Temozolomide therapy in patients with aggressive pituitary adenomas or carcinomas

Temozolomide (TMZ) in the Treatment of Glioblastoma Multiforme-A Literature Review and Clinical Outcomes

Glioblastoma multiforme (GBM) is one of the most aggressive primary tumors of the central nervous system. It is associated with a very poor prognosis, with up to half of patients failing to survive the first year after diagnosis. It develops from glial tissue and belongs to the adult-type diffuse glioma group according to the WHO classification of 2021. Therapy for patients with GBM is currently based on surgical resection, radiation therapy, and chemotherapy, but despite many efforts, there has been minimal progress in tumor management. The most important chemotherapeutic agent in the treatment of this tumor is temozolomide (TMZ), a dacarbazine derivative that presents alkylating activity. It is usually administered to patients concurrently with radiation therapy after surgical resection of the tumor, which is defined as the Stupp protocol. Temozolomide demonstrates relatively good efficacy in therapy, but it could also present with several side effects. The resistance of GBM to the drug is currently the subject of work by specialists in the field of oncology, and its use in various regimens and patient groups may bring therapeutic benefits in the future. The aim of this review paper is to summarize the relevance of TMZ in the treatment of GBM based on recent reports.

Establishment of Human Pituitary Neuroendocrine Tumor Derived Organoid and Its Pilot Application for Drug Screening

CONTEXT

Precision medicine for pituitary neuroendocrine tumors (PitNETs) is limited by the lack of reliable research models.

OBJECTIVE

To generate patient-derived organoids (PDOs), which could serve as a platform for personalized drug screening for PitNET patients.

DESIGN

From July 2019 to May 2022, a total of 32 human PitNET specimens were collected for the establishment of organoids with an optimized culture protocol.

SETTING

This study was conducted at Sun Yat-Sen University Cancer Center.

PATIENTS

PitNET patients who were pathologically confirmed were enrolled in this study.

INTERVENTIONS

Histological staining and whole-exome sequencing were utilized to confirm the pathologic and genomic features of PDOs. A drug response assay on PDOs was also performed.

MAIN OUTCOME MEASURES

PDOs retained key genetic and morphological features of their parental tumors.

RESULTS

PDOs were successfully established from various types of PitNET samples with an overall success rate of 87.5%. Clinical nonfunctioning PitNETs-derived organoids (22/23, 95.7%) showed a higher likelihood of successful generation compared to those from functioning PitNETs (6/9, 66.7%). Preservation of cellular structure, subtype-specific neuroendocrine profiles, mutational features, and tumor microenvironment heterogeneity from parental tumors was observed. A distinctive response profile in drug tests was observed among the organoids from patients with different subtypes of PitNETs. With the validation of key characteristics from parental tumors in histological, genomic, and microenvironment heterogeneity consistency assays, we demonstrated the predictive value of the PDOs in testing individual drugs.

CONCLUSION

The established PDOs, retaining typical features of parental tumors, indicate a translational significance in innovating personalized treatment for refractory PitNETs.

Pharmacological Treatment of Non-Functioning Pituitary Adenomas

Treatment strategies for NFPA include surgery, radiotherapy, medical treatment, or follow-up. The treatment of NFPAs with compressive symptoms is surgical. However, in case of post-surgical tumor remnants, there may be treatment strategies that include observation and radiotherapy. Recently, medical treatment with cabergoline (CAB) has been recommended to contain and/or reduce the size of the tumor remnant. Based on the findings that many NFPAs show a dopamine receptor (DR) and somatostatin receptor (SR) expression, medical therapy with dopamine agonists (DAs) and somatostatin receptor ligands (SSRLs) has been tested as an alternative to prevent recurrence after surgery. The DAs have been the most extensively studied, showing some potential in terms of tumor shrinkage. SSRLs and other emerging medical options are much less studied. We will review and critically evaluate the current data on the medical therapy of NFPAs to elucidate their role in the management of this tumor type. In the case of actively growing remnants (more than 10% growth per year) and high-risk pituitary adenomas, treatment with CAB at a dose of 1.5-3.0 mg is indicated for tumor containment and/or reduction. In relation to combined chemotherapy with CAB, there is little information in the literature to support its use. In our experience, CAB treatment can be used after radiotherapy as an adjuvant treatment.

Diagnosis and management of prolactin-secreting pituitary adenomas: a Pituitary Society international Consensus Statement

This Consensus Statement from an international, multidisciplinary workshop sponsored by the Pituitary Society offers evidence-based graded consensus recommendations and key summary points for clinical practice on the diagnosis and management of prolactinomas. Epidemiology and pathogenesis, clinical presentation of disordered pituitary hormone secretion, assessment of hyperprolactinaemia and biochemical evaluation, optimal use of imaging strategies and disease-related complications are addressed. In-depth discussions present the latest evidence on treatment of prolactinoma, including efficacy, adverse effects and options for withdrawal of dopamine agonist therapy, as well as indications for surgery, preoperative medical therapy and radiation therapy. Management of prolactinoma in special situations is discussed, including cystic lesions, mixed growth hormone-secreting and prolactin-secreting adenomas and giant and aggressive prolactinomas. Furthermore, considerations for pregnancy and fertility are outlined, as well as management of prolactinomas in children and adolescents, patients with an underlying psychiatric disorder, postmenopausal women, transgender individuals and patients with chronic kidney disease. The workshop concluded that, although treatment resistance is rare, there is a need for additional therapeutic options to address clinical challenges in treating these patients and a need to facilitate international registries to enable risk stratification and optimization of therapeutic strategies.

