Transsphenoidal surgery in Cushing disease: 10 years of experience in 34 consecutive cases

Surgery and perioperative management of patients with Cushing's disease

Transsphenoidal surgery (TSS) is the initial treatment modality of first choice in Cushing's disease (CD). With microscopic TSS and endoscopic TSS, two operative techniques with equally favourable remission rates and operative morbidity are available. On average, remission is achieved with primary TSS in 80% of patients with microadenomas and 60% of patients with macroadenomas. The current literature indicates that remission rates in repeat TSS for microadenomas can also exceed 70%. Experience with TSS in CD plays an important role in the success rate and centralization in Pituitary Centres of Excellence has been proposed. Microadenoma stage, imaging-visible adenoma, confirmation of ACTH-positive adenoma on histopathology and noninvasiveness are positive predictors for postoperative remission. In postoperative management, a steroid-sparing protocol with early postoperative assessment of remission status is recommended. Convincing evidence suggests that prolonged postoperative prophylactic antithrombotic measures can significantly reduce the risk of postoperative thromboembolic events in CD. Prevention or successful treatment of cortisol withdrawal syndrome remains an unsolved issue that should be a focus of future research. The further development and broad availability of functional imaging hold promise for improved preoperative detection of microadenomas. Intraoperative identification of microadenomas by specific fluorescent targeting could be a promising future avenue for the treatment of patients with negative imaging.

Outcomes of pituitary surgery for Cushing's disease: a systematic review and meta-analysis

PURPOSE

Transsphenoidal surgery (TSS) is the first-line treatment for Cushing's disease (CD). This review aimed to synthesize the remission and recurrence rates following TSS for CD and identify predictors of these outcomes.

METHODS

Medline (1946-) and Embase (1947-) were searched until 23rd January 2019 for original studies. A meta-analysis was performed of remission and recurrence rates. Studies were excluded if patients had prior radiosurgery/radiotherapy, mixed pathologies or interventions without separated data, follow-up not reported or population size < 20. For recurrence rate syntheses, studies with follow-up < 6 months were excluded.

RESULTS

The search produced 2663 studies, of which n = 68 were included, involving 5664 patients. Remission rates after primary and revision TSS were 80% [77-82] and 58% [50-66] at last follow-up. After primary TSS, predictors of remission were micro- v macroadenomas (83% v 68%, p < 0.01), imaging-visible adenomas (81% v 69%, p < 0.01), adenomas confirmed on histopathology (87% v 45%, p < 0.01), absence of cavernous sinus invasion (80% v 30%, p < 0.01), postoperative serum cortisol (MSeC) nadir < 2 μg/dL (< 55 nmol/L; 95% v 46%, p < 0.01) and lower preoperative 24-h urine free cortisol (1250 nmol v 1726 nmol, p < 0.01). For revision TSS, predictors of remission were postoperative MSeC nadir < 2 μg/dL (< 55 nmol/L; 100% v 38%, p < 0.01) and operations for recurrence v persistence (80% v 54%, p < 0.01). Recurrence rates after primary and revision TSS were 18% [14-22] and 28% [16-42].

CONCLUSIONS

TSS is most effective in primary microadenomas, visible on preoperative imaging and without CS invasion, lower preoperative 24-h urine free cortisol and postoperative MSeC nadir < 2 μg/dL (< 55 nmol/L).

Endoscopic Transsphenoidal Surgery for Cushing's Disease: A Review

Ever since the 1960s, transsphenoidal surgery has been the modality of choice for treating Cushing's disease. Subsequent visualization of the pituitary fossa and sphenoid sinus may be done either with the operating microscope or with the relatively new endoscope. The endoscope due to its panoramic view allows greater visualization as compared to the operating microscope. It confers greater access to the cavernous sinus, sella, suprasellar, and parasellar regions and accommodates higher magnifications. It is bi-dimensional, however as opposed to the operating microscope that provides a three-dimensional view and allows greater depth perception. This article provides a comprehensive review of the advantages and disadvantages of the endoscope and compares it to the operating microscope. We hope this article will prove useful to both clinicians and academicians alike in their approach and management of Cushing's disease.

Endoscopic vs. microscopic transsphenoidal surgery for Cushing's disease: a systematic review and meta-analysis

PURPOSE

Systematic review and meta-analysis comparing endoscopic and microscopic transsphenoidal surgery for Cushing's disease regarding surgical outcomes (remission, recurrence, and mortality) and complication rates. To stratify the results by tumor size.

METHODS

Nine electronic databases were searched in February 2017 to identify potentially relevant articles. Cohort studies assessing surgical outcomes or complication rates after endoscopic or microscopic transsphenoidal surgery for Cushing's disease were eligible. Pooled proportions were reported including 95% confidence intervals.

RESULTS

We included 97 articles with 6695 patients in total (5711 microscopically and 984 endoscopically operated). Overall, remission was achieved in 5177 patients (80%), with no clear difference between both techniques. Recurrence was around 10% and short term mortality < 0.5% for both techniques. Cerebrospinal fluid leak occurred more often in endoscopic surgery (12.9 vs. 4.0%), whereas transient diabetes insipidus occurred less often (11.3 vs. 21.7%). For microadenomas, results were comparable between both techniques. For macroadenomas, the percentage of patients in remission was higher after endoscopic surgery (76.3 vs. 59.9%), and the percentage recurrence lower after endoscopic surgery (1.5 vs. 17.0%).

