Trans-sphenoidal surgery for microprolactinoma: an acceptable alternative to dopamine agonists?

The role of surgical management for prolactin-secreting tumors in the era of dopaminergic agonists: An international multicenter report

OBJECTIVE

First-line prolactin-secreting tumor (PST) management typically involves treatment with dopamine agonists and the role of surgery remains to be further explored. We examined the international experience of 12 neurosurgical centers to assess the patient characteristics, safety profile, and effectiveness of surgery for PST management.

METHODS

Patients surgically treated for PST from January 2017 through December 2020 were evaluated for surgical characteristics, outcomes, and safety.

RESULTS

Among 272 patients identified (65.1% female), the mean age was 38.0 ± 14.3 years. Overall, 54.4% of PST were macroadenomas. Minor complications were seen in 39.3% of patients and major complications were in 4.4%. The most common major complications were epistaxis and worsened vision. Most minor complications involved electrolyte/sodium dysregulation. At 3-6 months, local control on imaging was achieved in 94.8% of cases and residual/recurrent tumor was seen in 19.3%. Reoperations were required for 2.9% of cases. On multivariate analysis, previous surgery was significantly predictive of intraoperative complications (6.14 OR, p < 0.01) and major complications (14.12 OR, p < 0.01). Previous pharmacotherapy (0.27 OR, p = 0.02) and cavernous sinus invasion (0.19 OR, p = 0.03) were significantly protective against early endocrinological cure. Knosp classification was highly predictive of residual tumor or PST recurrence on 6-month follow-up imaging (4.60 OR, p < 0.01). There was noted institutional variation in clinical factors and outcomes.

CONCLUSION

Our results evaluate a modern, multicenter, global series of PST. These data can serve as a benchmark to compare with DA therapy and other surgical series. Further study and longer term outcomes could provide insight into how patients benefit from surgical treatment.

Surgery as a first-line option for prolactinomas

INTRODUCTION

Treatment of prolactinomas with dopamine agonists has been the established first-line treatment option for many years, with surgery reserved for refractory cases or medication intolerance. This approach may not be the best option in many cases.

AREAS COVERED

Review of the epidemiology, biology, and treatment options available for prolactinomas, including best available data on outcomes, costs, and morbidities for each therapy. These data are then used to propose a 'surgery-first' treatment approach for a subset of prolactinomas as an alternative to primary medical management.

EXPERT OPINION

Based on the available data, there is a strong rationale that transsphenoidal surgery should be considered a first-line treatment option for both micro- and macro-prolactinomas that do not demonstrate high grade cavernous sinus invasion on MRI imaging, with dopamine agonists administered as a secondary therapy for tumors not in remission following surgery, and for giant tumors. This 'surgery-first' approach assumes the availability of skilled and experienced pituitary surgeons to ensure optimal outcomes. This approach should result in high cure rates and reduced DA requirements for patients not cured from initial surgery. Further, it will reduce medical costs over a patient's lifetime and the chronic morbidities associated with protracted dopamine agonist usage.

Changes in the Options for Management of Prolactin Secreting Pituitary Adenomas

Objectives Initial therapy for the management of prolactinomas has long been maintained to be medical, consisting of a dopamine agonist. These therapies may have troublesome side effects, and some prolactinomas are resistant to medical therapy regarding lowering prolactin levels or shrinking the tumor. These issues have revived interest in surgery for prolactin-secreting adenomas as an early therapeutic option. We report our analysis of surgery for prolactin microadenomas in women, using the transsphenoidal endoscopic approach.

Design We reviewed a contemporary series of 33 women (mean age = 31.8 years) with microprolactinomas who underwent early surgical intervention, which was a three-dimensional transnasal transsphenoidal endoscopic operation.

Setting The study was conducted at a tertiary academic referral center for pituitary tumors.

Main Outcome Measures Preoperative and postoperative prolactin.

Results Overall, 28 patients had received preoperative dopamine agonists, 24 of these experienced a variety of drug-related side effects, and 4 had tumors that were resistant to lowering prolactin or tumor shrinkage. Preoperative prolactin levels averaged 90.3 ng/mL (range = 30.7–175.8 ng/mL). We observed a 94% normalization rate in postoperative prolactin (mean = 10.08 ng/mL, range = 0.3–63.1 ng/mL). During the follow-up (mean = 33.9 months), five patients had elevated prolactin; four required reinitiation of medical therapy, two had surgical reexploration, and none received radiation therapy. Complications included syndrome of inappropriate antidiuretic hormone secretion (n = 3), transient diabetes insipidus (n = 1), postoperative epistaxis (n = 1), and fat graft site infection (n = 1).

Conclusion This review supports the consideration of transsphenoidal surgery as an early intervention for some women with prolactin-secreting microadenoma. Indications include significant side effects of medical therapy and tumors that do not respond to standard medical management.

Are dopamine agonists still the first-choice treatment for prolactinoma in the era of endoscopy? A systematic review and meta-analysis

Background

For prolactinoma patients, dopamine agonists (DAs) are indicated as the first-line treatment and surgery is an adjunctive choice. However, with the development of surgical technique and equipment, the effect of surgery has improved. The aim of this study was to assess the efficacy and safety of surgery versus DAs in patients with different types of prolactinomas.

Methods

A systematic search of literature using Web of Science, PubMed, Cochrane Library, and Clinical Trial databases was conducted until July 12, 2019. Prolactinoma patients treated with DAs (bromocriptine or cabergoline) or surgery (microscopic or endoscopic surgery) were included. Outcomes included the biochemical cure rate, recurrence rate, prolactin level, improvement rates of symptoms, and incidence rates of complications. A random-effects model was used to pool the extracted data. Qualitative comparisons were conducted instead of quantitative comparison.

Results

DAs were better than surgery in terms of the biochemical cure rate (0.78 versus 0.66), but surgery had a much lower recurrence rate (0.19 versus 0.57). Full advantages were not demonstrated in improvement rates of symptoms and incidence rates of complications with both treatment options. In microprolactinoma patients, the biochemical cure rate of endoscopic surgery was equal to the average cure rate of DAs (0.86 versus 0.86) and it surpassed the biochemical cure rate of bromocriptine (0.86 versus 0.76). In macroprolactinoma patients, endoscopic surgery was slightly higher than bromocriptine (0.66 versus 0.64) in terms of the biochemical cure rate.

Conclusion

For patients with clear indications or contraindications for surgery, choosing surgery or DAs accordingly is unequivocal. However, for patients with clinical equipoise, such as surgery, especially endoscopic surgery, in microprolactinoma and macroprolactinoma patients, we suggest that neurosurgeons and endocrinologists conduct high-quality clinical trials to address the clinical equipoise quantitatively.

Supplementary Information

The online version contains supplementary material available at 10.1186/s41016-022-00277-1.

Postoperative remission of non-invasive lactotroph pituitary tumor: a single-center experience

BACKGROUND

Dopaminergic agonists (DA) are the first-line treatment in lactotroph pituitary tumor but treatment usually needs to be life-long. After surgical transphenoid resection, remission rates range from 60% to 90%, with low morbidity.

OBJECTIVE

The objective was to evaluate outcome of surgical treatment of selected non-invasive prolactinoma, and to identify factors associated with long-term remission.

METHOD

Early postoperative (3 months) and last follow-up data for non-invasive lactotroph tumors operated on in intention-to-cure in our center, between 2008 and 2017 were retrospectively reviewed: prolactin (PRL) level, DA treatment, pituitary function, and MRI data. Remission was defined as PRL plasma level below the upper limit of normal without DA treatment.

RESULTS

Fifty-three of the 60 patients (32 of the 33 microadenomas) were in remission at 3 months and 46 (28/33 microadenomas) at last follow-up 22.7 months (range, 1.1-126.5 months) after surgery. Five-year recurrence-free survival was 77.5% [65.8-91.2]. Male gender, larger tumor size at diagnosis and before surgery and higher plasma PRL level at diagnosis were all significantly associated with lower remission rates on univariate analysis. Transient diabetes insipidus and hyponatremia occurred in 2 and 5 patients respectively. One case of isolated thyrotroph insufficiency was observed. During follow-up, 13 women became pregnant (12 spontaneously).