Efficacy and safety of temozolomide in the treatment of aggressive pituitary neuroendocrine tumours in Spain

Current guidelines recommend temozolomide as the first-line chemotherapy for aggressive pituitary neuroendocrine tumours. However, no clinical trials have been conducted to date and clinical experience is quite limited. We retrospectively analyzed 28 patients (9 women and 19 men), aged 46.6 + 16.9, with aggressive pituitary tumours (4 pituitary carcinomas and 24 aggressive adenomas) treated with temozolomide in 10 Spanish pituitary reference centres. Four patients had Cushing's disease, 9 prolactinomas and 15 clinically non-functioning pituitary tumours (seven silent corticotroph, three silent somatotroph, one silent lactotroph, one silent gondotroph and three null-cell tumours). Median size at diagnosis was 10.5 cm3 (IQR 4.7-22.5), with cavernous sinus invasion in 88% and no metastases. Pre-temozolomide treatment, these data were 5.2 cm3 (IQR 1.9-12.3), 89.3% and 14.3% (2 intracranial and 2 spinal metastases). All patients had undergone surgery (1-5 surgeries), 25 (89.3%) had received radiotherapy (7 of them reirradiated) and 13(46.4%) had received cabergoline. One patient interrupted temozolomide prematurely. The remaining 27 patients received a median of 13 cycles (range 3-66) of 5 days every 28 days, with a mean initial dose of 265 ± 73 mg when administered alone and of 133 ± 15 mg when co-administered with radiotherapy. Eight patients (29.6%) had a significant reduction (>30%) in tumour volume and 14 (51.9%) attained tumour stabilization. After a median follow-up of 29 months (IQR 10-55), 8 out of these 22 showed disease progression. A longer progression-free survival was found in the five patients who received concomitant radiotherapy. Seven patients (25%) died (all of them because of tumour progression or complications of treatments) at 77 months (IQR 42-136) after diagnosis and 29 months (IQR 16-55) after the first dose of temozolomide. Adverse effects occurred in 18 patients (14 mild and 4 moderate or severe). In conclusion, temozolomide is an effective medical treatment for aggressive pitNET and pituitary carcinomas but is sometimes followed by tumour progression. Co-administration with radiotherapy may increase progression-free survival.

Aggressive Pituitary Tumors and Pituitary Carcinomas: From Pathology to Treatment

Aggressive pituitary tumors (APTs) and pituitary carcinomas (PCs) are heterogeneous with regard to clinical presentation, proliferative markers, clinical course, and response to therapy. Half of them show an aggressive course only many years after the first apparently benign presentation. APTs and PCs share several properties, but a Ki67 index greater than or equal to 10% and extensive p53 expression are more prevalent in PCs. Mutations in TP53 and ATRX are the most common genetic alterations; their detection might be of value for early identification of aggressiveness. Treatment requires a multimodal approach including surgery, radiotherapy, and drugs. Temozolomide is the recommended first-line chemotherapy, with response rates of about 40%. Immune checkpoint inhibitors have emerged as second-line treatment in PCs, with currently no evidence for a superior effect of dual therapy compared to monotherapy with PD-1 blockers. Bevacizumab has resulted in partial response (PR) in few patients; tyrosine kinase inhibitors and everolimus have generally not been useful. The effect of peptide receptor radionuclide therapy is limited as well. Management of APT/PC is challenging and should be discussed within an expert team with consideration of clinical and pathological findings, age, and general condition of the patient. Considering that APT/PCs are rare, new therapies should preferably be evaluated in shared standardized protocols. Prognostic and predictive markers to guide treatment decisions are needed and are the scope of ongoing research.

Refractory Pit1 plurihormonal tumours and thyrotroph adenomas

Pit-1 tumours are derived from neoplastic cells of either somatotroph, lactotroph or thyrotroph cell lineages, but there are also distinct mixed tumours and plurihormonal tumours within this category as described within the 2022 edition of the WHO classification of pituitary tumours. Plurihormonal tumours and thyrotroph adenomas are transcriptionally similar and grouped together to discuss in this review, although it is clear an immature type of plurihormonal tumour exists which are more commonly associated with refractory disease. Management of residual or recurrent disease should follow that of other aggressive pituitary tumours, although a trial of somatostatin analogue therapy is certainly warranted before considering temozolomide therapy.

Aggressive pituitary tumors (PitNETs)

The majority of anterior pituitary tumors behave benignly, that is, they grow slowly and do not metastasize, and were therefore called adenomas. However, they would frequently invade adjacent structures, leading to recurrence. One of the misleading assumptions in their previous classification was the simplistic distinction made between adenoma and carcinoma. In the upcoming WHO 2022 classification, a new terminology will be introduced: pituitary neuroendocrine tumor (PitNET) which is consistent with that used for other neuroendocrine neoplasms. In general, aggressive PitNETs are invasive and proliferative tumors with frequent recurrences, resistant to conventional treatments, and yet virtually without metastases. At present, no single morphological or histological marker has been shown as yet to reliably predict their aggressive behavior. In terms of treatment, temozolomide (TMZ) had been considered promising and the sole therapeutic option for aggressive and malignant PitNETs following failure of standard therapies. However, recent reports have disclosed that TMZ does not provide long-term control of many aggressive PitNETs. A further multidisciplinary approach is necessary for both reliable prediction and successful management of aggressive PitNETs.

Knowing when to discontinue Temozolomide therapy in responding aggressive pituitary tumors and carcinomas: a systematic review and Padua (Italy) case series

INTRODUCTION

Pituitary adenomas can show a tendency to grow, despite multimodal treatment. Temozolomide (TMZ) has been used in the last 15 years in patients with aggressive pituitary tumors. TMZ requires a careful balance of different expertise, especially for selection criteria.

AREAS COVERED

We conducted: (1) a systematic review of the published literature from 2006 to 2022, collecting only cases with a complete description of patient follow-up after TMZ discontinuation; (2) a description of all patients with aggressive pituitary adenoma or carcinoma treated in Padua (Italy).

EXPERT OPINION

There is considerable heterogeneity in the literature: TMZ cycles duration ranged from 3 to 47 months; the follow-up time after TMZ discontinuation ranged from 4 to 91 months (mean 24 months, median 18 months), at least a stable disease has been reported in 75% of patients after a mean 13 months (range 3-47 months, median 10 months). The Padua (Italy) cohort reflects the literature. Future directions to explore are to understand the pathophysiological mechanism of TMZ resistance escape, to develop predicting factors to TMZ treatment (especially through the delineation of the underlying transformation processes), and to further expand the therapeutic applications of TMZ (as neoadjuvant, combined with radiotherapy).