CONCLUSIONS

Endoscopic surgery for patients with Cushing's disease reaches comparable results for microadenomas, and probably better results for macroadenomas than microscopic surgery. This is present despite the presumed learning curve of the newer endoscopic technique, although confounding cannot be excluded. Based on this study, endoscopic surgery may thus be considered the current standard of care. Microscopic surgery can be used based on neurosurgeon's preference. Endocrinologists and neurosurgeons in pituitary centers performing the microscopic technique should at least consider referring Cushing's disease patients with a macroadenoma.

The experience with transsphenoidal surgery and its importance to outcomes

PURPOSE

Surgical experience is considered paramount for excellent outcome of transsphenoidal surgery (TSS). However, objective data demonstrating the surgical success in relation to the experience of pituitary surgery units or individual experience of pituitary surgeons is sparse.

METHODS

Based on literature data, we have investigated the influence of experience with TSS for pituitary adenomas on endocrinological remission rates and on operative complications. The surgical experience was assessed by calculating the number of transsphenoidal operations per year.

RESULTS

For TSS of microprolactinomas, mean remission rates were 77% in centers with < 2 operations per year for microprolactinomas, 82% with 2-4 operations, 84% with 4-6 operations, and 91% with > 6 operations. A yearly experience with more than 10 initial operations for Cushing's disease (CD) warrants a remission rate exceeding 70%. Remission rates in CD exceeding 86% have only been reported for single surgeon series. Extraordinarily high complication rates were found in some series with < 25 yearly total operations for pituitary adenomas. Major vascular complications were less than 2% and revision rates for rhinorrhea usually < 2.5% in centers performing > 25 transsphenoidal operations per year.

CONCLUSIONS

We conclude that a center with experience of > 25 transsphenoidal operations for pituitary adenomas per year provides a high likelihood of safe TSS. Surgery for CD requires a particularly high level of practice to guarantee excellent remission rates. The endocrinologist has the unique opportunity to audit the surgical success by hormone measurement and to refer patients to neurosurgeons with proven excellence.

Endoscopic endonasal resection of ACTH secreting pituitary microadenoma; how I do it

BACKGROUND

Transsphenoidal selective adenectomy is considered the treatment of choice in patients with Cushing's disease given the possibility for high remission and low complication rates. The endoscopic endonasal surgical nuances for Cushing's disease are not well illustrated in the neurosurgical technique and video collections.

METHODS

We describe the technical nuances of microadenoma resection for two cases of Cushing's disease, one in which the adenoma is visualized on imaging and one in which the pre-operative MRI is negative.

CONCLUSIONS

Transsphenoidal endoscopic selective adenectomy is a safe and effective surgery for patients with Cushing's disease regardless of preoperative MRI findings.

[Retrospective analysis to evaluate efficacy and safety of stereotactic radiosurgery in Cushing's disease: 24 cases and a review]

BACKGROUND

In the past few years, stereotactic radiosurgery (SRS) has been suggested as a good alternative, second line therapy for the management of patients with ACTH-secreting pituitary adenomas. A retrospective study has been conducted in order to evaluate the efficacy and safety of this treatment in these patients.

MATERIAL AND METHODS

Data were collected on all patients treated with SRS for an ACTH-secreting pituitary adenoma between 1996 and 2008, and with at least one year of follow-up. An analysis was carried out by analysing the return to normal of the hormone levels and clinical improvement rates (including Cushing signs, arterial hypertension), as well as adverse effects, and disease relapse. A return to normal of the 24 hour urinary free cortisol (24-UFC) levels (<100 μg/day) without any ACTH-secretion suppressor drug treatment, was considered as cure or improvement.

RESULTS

A total of 30 patients were treated with SRS, of which 24 were included in the analysis. They all had high 24-UFC levels before the treatment. Cure was achieved in 12 (50%) in a mean of 28 months, and in other 3 patients 24-UFC levels returned to normal with treatment with ketoconazole after the SRS. Cushing signs improved in all cases, as well as arterial hypertension in 13 out of 14 cases. There were relapses after cure consolidation. As far as adverse effects, it should be mentioned that there were 9 cases of new pituitary hormonal dysfunction (the most frequent being hypothyroidism), one radionecrosis, and one case of visual field defect impairment. Radiation-related neoplasm was not detected in any of the cases.

CONCLUSIONS

SRS is an effective treatment for those patients with ACTH-secreting pituitary adenoma in whom surgery has failed, or in those that are not good candidates for it. It showed good rates of hormone levels returning to normal, as well as clinical disease control and a low level of adverse effects.