CONCLUSION

This cohort confirmed the high remission rate of lactotroph tumors after surgery in a selected population, with limited morbidity, and conserved pituitary function in almost all cases.

Long-term Outcome of Microscopic Transsphenoidal Surgery for Prolactinomas as an Alternative to Dopamine Agonists

BACKGROUND

Although long-term dopamine agonist (DA) therapy is recommended as a first-line treatment for prolactinoma, some patients may prefer surgical treatment because of the potential adverse effects of long-term medication, or the desire to become pregnant. This study aimed to determine whether surgical treatment of prolactinomas could be an alternative to DA therapy.

METHODS

In this retrospective study, 96 consecutive patients (74 female, 22 male) underwent primary pituitary surgery without long-term DA treatment for prolactinomas at a single institution from 1990 to 2010. All patients underwent primary surgical treatment in the microscopic transsphenoidal approach (TSA).

RESULTS

The median age and median follow-up period were 31 (16-73) years and 139.1 (12.2-319.6) months, respectively. An initial overall remission was accomplished in 47.9% (46 of 96 patients, 33 macroadenomas, and 13 microadenomas) of patients. DA dose reduction was achieved in all patients after TSA. A better remission rate was independently predicted by lower diagnostic prolactin levels and by a greater extent of surgical resection. Overall remission at the last follow-up was 33.3%, and the overall recurrence rate was 30.4%. The permanent complication rate was 3.1%, and there was no mortality.

CONCLUSION

TSA can be considered a safe and potentially curative treatment for selective microprolactinomas as an alternative to treatment with a long-term DA.

Evaluation of Complications and Costs During Overlapping Transsphenoidal Surgery in the Treatment of Pituitary Adenoma

BACKGROUND

Pituitary adenomas are among the most common primary brain tumors. Recently, overlapping surgery has been curbed in many institutions because of the suggestion there might be more significant adverse events, despite several studies showing that complication rates are equivalent.

OBJECTIVE

To assess complications and costs associated with overlapping surgery during the transsphenoidal resection of pituitary adenomas.

METHODS

A single-center, retrospective cohort study was performed to evaluate the cases of patients who underwent a transsphenoidal approach for pituitary tumor resection. Patient, surgical, complication, and cost (value-driven outcome) variables were analyzed.

RESULTS

A total of 629 patients (302 nonoverlapping, 327 overlapping cases) were identified. No significant differences in age (P = .6), sex (P = .5), tumor type (P = .5), or prior rates of pituitary adenoma resection (P = .5) were seen. Similar presenting symptoms were observed in the 2 groups, and follow-up length was comparable (P = .3). No differences in tumor sizes (P = .5), operative time (P = .4), fat/fascia use (P = .4), or cerebrospinal fluid diversion (P = .8) were seen between groups. The gross total resection rate was not significantly different (P = .9), and no difference in recurrence rate was seen (P = .4). A comparable complication rate was seen between groups (P = .6). No differences in total or subtotal costs were seen either.

CONCLUSION

The results of this study offer additional evidence that overlapping surgery does not result in worsened complications, lengthened surgery, or increased patient cost for patients undergoing transsphenoidal resection of pituitary adenomas. Thus, studies and policy aiming to improve patient safety and cost should focus on optimizing other aspects of healthcare delivery.

Endoscopic Transsphenoidal Surgery of Microprolactinomas: A Reappraisal of Cure Rate Based on Radiological Criteria

BACKGROUND

Current standard treatment of microprolactinomas is dopamine agonist therapy. As this drug treatment is lifelong in up to 80% of cases, many patients consult pituitary surgeons regarding a surgical alternative.

OBJECTIVE

To identify prognostic criteria for surgical remission, we reviewed outcomes of our series of microprolactinomas treated with endoscopic transsphenoidal surgery, with a special emphasis on magnetic resonance adenoma delineation and position.

METHODS

Our study cohort comprises a single center series of 60 patients operated for histopathologically verified magnetic resonance imaging unequivocally identifiable endosellar microprolactinoma between 2003 and 2017. In 31 patients the adenoma was enclosed by pituitary gland (group ENC), in 29 patients the adenoma was located lateral to the gland adherent to the medial cavernous sinus wall (group LAT).

RESULTS

After a mean follow-up of 37 mo (range 4-143 mo), remission rate was significantly higher in adenomas enclosed by pituitary gland (group ENC) than adenomas located lateral to the gland (group LAT), with 87% vs 45%, P = .01. Intraoperatively, 4 patients showed signs of invasiveness. Preoperative prolactin levels did not differ between the groups (mean 155 and 187 ng/ml in group ENC and LAT, respectively).A binary logistic regression model revealed that only the radiological criteria applied showed a significant correlation (P = .003) with endocrine remission.

CONCLUSION

According to our results, remission rate is significantly higher in microprolactinomas enclosed by the pituitary gland. However, the decision for surgery should take into account surgeons experience and possibility of complications.

Surgery for prolactinomas: a better choice?

PURPOSE

Renewed interest in transsphenoidal surgery (TSS) as a therapeutic option for prolactinomas has emerged.

METHODS

Based on contemporary literature and own experience, the changing role of surgery for treatment of prolactinomas is discussed.

RESULTS

Today, TSS is performed by minimally invasive microscopic or endoscopic techniques. Normoprolactinemia is obtained in 71-100% of patients with microprolactinomas by TSS. Almost equal results are found in circumscribed intrasellar macroprolactinomas. In experienced hands, pituitary function is preserved in TSS. The risk of cardiac valve disease is still a concern with ergot-derived dopamine-agonists (DAs) in patients requiring long-term, high-dose dopamine-agonist (DA) treatment. Cost-utility analysis favors TSS over DA treatment. The possible negative impact of DA treatment on future surgical results is still a controversial and unsettled issue. In patients who wish to become pregnant, the advantages of microprolactinoma removal to avoid DAs and macroprolactinoma debulking to avoid symptomatic enlargement during pregnancy should be discussed with the patients. Young patients' age is an argument for surgery to circumvent the unpredictable sequelae of long-term DA treatment. Surgery should be discussed in male gender because of a higher likelihood of DA resistance and aggressive behavior of prolactinoma.

CONCLUSION

Given excellent results of TSS and concerns about medical treatment, the scale of indications for TSS as an alternative to DAs has increased. The patient's wishes concerning a chance at a cure with TSS instead of a long-term treatment with DAs has become an important and accepted indication. With DA medication and TSS, two effective treatment modalities for prolactinomas are available that can be used in a complementary fashion.

Prolactinomas and nonfunctioning adenomas: preoperative diagnosis of tumor type using serum prolactin and tumor size

OBJECTIVE

Prolactinoma and nonfunctioning adenoma (NFA) are the most common sellar pathologies, and both can present with hyperprolactinemia. There are no definitive studies analyzing the relationship between the sizes of prolactinomas and NFAs and the serum prolactin level. Current guidelines for serum prolactin level cutoffs to distinguish between pathologies are suboptimal because they fail to consider the adenoma volume. In this study, the authors attempted to describe the relationship between serum prolactin level and prolactinoma volume. They also examined the predictive value that can be gained by considering tumor volume in differentiating prolactinoma from NFA and provide cutoff values based on a large sample of patients.

METHODS

A retrospective analysis of consecutive patients with prolactinomas (n = 76) and NFAs (n = 217) was performed. Patients were divided into groups based on adenoma volume, and the two pathologies were compared.

RESULTS

A strong correlation was found between prolactinoma volume and serum prolactin level (r = 0.831, p < 0.001). However, there was no significant correlation between NFA volume and serum prolactin level (r = -0.020, p = 0.773). Receiver operating characteristic curve analysis of three different adenoma volume groups was performed and resulted in different serum prolactin level cutoffs for each group. For group 1 (≤ 0.5 cm3), the most accurate cutoff was 43.65 μg/L (area under the curve [AUC] = 0.951); for group 2 (> 0.5 to 4 cm3), 60.05 μg/L (AUC = 0.949); and for group 3 (> 4 cm3), 248.15 μg/L (AUC = 1.0).

