Frederic Castinetti

Long-term results of stereotactic radiosurgery in secretory pituitary adenomas.

CONTEXT To date, no study reported long-term follow-up results of gamma knife stereotactic radiosurgery (SR). OBJECTIVE The aim of the study was to determine long-term efficacy and adverse effects of SR in secreting pituitary adenomas. DESIGN We conducted a retrospective study of patients treated by SR in the center of Marseille, France, with a follow-up of at least 60 months. PATIENTS A total of 76 patients were treated by SR for acromegaly (n = 43), Cushings disease (CD; n = 18), or prolactinoma (n = 15) as a primary (n = 27) or adjunctive postsurgical treatment (n = 49). MAIN OUTCOME MEASURES After withdrawal of antisecretory drugs, patients were considered in remission if they had mean GH levels below 2 ng/ml and normal IGF-I (acromegaly), normal 24-h urinary free cortisol, and cortisol less than 50 nmol/liter after low-dose dexamethasone test (CD) or two consecutive normal samplings of prolactin levels (prolactinoma). RESULTS After a mean follow-up of 96 months, 44.7% of the patients were in remission. Mean time to remission was 42.6 months. Twelve patients presented late remission at least 48 months after SR. Two patients with CD presented late recurrence 72 and 96 months after SR. Forty percent of patients treated primarily with SR were in remission. Target volume and initial hormone levels were significant predictive factors of remission in univariate analysis. Radiation-induced hypopituitarism was observed in 23% patients; in half of them, hypopituitarism was observed after a mean time of 48 to 96 months. Twenty-four patients were followed for more than 120 months; rates of remission and hypopituitarism were similar to the whole cohort. CONCLUSIONS SR is an effective and safe primary or adjunctive treatment in selected patients with secreting pituitary adenomas.

Molecular mechanisms of pituitary organogenesis: In search of novel regulatory genes

Defects in pituitary gland organogenesis are sometimes associated with congenital anomalies that affect head development. Lesions in transcription factors and signaling pathways explain some of these developmental syndromes. Basic research studies, including the characterization of genetically engineered mice, provide a mechanistic framework for understanding how mutations create the clinical characteristics observed in patients. Defects in BMP, WNT, Notch, and FGF signaling pathways affect induction and growth of the pituitary primordium and other organ systems partly by altering the balance between signaling pathways. The PITX and LHX transcription factor families influence pituitary and head development and are clinically relevant. A few later-acting transcription factors have pituitary-specific effects, including PROP1, POU1F1 (PIT1), and TPIT (TBX19), while others, such as NeuroD1 and NR5A1 (SF1), are syndromic, influencing development of other endocrine organs. We conducted a survey of genes transcribed in developing mouse pituitary to find candidates for cases of pituitary hormone deficiency of unknown etiology. We identified numerous transcription factors that are members of gene families with roles in syndromic or non-syndromic pituitary hormone deficiency. This collection is a rich source for future basic and clinical studies.

Merits and pitfalls of mifepristone in Cushing's syndrome

OBJECTIVE Mifepristone is the only available glucocorticoid receptor antagonist. Only few adult patients with hypercortisolism were treated to date by this drug. Our objective was to determine effectiveness and tolerability of mifepristone in Cushings syndrome (CS). DESIGN Retrospective study of patients treated in seven European centers. METHODS Twenty patients with malignant (n=15, 12 with adrenocortical carcinoma, three with ectopic ACTH secretion) or benign (n=5, four with Cushings disease, one with bilateral adrenal hyperplasia) CS were treated with mifepristone. Mifepristone was initiated with a median starting dose of 400 mg/day (200-1000). Median treatment duration was 2 months (0.25-21) for malignant CS, and 6 months (0.5-24) for benign CS. Clinical (signs of hypercortisolism, blood pressure, signs of adrenal insufficiency), and biochemical parameters (serum potassium and glucose) were evaluated. RESULTS Treatment was stopped in one patient after 1 week due to severe uncontrolled hypokalemia. Improvement of clinical signs was observed in 11/15 patients with malignant CS (73%), and 4/5 patients with benign CS (80%). Psychiatric symptoms improved in 4/5 patients within the first week. Blood glucose levels improved in 4/7 patients. Signs of adrenal insufficiency were observed in 3/20 patients. Moderate to severe hypokalemia was observed in 11/20 patients and increased blood pressure levels in 3/20 patients. CONCLUSION Mifepristone is a rapidly effective treatment of hypercortisolism, but requires close monitoring of potentially severe hypokalemia, hypertension, and clinical signs of adrenal insufficiency. Mifepristone provides a valuable treatment option in patients with severe CS when surgery is unsuccessful or impossible.