Benign and Malignant Tumors of the Pituitary Gland

Pituitary gland tumors represent approximately 10-15% of all brain tumors and the most common neoplasms of the sellar region. Among them, pituitary adenomas are the widespread accounting for more than 80%. Recently, the fourth edition of the World Health Organization (WHO) 2017 classified pituitary tumors focusing on histopathologic and molecular genetics features and introduced new entities like pituitary blastoma. Most of pituitary gland neoplasms occur sporadically, whereas 5% are related to familial syndromes. They present with several clinical manifestations including signs and symptoms related to excessive hormone secretion by the tumor, signs of hormone deficits by the normal pituitary gland and others commonly secondary to mass effects, and compression of nearby structures such as the optic chiasm; headache and visual disturbance are the most frequent mass effect symptoms. Some tumors, however, are detected as an incidental finding on magnetic resonance imaging (MRI) or computed tomography (CT) scans performed for some other reasons. A correct evaluation involves the assessment of hypothalamic-pituitary hormonal function and an ophthalmological examination once a pituitary lesion is encountered. Surgery, more specifically transsphenoidal approach, represents the primary treatment chosen for the majority of pituitary tumors (except for prolactinomas where medical treatment is indicated) allowing for pathologic analysis and complete or partial tumor removal. On the contrary, to date, craniotomy is rarely performed. Sometimes, due to the proximity of critical structures and to tumor's location and characteristics, a successful surgical procedure may often not be achievable due to the high risks related to the procedure itself. Therefore, the treatment of pituitary tumors commonly requires a multimodal approach, including surgery, radiosurgery, radiation therapy, and medical therapy. Aggressive pituitary tumors or carcinomas are associated with poor prognosis due to limited therapeutic options. Furthermore, they tend to recur quickly after initial surgical treatment or present metastasis, may be unresponsive to therapy, and are difficult to manage. In this chapter, we provide an overview of the most common pituitary gland tumors focusing on epidemiology, new pathological features, diagnosis, available treatment, and prognosis.

Multidisciplinary management of difficult/aggressive growth-hormone pituitary neuro-endocrine tumors

Growth Hormone-secreting adenomas exhibits variable biological behavior and heterogeneous natural history, ranging from small adenomas and mild disease, to invasive and aggressive neoplasms with more severe clinical picture. Patients not cured or controlled after neurosurgical and first-generation somatostatin receptor ligands (SRL) therapy could require multiple surgical, medical and/or radiation treatments to achieve disease control. To date, no clinical, laboratory, histopathological, or neuroradiological markers are able to define the aggressiveness or predict the disease prognosis in patients with acromegaly. Therefore, the management of these patients requires careful evaluation of laboratory assessments, diagnostic criteria, neuroradiology examinations, and neurosurgical approaches to choose an effective and patient-tailored medical therapy. A multidisciplinary approach is particularly useful in difficult/aggressive acromegaly to schedule multimodal treatment, which includes radiation therapy, chemotherapy with temozolomide and other, recent emerging treatments. Herein, we describe the role of the different members of the multidisciplinary team according to our personal experience; a flow-chart for the therapeutic approach of difficult/aggressive acromegaly patients is proposed.

Innovative tumour targeting therapeutics in Cushing's disease

Cushing's disease (CD) is the most frequent form of endogenous hypercortisolism. Management of this devastating condition relies on pituitary surgery, while effective pharmacological treatment mainly focus on periphery targeting pharmaceuticals. Approved tumour-targeting drugs are limited to dopamine agonists and somatostatin analogues with frequently low efficacy and substantial side effects. Discoveries on the genetics and pathophysiology of corticotroph tumorigenesis brought forward new potential pharmacological targets. Compounds such as retinoic acid although promising in preclinical studies, are not as efficient in the clinic. Others, such as, silibinin, gefitinib and roscovitine are effective in preclinical models, but their efficacy and safety still needs to be determined in patients with CD.

Temozolomide in aggressive pituitary tumours and pituitary carcinomas

Survival for patients with aggressive pituitary tumours (APT) and pituitary carcinomas (PC) has significantly improved following the increasing use of temozolomide (TMZ) since the first reports of response in 2006. TMZ was established as first line chemotherapy for APT/PC in the 2018 ESE guidelines on the management of APT/PC. There is no controversy over its use as salvage therapy however there is increasing interest in exploring TMZ use earlier in the treatment algorithm for APT/PC. Overall response rates as reported in systematic reviews are around 40% but stable disease in another 25% illustrates the clinical effectiveness of TMZ. Response is higher among functional compared to non-functional tumours. Where maximal radiation thresholds have not been reached in a patient, combination radiotherapy and TMZ appears more effective. Whether combination TMZ and capecitabine (CAPTEM) offers increased benefit remains uncertain particularly given added toxicity. O6-methyl guanine DNA methyl transferase (MGMT) status is important in determining response to treatment, although examination via immunohistochemistry versus PCR-based promoter-methylation analysis remains somewhat controversial. Optimal duration of TMZ treatment has still not been determined although longer treatment courses have been associated with increased progression-free survival. Treatment options following disease progression after TMZ remain unclear but include a second course of TMZ, immunotherapy and targeted oncological agents such as bevacizumab and lapatinib as well as peptide receptor radionuclide treatment (PRRT). An experienced pituitary multidisciplinary team is essential to all management decisions in patients with APT/PC.

Aggressive pituitary tumours and carcinomas, characteristics and management of 171 patients

OBJECTIVE

To describe clinical and pathological characteristics and treatment outcomes in a large cohort of aggressive pituitary tumours (APT)/pituitary carcinomas (PC).

DESIGN

Electronic survey August 2020-May 2021.

RESULTS

96% of 171 (121 APT, 50 PC), initially presented as macro/giant tumours, 6 were microadenomas (5 corticotroph). Ninety-seven tumours, initially considered clinically benign, demonstrated aggressive behaviour after 5.5 years (IQR: 2.8-12). Of the patients, 63% were men. Adrenocorticotrophic hormone (ACTH)-secreting tumours constituted 30% of the APT/PC, and the gonadotroph subtypes were under-represented. Five out of 13 silent corticotroph tumours and 2/6 silent somatotroph tumours became secreting. Metastases were observed after median 6.3 years (IQR 3.7-12.1) from diagnosis. At the first surgery, the Ki67 index was ≥3% in 74/93 (80%) and ≥10% in 38/93 (41%) tumours. An absolute increase of Ki67 ≥ 10% after median of 6 years from the first surgery occurred in 18/49 examined tumours. Tumours with an aggressive course from outset had higher Ki67, mitotic counts, and p53. Temozolomide treatment in 156/171 patients resulted in complete response in 9.6%, partial response in 30.1%, stable disease in 28.1%, and progressive disease in 32.2% of the patients. Treatment with bevacizumab, immune checkpoint inhibitors, and peptide receptor radionuclide therapy resulted in partial regression in 1/10, 1/6, and 3/11, respectively. Median survival in APT and PC was 17.2 and 11.3 years, respectively. Tumours with Ki67 ≥ 10% and ACTH-secretion were associated with worse prognosis.