The Treatment of Cushing's Disease

Cushing's disease (CD), or pituitary-dependent Cushing's syndrome, is a severe endocrine disease caused by a corticotroph pituitary tumor and associated with increased morbidity and mortality. The first-line treatment for CD is pituitary surgery, which is followed by disease remission in around 78% and relapse in around 13% of patients during the 10-year period after surgery, so that nearly one third of patients experience in the long-term a failure of surgery and require an additional second-line treatment. Patients with persistent or recurrent CD require additional treatments, including pituitary radiotherapy, adrenal surgery, and/or medical therapy. Pituitary radiotherapy is effective in controlling cortisol excess in a large percentage of patients, but it is associated with a considerable risk of hypopituitarism. Adrenal surgery is followed by a rapid and definitive control of cortisol excess in nearly all patients, but it induces adrenal insufficiency. Medical therapy has recently acquired a more important role compared to the past, due to the recent employment of novel compounds able to control cortisol secretion or action. Currently, medical therapy is used as a presurgical treatment, particularly for severe disease; or as postsurgical treatment, in cases of failure or incomplete surgical tumor resection; or as bridging therapy before, during, and after radiotherapy while waiting for disease control; or, in selected cases, as primary therapy, mainly when surgery is not an option. The adrenal-directed drug ketoconazole is the most commonly used drug, mainly because of its rapid action, whereas the glucocorticoid receptor antagonist, mifepristone, is highly effective in controlling clinical comorbidities, mainly glucose intolerance, thus being a useful treatment for CD when it is associated with diabetes mellitus. Pituitary-directed drugs have the advantage of acting at the site responsible for CD, the pituitary tumor. Among this group of drugs, the dopamine agonist cabergoline and the somatostatin analog pasireotide result in disease remission in a consistent subgroup of patients with CD. Recently, pasireotide has been approved for the treatment of CD when surgery has failed or when surgery is not an option, and mifepristone has been approved for the treatment of Cushing's syndrome when associated with impairment of glucose metabolism in case of the lack of a surgical indication. Recent experience suggests that the combination of different drugs may be able to control cortisol excess in a great majority of patients with CD.

Short-term outcome of endoscopic versus microscopic pituitary adenoma surgery: a systematic review and meta-analysis

Endoscopic transsphenoidal pituitary surgery has become increasingly more popular for the removal of pituitary adenomas. It is also widely recognised that transsphenoidal microscopic removal of pituitary adenomas is a well-established procedure with good outcomes. Our objective was to meta-analyse the short-term results of endoscopic and microscopic pituitary adenoma surgery. We undertook a systematic review of the English literature on results of transsphenoidal surgery, both microscopic and endoscopic from 1990 to 2011. Series with less than 10 patients were excluded. Pooled data were analysed using meta-analysis techniques to obtain estimate of death, complication rates and extent of tumour removal. Complications evaluated included cerebrospinal fluid leak, meningitis, vascular complications, visual complications, diabetes insipidus, hypopituitarism and cranial nerve injury. Data were also analysed for tumour size and sex. 38 studies met the inclusion criteria yielding 24 endoscopic and 22 microscopic datasets (eight studies included both endoscopic and microscopic series). Meta-analysis of the available literature showed that the endoscopic transsphenoidal technique was associated with a higher incidence of vascular complications (p<0.0001). No difference was found between the two techniques in all other variables examined. Meta-analysis of the available literature reveals that endoscopic removal of pituitary adenoma, in the short term, does not seem to confer any advantages over the microscopic technique and the incidence of reported vascular complications was higher with endoscopic than with microscopic removal of pituitary adenomas. While we recognise the limitations of meta-analysis, our study suggests that a multicentre, randomised, comparative effectiveness study of the microscopic and endoscopic transsphenoidal techniques may be a reasonable approach towards establishing a true valuation of these techniques.

Medical management of persistent and recurrent cushing disease

Recent evidence supports the notion that the incidence of Cushing disease is higher than previously thought. Transphenoidal surgery, in the hands of experienced neurosurgeons, is currently considered the first-line treatment of choice. However, an examination of remission and recurrence rates in long-term follow-up studies reveals that potentially up to 40% to 50% of patients could require additional treatment. If left untreated, the resultant morbidity and mortality are high. Successful clinical management of patients with Cushing disease remains a challenge. The development of new therapeutic agents has been eagerly anticipated. This article discusses the results of currently available and promising new therapeutic agents used to treat this challenging disease.

Cushing's disease

Cushing’s disease, or pituitary ACTH dependent Cushing’s syndrome, is a rare disease responsible for increased morbidity and mortality. Signs and symptoms of hypercortisolism are usually non specific: obesity, signs of protein wasting, increased blood pressure, variable levels of hirsutism. Diagnosis is frequently difficult, and requires a strict algorithm. First-line treatment is based on transsphenoidal surgery, which cures 80% of ACTH-secreting microadenomas. The rate of remission is lower in macroadenomas. Other therapeutic modalities including anticortisolic drugs, radiation techniques or bilateral adrenalectomy will thus be necessary to avoid long-term risks (metabolic syndrome, osteoporosis, cardiovascular disease) of hypercortisolism. This review summarizes potential pathophysiological mechanisms, diagnostic approaches, and therapies.