Pituitary carcinomas and aggressive pituitary tumours: merits and pitfalls of temozolomide treatment

Pituitary carcinomas are rare, accounting for about 0·2% of all pituitary tumours. They represent a challenge to clinical practice in both diagnosis and treatment. They may present initially as typical pituitary adenomas, with a delayed appearance of aggressive signs, or as aggressive tumours from the outset. Predicting the pituitary tumour behaviour remains difficult: increased mitotic, Ki‐67 and P53 indices might be associated with tumour aggression. The treatment of pituitary carcinomas and aggressive pituitary tumours includes surgery, adjuvant medical treatment, external beam radiotherapy and chemotherapy. Until recently, the treatment of pituitary carcinomas was mainly palliative and did not seem to increase overall survival. Recent case reports have detailed the successful use of temozolomide, an orally administered alkylating agent used to treat malignant gliomas, in the management of pituitary carcinomas and aggressive pituitary tumours. The outcome of treatment might depend on the expression of O 6 ‐methylguanine‐DNA methyltransferase (MGMT), a DNA repair enzyme that potentially interferes with drug efficacy. This review describes the clinical presentation and response to temozolomide in 44 patients with pituitary carcinomas or aggressive pituitary tumours reported in the literature. The results suggest that temozolomide should be considered a drug of major importance in the therapeutic algorithm of aggressive pituitary tumours and pituitary carcinomas. Because of the inconsistency of published data, MGMT expression should probably not be taken as a reason to deny these patients the potential benefit of temozolomide treatment, taking into account the paucity of other available treatments.

Ketoconazole in Cushing's Disease: Is It Worth a Try?

BACKGROUND The use of ketoconazole has been recently questioned after warnings from the European Medicine Agencies and the Food and Drug Administration due to potential hepatotoxicity. However, ketoconazole is frequently used as a drug to lower circulating cortisol levels. Several pharmacological agents have recently been approved for the treatment of Cushings disease (CD) despite limited efficacy or significant side effects. Ketoconazole has been used worldwide for more than 30 years in CD, but in the absence of a large-scale study, its efficacy and tolerance are still under debate. PATIENTS AND METHODS We conducted a French retrospective multicenter study reviewing data from patients treated by ketoconazole as a single agent for CD, with the aim of clarifying efficacy and tolerance to better determine the benefit/risk balance. RESULTS Data from 200 patients were included in this study. At the last follow-up, 49.3% of patients had normal urinary free cortisol (UFC) levels, 25.6% had at least a 50% decrease, and 25.4% had unchanged UFC levels. The median final dose of ketoconazole was 600 mg/d. Forty patients (20%) received ketoconazole as a presurgical treatment; 40% to 50% of these patients showed improvement of hypertension, hypokalemia, and diabetes, and 48.7% had normal UFC before surgery. Overall, 41 patients (20.5%) stopped the treatment due to poor tolerance. Mild (<5N, inferior to 5-fold normal values) and major (>5N, superior to 5-fold normal values) increases in liver enzymes were observed in 13.5% and 2.5% of patients, respectively. No fatal hepatitis was observed. CONCLUSIONS Ketoconazole is an effective drug with acceptable side effects. It should be used under close liver enzyme monitoring. Hepatotoxicity is usually mild and resolves after drug withdrawal.