CONCLUSION

APT/PCs exhibit a wide and challenging spectrum of behaviour. Temozolomide is the first-line chemotherapy, and other oncological therapies are emerging. Treatment response continues to be difficult to predict with currently studied biomarkers.

PDCD10 promotes the aggressive behaviors of pituitary adenomas by up-regulating CXCR2 and activating downstream AKT/ERK signaling

As the second most common primary intracranial neoplasms, about 40% of pituitary adenomas (PAs) exhibit aggressive behaviors and resulting in poor patient prognosis. The molecular mechanisms underlying the aggressive behaviors of PAs are not yet fully understood. Biochemical studies have reported that programmed cell death 10 (PDCD10) is a component of the striatin-interacting phosphatase and kinase (STRIPAK) complex and plays a dual role in cancers in a tissue- or disease-specific manner. In the present study, we report for the first time that the role of PDCD10 in PAs. Cell proliferation, migration and invasion were either enhanced by overexpressing or inhibited by silencing PDCD10 in PA cells. Moreover, PDCD10 significantly promoted epithelial–mesenchymal transition (EMT) of pituitary adenoma cells. Mechanistically, we showed that the expression of CXCR2, together with phosphorylation levels of AKT and ERK1/2 were regulated by PDCD10. Activation of CXCR2 inversed inactivation of AKT/ERK signal pathways and the tumor-suppressive effects induced by PDCD10 silencing. Finally, the pro-oncogenic effect of PDCD10 was confirmed by in vivo tumor grafting. Taken together, we demonstrate for the first time that PDCD10 can induce aggressive behaviors of PAs by promoting cellular proliferation, migration, invasion and EMT through CXCR2-AKT/ERK signaling axis.

Aggressive prolactinomas responsive to temozolomide treatment: Report of two cases

Refractory aggressive prolactinomas are detected after the unresponsiveness to conventional therapies. We report two cases that underwent temozolomide treatment and have been in near-complete remission ever since. We suggest the pathology techniques for earlier detection and, subsequently, treatment with temozolomide to reduce morbidities and better respond to therapy.

Delayed Craniospinal Metastasis of Aggressive Nonfunctioning Pituitary Adenomas as Pituitary Carcinomas

Background Clinical behavior of pituitary neoplasms is peculiar and notoriously difficult to predict. While aggressive tumors are common, metastasis is very rare, can be highly delayed, and there are no histological or clinical features to meaningfully predict this happening. Endocrinologically silent tumors are particularly difficult, as there is less opportunity to detect early metastasis. Together, this amounts to a situation of uncertainty over the appropriate management of such tumors before and after metastasis.

Case Description The authors report two cases of nonfunctioning aggressive pituitary adenoma (APA) each requiring two transsphenoidal surgeries, a transcranial resection and radiotherapy. Both these tumors subsequently metastasized caudally along the neuraxis, years later, as a null cell carcinoma associated with a germline CHEK2 mutation and a silent Crooke's cell carcinoma. The former represents a novel oncogenetic association.

Conclusion Delayed drop dural metastasis of pituitary carcinoma is becoming increasingly recognized. Surgical resection of the distant disease to confirm the diagnosis and relieve the mass effect, followed by temozolomide chemotherapy, is the current treatment of choice. The need for both long-term follow-up in patients with APA, and a high degree of suspicion toward dural-based radiographic findings is emphasized.

The Clinical and Pathological Characteristics of Refractory Pituitary Adenomas: A Single Center Experience

Background

Most of pituitary adenomas (PAs) are slow-growing benign tumors which can be cured or controlled by conventional therapies, including surgery, medical treatment or radiotherapy. A small set of PAs, usually known as aggressive PAs or refractory PAs, present with more aggressive behavior and lead to poorer prognosis than classical PAs.

Methods

We retrospectively analyzed the clinical and pathological characteristics of 44 patients who were diagnosed with refractory PAs by a multidisciplinary team (MDT). All the patients’ demographic characteristics, radiological findings, Knosp grade, treatment details and clinical outcomes were abstracted from the medical records. Additionally, 44 patients with nonrefractory PAs (NRPAs) matched for age and gender were selected to serve as the control group.

Results

Despite using all combined treatments including surgery, radiotherapy and conventional medical treatments, all the refractory PAs showed tumor progression or hormone hypersecretion which caused increased morbidity and mortality and remained challenging to management. Compared with those of the non-refractory PAs, the tumor size, invasive rate and tumor growth rate (TGR) were significantly higher in the refractory PAs. TGR >2.2% per month may be considered as a preoperative indicator of refractoriness. The Ki-67 index in the refractory PAs were all ≥3%. EGFR, but not MMP2 or MMP9, was significantly overexpressed in refractory PAs compared with the corresponding levels in nonrefractory PAs.

Conclusion

Refractory PAs are unresponsive to surgery, radiotherapy and conventional medical treatments with a poor prognosis. Moreover, a TGR ≥2.2% per month, Ki-67 index ≥3% and EGFR overexpression may be independent predictors of clinical refractoriness.

Efficacy of temozolomide combined with capecitabine (CAPTEM) on refractory prolactinomas as assessed using an ex vivo 3D spheroid assay

PURPOSE

Refractory prolactinomas resistant to dopamine agonists (DAs) pose a clinical challenge. Temozolomide (TMZ) is a recommended treatment option, but its effects are difficult to predict, and the alternatives are limited. Recent reports suggested that TMZ combined with capecitabine (CAPTEM) can be effective for the treatment of aggressive pituitary tumors. This study sought to evaluate the effect of TMZ in an ex vivo three-dimensional (3D) spheroid culture assay and determine if this assay could be used to predict the therapeutic effect of CAPTEM in actual refractory prolactinomas.

METHODS

Surgically resected tumor tissues from two patients with refractory prolactinoma were cultured as 3D spheroids. The effects of TMZ were assessed based on its suppression of cell viability and reduction of prolactin (PRL) levels.