Contemporary microsurgical concept for the treatment of Cushing's disease: endocrine outcome in 83 consecutive patients

BACKGROUND

Evidence suggests that occult adenoma remnants are responsible for persistent Cushing's disease (CD) following transsphenoidal surgery (TSS). To optimize the outcome, we have adapted our microsurgical concept. The influence of our surgical strategy on remission rate and pituitary function is presented.

DESIGN AND PATIENTS

83 patients undergoing TSS for newly diagnosed CD. An enlarged resection was performed in 36 patients. A modified exploration technique with radial incisions was performed in 19 patients in whom an adenoma was not readily detectable.

RESULTS

The overall remission rate of primary surgery was 84·3% (70/83). A remission rate of 87·5% (63/72) was achieved in microadenomas. Six patients with microadenomas were re-operated for persistence, and hypercortisolism was corrected in five of them. With re-operation included, the overall remission rate for microadenomas was 94·4%. No procedure-related complications occurred in primary surgery. Of the patients in remission, 72·5% had early postoperative random cortisol levels below 2 μg/dl, 17·4% had cortisol levels between 2 and 5 μg/dl, and 10·1% had cortisol levels >5 μg/dl. 15·2% of the patients with microadenomas developed postoperative partial hypopituitarism and 3% diabetes insipidus. No increased rate of hypopituitarism was found with enlarged adenomectomy compared to selective adenomectomy. Only a slightly higher rate of partial hypopituitarism (23·1%) was found if extensive exploration was required.

CONCLUSION

With our microsurgical concept, a high initial cure rate is achievable with minimal surgical morbidity. Enlarged adenomectomy has no adverse effect on the rate of postoperative hypopituitarism. Early repeat surgery is a successful option if CD persists.

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.

Treatment Options in Cushing's Disease

Endogenous Cushing’s syndrome is a grave disease that requires a multidisciplinary and individualized treatment approach for each patient. Approximately 80% of all patients harbour a corticotroph pituitary adenoma (Cushing’s disease) with excessive secretion of adrenocorticotropin-hormone (ACTH) and, consecutively, cortisol. The goals of treatment include normalization of hormone excess, long-term disease control and the reversal of comorbidities caused by the underlying pathology. The treatment of choice is neurosurgical tumour removal of the pituitary adenoma. Second-line treatments include medical therapy, bilateral adrenalectomy and radiation therapy. Drug treatment modalities target at the hypothalamic/pituitary level, the adrenal gland and at the glucocorticoid receptor level and are commonly used in patients in whom surgery has failed. Bilateral adrenalectomy is the second-line treatment for persistent hypercortisolism that offers immediate control of hypercortisolism. However, this treatment option requires a careful individualized evaluation, since it has the disadvantage of permanent hypoadrenalism which requires lifelong glucocorticoid and mineralocorticoid replacement therapy and bears the risk of developing Nelson’s syndrome. Although there are some very promising medical therapy options it clearly remains a second-line treatment option. However, there are numerous circumstances where medical management of CD is indicated. Medical therapy is frequently used in cases with severe hypercortisolism before surgery in order to control the metabolic effects and help reduce the anestesiological risk. Additionally, it can help to bridge the time gap until radiotherapy takes effect. The aim of this review is to analyze and present current treatment options in Cushing’s disease.

Intraoperative multiple-staged resection and tumor tissue identification using frozen sections provide the best result for the accurate localization and complete resection of tumors in Cushing's disease

The treatment of choice in Cushing's disease (CD) is surgical removal; however, most tumors are too small to be detected. The objective was to establish a method to achieve the complete removal of tumors on the basis of the results of high-resolution magnetic resonance imaging (MRI), inferior petrosal sinus sampling (IPSS), and a surgical resection technique using frozen biopsy. Eighteen patients who underwent transsphenoidal surgery from 2004 to 2010 were included. High-resolution MRI and IPSS, multiple-staged resection, and tumor tissue identification in frozen sections (surgical and histological identification, SHI) were performed. All patients achieved surgical remission, as confirmed by 24 h urinary free cortisol excretion tests. Visible microlesions were identified on the initial MRI in 11 patients (61%). The SHI findings agreed with the MRI findings in 10 of the 11 patients (90.9%) and with IPSS lateralization in 6 of the 11 patients (54.5%). In the 7 patients whose lesions were not visible on the initial MRI, only 1 (14.3%) showed an agreement between IPSS and SHI. In 3 of the 7 patients, the microlesions were identified by additional MRI. The rate of concordance with SHI was 77.8% for the overall MRI and 38.9% for IPSS. High-resolution MRI is better than IPSS for localizing corticotroph adenomas. In patients with lesions not visible on the initial MRI, additional MRI should be performed using a different protocol. Although high-resolution MRI is better for localizing tumors, SHI remains an important approach for removing the tumors completely.

[Hormonal control of pituitary adenomas by transsphenoidal surgery: results of the first five years of experience]

OBJECTIVE

To evaluate the initial results of a surgical team in the hormonal control of secreting pituitary adenomas.

MATERIALS AND METHODS

In five years 51 functioning adenomas were operated (31 GH-secreting, 14 ACTH-secreting, 5 PRL-secreting and 1 TSH-secreting). Hormonal control was defined as GH < 2,5 ng/mL, normal free-urinary cortisol, lower prolactin and normal T3 and FT4.

