Long-term Outcomes of Hypofractionated Stereotactic Radiotherapy for the Treatment of Perioptic Nonfunctioning Pituitary Adenomas

The efficacy of stereotactic radiotherapy (SRT) has been well established for postoperative residual and recurrent nonfunctioning pituitary adenomas (NFPAs). However, the risk of visual impairment due to SRT for lesions adjacent to the optic pathways remains a topic of debate. Herein, we evaluated the long-term clinical outcomes of hypofractionated stereotactic radiotherapy (HFSRT) for perioptic NFPAs. From December 2002 to November 2015, 32 patients (18 males and 14 females; median age 63 years; range, 36-83 years) with residual or recurrent NFPAs abutting or displacing the optic nerve and/or chiasm (ONC) were treated with HFSRT. The median marginal dose was 31.3 Gy (range, 17.2-39.6) in 8 fractions (range, 6-15). Magnetic resonance imaging (MRI) and visual and hormonal examinations were performed before and after HFSRT. The median follow-up period was 99.5 months (range, 9-191). According to MRI findings at the last follow-up, the tumor size had decreased in 28 (88%) of 32 patients, was unchanged in 3 (9%), and had increased in 1 (3%). The successful tumor size control rate was 97%. Visual functions remained unchanged in 19 (60%) out of 32 patients, improved in 11 (34%), and deteriorated in 2 (6%). Two patients had deteriorated visual functions; no complications occurred because of the HFSRT. One patient developed hypopituitarism that required hormone replacement therapy. The result of this long-term follow-up study suggests that HFSRT is safe and effective for the treatment of NFPAs occurring adjacent to the ONC.

Target delineation and optimal radiosurgical dose for pituitary tumors

Stereotactic radiosurgery (SRS) delivered as either single-fraction or multi-fraction SRS (2–5 fractions) is frequently employed in patients with residual or recurrent pituitary adenoma. The most common delivery systems used for SRS include the cobalt-60 system Gamma Knife, the CyberKnife (CK) robotic radiosurgery system, or a modified conventional radiotherapy machine (linear accelerator, LINAC). Tumor control and normalization of hormone hypersecretion have been reported in 75–100 % and 25–80 % of patients, respectively. Hypopituitarism is the most commonly reported late complication of radiation treatment, whereas other toxicities occur less frequently. We have provided an overview of the recent available literature on SRS in patients with a pituitary adenoma. Critical aspects of pituitary irradiation, including target delineation and doses to organs at risk, optimal radiation dose, as well as the long-term efficacy and toxicity of SRS for either nonfunctioning or secreting pituitary adenomas are discussed. Single-fraction SRS represents an effective treatment for patients with a pituitary adenoma; however, caution should be used for lesions > 2.5–3 cm in size and/or involving the anterior optic pathway. Future studies will be necessary to optimize target doses and critical organ dose constrains in order to reduce the long-term toxicity of treatments while maintaining high efficacy.

Long-term outcomes of surgery and radiotherapy for secreting and non-secreting pituitary adenoma

Purpose:

To investigate treatment outcome and long term complication after surgery and radiotherapy (RT) for pituitary adenoma.

Materials and Methods:

From 1990 to 2009, 73 patients with surgery and RT for pituitary adenoma were analyzed in this study. Median age was 51 years (range, 25 to 71 years). Median tumor size was 3 cm (range, 1 to 5 cm) with suprasellar (n = 21), cavernous sinus extension (n = 14) or both (n = 5). Hormone secreting tumor was diagnosed in 29 patients; 16 patients with prolactin, 12 patients with growth hormone, and 1 patient with adrenocorticotrophic hormone. Impairment of visual acuity or visual field was presented in 33 patients at first diagnosis. Most patients (n = 64) received RT as postoperative adjuvant setting. Median RT dose was 45 Gy (range, 45 to 59.4 Gy).

Results:

Median follow-up duration was 8 years (range, 3 to 22 years). In secreting tumors, hormone normalization rate was 55% (16 of 29 patients). For 25 patients with evaluable visual field and visual acuity test, 21 patients (84%) showed improvement of visual disturbance after treatment. The 10-year tumor control rate for non-secreting and secreting adenoma was 100% and 58%, respectively (p < 0.001). Progression free survival rate at 10 years was 98%. Only 1 patient experienced endocrinological recurrence. Following surgery, 60% (n = 44) suffered from pituitary function deficit. Late complication associated with RT was only 1 patient, who developed cataract.