CONCLUSIONS

Prolactinoma volume has a significant impact on serum prolactin level, whereas NFA volume does not. This finding indicates that the amount of prolactin-producing tissue is a more important factor regarding serum prolactin level than absolute adenoma volume. Hence, volume should be a determining factor to distinguish between prolactinoma and NFA prior to surgery. Current serum prolactin threshold level guidelines are suboptimal and cannot be generalized across all adenoma volumes.

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.

Cost-Effectiveness Analysis of Surgical versus Medical Treatment of Prolactinomas

Background Few studies address the cost of treating prolactinomas. We performed a cost-utility analysis of surgical versus medical treatment for prolactinomas. Materials and Methods We determined total hospital costs for surgically and medically treated prolactinoma patients. Decision-tree analysis was performed to determine which treatment produced the highest quality-adjusted life years (QALYs). Outcome data were derived from published studies. Results Average total costs for surgical patients were $19,224 ( ± 18,920). Average cost for the first year of bromocriptine or cabergoline treatment was $3,935 and $6,042, with $2,622 and $4,729 for each additional treatment year. For a patient diagnosed with prolactinoma at 40 years of age, surgery has the lowest lifetime cost ($40,473), followed by bromocriptine ($41,601) and cabergoline ($70,696). Surgery also appears to generate high health state utility and thus more QALYs. In sensitivity analyses, surgery appears to be a cost-effective treatment option for prolactinomas across a range of ages, medical/surgical costs, and medical/surgical response rates, except when surgical cure rates are ≤ 30%. Conclusion Our single institution analysis suggests that surgery may be a more cost-effective treatment for prolactinomas than medical management for a range of patient ages, costs, and response rates. Direct empirical comparison of QALYs for different treatment strategies is needed to confirm these findings.

Postoperative Care Following Pituitary Surgery

Patients undergoing surgery for pituitary tumors represent a heterogeneous population each with unique clinical, biochemical, radiologic, pathologic, neurologic, and/or ophthalmologic considerations. The postoperative management of patients following pituitary surgery often occurs in the context of a dynamic state of the hypothalamic-pituitary-end organ axis. Consequently, a significant component of the postoperative care of these patients focuses on vigilant screening and observation for neuroendocrinologic perturbations such as varying degrees of hypopituitarism and disorders of water balance (diabetes insipidus and the syndrome of inappropriate antidiuretic hormone). Additionally, one must be cognizant of other potential complications specific to the transsphenoidal approach for tumor removal including cerebrospinal fluid leakage and meningitis. This review addresses the postoperative management of patients undergoing pituitary surgery with an emphasis on careful screening and recognition of complications.

THERAPY OF ENDOCRINE DISEASE: Surgery in microprolactinomas: effectiveness and risks based on contemporary literature

Microprolactinomas are the most common pituitary adenomas. In symptomatic patients, dopamine agonists are the first-line treatment of choice; when cabergoline is used, biochemical control rates between 85 and 93% have been reported. Long-term treatment is needed in most of the cases with compliance, patient convenience, and potential adverse effects representing areas requiring attention. Based on the literature published in the past 15 years, transsphenoidal surgery can lead to normal prolactin in the postoperative period in usually 71-100% of the cases with very low postoperative complication rates. Surgical expertise is the major determinant of the outcomes, and it may be a cost-effective option in young patients with life expectancy greater than 10 years (provided it is performed by experienced surgeons at high volume centers with confirmed optimal outcomes). Larger series of patients with adequate follow-up could further validate the place of transsphenoidal surgery (particularly through the endoscopic approach for which long-term results are currently limited) in the management algorithm of patients with microprolactinoma.

Effect of the preoperative use of dopamine agonists in the postoperative course of prolactinomas: a systematic review

OBJECTIVE

Since the 1980s, it has been discussed whether the preoperative treatment of prolactinomas with dopamine agonists (DAs) is beneficial or detrimental regarding postoperative residue or recurrence. Many neurosurgeons have emphasized the difficulties caused by fibrosis during the ablation of such prolactinomas.

METHODS

From February to December 2012, the authors searched electronic databases and book chapters published from 1991 to 2012; a total of 3,771 articles and 37 book chapters were searched. Ten articles that explicitly addressed this issue were identified.

RESULTS

Five articles reported that preoperative treatment did not affect postoperative status. One article described a positive influence of preoperative treatment with DAs (P < .01), and 3 articles found a negative influence (P = .040, P = .02, no significance value reported). One article described histopathological evidence of tumor fibrosis that was found intraoperatively after preoperative DA treatment.

CONCLUSIONS

This systematic review did not identify any strong evidence that preoperative treatment of prolactinomas with DAs is harmful or beneficial. Therefore, further studies are needed.

Cost-Effectiveness Analysis of Microscopic and Endoscopic Transsphenoidal Surgery Versus Medical Therapy in the Management of Microprolactinoma in the United States

BACKGROUND

Although prolactinomas are treated effectively with dopamine agonists, some have proposed curative surgical resection for select cases of microprolactinomas to avoid life-long medical therapy. We performed a cost-effectiveness analysis comparing transsphenoidal surgery (either microsurgical or endoscopic) and medical therapy (either bromocriptine or cabergoline) with decision analysis modeling.

METHODS

A 2-armed decision tree was created with TreeAge Pro Suite 2012 to compare upfront transsphenoidal surgery versus medical therapy. The economic perspective was that of the health care third-party payer. On the basis of a literature review, we assigned plausible distributions for costs and utilities to each potential outcome, taking into account medical and surgical costs and complications. Base-case analysis, sensitivity analysis, and Monte Carlo simulations were performed to determine the cost-effectiveness of each strategy at 5-year and 10-year time horizons.

RESULTS

In the base-case scenario, microscopic transsphenoidal surgery was the most cost-effective option at 5 years from the time of diagnosis; however, by the 10-year time horizon, endoscopic transsphenoidal surgery became the most cost-effective option. At both time horizons, medical therapy (both bromocriptine and cabergoline) were found to be more costly and less effective than transsphenoidal surgery (i.e., the medical arm was dominated by the surgical arm in this model). Two-way sensitivity analysis demonstrated that endoscopic resection would be the most cost-effective strategy if the cure rate from endoscopic surgery was greater than 90% and the complication rate was less than 1%. Monte Carlo simulation was performed for endoscopic surgery versus microscopic surgery at both time horizons. This analysis produced an incremental cost-effectiveness ratio of $80,235 per quality-adjusted life years at 5 years and $40,737 per quality-adjusted life years at 10 years, implying that with increasing time intervals, endoscopic transsphenoidal surgery is the more cost-effective treatment strategy.

CONCLUSIONS

On the basis of the results of our model, transsphenoidal surgical resection of microprolactinomas, either microsurgical or endoscopic, appears to be more cost-effective than life-long medical therapy in young patients with life expectancy greater than 10 years. We caution that surgical resection for microprolactinomas be performed only in select cases by experienced pituitary surgeons at high-volume centers with high biochemical cure rates and low complication rates.

Update on prolactinomas. Part 2: Treatment and management strategies

The authors present an update on the various treatment modalities and discuss management strategies for prolactinomas. Prolactinomas are the most common type of functional pituitary tumor. Effective hyperprolactinemia treatment is of great importance, due to its potential deleterious effects including infertility, gonadal dysfunction and osteoporosis. Dopamine agonist therapy is the first line of treatment for prolactinomas because of its effectiveness in normalizing serum prolactin levels and shrinking tumor size. Though withdrawal of dopamine agonist treatment is safe and may be implemented following certain recommendations, recurrence of disease after cessation of the drug occurs in a substantial proportion of patients. Concerns regarding the safety of dopamine agonists have been raised, but its safety profile remains high, allowing its use during pregnancy. Surgery is typically indicated for patients who are resistant to medical therapy or intolerant of its adverse side effects, or are experiencing progressive tumor growth. Surgical resection can also be considered as a primary treatment for those with smaller focal tumors where a biochemical cure can be expected as an alternative to lifelong dopamine agonist treatment. Stereotactic radiosurgery also serves as an option for those refractory to medical and surgical therapy.