RESULTS

Control rates were 36% in acromegaly, and 57% in Cushing's disease. Two prolactinomas normalized prolactin levels. Thyroid hormone levels were normalized in the TSH-secreting adenoma. Control of hypercortisolism was positively correlated with years of experience (p = 0.01).

CONCLUSION

Our results, although restricted to the beginning of our experience, lie below the reported range of other surgical series with much longer experience. During these years, there was a significant improvement in initial post surgery urinary cortisol levels in Cushing's disease as a function of surgical experience.

Peri-operative management of Cushing's disease

Management of patients with ACTH producing pituitary adenoma remains to be challenging. Removal of the pituitary adenoma through transsphenoidal surgery is the main stay of treatment. Complete resection of the adenoma is followed by the development of ACTH deficiency since the normal corticotrophs are suppressed by the pre-existing hypercortisolemia. The concern for ACTH deficiency has led many centers to advocate the use glucocorticoids before, during and after surgery. We provide evidence that such coverage with glucocorticoids is unnecessary until clinical or biochemical documentation of need is established. Given that patients are closely monitored, they are immediately treated with glucocorticoids once they exhibit any clinical and/or biochemical evidence of adrenal insufficiency. Defining remission in the immediate postoperative period has been rather difficult despite using different biochemical markers. Serum cortisol continues to be the best determinant of disease activity after surgical adenomectomy. However it needs to be interpreted with caution as a biochemical marker of remission in patients given glucocorticoids during and after surgery. Other biochemical markers are also used in the peri-operative period to determine the possibility of remission. These include the dexamethasone suppression test, CRH stimulation without dexamethasone, urinary free cortisol measurements, desmopressin stimulation test, the determination of salivary cortisol and / or plasma ACTH concentrations. Each test has its own advantages and limitations. The simplest and most informative approach is to measure serum cortisol levels repeatedly after surgery without the administration of exogenous glucocorticoids. Low serum cortisol levels (less than 2 μg/dL) in the peri-operative period are highly indicative of surgical success and a high likelihood for clinical remission. Higher serum cortisol levels require careful interpretation and further planning and discussions between the patient and the management team.

Outcome of transsphenoidal surgery for Cushing's disease: a high remission rate in ACTH-secreting macroadenomas

OBJECTIVE

Although numerous studies have shown that transsphenoidal surgery is the best initial treatment for Cushing disease offering 59-95% of success, fewer information is available on the long-term outcome in the subgroup of patients harboring ACTH-secreting macroadenomas. The aims of this study were to analyze our 10-year experience with transsphenoidal surgery in Cushing's disease and to examine whether remission rates were different between micro- and macroadenomas.

PATIENTS AND METHODS

Forty consecutive patients with proven Cushing's disease (28 microadenomas, 12 macroadenomas [diameter: 10-25 mm], 3 patients with no visible adenoma at MRI) underwent transsphenoidal surgery (TSS) assisted by neuronavigation in our center between 1996 and 2007. The diagnosis was made using standard endocrinological criteria including bilateral inferior petrosal sinus sampling (BIPSS) with CRH stimulation in all patients with discordant or equivocal biochemical and radiological testing. Morning serum cortisol was measured during the first week postoperatively, and a complete endocrine evaluation was made in all patients at 6-8 weeks. Remission at follow-up was defined as a normal postoperative 24-h urinary free cortisol (UFC) or continued need for glucocorticoid hormone replacement after TSS.

RESULTS

Overall, 32/40 patients (80%) were in remission after one or more TSS. Interestingly, a very good remission rate (92%) was observed in the subset of macroadenomas, similar to that found in the group of microadenomas (84%, NS), while no post-surgical remission was observed in the 3 patients with no visible adenoma at MRI (p<0.01). Of the 8 patients not in remission after repeated TSS surgery, 3 underwent radiation therapy and three had bilateral adrenalectomy, allowing remission of their hypercortisolism. There was minor morbidity and no death.

CONCLUSION

While our overall results are in accordance with other published series, we show here that ACTH-secreting pituitary macroadenomas are usually not associated with a bad outcome, in contrast with patients with no visible adenoma at preoperative MRI.

Prospective evaluation of transsphenoidal pituitary surgery in 108 patients with Cushing's disease

Transsphenoidal pituitary surgery (TSS) remains the treatment of choice for Cushing's disease (CD). Despite the widespread acceptance of this procedure as the first line treatment in CD, the indication of a second TSS in not cured or relapsed DC patients is not consensus. We report the results of TSS in 108 patients with CD (a total of 117 surgeries). The mean postoperative follow-up period was 6 years. Remission was defined as clinical and laboratorial signs of adrenal insufficiency, period of glucocorticoid dependence, serum cortisol suppression on oral 1-mg dexamethasone overnight suppression test and clinical remission of hypercortisolism. We evaluated 103 patients with CD by the time of the first TSS. Fourteen patients underwent second TSS (5 had already been operated in others centers; in 5 patients the first surgery was not curative; in 4 patients CD relapsed). Remission rates were 85.4% and 28.6% (p < 0.001) after first and second TSS, respectively. In microadenomas, remission rates were higher than macroadenomas (94.9% vs. 73.9%; p = 0.006). In patients with negative pituitary imaging remission rates were 71.4% (p = 0.003; vs. microadenomas). Postoperative complications were: transient diabetes insipidus, definitive diabetes insipidus, hypopituitarism, stroke and one death. Only hypopituitarism was more frequent after second TSS (p = 0.015). In conclusion, TSS for CD is an effective and safe treatment. The best remission rates were observed at the first surgery and in microadenomas. The low remission rates after a second TSS suggest that this approach could not be a good therapeutic choice when the first one was not curative.