Conclusion:

Surgery and RT are very effective and safe in hormonal and tumor growth control for secreting and non-secreting pituitary adenoma.

Gamma knife radiosurgery in patients with persistent acromegaly or Cushing's disease: long-term risk of hypopituitarism

INTRODUCTION

For patient with a recurrent or residual acromegaly or Cushing's disease (CD) after resection, gamma knife radiosurgery (GKRS) is often used. Hypopituitarism is the most common adverse effect after GKRS treatment. The paucity of studies with long-term follow-up has hampered understanding of the latent risks of hypopituitarism in patients with acromegaly or CD. We report the long-term risks of hypopituitarism for patients treated with GKRS for acromegaly or CD.

METHODS

From a prospectively created, IRB-approved database, we identified all patients with acromegaly or CD treated with GKRS at the University of Virginia from 1989 to 2008. Only patients with a minimum endocrine follow-up of 60 months were included. The median follow-up is 159·5 months (60·1-278). Thorough radiological and endocrine assessments were performed immediately before GKRS and at regular follow-up intervals. New onset of hypopituitarism was defined as pituitary hormone deficits after GKRS requiring corresponding hormone replacement.

RESULTS

Sixty patients with either acromegaly or CD were included. Median tumour volume at time of GKRS was 1·3 cm(3) (0·3-13·4), and median margin dose was 25 Gy (6-30). GKRS-induced new pituitary deficiency occurred in 58·3% (n = 35) of patients. Growth hormone deficiency was most common (28·3%, n = 17). The actuarial overall rates of hypopituitarism at 3, 5 and 10 years were 10%, 21·7% and 53·3%, respectively. The median time to hypopituitarism was 61 months after GKRS (range, 12-160). Cavernous sinus invasion of the tumour was found to correlate with the occurrence of a new or progressive hypopituitarism after GKRS (P = 0·018).

CONCLUSIONS

Delayed hypopituitarism increases as a function of time after radiosurgery. Hormone axes appear to vary in terms of radiosensitivity. Patients with adenoma in the cavernous sinus are more prone to develop loss of pituitary function after GKRS.

[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.

Gamma knife radiosurgery for Cushing's disease and Nelson's syndrome

PURPOSE

This paper presents our 18 years of experience in treating ACTH secreting adenomas (Cushing's disease and Nelson's syndrome) using the Leksell gamma knife (LGK) irradiation.

METHODS

Twenty-six patients with Cushing's disease were followed-up after LGK irradiation for 48-216 months (median 78 months). Seventeen patients had undergone previous surgery, in nine patients LGK irradiation was the primary therapy. Furthermore, 14 patients with Nelson's syndrome were followed-up for 30-204 months (median 144 months).

RESULTS

LGK treatment resulted in hormonal normalization in 80.7 % of patients with Cushing's disease. Time to normalization was 6-54 months (median 30 months). The volume of the adenoma decreased in 92.3% (in 30.7% disappeared completely). There was no recurrence of the disease. In all 14 patients with Nelson's syndrome ACTH levels decreased (in two patients fully normalized) their ACTH levels. When checked up 5-10 years after irradiation regrowth of the adenoma was only detected in one patient (9.1%), in 27.3% adenoma volume remained unchanged, in 45.4% adenoma volume decreased and in 18.2% adenoma completely disappeared. Hypopituitarism did not develop in any patient where the critical dose to the pituitary and distal infundibulum was respected.

CONCLUSION

LGK radiation represents an effective and well-tolerated option for the treatment of patients with Cushing's disease after unsuccessful surgery and may be valuable even as a primary treatment in patients who are not suitable for, or refuse, surgery. In the case of Nelson's syndrome it is possible to impede tumorous growth and control the size of the adenoma in almost all patients.

Efficacy and complications of pituitary irradiation

Radiation therapy is widely used in the management of intracranial (including sellar and parasellar) and systemic disorders. Although in many cases the irradiation aims to prevent the growth or regrowth and to control the hormonal hypersecretion of a pituitary tumor, in many others it adversely affects the hypothalamo-pituitary function simply because this area receives significant doses of radiation delivered for non-hypothalamo-pituitary disorders. The main long-term complications include hypopituitarism, optic neuropathy, cerebrovascular morbidity, and second brain tumors. Radiation technique and schedule are important determinants of these adverse effects.

Outcomes of proton therapy for patients with functional pituitary adenomas

PURPOSE/OBJECTIVE(S)

This study evaluated the efficacy and toxicity of proton therapy for functional pituitary adenomas (FPAs).