Endocrinological outcomes of pure endoscopic transsphenoidal surgery: a Croatian Referral Pituitary Center experience

AIM

To analyze early remission, complications, and pituitary function recovery after pure endoscopic endonasal transsphenoidal surgery (PEETS), a novel method in pituitary adenoma treatment.

METHODS

Testing of all basal hormone values and magnetic resonance imaging (MRI) were performed preoperatively and postoperatively (postoperative MRI only in nonfunctioning adenomas) in 117 consecutive patients who underwent PEETS in the period between 2007 and 2010. The series consisted of 21 somatotroph adenomas, 61 prolactinomas, and 4 corticotroph and 31 nonfunctioning adenomas. Sixty-three were macroadenomas and 54 were microadenomas. Remission was defined as hormonal excess normalization on the seventh postoperative day in functioning adenomas and as normal MRI findings approximately four months postoperatively in nonfunctioning adenomas. The presence of hypogonadism, growth hormone deficiency, and hypothyroidism was assessed on the seventh postoperative day. Hypocortisolism was assessed through necessity for replacement therapy within 18 months postoperatively.

RESULTS

Remission was achieved in 84% of patients: in 100% of microadenoma and 70% of macroadenoma patients (P<0.001, odds ratio [OR], 28.16, 95% confidence interval [CI], 1.61-491.36), respectively. Endocrinological complications occurred in 17.1% of patients: in 9% of microadenoma and 24% of macroadenoma patients (P=0.049, OR, 3.06; 95% CI, 1.03-9.08). Duration of empirical hydrocortisone replacement therapy was significantly shorter in microadenoma patients (P<0.001). Thirty-five percent of preoperatively present hormonal deficiencies improved after the surgery. Between tumor types there were no significant differences in remission, complications, and normal pituitary function recovery.

CONCLUSION

Patients with microadenomas had higher remission and lower complication rates following PEETS, emphasizing the necessity for early detection and treatment of pituitary adenomas. PEETS is a discussion-worthy method for microprolactinoma treatment.

Transsphenoidal surgery for microprolactinomas in women: results and prognosis

BACKGROUND

Long-term dopamine agonist (DA) therapy is recommended as a first-line approach for the management of microprolactinomas. However, DA therapy may be poorly tolerated by some patients, and therefore some patients continue to prefer surgery over DA therapy.

AIM

The aim of our study was to evaluate factors associated with favorable outcomes after surgical treatment of microprolactinomas in women.

METHODS

Thirty-two women (mean age 31.0 ± 8.2 years) with confirmed microprolactinomas who were operated using transsphenoidal approach were included to the study. Twenty-two (61 %) women had previous DA therapy and ten (39 %) women preferred surgery as a first treatment. Mean follow-up was 4.2 ± 2.7 years. Surgery was considered to be effective and remission achieved if serum prolactin was normal without DA therapy and there were no signs of tumor re-growth on neuroimaging.

RESULTS

Nine (47.4 %) patients in whom remission was achieved did not receive preoperative DA therapy when compared to one (7.7 %) patient in whom remission was not achieved (p = 0.02). Remission after operation was achieved in nine out of ten (90 %) patients who did not receive DA therapy compared to ten out of 22 patients (45.5 %) who were treated with DAs (p = 0.01). The independent factor associated with good outcome following surgical treatment was no preoperative DA therapy (RR = 14.57 (1.43-148.1), p = 0.02). Surgical complications were permanent diabetes insipidus in two patients (6.3 %) and transient DI in five (15.6 %) patients.

CONCLUSIONS

The main factor associated with favorable microprolactinoma surgery outcome in women was the absence of preoperative DA therapy.

Clinical factors involved in the recurrence of pituitary adenomas after surgical remission: a structured review and meta-analysis

To study the currently available data of recurrence rates of functioning and nonfunctioning pituitary adenomas following surgical cure and to analyze associated predisposing factors, which are not well established. A systematic literature search was conducted using Medline, Embase, Web of Science and the Cochran Library for studies reporting data on recurrence of pituitary adenoma after surgery, in nonfunctioning adenoma (NF), prolactinoma (PRL) acromegaly (ACRO) and Cushing's disease (CUSH). Of 557 initially retrieved potential relevant studies 143 were selected. Recurrence in NFA was defined as reappearance of tumor on MRI or CT. Increase of hormone levels above normal limits as set by the authors after initial remission was used to indicate recurrence in the functioning tumor types. Remission percentage was lowest in NFA compared with other tumor types (P < 0.001). Surgery-related hypopituitarism was more frequent in CUSH than in the other tumors (P < 0.001). Recurrence, expressed as percentage of the cured population or as ratio of recurrence and total patient years of follow-up was highest in PRL (P < 0.001). The remission percentage did not improve over 3 decades of publications, but there was a modest decrease in recurrence rate (P = 0.04). Recurrences peaked between 1 and 5 years after surgery. Most of the studies with a sufficient number of recurrences did not apply multivariate statistics, and mentioned at best associated factors. Age, gender, tumor size and invasion were generally unrelated to recurrence. For functioning adenomas a low postoperative hormone concentration was a prognostically favorable factor. In NFA no specific factor predicted recurrence. Recurrence rate differs between pituitary adenomas, being highest in patients with prolactinoma, with the highest incidence of recurrence between 1 and 5 years after surgery in all adenomas. Patients with NFA have a lower chance of remission than patients with functioning adenomas. The postoperative basal hormone level is the most important predictor for recurrence in functioning adenomas, while in NFA no single convincing factor could be identified.

Recurrence of hyperprolactinaemia following discontinuation of dopamine agonist therapy in patients with prolactinoma occurs commonly especially in macroprolactinoma

CONTEXT

The optimal duration of dopamine agonist (DA) therapy in prolactinoma is unknown. There are concerns that despite low recurrence rates in highly selected groups, high recurrence rates after DA withdrawal may occur in routine practice.

OBJECTIVE

To explore recurrence of hyperprolactinaemia and predictive factors following DA withdrawal in patients with microprolactinoma and macroprolactinoma.

DESIGN

A retrospective study on adult patients with confirmed prolactinoma attending the Oxford Endocrine Department.

PATIENTS AND MEASUREMENTS

We identified patients with macroprolactinoma (n = 15) and microprolactinoma (n = 45) treated with DA therapy for >3 years, with a trial off DA therapy. None had other treatments. Measurements included recurrence of hyperprolactinaemia following DA withdrawal, tumour size (macroprolactinomas), duration of DA therapy, prolactin levels (baseline, during DA therapy, recurrence) and time to recurrence. Data were reported as mean (range).

RESULTS

During DA therapy, prolactin levels suppressed to normal range in all patients with macroprolactinoma and microprolactinoma, and most macroprolactinomas (n = 14) had substantial tumour shrinkage. Hyperprolactinaemia recurred in 93% of macroprolactinomas (n = 14) at 8·8 months (3-36) and 64% of microprolactinomas (n = 29) at 4·8 months (3-12). Duration of DA therapy was 7·5 years (4-15) for macroprolactinomas and 4·1 years (3-10) for microprolactinomas. Prolactin levels during DA therapy were 144 mU/l (7-336) for macroprolactinomas and 278 mU/l (30-629) for microprolactinomas. For microprolactinomas, prolactin levels during DA therapy were less suppressed in those with recurrence than in those without recurrence (P < 0·05).

CONCLUSIONS

In routine practice, hyperprolactinaemia recurs early in most macroprolactinomas (93%) and microprolactinomas (64%) following DA therapy discontinuation. For most macroprolactinomas, cessation of DA cannot be recommended even after 7 years of therapy.

