarding the effectiveness of surgery to treat prolactinomas in patients who have failed DA therapy.

METHOD

A literature search was conducted according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines for studies that reported outcomes of medically resistant and intolerant prolactinoma treated surgically.

RESULTS

10 articles (Total N = 816, Surgery N = 657) met the inclusion criteria. 38% of patients who underwent surgery following DA failure achieved remission without need for further treatment (p < 0.001, I² = 67.09%) with a median follow-up of 49.2 +/- 40 months. 62% achieved remission with multimodal treatment (p < 0.001, I² = 93.28%) with a median follow-up of 53 +/- 39.8 months. 16% of cases demonstrated recurrence after early remission (p = 0.02, I² = 62.91%) with recurrence occurring on average at 27 +/- 9 months. Overall, 46% of patients required reinstitution of postoperative DA therapy at last follow up (p < 0.001, I² = 82.57%). Subgroup analysis of macroprolactinoma and microprolactinoma has demonstrated that there is no statistical significance in achieving long-term remission with surgery stand-alone in macroprolactinoma group (p = 0.49) although 43% of patients were able to achieve remission with multimodal therapy at last follow-up in the same group (p < 0.001, I² = 86.34%).

CONCLUSIONS

This systematic review and meta-analysis revealed 38% of operated patients achieved remission, while 62% achieved remission when additional modes of therapy were implemented. Therefore, although surgery has not been initial therapeutic choice for prolactinoma, it plays a significant role in medically failed prolactinoma care.

Molecular Pathways in Prolactinomas: Translational and Therapeutic Implications

Prolactinoma has the highest incidence rate among patients with functional pituitary tumours. Although mostly benign, there is a subgroup that can be aggressive. Some clinical, radiological and pathology features have been associated with a poor prognostic. Therefore, it can be considered as a group of heterogeneous tumours. The aim of this paper is to give an overview of the molecular pathways involved in the behaviour of prolactinoma in order to improve our approach and gain deeper insight into the better understanding of tumour development and its management. This is essential for identifying patients harbouring aggressive prolactinoma and to establish personalised therapeutics options.

Cure and Hormonal Control After Prolactinoma Resection: Case Series and Systematic Review

Context

Surgical management of prolactinomas is an important treatment for patients intolerant of dopamine agonist therapy. However, predictors of postoperative outcomes remain unclear.

Object

While transsphenoidal surgical resection (TSSR) is important second-line therapy in prolactinoma patients, predictors of surgical cure and biochemical remission following TSSR remain sparse.

Methods

A retrospective review of prolactinoma patients undergoing TSSR at the USC Pituitary Center from 1995 to 2020 was conducted. Participants were categorized as surgical cure (normalization of serum prolactin without medical treatment), surgical noncure, biochemical control (prolactin normalization with or without adjuvant therapy), and nonbiochemical control. A systematic review of the outcomes of surgically managed prolactinomas was performed.

Results

The 40 female and 16 male participants had an average age of 35.6 years. Prior treatment included transsphenoidal resection (6, 11%) and dopamine agonist treatment (47, 84%). The 40 macroadenomas and 15 microadenomas exhibited suprasellar extension (24, 43%) and parasellar invasion (20, 36%). Fifteen (27%) were purely intrasellar. Gross total resection was achieved in 25 patients (45%) and subtotal in 26 (46%). Surgical cure was achieved in 25 patients (46%) and biochemical control in 35 (64%). Surgical cure was more likely in smaller, noninvasive tumors, those that were fully resected, and patients with lower preoperative (< 1000 ng/mL) and immediately postoperative (< 7.6 ng/mL) prolactin levels. Ten of 26 patients (38%) undergoing adjuvant therapy achieved biochemical control, which was less likely in men and those with higher preoperative prolactin or invasive tumors.

Conclusion

Surgical resection of prolactinomas is a safe procedure that, when offered judiciously, can achieve symptom and/or biochemical control in a majority of patients. A variety of predictors may be useful in advising patients on likelihood of postoperative remission.

Surgery and Medical Treatment in Microprolactinoma: A Systematic Review and Meta-Analysis

OBJECTIVE

Dopamine agonists (DAs) are recommended as the first-line treatment for prolactinomas; however, tumour recurrence after drug withdrawal remains a clinical problem. Recent studies have reported high remission rates via surgery in microprolactinomas. The aim of this systematic review and meta-analysis was to compare the clinical result of DA treatment with surgery as initial therapy in patients with treatment-naive microprolactinoma.