Long-term results after microsurgery for Cushing disease: experience with 426 primary operations over 35 years

OBJECTIVES

The aim of this paper was to demonstrate the long-term results following microsurgery in a single surgeon's continuous series of patients with Cushing disease (CD), to assess the influence of changes in surgical procedures, and to compare the results with those of other treatment modalities. In particular, preoperative diagnosis, tumor size, results of histological examination, and complications were considered.

METHODS

Between 1971 and 2004, 426 patients suffering from newly diagnosed CD underwent primary surgery. Pre-operative measures included clinical examination, endocrinological workup (testing of the hypothalamic-pituitary-adrenal axis, and 2- and 8-mg dexamethasone overnight suppression tests), sellar imaging (polytomography, computed tomography, and magnetic resonance [MR] imaging), and in patients with negative results on imaging studies, inferior petrosal sinus sampling. Follow-up examinations consisting of endocrinological workup, and imaging took place 1 week and 3 months after surgery and then at yearly intervals.

RESULTS

During microsurgery as first treatment, the adenoma finding rate was 86.6%. After selective adenomectomy, the remission rate was 75.9%, and this rate showed no improvement over the years. The best results were achieved in microadenomas confirmed on MR imaging or histopathological investigation. The recurrence rate (15%) and the complication rate (5.9%) declined over the years. If no adenoma was found, exploration of the sella turcica was performed in 45.6%, hypophysectomy in 3.5%, and hemihypophysectomy in 50.9% of these patients, leading to an early remission in 37.9%. In case of persistence or recurrence, further treatment (repeated operation, adrenalectomy, radio-therapy, or medical treatment) was used to control the disease.

CONCLUSIONS

Microsurgery remains the treatment of first choice in CD, even though no improvement in remission rates was observed over the years, because complication or remission rates for other treatment options are comparable or worse.

Stereotactic radiosurgery for Cushing disease: a review

✓ A contemporary review of the use of stereotactic radiosurgery in the treatment of Cushing disease (CD) is presented with information drawn from a literature review and from the author's experience. Stereotactic radiosurgery is an effective and safe therapeutic alternative for treating CD in carefully selected cases. Improvements in imaging, dose planning, and general understanding of radiobiology are likely to yield better results in the future.

Prognostic factors for outcome after transsphenoidal hypophysectomy in dogs with pituitary-dependent hyperadrenocorticism

Object

The aim of this study was to determine prognostic factors for outcome after transsphenoidal hypophysectomy in dogs with pituitary-dependent hyperadrenocorticism (PDH).

Methods

One veterinary neurosurgeon performed transsphenoidal hypophysectomies in 181 dogs with PDH over a 12-year period. Survival analysis was performed with the Kaplan–Meier method. Prognostic factors were analyzed with the univariate Cox proportional hazard analysis followed by stepwise multivariate analysis. The log-rank test was used to assess disease-free fractions in three groups categorized according to early postoperative urinary corticoid/creatinine (C/C) ratios.

Results

Multivariate analysis revealed that old age, large pituitary size, and high preoperative concentrations of plasma adrenocorticotropic hormone were associated with an increased risk of PDH-related death. In addition, large pituitary size, thick sphenoid bone, high C/C ratio, and high concentration of plasma α-melanocyte–stimulating hormone (α-MSH) before surgery were associated with an increased risk of disease recurrence in the dogs that went into remission after hypophysectomy. Disease-free fractions were significantly higher in dogs with postoperative urinary C/C ratios in the lower normal range (< 5 × 10−6) than in dogs with postoperative C/C ratios in the upper normal range (5–10 × 10−6).

Conclusions

The results of this study indicate that pituitary size, sphenoid bone thickness, plasma α-MSH concentration, and preoperative level of urinary cortisol excretion are predictors of long-term remission after transsphenoidal hypophysectomy for PDH in dogs. Urinary C/C ratios measured 6 to 10 weeks after surgery can be used as a guide for predicting the risk of tumor recurrence.