METHODS AND MATERIALS

We analyzed 165 patients with FPAs who were treated at a single institution with proton therapy between 1992 and 2012 and had at least 6 months of follow-up. All but 3 patients underwent prior resection, and 14 received prior photon irradiation. Proton stereotactic radiosurgery was used for 92% of patients, with a median dose of 20 Gy(RBE). The remainder received fractionated stereotactic proton therapy. Time to biochemical complete response (CR, defined as ≥ 3 months of normal laboratory values with no medical treatment), local control, and adverse effects are reported.

RESULTS

With a median follow-up time of 4.3 years (range, 0.5-20.6 years) for 144 evaluable patients, the actuarial 3-year CR rate and the median time to CR were 54% and 32 months among 74 patients with Cushing disease (CD), 63% and 27 months among 8 patients with Nelson syndrome (NS), 26% and 62 months among 50 patients with acromegaly, and 22% and 60 months among 9 patients with prolactinomas, respectively. One of 3 patients with thyroid stimulating hormone-secreting tumors achieved CR. Actuarial time to CR was significantly shorter for corticotroph FPAs (CD/NS) compared with other subtypes (P=.001). At a median imaging follow-up time of 43 months, tumor control was 98% among 140 patients. The actuarial 3-year and 5-year rates of development of new hypopituitarism were 45% and 62%, and the median time to deficiency was 40 months. Larger radiosurgery target volume as a continuous variable was a significant predictor of hypopituitarism (adjusted hazard ratio 1.3, P=.004). Four patients had new-onset postradiosurgery seizures suspected to be related to generously defined target volumes. There were no radiation-induced tumors.

CONCLUSIONS

Proton irradiation is an effective treatment for FPAs, and hypopituitarism remains the primary adverse effect.

Encouraging efficacy of modern conformal fractionated radiotherapy in patients with uncured Cushing's disease

The objective of this study was to assess the efficacy of modern conformal fractionated radiotherapy (RT) in patients with uncured Cushing's disease (CD) after failed transsphenoidal surgery (TSS). In this retrospective analysis, we reviewed records of patients with CD who received modern conformal fractionated RT between 2001 and 2010. Records were evaluated for frequency and interval of remission post RT. The change in the tumour size, endocrine insufficiencies and complications developing post RT were noted. Remission was defined as 2 mg Low dose dexamethasone suppressed cortisol of <50 nmol/l. During the study period of 10 years, a total of 24 patients (mean age: 27.9, range: 21-48 years) underwent pituitary RT for CD. Out of these, long term follow up was available for 22 patients and 20 patients (15F/5M, 12 microadenomas/8 macroadenomas) were included for final analysis. All the patients received modern conformal fractionated external beam RT (45 Gy in 25 fractions) with the median follow up of 37.5 months (range 12-144). Fifteen patients (10 microadenomas/5 macroadenomas) underwent remission after a median follow up period of 20 months. None of the patients had recurrence. Post RT, new onset endocrine deficiencies were seen in 8 (40 %) patients. Modern conformal fractionated external beam radiotherapy is an effective modality for treatment of adult patients with CD after failed TSS.

Radiation therapy in the management of pituitary adenomas

Radiation therapy in the form of fractionated treatment or radiosurgery has an important role in the management of pituitary adenomas. Radiation is a reliable way of gaining local control for radiographically progressing pituitary adenomas. For functioning adenomas that are biochemically recurrent or persistent, radiation therapy is less consistent in offering biochemical normalization and often requires a latency period of years or decades. The decision of when to use radiation therapy is a delicate balance between its benefits and late sequelae, especially in the context of benign disease. Recent technological advances in radiation oncology hold the potential to minimize dose to uninvolved normal tissue and therefore reduce the risk of toxicity.

Fractionated stereotactic radiosurgery using the Novalis system for the management of pituitary adenomas close to the optic apparatus

Radiosurgery has been proven to be an effective treatment for residual or recurrent pituitary adenomas after surgery. However, it causes severe complications when the optic apparatus is irradiated over the tolerance dose. In this study, we analyzed the feasibility of fractionated stereotactic radiosurgery to treat pituitary tumors close to the optic apparatus. Thirty-four patients from June 2006 to June 2011 with recurrent or residual pituitary adenomas close to (<3 mm) the optic apparatus were treated with fractionated stereotactic radiosurgery. Three fractions with a total dose of 2100 cGy were applied to the tumors. Imaging, examination of vision, and estimation of hormone level were regularly performed before and after radiosurgery. The mean tumor volume before fractioned stereotactic radiosurgery was 5.06±3.08 cm3 (range: 0.82-12.69 cm3). After a mean follow up of 36.8±15.7 months (range: 16-72 months), tumor size was reduced in seven (20.6%) patients and remained the same in the other 27 (79.4%) patients. Vision was improved in one patient and remained stable in the rest. Only one patient developed transient post-treatment diplopia. This study suggests that fractionated stereotactic radiosurgery is safe for treating pituitary adenomas close to the optic apparatus. Studies with more patients and longer follow-up are required to draw definite conclusions.