METHODS

A comprehensive literature search for studies and reports regarding microprolactinoma patients treated with DAs and/or surgery published between January 1970 and November 2020 was conducted using four electronic databases (PubMed, Embase, Google Scholar, and the Cochrane Library). Clinical treatment outcome was evaluated by the biochemical remission of serum prolactin level to normal after treatment. The I ² statistic was used to quantify heterogeneity. Pooled data were analysed according to a random effect model.

RESULTS

Eighteen studies with 661 patients were included for analysis. The DA treatment group achieved a higher remission rate at ≥12 months follow-up (96% vs. 86%; P=0.019). Surgery showed a higher remission rate than the DA treatment group after the treatment withdrawal (78% vs. 44%; P=0.003). Patients with preoperative prolactin level of ≤200 ng/mL had a higher remission rate than patients with preoperative prolactin level of >200 ng/mL (92% vs. 40%; P=0.029).

CONCLUSION

Surgery showed a high remission rate in treatment-naive microprolactinoma patients after treatment withdrawal and may be an alternative first-line treatment strategy in addition to DAs, particularly in patients with a preoperative prolactin level of ≤200 ng/mL.

Temozolomide cytoreductive treatment in a giant cabergoline-resistant prolactin-secreting pituitary neuroendocrine tumor

Dopamine agonists (DAs, especially cabergoline) are recommended as first-line treatment in patients with prolactin-secreting pituitary adenomas, to reduce hormone secretion and tumor size. Pituitary surgery, suggested in nonresponsive patients, cannot achieve a gross total resection or is not feasible in some cases. Temozolomide (TMZ) has been proposed in patients with aggressive pituitary neuroendocrine tumors (PitNETs) who do not respond to conventional treatments. We present a 47-year-old man with a giant (70×51×64 mm) prolactin-secreting PitNET. Cabergoline treatment (at first 1.5 mg/week, and then increased to 3.5 mg/week after 3 months) achieved prolactin suppression; however, magnetic resonance revealed a stable mass. After explanation of surgical complications, the patient rejected the procedure. Therefore, a primary neoadjuvant cytoreductive TMZ treatment was discussed during a meeting of the Pituitary Multidisciplinary Team, and added to cabergoline. After 13 cycles of TMZ (1 year of treatment), we observed dramatic reduction of the PitNET (from 18 cm of adenoma to 6 cm of necrotic tissue). MRI performed 4, 12, and 18 months after TMZ discontinuation revealed a stable residual PitNET, and 1.5 mg/week of cabergoline has been continued until today. Recently, the criteria for developing Pituitary Tumors Centers of Excellence have been proposed, indicating that a multidisciplinary team is the best care for patients. Surgery, rejected by the patient, could only achieve a partial resection; therefore, we decided to combine TMZ and cabergoline. An early initiation of TMZ could be considered in selected cases, especially when surgery could be only partially effective.

Predictors of dopamine agonist resistance in prolactinoma patients

BACKGROUND

Surgical resection of prolactinomas resistant to dopamine agonists is frequently incomplete due to fibrotic changes of the tumour under pharmacological therapy. In order to identify a subgroup of patients who may benefit from early surgery, we thought to investigate possible predictive factors of pharmacological resistance of prolactinomas to dopamine agonists.

METHODS

We retrospectively analyzed a database of a Belgian tertiary reference center for patients with pituitary tumours from 2014 to 2016. The groups of interest were patients with dopamine agonist responsive and resistant prolactinomas. The possible predictive factors, including MRI findings, endocrinological parameters, response of tumour and patient factors for dopamine agonist resistance were investigated.

RESULTS

We included 69 patients of whom 52 were women (75,4%) and 17 were men (24,6%). Rate of dopamine agonist resistance was 15.9%. We identified four significant predictors of dopamine agonist resistance: male gender, a large tumour volume, prolonged time to prolactin normalization and presence of a cystic, hemorrhagic and/or necrotic component. In addition, symptoms due to mass effect, high baseline prolactin level and a high contrast capture on MRI are factors that can be taken into consideration.