Cushing disease: use of perioperative serum cortisol measurements in early determination of success following pituitary surgery

✓Despite many recent advances, management of cases of Cushing disease continues to be challenging. After complete resection of ACTH-secreting adenomas, patients develop transient ACTH deficiency requiring glucocorticoid replacement for several months. The current recommendation by many centers, including ours, for patients with ACTH-secreting adenomas is to withhold glucocorticoid therapy during and immediately after adenomectomy until there is clinical or biochemical evidence of ACTH deficiency. A serum cortisol level of less than 2 μg/dl within the first 48 hours after adenomectomy is a reliable biochemical marker of ACTH deficiency and is associated with clinical remission of Cushing disease. Higher serum cortisol levels in the immediate postoperative period should be interpreted with caution. The decision to immediately reexplore the sella turcica should be individualized, taking into account the findings at surgery, the histopathological findings, and the changes in serum cortisol levels as well as the patient's wishes and concerns. Optimal diagnosis and therapy for patients with Cushing disease require thorough and close coordination and involvement of all members of the management team.

Current state of the art in the diagnosis and surgical treatment of Cushing disease: early experience with a purely endoscopic endonasal technique

Object

Transsphenoidal pituitary surgery is the primary therapy for Cushing disease because of its potential to produce lasting remission without the need for long-term drug or hormone replacement therapy. The authors evaluated the current role of pure endoscopic endonasal pituitary surgery in the treatment of Cushing disease.

Methods

Twenty-five patients underwent pure endoscopic surgery for confirmed Cushing disease. Thirteen patients had microadenomas and seven had macroadenomas; magnetic resonance images obtained in five patients were only suspicious or nondiagnostic, and thus they underwent inferior petrosal sinus sampling. Two patients had evidence of cavernous sinus involvement. Final histological results were consistent with adrenocorticotropin hormone (ACTH)–secreting adenoma in 20 patients.

Results

Twenty patients (80%) had clinical remission and laboratory confirmation of hypocortisolemia (serum cortisol < 100 nmol/L requiring substitution therapy), suppression to low-dose dexamethasone, and normal 24-hour urinary free cortisol. The median follow-up period was 17 months (range 3–32 months). There was no recurrence at the time of the last follow-up. Three patients presented with new anterior pituitary deficiency, but no one had permanent diabetes insipidus. In one patient a cerebrospinal fluid leak developed but later resolved following lumbar drainage. Treatment failure was attributable to involvement of the cavernous sinus in two patients, incomplete tumor removal in one, negative exploration in one, and nodular corticotroph hyperplasia of the pituitary gland in one.

Conclusions

Early results indicated that endoscopic endonasal surgery is a safe and effective treatment for ACTH-producing adenomas. The rate of remission in this study is comparable to those in previous series, and the rate of major postoperative complications is extremely low. Further studies with a larger number of patients and longer follow-ups are required to determine whether this more minimally invasive pure endoscopic approach should become the standard of care for the surgical treatment of Cushing disease.

Second-line treatment for Cushing's disease when initial pituitary surgery is unsuccessful

PURPOSE OF REVIEW

Adenectomy via transsphenoidal surgery is considered the treatment of choice for Cushing's disease. It is successful in about 80% of patients in the hands of an experienced surgeon. When transsphenoidal surgery fails or is contraindicated, a second-line treatment must be chosen. The review focuses on second-line treatment options.

RECENT FINDINGS

Repeat pituitary surgery results in the cure of Cushing's disease in about 50% of cases. Bilateral adrenalectomy results in resolution of hypercortisolemia in almost all patients, but leaves the patient glucocorticoid and mineralocorticoid deficient. Nelson's syndrome, depending on the definition, occurs in up to 35% of these patients. Irradiation of the residual pituitary tumor typically takes several years before the full effect is realized; it can cause panhypopituitarism. Finally, pharmacologic treatment of persistent hypercortisolemia can be effective, but is often associated with untoward side effects. These side effects are a powerful deterrent to its use. Several new pharmacologic agents are being studied and show some promise.

SUMMARY

Each of the second-line treatments for Cushing's disease currently available can be effective at treating hypercortisolism, but each has significant limitations. New pharmacologic agents may soon offer some very exciting treatment options.

Gamma Knife surgery for adrenocorticotropic hormone–producing pituitary adenomas after bilateral adrenalectomy

Object

Patients with adrenocorticotropic hormone (ACTH)–secreting pituitary adenomas may require a bilateral adrenalectomy to treat their Cushing's disease. Approximately one third of these patients, however, will experience progressive enlargement of the residual pituitary adenoma, develop hyperpigmentation, and have an elevated level of serum ACTH. These patients with Nelson's syndrome can be treated with Gamma Knife surgery (GKS).

Methods

The prospectively collected University of Virginia Gamma Knife database of patients with pituitary adenomas was reviewed to identify all individuals with Nelson's syndrome who were treated with GKS. Twenty-three patients with a minimum of 6 months of follow up were identified in the database. These patients were assessed for tumor control (that is, lack of tumor growth over time) with neuroimaging studies (median follow-up duration 22 months) and for biochemical normalization of their ACTH levels (median follow-up duration 50 months). Neuroimaging follow-up studies were available for 22 patients, and endocrine follow up was available for 15 patients in whom elevation of ACTH levels was documented prior to GKS.

In the 22 patients in whom neuroimaging follow-up studies were available, 12 had a decrease in tumor size, eight had no tumor growth, and two had an increase in tumor volume. Ten of 15 patients with elevated ACTH levels prior to GKS showed a decrease in their ACTH levels at last follow up; three of these 10 patients achieved normal ACTH levels (< 50 pg/ml) and the other five patients with initially elevated values had an increase in ACTH levels.