Pituitary surgery for small prolactinomas as an alternative to treatment with dopamine agonists

Despite the fact that consensus guidelines recommend long-term dopamine agonist (DA) therapy as a first-line approach to the treatment of small prolactinoma, some patients continue to prefer a primary surgical approach. Concerns over potential adverse effects of long-term medical therapy and/or the desire to become pregnant and avoid long-term medication are often mentioned as reasons to pursue surgical removal. In this retrospective study, 34 consecutive patients (30 female, 4 male) preferably underwent primary pituitary surgery without prior DA treatment for small prolactinomas (microprolactinoma 1-10 mm, macroprolactinoma 11-20 mm) at the Department of Neurosurgery, University of Bern, Switzerland. At the time of diagnosis, 31 of 34 patients (91%) presented with symptoms. Patients with microprolactinomas had significantly lower preoperative prolactin (PRL) levels compared to patients with macroprolactinomas (median 143 μg/l vs. 340 μg/l). Ninety percent of symptomatic patients experienced significant improvement of their signs and symptoms upon surgery. The postoperative PRL levels (median 3.45 μg/l) returned to normal in 94% of patients with small prolactinomas. There was no mortality and no major morbidities. One patient suffered from hypogonadotropic hypogonadism after surgery despite postoperative normal PRL levels. Long-term remission was achieved in 22 of 24 patients (91%) with microprolactinomas, and in 8 of 10 patients (80%) with macroprolactinomas after a median follow-up period of 33.5 months. Patients with small prolactinomas can safely consider pituitary surgery in a specialized centre with good chance of long-term remission as an alternative to long-term DA therapy.

Pure endoscopic transsphenoidal surgery for treatment of acromegaly: results of 67 cases treated in a pituitary center

Object

Acromegaly is a chronic disease related to the excess of growth hormone (GH) and insulin-like growth factor–I secretion, usually by pituitary adenomas. Traditional treatment of acromegaly consists of surgery, drug therapy, and eventually radiotherapy. The introduction of endoscopy as an additional tool for surgical treatment of pituitary adenomas and, therefore, acromegaly represents an important advance of pituitary surgery in the recent years. The aim of this retrospective study is to evaluate the results of pure transsphenoidal endoscopic surgery in a series of patients with acromegaly who were operated on by a pituitary specialist surgeon. The authors discuss the advantages, outcome, complications, and factors related to the success of the endoscopic approach in cases of GHsecreting adenomas.

Methods

The authors retrospectively analyzed data from cases involving patients with GH-secreting adenomas who underwent pure transsphenoidal endoscopic surgery at the Department of Neurosurgery of the General Hospital in Fortaleza, Brazil, between 2000 and 2009. Tumors were classified according to size as micro- or macroadenomas, and tumor extension was analyzed based on suprasellar/parasellar extension and sella floor destruction. All patients were followed up for at least 1 year. The criteria of disease control were GH levels < 1 ng/L after oral glucose tolerance test and normal insulin-like growth factor–I levels for age and sex.

Results

During the study period, 67 patients underwent pure endoscopic transsphenoidal surgery for treatment of acromegaly. Disease control was obtained in 50 cases (74.6%). The rate of treatment success was higher in patients with microadenomas (disease control achieved in 12 [85.7%] of 14 cases) than in those with larger lesions. Suprasellar/parasellar extension and high levels of sella floor erosion were associated with lower rates of disease control (p = 0.01 and p = 0.02, respectively). Complications related to the endoscopic surgery included epistaxis (6.0%), transitory diabetes insipidus (4.5%), and 1 case of seizure (1.5%).

Conclusions

Endoscopic transsphenoidal surgery represents an effective option for treatment of patients with acromegaly. High disease control rates and a small number of complications are some of the most important points related to the technique. Factors related to the success of the endoscopic surgery are lesion size, suprasellar/parasellar extension, and the degree of sella floor erosion. Although presenting important advantages, there is no conclusive evidence that endoscopy is superior to microsurgery in treatment of GH-secreting adenomas.

Diagnosis and treatment of prolactinomas

Prolactinomas account for approximately 40% of all pituitary adenomas. Hyperprolactinemia causes hypogonadism, infertility and galactorrhea. Macroprolactinomas may cause signs of local expansion, such as headache, visual field defects and paresis of oculomotor nerves during suprasellar and parasellar extensions. Compression of healthy pituitary tissue together with the blockade of the flow of hypothalamic released hormones to the pituitary by macroprolactinomas results in the development of hypopituitarism. The aim of treatment is restoration of hypogonadism and fertility in the microprolactinoma patients, as well as tumor shrinkage in macroprolactinoma patients. Primary therapy for prolactinomas is pharmacological treatment with dopamine agonists (DAs). However, surgical or radiation treatment is recommended for prolactinoma patients resistant or intolerant to DAs. In patients with long-term normoprolactinemia and significant tumor shrinkage, a trial of tapering and discontinuation of medical therapy is possible. After discontinuation of DAs, a long-term follow-up is necessary. In cases of recurrence displaying hyperprolactinemia and tumor enlargement, treatment must be resumed.

Diagnosis and treatment of pituitary microadenoma: report of 80 cases

OBJECTIVE

To analyse and discuss the diagnosis and treatment of pituitary microadenoma.

SUBJECTS AND METHODS

Eighty cases of pituitary microadenoma treated with transsphenoidal approach in our department were analysed retrospectively during the last 2 years.

RESULTS

During following-up of 13.0+/-3.2 months, neither remained tumor was found except one patients with microprolactinoma, nor recurrence. Diabetes insipidus occurred in 19 patients, among which 15 patients recovered in 1 week, three in 1 month and one in 7 months. The adrenocorticotrophic hormone deficiency was found in nine of 63 patients with PRL-, GH- and non-functioning microadenoma (12%), but hypoadrenalemia recovered in all patients. Among these nine patients, seven recovered in 3 months and two in 6 months. Dysosphesia occurred in 32 cases: 30 recovered in 1 month and two in 4 months. Thirteen of 15 patients (86.7%) with ACTH-secreting microadenoma achieved chemical remission judged by plasma cortisol levels<or=2 microg/dl within 72 hours of surgery. During the mean 13.0 months of follow-up, the symptoms of amenorrhea, galactorrhea, headache, obesity and sexual disturbance were improved greatly. In total, 93.7% (45/48) of patients had normal post-operative PRL levels in the patients who had no pre-operative treatment history of long time medical therapy and large dose medical therapy in short time.

CONCLUSIONS

(1) Transsphenoidal surgery (TSS) is safe and effective treatment for pituitary microadenoma; (2) TSS is considered to be definitive treatment for ACTH- and GH-secreting microadenoma once the diagnosis is established; (3) in order to obtain better effects, TSS could be offered as first-line treatment for patients with locally non-invasive PRL-secreting microadenoma (tumor larger than 3 mm in diameter) and non-functioning microadenoma.

Outcome of surgical intrasellar growth hormone tumor performed by a pituitary specialist surgeon in a developing country

BACKGROUND

Acromegaly is an excessive GH secretion, which in most cases, is caused by a pituitary GH-secreting adenoma. Traditional treatment of acromegaly consists of surgery, drug therapy, and eventually radiotherapy. The aim of this retrospective study is to evaluate the results of transsphenoidal endoscopic surgery in a group of patients with intrasellar GH adenoma who were operated by a pituitary specialist surgeon. We shall then argue about the economical advantages, for the NHS of a developing country, between surgical and medical treatment.

METHODS

We have analyzed data from 33 patients with intrasellar GH tumor who had been referred to the neuroendocrine department of the HGF, Brazil. The patients underwent a transsphenoidal endoscopic adenomectomy for acromegaly between 2000 and 2005. Their ages were between 20 and 67 years (mean, 44 years) at the moment of surgery. No cavernous sinus invasion was present. Follow-up was a median of 2 years (range, 12 months-6 years).

RESULTS

All 33 patients had intrasellar adenoma, 84.84% of patients achieved remission by surgery. One patient was operated twice and reached hormonal normalization. Five patients still had the disease and refused a second surgery. A treatment with octreotide was started for these 5 patients and resulted in an adequate control of GH and IGF-1 levels. No patients had radiotherapy.