Stereotactic radiosurgery for treatment of Cushing disease: an Australian experience

Stereotactic radiation therapy has emerged as an alternative to conventional radiotherapy for treatment of Cushing disease. The aim of this study was to investigate the efficacy and safety of this treatment. Records of patients with Cushing disease treated with stereotactic radiation were reviewed. Seventeen patients underwent stereotactic radiosurgery. Ten achieved remission after a mean of 23 (95% confidence interval, 15-31) months, and two developed hormone deficiencies.

Excess mortality for patients with residual disease following resection of pituitary adenomas

The importance of achieving tumor control in pituitary adenoma surgery is not entirely established. This manuscript reviews the literature linking residual pituitary tumor and hormonal hypersecretion to increases in long term mortality. When possible, we utilized meta-analysis methods to estimate a pooled standardized mortality ratio (SMR), which relates the risk of mortality for a cohort of patients compared to a similar age and gender matched cohort in the general population, for patients with endocrinologic evidence of residual disease. When this was not possible, we review the existing literature in the results and discussion section of this review. We identified 10 articles regarding acromegaly and three articles regarding Cushing's disease which presented SMR data for adult patients undergoing transphenoidal surgery with data divided into subgroups based on post-operative growth hormone levels. Using growth hormone levels of 2.5 μg/l as a cutoff, the mortality rate ratio was 1.83 (95% CI = 1.03-3.24) for patients with persistent acromegaly. Similarly, patients with persistent Cushing's disease experienced a marked increase in mortality rate ratio compared to those experiencing initial cure (mortality rate ratio = 3.25 (95% CI = 1.54-6.84). For other tumor subtypes, (i.e. Endocrine inactive adenomas, Prolactinomas, and TSH secreting tumors) there were not enough studies identified to allow for rigorous statistical analysis. There is an increasing body of data suggesting that treatment refractory acromegaly and Cushing's disease puts patients at risk for early mortality, suggesting that aggressive efforts to normalize hormone levels in these patients are justified.

Hypothalamic/pituitary morbidity in skull base pathology

In this article the epidemiology, pathophysiology, clinical presentation, investigation, management, and prognosis of hypopituitarism and hypothalamic dysfunction, arising from skull base pathologies and treatment of these conditions, are reviewed and discussed. The clinical question: "What is the consequence of pituitary hypofunction in young patients (ie, craniopharyngioma)?" is answered based on information provided in the review.

Liver X receptor-α/β expression ratio is increased in ACTH-secreting pituitary adenomas

The liver X receptors (LXR-α and -β) are nuclear oxysterol receptors that play pivotal roles in regulating the expression of genes involved in cholesterol transport and metabolism. Recently, several groups have reported that the LXRs also regulate adrenal steroidogenesis. In the previous report, we demonstrated that LXR-α is dominantly expressed in the pituitary and that LXR-α positively regulates the proopiomelanocortin (POMC) gene promoter at the transcriptional level. In this report, we evaluated the expression levels of LXR-α and -β gene in the human pituitary tumor. Even though LXR-α mRNA levels are not significantly increased in ACTH-secreting adenomas, LXR-α/β expression ratio is significantly higher than other pituitary tumors including normal pituitaries. Furthermore, in At-T20 cells, which express POMC gene, overexpression of LXR-β decreased POMC gene promoter activities. Thus, we concluded that LXR-α/β gene expression ratio is a critical factor to activate POMC gene expression in ACTH-secreting pituitary adenomas.