CONCLUSION

We identified predictive factors for pharmacological resistance and developed a scoring system for patient specific prediction of resistance to dopamine agonists. This scoring system may have impact on the timing and decision of surgery in prolactinoma patients after further prospective evaluation.

Macroprolactinomas: longitudinal assessment of biochemical and imaging therapeutic responses

PURPOSE

To assess biochemical and imaging therapeutic response rates, when these occur and their predictive factors in patients with macroprolactinomas treated with dopamine agonists (DA).

METHODS

Retrospective, longitudinal study of patients with macroprolactinomas treated with DA for ≥12 months.

OUTCOMES

prolactin normalization, reduction in maximum tumor diameter ≥50% and time until therapeutic responses.

RESULTS

We included 67 patients; 49.3% females, with median age at diagnosis of 43 years, 61.2% only treated with bromocriptine, 10.4% only with cabergoline, and 28.4% with both DA. Median follow-up time was 73 months. Prolactin levels normalized in 87%, mostly during the first 2 years. Prolactin levels after 6 months (HR 0.994, p = 0.012), 1 year (HR 0.970, p = 0.003), and 2 years (HR 0.970, p = 0.015) predicted its normalization time. Only 62% of the patients achieved a ≥50% reduction in maximum tumor diameter. Percent tumor diameter reduction after 1 year (OR 1.098, p = 0.022) and 2 years (OR 1.102, p = 0.008) predicted a ≥50% size reduction. Size reduction occurred later than prolactin normalization. Initial tumor diameter (HR 1.050, p = 0.032) and its percent reduction at 6 months (HR 1.110, p = 0.002), 1 (HR 1.060, p < 0.001), 2 (HR 1.045, p < 0.001), 3 (HR 1.048, p = 0.002), and 4 years (HR 1.074, p = 0.042) predicted the time until imaging response.

CONCLUSION

A significant number of patients did not obtain an imaging response. Biochemical and imaging responses were asynchronous and occurred mainly in the first 4 years of treatment. This may allow an earlier identification of partially resistant and resistant macroprolactinomas, with consequent change in the therapeutic approach.

Long-term follow-up of female prolactinoma patients at child-bearing age after transsphenoidal surgery

CONTEXT

Prolactinoma is the most common subtype of functional pituitary adenoma. Effective therapy is required for women of child-bearing age to achieve remission at serum prolactin level and regain reproductive function.

PURPOSE

To evaluate long-term outcomes, including menstrual recovery, after transsphenoidal surgery on female prolactinoma patients by experienced neurosurgeons.

DESIGN

Observational study.

PATIENTS

Consecutive female prolactinoma patients aged from 16 to 45 years were included. Histological analysis after surgery revealed adenoma with positive staining for prolactin. Plurihormonal cell adenomas were excluded.

MAIN MEASUREMENTS

Clinical manifestations, surgical indications, serum prolactin level before and after surgery, surgical complications, pituitary fuctions, drug maintenance, the status of menstruation, and pregnancy.

RESULTS

Sixty-three consecutive female patients with a mean age of 29.5 ± 1.1 years were included. Based on magnetic resonance imaging findings before surgery, 31 (49.2%) patients had microadenoma, and the remaining 32 (50.8%) had macroadenoma. The median follow-up after transsphenoidal surgery was 53 (33-74) months, and long-term surgical remission was achieved in 50 (79.37%) patients with 28 (90.32%) microadenomas and 22 (68.75%) macroadenomas. No meningitis or persistent cerebrospinal fluid leaks occurred. Only one case suffered from persistent diabetes insipidus at follow-up. No severe pituitary dysfunction was observed in microprolactinoma patients. Of patients with menstrual disorders, 85% regained regular menstrual cycles after surgery. Nineteen patients in this cohort desired pregnancy and 15 of them successfully gave birth after surgery. All 17 microadenoma patients with modern surgical indications achieved normal prolactin levels and regular menstrual cycles with only one patient on drug therapy at follow-up.

CONCLUSION

Long-term follow-up showed a high remission rate in female prolactinoma patients, especially in microadenoma patients, after surgery. Transsphenoidal surgery performed by experienced neurosurgeons may offer a valuable approach to treat female microprolactinoma patients of child-bearing age with modern indications for surgery.