RESULTS

In Case 1, the 3D culture assay showed no effect of TMZ on cell viability or PRL suppression. Clinically, TMZ treatment did not reduce PRL levels (8870→8274 ng/mL) and the tumor progression. However, CAPTEM partially reduced PRL levels (9070→4046 ng/mL) and suppressed the tumor growth. In Case 2, TMZ in the 3D culture assay showed a 50% reduction of cell viability and 40% reduction of PRL levels. Clinically, CAPTEM was highly effective, with a considerable reduction in PRL level (17,500→210 ng/mL), and MRI showed almost no residual tumor.

CONCLUSIONS

This is the first report to describe the effects of CAPTEM treatment on refractory prolactinomas. The ex vivo 3D spheroid culture assay reliably predicted TMZ sensitivity and informed the selection between TMZ or CAPTEM treatment for refractory prolactinomas.

Tamoxifen Exerts Anticancer Effects on Pituitary Adenoma Progression via Inducing Cell Apoptosis and Inhibiting Cell Migration

Although pituitary adenomas are histologically benign, they are often accompanied by multiple complications, such as cardiovascular disease and metabolic dysfunction. In the present study, we repositioned the Food and Drug Administration -approved immune regulator tamoxifen to target STAT6 based on the genomics analysis of PAs. Tamoxifen inhibited the proliferation of GH3 and AtT-20 cells with respective IC₅₀ values of 9.15 and 7.52 μM and increased their apoptotic rates in a dose-dependent manner. At the molecular level, tamoxifen downregulated phosphorylated PI3K, phosphorylated AKT and the anti-apoptotic protein Bcl-2 and increased the expression of pro-apoptotic proteins p53 and Bax in GH3 and AtT-20 cells. Furthermore, tamoxifen also inhibited the migration of both cell lines by reprogramming tumor-associated macrophages to the M1 phenotype through STAT6 inactivation and inhibition of the macrophage-specific immune checkpoint SHP1/SHP. Finally, administration of tamoxifen (20, 50, 100 mg·kg⁻¹·d⁻¹, for 21 days) inhibited the growth of pituitary adenomas xenografts in nude mice in a dose-dependent manner. Taken together, tamoxifen is likely to be a promising combination therapy for pituitary adenomas and should be investigated further.

Temozolomide Nonresponsiveness in Aggressive Prolactinomas and Carcinomas: Management and Outcomes

Context

Temozolomide (TMZ) is endorsed as the treatment of choice in aggressive or malignant pituitary adenomas.

Objective

Herein we describe a case of an aggressive prolactinoma that was resistant to TMZ. We performed a literature review of similar nonresponsive, aggressive prolactinomas.

Methods

A 40-year-old woman presented with a giant prolactinoma that required cabergoline, transsphenoidal surgery, and radiotherapy to achieve near-normal prolactin and apparently no residual tumor. A year later, she presented with multiple cranial nerve involvement due to a recurrent tumor extending to the infratemporal fossa. She underwent transfrontal surgery, second radiotherapy, and was started on TMZ. Despite 8 cycles of temozolomide (200 mg/m², 5/28-day cycle), she had progressive disease and ultimately succumbed to the disease. PubMed/MEDLINE, Google Scholar, and prior review articles were searched for manuscripts about patients with aggressive prolactinomas who had been treated with TMZ. Data on demography, duration of therapy, and management outcomes were analyzed in those with progressive disease.

Results

We identified 94 cases of patients with aggressive/malignant prolactinomas in the literature who had received TMZ. Progressive disease despite TMZ was present in 36 cases (38%). There was a male preponderance (65%) among these and 40% had aggressive prolactinomas, whereas the rest had carcinomas. Patients received a median of 8 cycles (interquartile range, 3.5-11.5) of TMZ. O6‐methylguanine‐DNA‐methyltransferase (MGMT) immunostaining was negative in 35%. Overall mortality at the time of publication was 40%, at a duration varying from 2 to 20 years from diagnosis.

Conclusion

TMZ resistance in aggressive/malignant prolactinomas is challenging. Progressive disease on optimal TMZ treatment entails the use of newer agents.

Aggressive pituitary neuroendocrine tumors: current practices, controversies, and perspectives, on behalf of the EANS skull base section

Aggressive pituitary neuroendocrine tumors (APT) account for 10% of pituitary tumors. Their management is a rapidly evolving field of clinical research and has led pituitary teams to shift toward a neuro-oncological-like approach. The new terminology "Pituitary neuroendocrine tumors" (PitNet) that was recently proposed to replace "pituitary adenomas" reflects this change of paradigm. In this narrative review, we aim to provide a state of the art of actual knowledge, controversies, and recommendations in the management of APT. We propose an overview of current prognostic markers, including the recent five-tiered clinicopathological classification. We further establish and discuss the following recommendations from a neurosurgical perspective: (i) surgery and multi-staged surgeries (without or with parasellar resection in symptomatic patients) should be discussed at each stage of the disease, because it may potentialize adjuvant medical therapies; (ii) temozolomide is effective in most patients, although 30% of patients are non-responders and the optimal timeline to initiate and interrupt this treatment remains questionable; (iii) some patients with selected clinicopathological profiles may benefit from an earlier local radiotherapy and/or chemotherapy; (iv) novel therapies such as VEGF-targeted therapies and anti-CTLA-4/anti-PD1 immunotherapies are promising and should be discussed as 2nd or 3rd line of treatment. Finally, whether neurosurgeons have to operate on "pituitary adenomas" or "PitNets," their role and expertise remain crucial at each stage of the disease, prompting our community to deal with evolving concepts and therapeutic resources.

Clinical Efficacy of Temozolomide and Its Predictors in Aggressive Pituitary Tumors and Pituitary Carcinomas: A Systematic Review and Meta-Analysis

Background: A growing number of evidences suggest that TMZ applications can generate impressive benefits for APT and PC patients. However, the definite role of TMZ for individuals remains unclarified due to the variation between studies. And the predictive factors to alter its efficacy remain debatable.

Objective: To evaluate the long-term effectiveness and safety profile of TMZ in the treatment of pituitary malignancies, and delineate the predictors during its clinical employment.