Treatment of pituitary adenomas using radiosurgery and radiotherapy: a single center experience and review of literature

Fractionated radiotherapy (FRT) and gamma knife stereotactic radiosurgery (GKSRS) are used as adjuvant therapies to surgical resection for functional and non-functional pituitary adenomas, although their optimum role in the treatment algorithm, as well as long-term safety and efficacy, still awaits further study. We report a single center experience with 33 patients with non-functional (16 patients), ACTH- (five patients), GH- (four patients), or prolactin-secreting (eight patients) tumors treated with FRT or SRS. The median tumor diameter was 1.9 cm, and the median follow-up was 36 months. For GKSRS, the median dosage was 16 Gy for non-functional adenomas and 23 Gy for hormone-secreting tumors. The median total dose for FRT was 50.4 Gy over 28 fractions (median). Two patients (6%) demonstrated radiographic evidence of tumor progression, three patients (9%) demonstrated radiation-induced visual field deficits on neuro-ophthalmic evaluation, and two patients (6%) suffered from radiation-induced hypopituitarism. Biochemical control, defined as normalized hormone values in the absence of medical therapy, was achieved in five out of eight prolactinoma patients and two out of five patients with Cushing's disease, but none of the four patients with acromegaly. These results are presented with a review of the relevant literature on the differential characteristics of FRT versus SRS in the treatment of functional and non-functional pituitary adenomas and validate postoperative irradiation as a potentially safe and effective means for tumor control.

Pituitary tumours: the prolactinoma

This review focus on the epidemiology, diagnosis and treatment of prolactinomas. In particular, attention was given to recent data showing a high prevalence of these tumours in the general population, 3-5 times higher than previously reported. The diagnosis of hyperprolactinaemia has been simplified in recent years, and only prolactin (PRL) assay and magnetic resonance imaging of the sella are required. Nonetheless, macroprolactinaemia should be assessed in patients with hyperprolactinaemia in the absence of clinical symptoms of elevated PRL levels. The recent evidence that medical therapy with dopamine agonists should be continued lifelong has been confirmed by several studied. The patients achieving disappearance of the tumours and suppression of PRL levels during treatment are those showing the highest likelihood to have persistent remission of hyperprolactinaemia after treatment withdrawal.

MASEP gamma knife radiosurgery for secretory pituitary adenomas: experience in 347 consecutive cases

Background

Secretory pituitary adenomas are very common brain tumors. Historically, the treatment armamentarium for secretory pituitary adenomas included neurosurgery, medical management, and fractionated radiotherapy. In recent years, MASEP gamma knife radiosurgery (MASEP GKRS) has emerged as an important treatment modality in the management of secretory pituitary adenomas. The goal of this research is to define accurately the efficacy, safety, complications, and role of MASEP GKRS for treatment of secretory pituitary adenomas.

Methods

Between 1997 and 2007 a total of 347 patients with secretory pituitary adenomas treated with MASEP GKRS and with at least 60 months of follow-up data were identified. In 47 of these patients some form of prior treatment such as transsphenoidal resection, or craniotomy and resection had been conducted. The others were deemed ineligible for microsurgery because of body health or private choice, and MASEP GKRS served as the primary treatment modality. Endocrinological, ophthalmological, and neuroradiological responses were evaluated.

Results

MASEP GKRS was tolerated well in these patients under the follow-up period ranged from 60 to 90 months; acute radioreaction was rare and 17 patients had transient headaches with no clinical significance. Late radioreaction was noted in 1 patient and consisted of consistent headache. Of the 68 patients with adrenocorticotropic hormone-secreting(ACTH) adenomas, 89.7% showed tumor volume decrease or remain unchanged and 27.9% experienced normalization of hormone level. Of the 176 patients with prolactinomas, 23.3% had normalization of hormone level and 90.3% showed tumor volume decrease or remain unchanged. Of the 103 patients with growth hormone-secreting(GH) adenomas, 95.1% experienced tumor volume decrease or remain unchanged and 36.9% showed normalization of hormone level.

Conclusion

MASEP GKRS is safe and effective in treating secretory pituitary adenomas. None of the patients in our study experienced injury to the optic apparatus or had other neuropathies related with gamma knife. MASEP GKRS may serve as a primary treatment method in some or as a salvage treatment in the others. However, treatment must be tailored to meet the patient's symptoms, tumor location, tumor morphometry, and overall health. Longer follow-up is required for a more complete assessment of late radioreaction and treatment efficacy.