Role of stereotactic radiosurgery in the management of pituitary adenomas

Trans-sphenoidal neurosurgery is the gold standard treatment for pituitary adenomas, but it can be contraindicated or ineffective. Stereotactic radiosurgery is a procedure aimed at controlling hormone hypersecretion and tumor size of pituitary adenomas. This Review discusses the long-term efficacy and adverse effects of stereotactic radiosurgery with the Gamma Knife® in secreting and nonsecreting pituitary adenomas. Long-term data confirm the antisecretory efficacy of the procedure (about 50% remission in hypersecreting tumors) but also a previously unknown low risk of recurrence (2–10% of cases). The time to remission is estimated to range from 12 to 60 months. The antitumoral efficacy of this treatment against nonsecreting tumors is observed in about 90% of cases. Hypopituitarism is the main adverse effect, observed in 20–40% of cases. Comparisons with conventional fractionated radiotherapy reveal a lower rate of remission with Gamma Knife® radiosurgery, counterbalanced by a more rapid efficacy and a lower rate of hypopituitarism. Short-term follow-up results on stereotactic fractionated radiotherapy suggest a risk of hypopituitarism similar to the one observed with radiosurgery. Therefore, stereotactic radiosurgery is probably still useful to treat some cases of pituitary adenoma, despite the fact that antisecretory drugs, particularly for acromegaly and prolactinomas, are becoming more effective and are well tolerated, thus increasing the probability of success with nonsurgical therapy.

Long-term follow-up of ipilimumab-induced hypophysitis, a common adverse event of the anti-CTLA-4 antibody in melanoma.

OBJECTIVE Few data are published on the long-term follow-up of ipilimumab-induced hypophysitis, a cytotoxic T-lymphocyte antigen 4 antibody. We characterized hypophysitis in terms of clinical signs, endocrinological profile, and imaging at diagnosis and during a long-term follow-up. DESIGN AND PATIENTS Fifteen patients, treated for malignant melanoma and who presented ipilimumab-induced hypophysitis, were observed between June 2006 and August 2012 in Timone Hospital, Marseille. METHODS Symptoms, pituitary function, and pituitary imaging at diagnosis of hypophysitis and during the follow-up were recorded. RESULTS Of 131 patients treated with ipilimumab or a placebo, 15 patients (10 mg/kg in 11/15) presented with hypophysitis (≥11.5%) at 9.5±5.9 weeks (mean±s.d.) after treatment start, occurring in 66% after the third infusion. The main initial symptoms were headache (n=13) and asthenia (n=11). All patients but one had at least one hormonal defect: thyrotroph (n=13), gonadotroph (n=12), or corticotroph (n=11) deficiencies. None had diabetes insipidus. Pituitary imaging showed a moderately enlarged gland in 12 patients. Clinical symptoms improved rapidly on high-dose glucocorticoids (n=11) or physiological replacement doses (n=4). At the end of follow-up (median 33.6 months, range 7-53.5), corticotroph deficiency remained in 13 patients, 11 recovered thyrotroph and ten gonadotroph functions. Pituitary imaging remained abnormal in 11 patients. CONCLUSION Ipilimumab-induced hypophysitis is a common side-effect with frequent hormonal deficiencies at diagnosis. Usually, hormonal deficiencies improved, except for corticotroph function. Patients receiving these immunomodulatory therapies should be closely monitored especially by systematic baseline hormone measurements after the third infusion and remain at a risk of adrenal insufficiency in the long-term.

Pituitary Stem Cell Update and Potential Implications for Treating Hypopituitarism

Stem cells have been identified in organs with both low and high cell turnover rates. They are characterized by the expression of key marker genes for undifferentiated cells, the ability to self-renew, and the ability to regenerate tissue after cell loss. Several recent reports present evidence for the presence of pituitary stem cells. Here we offer a critical review of the field and suggest additional studies that could resolve points of debate. Recent reports have relied on different markers, including SOX2, nestin, GFRa2, and SCA1, to identify pituitary stem cells and progenitors. Future studies will be needed to resolve the relationships between cells expressing these markers. Members of the Sox family of transcription factors are likely involved in the earliest steps of pituitary stem cell proliferation and the earliest transitions to differentiation. The transcription factor PROP1 and the NOTCH signaling pathway may regulate the transition to differentiation. Identification of the stem cell niche is an important step in understanding organ development. The niche may be the marginal zone around the lumen of Rathkes pouch, between the anterior and intermediate lobes of mouse pituitary, because cells in this region apparently give birth to all six pituitary hormone cell lineages. Stem cells have been shown to play a role in recurrent malignancies in some tissues, and their role in pituitary hyperplasia, pituitary adenomas, and tumors is an important area for future investigation. From a therapeutic viewpoint, the ability to cultivate and grow stem cells in a pituitary predifferentiation state might also be helpful for the long-term treatment of pituitary deficiencies.