Results: A literature retrieval was conducted from online databases for studies published up to December 31, 2020. Twenty one studies involving 429 patients were identified. TMZ exhibited 41% radiological overall response rate (rORR). The biochemical response rate was determinate in 53% of the functioning subset. Two-year and 4-year survival rate were 79 and 61%, respectively. TMZ prolonged the median PFS and OS as 20.18 and 40.24 months. TMZ-related adverse events occurred in 19% of patients. Regarding predictors of TMZ response, rORR was dramatically improved in patients with low/intermediate MGMT expression than those with high-MGMT (>50%) (p < 0.001). The benefit of TMZ varied according to functioning subtype of patients, with greater antitumor activities in functioning subgroups and fewer activities in non-functioning sets (p < 0.001). Notably, the concomitant therapy of radiotherapy and TMZ significantly increased the rORR (p = 0.007).

Conclusion: TMZ elicits clinical benefits with moderate adverse events in APT and PC patients. MGMT expression and clinical subtype of secreting function might be vital predictors of TMZ efficacy. In the future, the combination of radiotherapy with TMZ may further improve the clinical outcomes than TMZ monotherapy.

Long-Term Use of Temozolomide as Safe and Effective Therapy for an Aggressive Corticotroph Adenoma in a Very Old Patient

Background

Temozolomide (TMZ) is safe and effective in the treatment of aggressive pituitary adenomas (PAs). However, the optimal duration of TMZ therapy is still unknown. Moreover, data about administration of TMZ in elderly (≥65 years) people to treat aggressive PAs are scarce. We report the case of the oldest female patient undergoing the longest TMZ protocol described so far to treat an aggressive, initially silent corticotroph PA.

Case report

The patient initially underwent partial surgical removal of the PA. Subsequent treatment with cabergoline was applied, but it was unsuccessful in controlling the growth of the residual tumor. Pasireotide and external radiation also showed to be ineffective; therefore, treatment with TMZ was started at the standard dose of 200 mg/m²/day for 5 days every 4 weeks for a total of 47 cycles. At the time of treatment’s beginning, the patient was 83 years old. Radiological follow-up documented a progressive, remarkable reduction of the adenoma and the last imaging, after 39 cycles of TMZ, showed an intrasellar lesion with large areas of cystic degeneration. The patient also developed adrenal deficiency managed with glucocorticoid replacement. No major side effects were observed throughout the treatment, with exception of nausea, well controlled with anti-emetic medication. TMZ therapy was discontinued after 47 cycles; hormonal and imaging follow-up investigations documented sustained functional and dimensional response.

Conclusions

Our case supports the long-term use of TMZ, confirming its safety and efficacy also for elderly patients.

New and emerging pharmacological treatment options for acromegaly

Introduction: Transsphenoidal surgery is the first-line treatment for acromegaly, but even in referral centers, approximately 50% of patients are not cured, and adjuvant pharmacological treatment is necessary. Widely used therapies encompass different drug classes, such as injectable somatostatin receptor ligands (SRLs), oral dopamine agonists and injectable growth hormone receptor antagonists, but approximately 40% of patients still have disease activity in real-life practice. Therefore, there is a need for new medical therapies to allow disease control in a larger proportion of patients, increase quality of life, reduce morbidity and mortality and improve treatment adherence in acromegaly.Areas covered: In this review, the authors cover new and emerging drugs under development or drugs recently approved for the treatment of acromegaly.Expert opinion: Disease control is essential to reduce morbidity and mortality in acromegaly but is still not achieved in a significant proportion of patients or takes a long time to be achieved with currently available options and treatment algorithms. Therefore, the development of new drugs as well as the establishment of biomarkers of disease control to allow precision medicine will improve treatment and outcomes in acromegaly.

Medical Therapy of Aggressive Pituitary Tumors

The rare aggressive pituitary adenoma presents a special challenge, due to the heterogenous presentation of the disease. The prognosis of aggressive pituitary adenomas has been improved due to recent studies demonstrating clinically-relevant efficacy of temozolomide, which is now considered first-line chemotherapy. However, there is limited data on second-line therapies in patients with treatment failure. This review presents a summary on the potential of medical therapies in aggressive pituitary tumors.

Characteristic of Tumor Regrowth After Gamma Knife Radiosurgery and Outcomes of Repeat Gamma Knife Radiosurgery in Nonfunctioning Pituitary Adenomas

Objective

This study aimed to report the characteristic of tumor regrowth after gamma knife radiosurgery (GKRS) and outcomes of repeat GKRS in nonfunctioning pituitary adenomas (NFPAs).

Design and Methods

This retrospective study consisted of 369 NFPA patients treated with GKRS. The median age was 45.2 (range, 7.2–84.0) years. The median tumor volume was 3.5 (range, 0.1–44.3) cm³.

Results

Twenty-four patients (6.5%) were confirmed as regrowth after GKRS. The regrowth-free survivals were 100%, 98%, 97%, 86% and 77% at 1, 3, 5, 10 and 15 year, respectively. In multivariate analysis, parasellar invasion and margin dose (<12 Gy) were associated with tumor regrowth (hazard ratio [HR] = 3.125, 95% confidence interval [CI] = 1.318–7.410, p = 0.010 and HR = 3.359, 95% CI = 1.347–8.379, p = 0.009, respectively). The median time of regrowth was 86.1 (range, 23.2–236.0) months. Previous surgery was associated with tumor regrowth out of field (p = 0.033). Twelve patients underwent repeat GKRS, including regrowth in (n = 8) and out of field (n = 4). Tumor shrunk in seven patients (58.3%), remained stable in one (8.3%) and regrowth in four (33.3%) with a median repeat GKRS margin dose of 12 (range, 10.0–14.0) Gy. The actuarial tumor control rates were 100%, 90%, 90%, 68%, and 68% at 1, 3, 5, 10, and 15 years after repeat GKRS, respectively.

Conclusions

Parasellar invasion and tumor margin dose (<12 Gy) were independent risk factors for tumor regrowth after GKRS. Repeat GKRS might be effective on tumor control for selected patients. For regrowth in field due to relatively insufficient radiation dose, repeat GKRS might offer satisfactory tumor control. For regrowth out of field, preventing regrowth out of field was the key management. Sufficient target coverage and close follow-up might be helpful.

Therapeutic approach to non-functioning pituitary adenomas

The treatment of non-functioning pituitary adenomas raises two questions: when should they be treated and what role does each available treatment play. We review the usefulness of the different treatments and propose a therapeutic scheme based on the existing literature. Active treatment of pituitary adenomas should be performed when they produce symptoms, have contact with the optic tract, or have grown on imaging tests. The treatment is surgical, using radiotherapy for cases with significant non-removable postsurgical tumour remnants and for those in which histopathology studies show aggressive features. Medical treatment is reserved for situations in which surgical and radiotherapy treatments have been exhausted. The most advisable surgical treatment is endoscopic, although experienced neurosurgeons achieve results with microsurgery that are only slightly inferior.