[Radiotherapy and radiosurgery of pituitary adenomas]

There are two principal types of treatment for pituitary adenomas: fractionated conventional radiation therapy, based on biological selectivity, and radiosurgery, which is delivered in a single dose, based on anatomic selectivity and indicated preferentially for small tumors sufficiently distant from the optic chiasm. Conventional radiation therapy is effective against secretion in 60-80% of cases and radiosurgery in 40-50%, depending on the type of secretion. Maximum antisecretory efficacy is not reached immediately: this delay is longer for conventional radiation therapy (5-10 years) than for radiosurgery (2-3 years). In both cases, antisecretory treatment must be started, while awaiting remission. Radiation therapy and radiosurgery make it possible to stabilize or diminish tumor volume in 70-100% of cases. This is especially useful in the case of an active residue after surgery for non-secreting adenoma, but the long-term side effects of radiation must be borne in mind. The principal side effect is the onset of a pituitary deficiency (in more than 50% of cases after radiation therapy, 20% after radiosurgery). The risk increases with time since treatment. Other very long-term side effects have been described with radiation therapy: radiation-induced tumors, cerebral necrosis, strokes, etc. The role of radiosurgery and radiation therapy is growing ever more limited, because of the increasing efficacy of drug treatments and the excellent surgical results of experienced teams.

Radiation therapy in the treatment of pituitary tumors

✓ The treatment of pituitary tumors has progressed into a multidisciplinary approach that involves neurosurgeons, radiation oncologists, and endocrinologists. This has allowed improved outcomes in treatment of pituitary tumors due to a combination of surgical, medical, and radiation therapies. In this study, the authors review the role of radiation therapy in the treatment of pituitary adenomas.

Radiotherapy for pituitary adenomas

This article describes the technical aspects and the clinical results of conventional radiotherapy and modern stereotactic radiotherapy for pituitary adenomas. Systematic review of the published literature provides a factual basis for the comparison and the selection of appropriate radiation technique in patients who have secreting and nonfunctioning pituitary adenomas not cured with surgery and medical therapy.

Nelson syndrome: comprehensive review of pathophysiology, diagnosis, and management

Nelson syndrome (NS) is a rare clinical manifestation of an enlarging pituitary adenoma that can occur following bilateral adrenal gland removal performed for the treatment of Cushing disease. It is characterized by excess adreno-corticotropin secretion and hyperpigmentation of the skin and mucus membranes. The authors present a comprehensive review of the pathophysiology, diagnosis, and management of NS. Corticotroph adenomas in NS remain challenging tumors that can lead to significant rates of morbidity and mortality. A better understanding of the natural history of NS, advances in neurophysiology and neuroimaging, and growing experience with surgical intervention and radiation have expanded the repertoire of treatments. Currently available treatments include surgical, radiation, and medical therapy. Although the primary treatment for each tumor type may vary, it is important to consider all of the available options and select the one that is most appropriate for the individual case, particularly in cases of lesions resistant to intervention.

Gamma Knife surgery for Cushing's disease

Object

In this study the authors address the efficacy and safety of Gamma Knife surgery (GKS) in patients with adrenocorticotropic hormone–secreting pituitary adenomas.

Methods

A review of data collected from a prospective GKS database between January 1990 and March 2005 was performed in patients with Cushing's disease. All but one patient underwent resection for a pituitary tumor, without achieving remission. Successful endocrine outcome after GKS was defined as a normal 24-hour urinary free cortisol (UFC) concentration posttreatment after a minimum of 1 year of follow up. Patient records were also evaluated for changes in tumor volume, development of new hormone deficiencies, visual acuity, cranial nerve neuropathies, and radiation-induced imaging changes. Ninety evaluable patients had undergone GKS, with a mean endocrine follow-up duration of 45 months (range 12–132 months). The mean dose to the tumor margin was 23 Gy (median 25 Gy).

Normal 24-hour UFC levels were achieved in 49 patients (54%), with an average time of 13 months after treatment (range 2–67 months). In the 49 patients in whom a tumor was visible on the planning magnetic resonance (MR) image, a decrease in tumor size occurred in 39 (80%), in seven patients there was no change in size, and tumor growth occurred in three patients. Ten patients (20%) experienced a relapse of Cushing's disease after initial remission; the mean time to recurrence was 27 months (range 6–60 months). Seven of these patients underwent repeated GKS, with three patients achieving a second remission. New hormone deficiencies developed in 20 patients (22%), with hypothyroidism being the most common endocrinopathy after GKS. Five patients experienced new visual deficits or third, fourth, or sixth cranial nerve deficits; two of these patients had undergone prior conventional fractionated radiation therapy, and four of them had received previous GKS. Radiation-induced changes were observed on MR images in three patients; one had symptoms attributable to these changes.

Conclusions

Gamma Knife surgery is an effective treatment for persistent Cushing's disease. Adenomas with cavernous sinus invasion that are not amenable to resection are treatable with the Gamma Knife. A second GKS treatment appears to increase the risk of cranial nerve damage. These results demonstrate the value of combining two neurosurgical treatment modalities—microsurgical resection and GKS—in the management of pituitary adenomas.