CONCLUSION

Our patients, with intrasellar GH tumor, operated by a pituitary specialist neurosurgeon had remission rates approaching those obtained by most specialized neurosurgical centers worldwide. For equal results, our study shows that the surgical treatment is the best issue for the patient and for the NHS.

Hyperprolactinaemia

Hyperprolactinaemia is a frequent cause of reproductive problems encountered in clinical practice. A variety of pathophysiological conditions can lead to hyperprolactinaemia; therefore, pregnancy, drug effects, hypothyroidism and polycystic ovary syndrome should be excluded before investigating for prolactin-secreting pituitary tumours. Prolactinomas are mainly diagnosed in women aged 20-40 years. They present with clinical features of hyperprolactinaemia (galactorrhoea, gonadal dysfunction), and more rarely with large tumours, headache and visual field loss due to optic chiasm compression. Medical therapy with dopamine agonists is the treatment of choice for both micro- and macroprolactinomas. Tumour shrinkage and restoration of gonadal function are achieved in the majority of cases with dopamine agonists. A trial of withdrawal of medical therapy may be considered in many patients with close follow-up. Pituitary surgery and radiotherapy currently have very limited indications. Pregnancies in patients with prolactinomas need careful planning and close monitoring.

Biochemical remission and recurrence rate of secreting pituitary adenomas after transsphenoidal adenomectomy: long-term endocrinologic follow-up results

BACKGROUND

Transsphenoidal surgery is safe and effective in patients with secreting pituitary adenomas; however, variable outcomes have been reported according to the different criteria used to define the biochemical remission of hormone hypersecretion. We report the long-term endocrinologic follow-up results of a large cohort of patients who underwent TSS for secreting pituitary adenomas according to the most recent stringent criteria of cure.

METHODS

Two hundred ten consecutive patients were operated on by TSS between 1995 and 2004 for a secreting pituitary adenoma (65 PRL-, 109 GH-, and 36 ACTH-secreting adenomas) and were considered for the study.

RESULTS

The overall remission rate was 65% for the whole series, being 64%, 61%, and 75% for PRL-, GH-, and ACTH-secreting adenomas, respectively. Eighty-six percent of microadenomas and 53% of macroadenomas were cured by surgery. Remission rates were significantly higher in GH- and ACTH-secreting pituitary macroadenomas than in macroprolactinomas. At a median follow-up of 56 months, tumor recurrence was 0%, 11%, and 14% for GH-, ACTH-, and PRL-secreting tumors. Tumor size, cavernous sinus invasion, and high hormone levels were negatively correlated to the outcome.

CONCLUSION

Transsphenoidal surgery remains an effective treatment for secreting pituitary tumors according to the most recent criteria of cure. Patients with PRL- or ACTH-secreting adenomas may recur after apparently successful surgery, thereby justifying long-term careful endocrinologic follow-up.

Operative treatment of prolactinomas: indications and results in a current consecutive series of 212 patients

OBJECTIVE

Medical therapy with dopamine agonists (DA) is the primary treatment of choice in most patients with prolactinomas. 'Classical' surgical indications are intolerance or lack of efficiency of DA therapy. Focusing on a possible shift of recent indications, we retrospectively analyzed our results of surgical treatment in prolactinomas.

PATIENTS AND METHODS

Between 1990 and 2005, we have operated on 212 consecutive patients with prolactinomas. Surgical indications were divided into 'classical' indications and 'modern' indications defined as cystic prolactinomas or patients with microprolactinomas who individually decided on a primary surgical treatment.

RESULTS

Initial overall remission was accomplished in 53.2% including giant prolactinomas. However, in microadenomas, the remission rate was significantly higher with 91.3%. Overall remission at the latest follow-up was 42.7%, but 72.5% in intrasellar tumors, 80% in cystic prolactinomas, and 84.8% in microprolactinomas. The overall recurrence rate was 18.7%. Relapse of hyperprolactinemia in microprolactinomas was 7.1%. In our series, continually less patients were surgically treated for 'classical' indications. By contrast, the number of patients who individually decided on a primary surgical therapy has increased considerably.

CONCLUSION

Remission rates after surgical treatment of prolactinomas remain excellent, particularly in microadenoma and intrasellar macroadenomas, whereas morbidity of transsphenoidal surgery is low in the hands of experienced pituitary surgeons. Our remission rates not only confirm the already interdisciplinarily accepted surgical indications, but also emphasize the value of primary transsphenoidal surgery as a discussion-worthy alternative to dopaminergic therapy in young patients with microprolactinomas or cystic tumors.

Transsphenoidal surgery

Transsphenoidal surgery has evolved much over nearly 100 years. Initially operations were performed often without any input from endocrinology colleagues, and without preoperative imaging, operative magnification and illumination. Advances in the understanding of the biology of pituitary tumours, close co-operation between endocrinologists, surgeons and oncologists, and huge advances in imaging and surgical techniques have led to the evolution of the current transsphenoidal operation to the pituitary fossa to the point where a 'cure' is often possible with low complication rates. The indications, contraindications of transsphenoidal surgery will be discussed, together with nature of the surgical approach and how it can be applied to particular pituitary tumours and suprasellar lesions.

Radiotherapy of pituitary adenomas: state of the art

Pituitary adenomas represent approximately 12% of intracranial tumors. They are defined as tumors that are functional or nonfunctional and invasive or noninvasive. Therapeutic strategies rely on surgery, medical treatment, and radiotherapy depending on histology. Neither the role of external radiotherapy nor the technique to be used are firmly established. Nonfunctioning adenomas must be operated on to relieve the compression. Prolactin-secreting adenomas are first treated with dopamine agonists, and GH-secreting adenomas are first treated by surgery if excising the complete tumor is possible; otherwise medical treatment is started. The first-line treatment of ACTH-secreting adenomas is surgery; however, in many cases, insufficient control of either secretion or tumoral volume leads to consideration of irradiation. Complications of conventional radiotherapy are well known and fractionated stereotactic radiotherapy appears to be as safe as radiosurgery. The volume to irradiate is still difficult to define, and this parameter can influence the technique chosen for treatment. Because the indications of radiotherapy are still debated, irradiation of pituitary adenomas must be decided by the complete team of endocrinologists, neurosurgeons, radiologists and radiotherapists.

Prolactinoma surgery

Surgery is generally used as second-line treatment in prolactinomas. For microprolactinomas, it may be indicated in cases of resistance or intolerance to dopamine agonists or where patients prefer definitive cure to lifelong drug treatment. In highly trained hands, selective adenomectomy results in normalization of prolactin levels in 75-90% of cases with little morbidity and no mortality. However, subsequent relapse is possible in up to 20% of cases. In macroprolactinoma, a definitive cure is unlikely due to the frequency of invasive tumor extension. A transsphenoidal or, less frequently, a transfrontal surgical approach is necessary in patients resistant to or intolerant of medical treatment, and also in rare cases such as pituitary apoplexy or cerebrospinal fluid rhinorrhea.

Advances in the treatment of prolactinomas

Prolactinomas account for approximately 40% of all pituitary adenomas and are an important cause of hypogonadism and infertility. The ultimate goal of therapy for prolactinomas is restoration or achievement of eugonadism through the normalization of hyperprolactinemia and control of tumor mass. Medical therapy with dopamine agonists is highly effective in the majority of cases and represents the mainstay of therapy. Recent data indicating successful withdrawal of these agents in a subset of patients challenge the previously held concept that medical therapy is a lifelong requirement. Complicated situations, such as those encountered in resistance to dopamine agonists, pregnancy, and giant or malignant prolactinomas, may require multimodal therapy involving surgery, radiotherapy, or both. Progress in elucidating the mechanisms underlying the pathogenesis of prolactinomas may enable future development of novel molecular therapies for treatment-resistant cases. This review provides a critical analysis of the efficacy and safety of the various modes of therapy available for the treatment of patients with prolactinomas with an emphasis on challenging situations, a discussion of the data regarding withdrawal of medical therapy, and a foreshadowing of novel approaches to therapy that may become available in the future.

Clonality of pituitary tumours: more complicated than initially envisaged?