A Silent Corticotroph Pituitary Carcinoma: Lessons From an Exceptional Case Report

Nowadays, neither imaging nor pathology evaluation can accurately predict the aggressiveness or treatment resistance of pituitary tumors at diagnosis. However, histological examination can provide useful information that might alert clinicians about the nature of pituitary tumors. Here, we describe our experience with a silent corticothoph tumor with unusual pathology, aggressive local invasion and metastatic dissemination during follow-up. We present a 61-year-old man with third cranial nerve palsy at presentation due to invasive pituitary tumor. Subtotal surgical approach was performed with a diagnosis of silent corticotroph tumor but with unusual histological features (nuclear atypia, frequent multinucleation and mitotic figures, and Ki-67 labeling index up to 70%). After a rapid regrowth, a second surgical intervention achieved successful debulking. Temozolomide treatment followed by stereotactic fractionated radiotherapy associated with temozolomide successfully managed the primary tumor. However, sacral metastasis showed up 6 months after radiotherapy treatment. Due to aggressive distant behavior, a carboplatine-etoposide scheme was decided but the patient died of urinary sepsis 31 months after the first symptoms. Our case report shows how the presentation of a pituitary tumor with aggressive features should raise a suspicion of malignancy and the need of follow up by multidisciplinary team with experience in its management. Metastases may occur even if the primary tumor is well controlled.

Aggressive Pituitary Macroadenoma Treated With Capecitabine and Temozolomide Chemotherapy Combination in a Patient With Nelson's Syndrome: A Case Report

Nelson's syndrome is considered a severe side effect that can occur after a total bilateral adrenalectomy in patients with Cushing's disease. It usually presents with clinical manifestations of an enlarging pituitary tumor including visual and cranial nerve alterations, and if not treated, can cause death through local brain compression or invasion. The first therapeutic option is surgery but in extreme cases of inaccessible or resistant aggressive pituitary tumors; the off-label use of chemotherapy with capecitabine and temozolomide can be considered. However, the use of this treatment is controversial due to adverse events, lack of complete response, and inability to predict results. We present the case of a 48-year-old man diagnosed with Nelson's syndrome with prolonged partial response and significant clinical benefit to treatment with capecitabine and temozolomide.

Treatment of Aggressive Pituitary Adenomas: A Case-Based Narrative Review

Management of aggressive pituitary adenomas is challenging due to a paucity of rigorous evidence supporting available treatment approaches. Recent guidelines emphasize the need to maximize standard therapies as well as the use of temozolomide and radiation therapy to treat disease recurrence. However, often these adenomas continue to progress over time, necessitating the use of additional targeted therapies which also impact quality of life and long-term outcomes. In this review, we present 9 cases of aggressive pituitary adenomas to illustrate the importance of a multidisciplinary, individualized approach. The timing and rationale for surgery, radiation therapy, temozolomide, somatostatin receptor ligands, and EGFR, VEGF, and mTOR inhibitors in each case are discussed within the context of evidence-based guidelines and clarify strategies for implementing an individualized approach in the management of these difficult-to-treat-adenomas.

Early Initiation of Temozolomide Therapy May Improve Response in Aggressive Pituitary Adenomas

INTRODUCTION

Aggressive pituitary adenomas (APAs) are, by definition, resistant to optimal multimodality therapy. The challenge lies in their early recognition and timely management. Temozolomide is increasingly being used in patients with APAs, but evidence supporting a favorable response with early initiation is lacking.

METHODS

This was a single-center study of all patients with APAs who received at least 3 cycles of temozolomide (150-200 mg/m²). Their baseline clinico-biochemical and radiological profiles were recorded. Immunohistochemical evaluation for cell-cycle markers O⁶-methylguanine-DNA methyltransferase (MGMT), MutS homolog 2 (MSH2), MutS homolog 6 (MSH6), MutL homolog 1 (MLH1), and postmeiotic segregation increased 2 (PMS2) was performed, and h-scores (product of the number of positive cells and staining intensity) were calculated. Response was assessed in terms of radiological response using the RECIST criteria. Patients with controlled disease (≥30% reduction in tumor volume) were classified as responders.

RESULTS

The study comprised 35 patients (48.6% acromegaly, 37.1% prolactinomas, and 14.3% non-functioning pituitary adenomas). The median number of temozolomide (TMZ) cycles was 9 (IQR 6-14). Responders constituted 68.6% of the cohort and were more likely to have functional tumors, a lower percentage of MGMT-positive staining cells, and lower MGMT h-scores. There was a significantly longer lag period in the initiation of TMZ therapy in non-responders as compared with responders (median 36 vs. 15 months, p = 0.01). ROC-derived cutoffs of 31 months for the duration between diagnosis and TMZ initiation, low-to-intermediate MGMT positivity (40% tumor cells), and MGMT h-score of 80 all had a sensitivity exceeding 80% and a specificity exceeding 70% to predict response.

CONCLUSION

Early initiation of TMZ therapy, functional tumors, and low MGMT h-score predict a favorable response to TMZ in APAs.

Multimodal Non-Surgical Treatments of Aggressive Pituitary Tumors

Up to 35% of aggressive pituitary tumors recur and significantly affect mortality and quality of life. Management can be challenging and often requires multimodal treatment. Current treatment options, including surgery, conventional medical therapies such as dopamine agonists, somatostatin receptor agonists and radiotherapy, often fail to inhibit pituitary tumor growth. Recently, anti-tumor effects of chemotherapeutic drugs such as Temozolomide, Capecitabine, and Everolimus, as well as peptide receptor radionuclide therapy on aggressive pituitary tumors have been increasingly investigated and yield mixed, although sometimes promising, outcomes. The purpose of this review is to provide thorough information on non-surgical medical therapies and their efficacies and used protocols for aggressive pituitary adenomas from pre-clinical level to clinical use.