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.

Intensity-modulated radiotherapy for pituitary adenomas: The preliminary report of the Cleveland Clinic experience

PURPOSE

Intensity-modulated radiotherapy (IMRT) is being increasingly used for the treatment of pituitary adenomas. However, there have been few published data on the short- and long-term outcomes of this treatment. This is the initial report of the Cleveland Clinic's experience.

METHODS AND MATERIALS

Between February 1998 and December 2003, 34 patients with pituitary adenomas were treated with IMRT. A retrospective chart review was conducted for data analysis.

RESULTS

With a median follow-up of 42.5 months, the treatment has proven to be well tolerated, with performance status remaining stable in 90% of patients. Radiographic local control was 89%, and among patients with secretory tumors, 100% had a biochemical response. Only 1 patient required salvage surgery for progressive disease, giving a clinical progression free survival of 97%. The only patient who received more than 46 Gy experienced optic neuropathy 8 months after radiation. Smaller tumor volume significantly correlated with subjective improvements in nonvisual neurologic complaints (p = 0.03), and larger tumor volume significantly correlated with subjective worsening of visual symptoms (p = 0.05). New hormonal supplementation was required for 40% of patients. Younger patients were significantly more likely to require hormonal supplementation (p = 0.03).

CONCLUSIONS

Intensity-modulated radiation therapy is a safe and effective treatment for pituitary adenomas over the short term. Longer follow-up is necessary to determine if IMRT confers any advantage with respect to either tumor control or toxicity over conventional radiation modalities.

Clinical results of conformal radiotherapy and radiosurgery for pituitary adenoma

Radiation therapy provides a valuable adjunct to surgery as well as a viable management alternative to surgery for pituitary adenomas. The availability of conformal radiotherapy has dramatically reduced complication rates, and the advent of radiosurgery has reduced the latency of response in these patients. Although extended follow-up is needed to elucidate the long-term outcomes of these treatments, they are likely to be a permanent part of the therapeutic armamentarium for these patients for the near future.

Gamma surgery in the treatment of nonsecretory pituitary macroadenoma

Object

The authors report on a retrospective analysis of the imaging and clinical outcomes following gamma surgery in 100 patients with nonsecretory pituitary macroadenoma.

Methods

Between June 1989 and March 2004, 100 consecutive patients with nonsecretory pituitary macroadenoma were treated at the Lars Leksell Center for Gamma Surgery, University of Virginia Health System (Charlottesville, VA). Ninety-two patients had residual or recurrent macroadenoma following one or more surgical procedures. In eight patients, gamma surgery was the primary treatment. Ten patients received conventional fractionated radiotherapy before the gamma surgery. Sixty-nine patients required hormone replacement therapy for one or more deficits before gamma knife treatment. Peripheral doses between 5 and 25 Gy (mean 18.5 Gy) were administered.

Imaging and endocrinological follow-up evaluations were performed in 90 patients; these studies ranged from 6 to 142 months (mean 44.9 months) and 6 to 127 months (mean 47.9 months), respectively. Tumor volume decreased in 59 patients (65.6%), remained unchanged in 24 (26.7%), and increased in seven (7.8%). The minimal effective peripheral dose was 12 Gy; peripheral doses greater than 20 Gy did not seem to provide additional benefit. Of 61 patients with a partially or fully functioning pituitary gland and follow-up data, 12 (19.7%) suffered new hormone deficits following gamma surgery. In patients with endocrinological follow-up data that had been collected over more than 2 years, the rate of new deficits was 25%. No neurological morbidity or death was related to treatment.

Conclusions

Current experience suggests that gamma surgery is an appropriate means of managing recurrent or residual nonsecretory pituitary macroadenoma following microsurgery and a primary treatment in selected patients. To evaluate definite rates of recurrence and new endocrine deficiencies, long-term follow-up studies are needed.

Hyperprolactinaemia in 271 women: up to three decades of clinical follow-up

OBJECTIVE

To characterize women with hyperprolactinaemia at diagnosis and to assess the effect of treatment after long duration of the disease.

DESIGN

Retrospective chart review.

PATIENTS AND MEASUREMENTS

Two hundred and seventy-one women with hyperprolactinaemia at the Karolinska University Hospital, Stockholm, Sweden between 1974 and 2002 were evaluated retrospectively. Criterion for inclusion was elevated S-PRL (> or = 20 microg/l) found on at least two occasions. Secondary hyperprolactinaemia was excluded. The patients were followed for a median time period of 111 (6-348) months. Two hundred and forty patients were treated with dopamine agonists, 17 underwent surgery, seven received radiotherapy and seven were followed without treatment.