The application of allelotype microsatellite polymorphisms and X chromosome inactivation analysis in samples from women allow assessment of clonality. Early studies showed that sporadic human pituitary tumors are benign adenomas of monoclonal origin. This implies that they arise from de novo somatic mutation(s) within a single pituitary cell. However, the evidence obtained from a number of studies indicate that morphology cannot predict clonality, clonality within a given tumour may be multiple or single, multiple tumours arising on the background of hyperplasia may be of identical or differing clonality, and multiple "sporadic" tumours within a gland may be of differing clonal origin. Thus, while the early available evidence indicated that pituitary tumours appear largely monoclonal, it is simplistic to assume that this is inevitable and that these cannot be multiclonal in origin. These observations would be entirely compatible with an initiating stimulus resulting in hyperplasia of specific cell types in the pituitary, which itself gives rise to several distinct clones with variable potential to develop into tumours. Such stimuli might include hypothalamic trophic factors, intrapituitary growth factors, or pituitary specific oncogenes.

Determinants of neurosurgical outcome in pituitary tumors

OBJECTIVE

Neurosurgery is one of the main therapies for pituitary tumors; optimising outcome is highly desirable for the patient and the health system. We have analysed predictors of outcome in surgically treated pituitary adenomas operated in this centre.

DESIGN AND PATIENTS

A total of 289 patients underwent neurosurgery for a pituitary tumor, by the same two neurosurgeons, between 1982 and 2001. Their records were examined to find predictors of post-surgical outcome. Thirty-eight percent were males, with a median age of 40.8 (8-82.7) yr; 51.9% had been operated since 1992, 92.2% by the transsphenoidal route. Most tumors (70.2%) were macroadenomas; 28.4% were non-functioning, 27.3% secreted PRL, 26.3% GH of which 14 (4.8%) also secreted PRL, 17.3% ACTH, 0.3% FSH and 0.3% TSH.

RESULTS

A stepwise, forward logistic regression analysis revealed tumor size as the only significant predictor of radiological cure [odds ratio (OR) for macroadenoma 0.16 vs microadenoma, p=0.0005]. Hormonally, PRL-secretion by the tumor was a predictor of poor prognosis (OR 3.29 for cure of non-PRL-secreting tumors, p=0.005), as was tumor size (OR 0.45 for cure of macroadenomas, p=0.005). Considering simultaneous radiological and hormonal remission, tumor size (OR 0.35 for macroadenoma, p=0.0002), and operation date (OR 0.40 for up to 1991, p=0.0002) were the only significant predictors.

CONCLUSIONS

PRL secretion, tumor size and operation date are the main predictors of neurosurgical outcome in pituitary tumors, the latter suggesting that neurosurgical experience plays an important role.

Surgical outcomes in hyporesponsive prolactinomas: analysis of patients with resistance or intolerance to dopamine agonists

Surgery for prolactinoma patients is usually reserved for those who are intolerant of or have an inadequate response to medication. We report the results of surgical treatment in these patients.

METHODS

We retrospectively analyzed a consecutive series of patients with histopathologically confirmed prolactinomas; two patients treated with craniotomy and 77 patients with prolactinomas treated by transsphenoidal surgery between 1993 and 2003. We evaluated symptomatic patients who did not tolerate or did not respond to dopamine agonist therapy (persistent hyperprolactinemia and/or no shrinkage of tumor mass). We report remission rates, prolactin levels, and medications either not tolerated or ineffective.

RESULTS

Eighteen patients were intolerant of medical therapy (nine with macroadenomas and nine with microadenomas). Postoperatively, 12 patients (67%) achieved normalization of prolactin and relief of symptoms from surgery alone. Sixty-one patients were resistant to dopamine agonist therapy (45 with macroadenomas and 16 with microadenomas). Forty-six patients had both elevated prolactin levels and no shrinkage. 22 patients (36%) achieved normal postoperative prolactin levels. Ten of the remaining 39 patients required adjunctive medical therapy to maintain normal prolactin levels and relief of symptoms.

CONCLUSIONS

Remission through surgery was achieved in 67% (12 of 18 patients, 4 macroadenomas and 8 microadenomas) of prolactinoma patients who fail medical therapy with dopamine agonists because of intolerance to medication. Remission was also achieved in 36% (22 of 61 patients, 12 macroadenomas and 10 microadenomas) of patients who demonstrated resistance to dopamine agonist medication.

Contemporary management of prolactinomas

Prolactin-secreting pituitary adenomas--prolactinomas--are the most common type of functional pituitary tumor. Treatment of hyperprolactinemia is indicated because of the consequences of infertility, gonadal dysfunction, and osteoporosis. Making the correct diagnosis is important because the first line of therapy is medical management with dopamine agonists. Medical therapy is effective in normalizing prolactin levels in more than 90% of patients, but longterm treatment may be required in some patients. Transsphenoidal surgery is usually indicated in those patients in whom medical therapy fails or cannot be tolerated, or in patients who harbor microprolactinomas. In experienced hands, a hormonal and oncological cure can be achieved in more than 90% of patients after transsphenoidal removal of microprolactinomas with minimal risks. Thus, surgery may be an option for microprolactinomas in a young patient who desires restoration of fertility and avoidance of long-term medical therapy. The authors review the diagnosis and management of prolactinomas, including medical therapy, surgical therapy, and stereotactic radiosurgery.

Diagnosis and management of pituitary tumors: recent advances

In recent years, the medical therapy for prolactinomas and GH-secreting adenomas has greatly improved due to the availability of new, highly effective, long-acting dopamine and somatostatin analogues. Although medical therapy has for some time been the first-line approach to prolactinoma management, the incidence of patients requiring surgery for resistance or intolerance/noncompliance is likely to decrease substantially with these new agents. Increasing efficacy and greater ease of administration of somatostatin analogues for GH, and for rare TSH, adenomas are also anticipated to lead to less reliance on surgery and radiation therapy as the primary therapy in these disorders. Although somewhat unclear at this time, GH antagonists hold promise for alternative or adjunct therapy for acromegaly. Given the significant morbidity and mortality associated with acromegaly, these advances are quite encouraging. Unfortunately, little if any progress has been made toward establishing an effective medical treatment for gonadotropin or nonsecreting tumors. However, new approaches to delivery of radiation therapy may reduce some of the inconvenience and risk of this treatment for patients when surgery alone is inadequate. In all of these disorders, the challenge to physicians and their patients remains one of choosing a rational combination of medical, surgical, and radiation therapy. Fortunately, for most patients, control, if not cure, of their pituitary adenoma is a reasonable expectation.

Role of surgery in the treatment of microprolactinomas

Prolactinomas are a common cause of reproductive and sexual dysfunction and account for a large proportion of pituitary adenomas. The objectives for treatment of hyperprolactinemia due to microprolactinomas are to suppress excessive hormone secretion, preserve residual pituitary function, and prevent disease recurrence. These objectives may be achieved in most patients harboring microprolactinomas by medical treatment with effective dopamine agonists or microsurgical or endoscopic adenomectomy by an experienced surgeon. The choice of pituitary surgery should be made in consideration of the volume and location of the adenoma, age of the patient, the desire for restoration of fertility, and the efficacy and tolerability of dopamine agonists. The presence of a symptomatic microprolactinoma, especially in a young patient, should remain an indication for micro- or endoscopic tumor removal. This article reviews the emergence of radiosurgery as a treatment for microprolactinomas.

Postoperative endocrine management of pituitary tumors

Pituitary tumors are common and are often associated with endocrine abnormalities. Furthermore, pituitary surgery itself may result in additional hormonal changes, including impairment of anterior pituitary hormone secretion and, more commonly, abnormalities of ADH regulation. Endocrine management of patients with pituitary or other sellar lesions involves acute hospital-based and longer term office-based evaluation and treatment. In the immediate postoperative period, careful attention must be directed toward sodium and water balance as well as toward recognition of changes in endocrine function. Postoperative measurement of serum hormone levels also helps to determine if resection of a hypersecreting tumor has been successful. To minimize postoperative morbidity, perioperative endocrine assessment and management of patients undergoing pituitary surgery should consist of a team approach, involving both the neurosurgeon and the endocrinologist.