Ten patients were thoroughly evaluated for post-GKS pituitary function; four were found to have new pituitary hormone deficiency and six did not have hypopituitarism after GKS. One patient suffered a permanent third cranial nerve palsy and four patients are now deceased.

Conclusions

Gamma Knife surgery may control the residual pituitary adenoma and decrease ACTH levels in patients with Nelson's syndrome. Delayed hypopituitarism or cranial nerve palsies can occur after GKS. Patients with Nelson's syndrome require continued multidisciplinary follow-up care. Given the difficulties associated with management of Nelson's syndrome, even the modest results of GKS may be helpful for a number of patients.

Pitfalls in the management of Cushing’s disease

Cushing's disease is caused by functional corticotroph adenomas of the pituitary gland, most commonly noninvasive microadenomas. Transsphenoidal microsurgery is an effective means of control for patients with adrenocorticotrophic hormone-producing microadenomas. However, a wide variation of clinical outcomes and recurrence rates has been reported. The major causes of surgical failure in the treatment of Cushing's disease lies in inadequate preoperative evaluation, unsuccessful identification of the adenoma and inexperience of the surgeon. Furthermore, appropriate use of combination therapy, including surgery, radiotherapy, radiosurgery and adrenalectomy can improve the outcome. For optimal results in this rare disease, endocrinological, radiological and surgical procedures should be co-ordinated in a specialized center. In this review, factors affecting preoperative evaluation, surgical success and outcome are outlined in the light of current knowledge.

Hypertension in Cushing's syndrome

Cushing's syndrome can be exogenous, resulting from the administration of glucocorticoids or adrenocorticotrophic hormone (ACTH), or endogenous, secondary to increased secretion of cortisol or ACTH. Hypertension is one of the most distinguishing features of endogenous Cushing's syndrome, as it is present in about 80% of adult patients and in almost half of children and adolescents patients. Hypertension results from the interplay of several pathophysiological mechanisms regulating plasma volume, peripheral vascular resistance and cardiac output, all of which may be increased. The therapeutic goal is to find and remove the cause of excess glucocorticoids, which, in most cases of endogenous Cushing's syndrome, is achieved surgically. Treatment of Cushing's syndrome usually results in resolution or amelioration of hypertension. However, some patients may not achieve normotension or may require a prolonged period of time for the correction of hypercortisolism. Therefore, therapeutic strategies for Cushing's-specific hypertension (to normalise blood pressure and decrease the duration of hypertension) are necessary to decrease the morbidity and mortality associated with this disorder. The various pathogenetic mechanisms that have been proposed for the development of glucocorticoid-induced hypertension in Cushing's syndrome and its management are discussed.

Evaluation and treatment of Cushing's syndrome

Cushing's syndrome results from sustained pathologic hypercortisolism caused by excessive corticotropin (ACTH) secretion by tumors in the pituitary gland (Cushing's disease, 70%) or elsewhere (15%), or by ACTH-independent cortisol secretion from adrenal tumors (15%). The clinical features are variable, and no single pattern is seen in all patients. Those features most specific for Cushing's syndrome include abnormal fat distribution, particularly in the supraclavicular and temporal fossae, proximal muscle weakness, wide purple striae, and decreased linear growth with continued weight gain in a child. Patients with characteristics of glucocorticoid excess should be screened with measurements of saliva or urine cortisol or dexamethasone suppression testing. The diagnosis of Cushing's syndrome should be followed by the measurement of plasma ACTH concentration to determine whether the hypercortisolism is ACTH-independent. In ACTH-dependent patients, bilateral inferior petrosal sinus sampling with measurement of ACTH before and after administration of ACTH-releasing hormone most accurately distinguishes pituitary from ectopic ACTH secretion. Surgical resection of tumor is the optimal treatment for all forms of Cushing's syndrome; bilateral adrenalectomy, medical treatment, or radiotherapy are sought in inoperable or recurrent cases. The medical treatment of choice is ketoconazole. The prognosis is better for Cushing's disease and benign adrenal causes of Cushing's syndrome than adrenocortical cancer and malignant ACTH-producing tumors.

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.

Secretion of high-molecular-weight adrenocorticotropic hormone from a pituitary adenoma in a patient without Cushing stigmata. Case report

The authors report a case in which a patient harbored a corticotroph macroadenoma that secreted biologically inactive high-molecular-weight adrenocorticotropic hormone (ACTH) as well as authentic ACTH 1-39. The secretion of the high-molecular-weight ACTH was determined using gel chromatography. The authors believe that these two molecules competed with each other at the ACTH receptor and, thus, the bioactivity of ACTH 1-39 was masked and Cushing features were not manifested in the patient. This type of silent corticotroph adenoma may be categorized as a clinically nonfunctioning adenoma. Plasmas from patients with silent corticotroph adenomas, which are identified by positive immunohistochemical staining of ACTH, should be frozen, stored, and analyzed using gel chromatography to examine whether the tumors produce and secrete high-molecular-weight ACTH.