Radiotherapy and radiosurgery in acromegaly

Growth-hormone hypersecretion, acromegaly, is associated with reduced life expectancy. First line treatment remains surgery, but remission rates vary between 50% and 90%. In case of lack of surgical remission or recurrence, somatostatin agonists can be proposed. However, about 30% of patients are partially or totally resistant to this treatment. The growth hormone receptor antagonist pegvisomant currently needs more prolonged follow-up studies. Conventional radiotherapy and radiosurgery are two radiation treatment modalities that can be proposed to these resistant patients. Reported rates of remission for conventional radiotherapy range between 50% and 60% in patients with acromegaly, with a time to remission delayed by several years, and adverse effects including high rates of hypopituitarism. This treatment could be proposed to patients with aggressive adenomas, in whom surgery cannot allow biochemical control. In contrast, studies on stereotactic radiosurgery reported lower rates of remission, with faster growth hormone hypersecretion decline, and a lower risk of adverse effects. However, this latter technique requires a well defined target volume, which limits its indications. The high precision of this technique makes it possible to be used as an alternative primary treatment to surgery. We reviewed major advantages and drawbacks of each of these techniques, based on recent studies to try to define their respective indications in the therapeutic algorithm of acromegaly.

Pharmacokinetic evidence for suboptimal treatment of adrenal insufficiency with currently available hydrocortisone tablets.

Background and ObjectiveAdrenal insufficiency is caused by primary adrenal failure or by impairment of the corticotropic axis. In both situations, cortisol secretion is deficient, and hydrocortisone is a logical replacement therapy. However, no consensus guideline for dosing has been published, and clinicians adapt the dose empirically after only a clinical evaluation. Under this regimen, some patients receiving an inappropriately high dose of cortisol feel comfortable and also have an increased risk of adverse effects. We performed a pharmacokinetic study of cortisol in patients with adrenal insufficiency to evaluate plasma concentrations when the dosing was based on clinical examination and to develop a model allowing optimization of drug dosing.Study DesignThis was a prospective, open-label study in two endocrinology departments and a clinical investigation centre (Assistance Publique Hôpitaux de Marseille, Marseille, France).MethodsFifty patients with primary (n = 20) or secondary (n = 30) adrenal insufficiency were recruited. All patients were given their usual hydrocortisone replacement regimen. Blood samples for cortisol measurements were drawn at 0600, 0800, 1000, 1200, 1400, 1600, 1800, 2000, 2200 and 0000 h. The observed values were compared with the known physiological range throughout the day (0800, 1600 and 0000 h). A population pharmacokinetic analysis was performed using nonlinear mixed-effects modelling software (NONMEM®). The final pharmacokinetic model was then used to simulate several hydrocortisone dosing scenarios.ResultsThirteen different treatment regimens for 50 patients were observed. The cortisol plasma concentrations were compared with the physiological range and showed that 79%, 55% and 45% of patients were over- or under-treated at 0800, 1600 and 2400 h, respectively. The cortisol concentrations showed wide variability and were best described using a one-compartment model with zero-order input and first-order elimination. The pharmacokinetic parameters (intersubject variability) were the following: duration of absorption 0.54 hour, volume of distribution 38.7 L (39.7%) and clearance 12.1 L/h (23.2%). The proportional residual error was 32.3%. This final model was then used to simulate 18 different dosing regimens. The regimen with the highest proportion of simulated patients within the physiological targets was 10 + 5 + 5 mg at 0730, 1200 and 1630 h, respectively. However, even with this regimen, about 54%, 44% and 32% of patients would remain over- or under-treated at 0800, 1600 and 2400 h, respectively.ConclusionsMost patients with adrenal insufficiency are imperfectly treated with hydrocortisone relative to their plasma cortisol concentrations. Using simulation, a standard dosing regimen is suggested, which increases the proportion of patients within the physiological target concentrations. However, an individualized dose adjustment would be more accurate.