Results of stereotactic radiosurgery in patients with hormone-producing pituitary adenomas: factors associated with endocrine normalization

OBJECT

The goal of this study was to determine factors associated with endocrine normalization after radiosurgery is performed in patients with hormone-producing pituitary adenomas.

METHODS

Between 1990 and 1999, 43 patients with hormone-producing pituitary adenomas underwent radiosurgery: 26 patients with growth hormone (GH)-producing tumors, nine with adrenocorticotrophic hormone-producing tumors, seven with tumors that produced prolactin (PRL) alone, and one with a tumor that secreted both GH and PRL. The median patient age was 42 years. Thirty-seven patients (86%) had undergone surgery earlier and in 30 (70%) there was tumor extension into the cavernous sinus. The product-limit method was used to calculate endocrine normalization while patients were not receiving any hormone-suppressive medication. The median follow-up period after radiosurgery was 36 months (range 12-108 months). In 20 patients (47%) there was normalization of hormone secretion at a median of 14 months (range 2-44 months) after radiosurgery; no correlation was found between tumor type and cure. Actuarial cure rates were 20, 32, and 61% at 1, 2, and 4 years posttreatment. Multivariate analysis demonstrated that the absence of hormone-suppressive medications at the time of radiosurgery (relative risk 8.9, 95% confidence interval [CI] 1.2-68.7, p = 0.04) and maximum radiation doses greater than 40 Gy (relative risk 3.9, 95% CI 1.3-11.7, p = 0.02) correlated with an endocrine cure. A new anterior pituitary deficiency developed in seven patients (16%), temporal lobe necrosis was identified in two patients, an asymptomatic internal carotid artery stenosis was detected in two patients, and unilateral blindness occurred in one patient.

CONCLUSIONS

Radiosurgery provides an endocrine cure for many patients with persistent or recurrent hormone-producing pituitary adenomas. Further study is needed to determine whether pituitary hormone-suppressive medications have a radioprotective effect.

Undetectable postoperative cortisol does not always predict long-term remission in Cushing's disease: a single centre audit

OBJECTIVE

An undetectable postoperative serum cortisol has been regarded as a definition of cure in Cushing's disease. However, we noted disease recurrence amongst patients with Cushing's disease despite undetectable postoperative cortisol levels, and this led us to audit our data. We have also previously assessed surgical outcome for acromegaly and microprolactinoma for a single surgeon. The aims of this study were two-fold: (i) to investigate the treatment and surgical outcome of patients with Cushing's disease. In particular, we wished to compare the data with outcome for other pituitary tumours in our centre; and (ii) to determine whether undetectable cortisol following surgery is predictive of long-term cure for Cushing's disease.

PATIENTS AND METHODS

We performed a retrospective audit of 97 patients; mean age 39.1 (range: 14-82) years, 78/97 (80.4%) female, mean follow-up 92 months (range: 6 months to 29 years), with Cushing's disease seen in our unit between 1969 and 1998. We documented diagnostic investigation, immediate surgical outcome and disease recurrence in these patients.

RESULTS

All patients had elevated urinary free cortisol (mean 1270.6 nmol/l, range: 327-3245 nmol/l). In total, 95.5% of patients did not suppress with low-dose dexamethasone suppression testing. Hypokalaemia (K < 3.2 mmol/l) was present in 15.6% of patients; 17.5% of patients did not show cortisol suppression with high-dose dexamethasone and 15.8% of patients did not show an ACTH rise of > 50% following corticotrophic releasing hormone (CRH) administration. There was no significant (> 3) gradient in ACTH or cortisol following CRH during inferior petrosal sinus sampling in 27.3% of patients who had the test. A pituitary tumour was demonstrated on imaging in 55.8% of patients; 10.3% were macroadenomas. Mortality rate following trans-sphenoidal surgery was 1%. Following surgery, the immediate postoperative remission rate (undetectable postoperative cortisol) was 68.5%. However, 11.5% of these patients developed disease recurrence during a mean follow-up period of 36.3 months. Considering microadenomas, Cushing's disease patients had an immediate postoperative remission rate of 63.2% which is significantly lower (P < 0.05) compared to a remission rate of 91.1% in acromegaly. Additionally, new postoperative gonadotrophin deficiency (13.9%) and TSH deficiency (25.8%) was higher in patients with Cushing's disease compared to patients with acromegaly or microprolactinoma. Immediate postoperative remission rates improved from 50% in the first decade of a surgeon's career to consistently above 60% in the second and third decades, demonstrating a trend which may be attributed to surgical experience.

CONCLUSIONS

(i) Despite strict criteria for immediate postoperative remission and recurrence, undetectable postoperative cortisol is not always predictive of long-term remission. (ii) Despite an aggressive surgical approach, immediate postoperative remission rates for Cushing's disease are lower compared to other microadenomas. The development of new pituitary hormonal deficiency following surgery is also commoner than that seen amongst other microadenomas. These data have important implications for the follow-up of patients with Cushing's disease.

Regulated, adenovirus-mediated delivery of tyrosine hydroxylase suppresses growth of estrogen-induced pituitary prolactinomas

Prolactin-secreting adenomas are one of the most common types of intracranial neoplasm found in humans. The modalities of clinical treatment currently in use include D(2)-dopamine receptor agonists, surgery, and radiotherapy, and the success rates for treatment are good. However, there are prolactinomas that are difficult to treat. As an alternative, we have developed a gene therapy strategy in which the rate-limiting enzyme in dopamine synthesis, tyrosine hydroxylase (TH), is overexpressed in the anterior pituitary (AP) gland. Because dopamine is known to have an inhibitory effect on lactotroph growth and prolactin secretion, we developed a system that would enable its local synthesis from freely available precursor amino acids. A dual adenovirus tetracycline-regulatable expression system was generated to control the production of TH. In the absence but not presence of the tetracycline analog doxycycline, TH expression was observed in AP tumor cell lines AtT20, GH3, and MMQ. In both primary AP cell cultures and the AP gland, in situ expression of TH was seen in lactotrophs, somatotrophs, corticotrophs, thyrotrophs, and gonadotrophs in the absence but not presence of doxycycline. The ability of this system to inhibit hyperprolactinemia and pituitary lactotroph hyperplasia was then assessed in a model of estrogen- or estrogen/sulpiride-induced pituitary tumors. In the absence but not presence of doxycycline, a 49% reduction in pituitary growth and 58% reduction in the increase of circulating prolactin levels were observed in estrogen, but not estrogen/sulpiride, treated rats. These results indicate that in situ dopamine enhancement gene therapy can be a useful tool for the treatment of prolactinoma. Dopamine synthesis can be tightly regulated and the therapeutic benefit of the system is only inhibited when local dopamine signaling is impaired.

Clinical management of prolactinomas

Prolactinomas are benign, sporadic pituitary tumours that typically present with amenorrhoea and galactorrhoea in women, and hypogonadism and space-occupying effects in men. Hyperprolactinaemic hypogonadism in either sex is associated with reduced bone mineral density, which may be progressive and only partially reversible. For most microprolactinomas, dopamine agonists are the treatment of choice, achieving normoprolactinaemia and restoring gonadal function in 80-90% of cases. Trans-sphenoidal surgery is curative in 60%, but may be complicated by hypopituitarism and is usually reserved for patients with dopamine agonist intolerance or resistance. A subgroup of patients with small tumours, mild symptoms and normal gonadal function may be monitored without specific treatment--the risk of tumour expansion is small. Macroprolactinomas should be treated medically, dopamine agonists controlling prolactin secretion and achieving significant tumour shrinkage in 80% of cases, whereas surgery is curative in only a quarter. Cabergoline is the dopamine agonist of choice in most situations, being better tolerated and more effective than bromocriptine. Quinagolide is an effective alternative. Dopamine agonist withdrawal or dose reduction should be considered after 2-5 years therapy. Oestrogens may be used with caution in women with prolactinomas.