RESULTS

Mean age at diagnosis was 31 (+/- 9.5) years and median PRL level was 72 (25-3500) microg/l. Menstrual disturbances were present in 87% of the women of reproductive age and 47% had galactorrhoea. Microadenomas were found in 63%, macroadenomas in 8% and idiopathic hyperprolactinaemia in 29%. Patients with menstrual disturbances had higher PRL levels than women with normal menstrual function (P < 0.001). We found no differences in PRL levels between patients with or without galactorrhoea (P = 0.578). At the end of clinical follow-up, menstrual cycle was normalized in 94% and galactorrhoea disappeared in 94%. In the medically treated patients, median PRL levels decreased from 70 (25-3100) to 13 (0-89) microg/l, (P < 0.0001). Normalization of PRL level was achieved in 71% of the patients and 80% showed a total or partial degree of tumour shrinkage. In the surgically treated patients, 53% had normal PRL levels without medication at follow-up.

CONCLUSION

Medical treatment was effective in correcting hypogonadism, normalizing PRL levels and reducing tumour size in the majority of the patients after short-term treatment and also in the long run. However, the possibility of transsphenoidal surgery in specific cases must be considered.

A study on the radiation tolerance of the optic nerves and chiasm after stereotactic radiosurgery

PURPOSE

To evaluate the risk of clinically significant radiation optic neuropathy (RON) for patients having stereotactic radiosurgery of benign tumors adjacent to the optic apparatus.

METHODS AND MATERIALS

We reviewed the dose plans and clinical outcomes of 218 gamma knife procedures (215 patients) for tumors of the sellar and parasellar region (meningiomas, n = 122; pituitary adenomas, n = 89; craniopharyngiomas, n = 7 patients). Previous surgery or radiation therapy was performed in 156 (66%) and 24 (11%) patients, respectively. Median follow-up was 40 months (range 4-115).

RESULTS

The median maximum radiation dose to the optic nerve was 10 Gy (range 0.4-16.0). Four patients (1.9%) developed RON at a median of 48 months after radiosurgery. All had prior surgery, and 3 of 4 had external beam radiotherapy (EBRT) in their management either before (n = 2) or adjuvantly (n = 1). The risk of developing a clinically significant RON was 1.1% for patients receiving 12 Gy or less. Patients receiving prior or concurrent EBRT had a greater risk of developing RON after radiosurgery (p = 0.004).

CONCLUSION

RON occurred in less than 2% of our patients, despite the majority (73%) receiving more than 8 Gy to a short segment of the optic apparatus. Knowledge of the dose tolerance of these structures permits physicians to be more aggressive in treating patients with sellar or parasellar tumors, especially those with hormone-producing pituitary adenomas that appear to require higher doses to achieve biochemical remission.

Stereotactic radiosurgery for patients with ACTH-producing pituitary adenomas after prior adrenalectomy

PURPOSE

To review the results of stereotactic radiosurgery for patients with adrenocorticotropic hormone (ACTH)-producing pituitary adenomas after bilateral adrenalectomy.

METHODS AND MATERIALS

Eleven patients with ACTH-producing pituitary adenomas after bilateral adrenalectomy underwent radiosurgery between 1990 and 1999. Nine patients had documented tumor growth, hyperpigmentation, and elevated ACTH levels (median 920 ng/mL) at the time of radiosurgery. Five of these patients had tumor enlargement despite prior fractionated radiotherapy (median dose 50 Gy). Two patients were treated prophylactically within 1 month of their adrenalectomies to prevent future tumor growth. The median follow-up was 37 months (range 22-74).

RESULTS

Tumor growth control was achieved in 9 patients (82%); 2 patients had had continued tumor growth after radiosurgery. The ACTH levels decreased a median of 66% (range -99% to +27%); 4 patients had normal ACTH levels. Three patients had radiation-related complications, including diplopia (n = 2), ipsilateral blindness (n = 1), testosterone/growth hormone deficiency (n = 1), and asymptomatic temporal lobe radiation necrosis (n = 1): all had received prior radiotherapy. One patient who had undergone three prior resections and radiotherapy died 59 months after radiosurgery despite two additional attempts at tumor resection.

CONCLUSION

Although our experience is limited, it appears that radiosurgery provides tumor control for most patients with ACTH-producing pituitary adenomas who have undergone bilateral adrenalectomy.

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.