Clinical features and their course of pituitary carcinoma with distant metastasis in a dog

An 11-year-old male toy poodle with neurological symptoms was diagnosed with a macroscopic pituitary tumor, which produced adrenocorticotropic hormone. Radiation therapy with a linear accelerator was performed for the pituitary tumor, and resulted in good local tumor control. However, serum endogenous adrenocorticotropic hormone concentrations were uncontrollable even after the tumor disappeared. Abdominal computed tomography revealed splenic masses, and splenectomy was performed. Histopathological examination of the surgical specimen showed tumor cells with eosinophilic and finely granular cytoplasm suggestive of endocrine origin. Since these cells were positive for adrenocorticotropic hormone, the case was diagnosed as a pituitary carcinoma with distant metastasis. Necropsy revealed multiple metastases to the abdominal organs. This is the first case report describing canine pituitary carcinoma with distant metastasis.

[Use of chemotherapy in the treatment of aggresive pituitary adenomas]

AIM

To clarify the concept of 'aggressive pituitary adenoma' using analysis of the current concepts, as well as to determine the optimal treatment algorithm for this disease and the place of chemotherapy in this treatment. Pituitary adenomas comprise from 10 to 15% of intracranial neoplasms. Despite the fact that pituitary adenomas are benign neoplasms, in 25-55% of cases they demonstrate invasive growth, growing into the surrounding structures (sphenoid sinus, cavernous sinus, etc.). Due to the lack of a standard definition of aggressive pituitary adenomas (due to the lack of clear criteria for this disease), there are no studies in the literature reporting optimal treatment for this group of patients, except for several publications describing the use of Temozolomide as palliative therapy.

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

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

Management of patients with persistent or recurrent Cushing's disease after initial pituitary surgery

INTRODUCTION

Treatment options for persistent and recurrent Cushing's disease (CD) include an individualized approach for repeat surgery, medical treatment, radiation therapy (RT), and bilateral adrenalectomy (BLA).

AREAS COVERED

In this expert opinion perspective, the authors review the latest treatment(s) for persistent/recurrent CD. A PubMed search was undertaken (English articles through May 2020) and relevant articles discussed. Repeat pituitary surgery should be considered in most patients with proven hypercortisolism; there is potential for cure with low risk of major complications. Medical therapy is valuable either alone, while awaiting the effects of RT, or in preparation for BLA. Medical therapy includes steroidogenesis inhibitors, agents that act at the pituitary or glucocorticoid receptor level, and novel agents in development. Radiation therapy has been used successfully to treat CD, but hypopituitarism risk and delayed efficacy (improved with radiosurgery) are major drawbacks. Laparoscopic BLA is safe and effective in patients with severe, difficult-to-manage hypercortisolism, but long-term follow-up is required as corticotroph tumor progression can develop.

EXPERT OPINION

Treatment of persistent/recurrent CD is challenging. Most patients require >1 therapy to achieve long-lasting remission. There is currently no ideal single treatment option that provides high and rapid efficacy, low adverse effects, and preserves normal pituitary-adrenal axis function.

Aggressive Pituitary Adenomas and Carcinomas

A subset of pituitary tumors present an aggressive behavior that remains difficult to predict, and in rare cases they metastasize. The current European Society for Endocrinology (ESE) guidelines for the management of aggressive pituitary tumors and carcinomas provide valuable guidance, but several issues remain unaddressed because of the scarcity of data in the literature. This article presents key clinical aspects regarding aggressive pituitary tumors and carcinomas, and also discusses some of the unanswered questions of the ESE guidelines, focusing on both diagnosis and treatment.

Long-course temozolomide in aggressive pituitary adenoma: real-life experience in two tertiary care centers and review of the literature

PURPOSE

Aggressive pituitary adenomas (APAs) and pituitary carcinomas (PCs) are challenging for their invasive nature, resistance to treatment and recurrences. Temozolomide (TMZ) is used with benefit and well-tolerated toxicity profile in APAs and PCs. In most studies patients received ≤ 12 cycles but the best length of treatment is debated since other options after discontinuation are scarce and a second course is mainly unsuccessful.

METHODS

We report outcomes of 8 patients with APAs and PCs treated with TMZ for more than 12 continuous cycles with a literature review. Data were retrospectively collected from Padua and Milan University Hospitals. TMZ was used as a single agent (150-200 p.o. mg/m2 daily, 5/28 days) for 14 to 45 cycles.

RESULTS

Eight patients (7 M), 7 APAs and 1 PC. Previous treatments included neurosurgery and radiotherapy in all cases except two giant masses (ACTH-silent APA and prolactinoma). No patient had progression disease (PD) during long-term treatment nor toxicities. No one had complete response (CR) but four had partial response (PR). Four ACTH+ tumors maintained stable disease (SD) but the secretion pattern improved in all. After drug withdrawal, three had delayed PD (2 after 18 and one after 29 months, all ACTH+); two are still in SD.

CONCLUSIONS

TMZ may be useful and well-tolerated in APAs and PCs as a long-term therapy. PR appears within the first cycles with no escape throughout the treatment; most patients achieve SD. We suggest extended protocols particularly in responsive ACTH+  PAs and PCs, when further therapies may be unsuccessful.

Stereotactic reirradiation with temozolomide in patients with recurrent aggressive pituitary tumors and pituitary carcinomas

OBJECTIVES

To evaluate the efficacy of a second course of fractionated stereotactic radiotherapy (re-SRT) and temozolomide (TMZ) as salvage treatment option in patients with aggressive pituitary tumors (APTs) and pituitary carcinomas (PCs).

PATIENTS AND METHODS

Twenty-one patients with recurrent or progressive APTs (n = 17) and PCs (n = 4) who received combined TMZ and re-SRT, 36 Gy/18fractions or 37.5 Gy/15fractions, were retrospectively evaluated. TMZ was given at a dose of 75 mg/m² given concurrently to re-SRT, and then 150-200 mg/m²/day for 5 days every 4 weeks or 50 mg/m² daily for 12 months. Local control (LC) and overall survival (OS) were calculated from the time of re-SRT by Kaplan-Meier method.

RESULTS

With a median follow-up of 27 months (range 12-58 months), 2-year and 4-year LC rates were 73% and 65%, respectively; 2-year and 4-year survival rates were 82% and 66%, respectively. A complete response was achieved in 2 and partial response in 11 patients. Six patients recurred with a median time to progression of 14 months. O(6)-Methylguanine-DNA methyltransferase (MGMT) status and tumor volume emerged as prognostic factors. Grade 3 radiation-related toxicities occurred in 3 (14%) patients. Grade 2 or 3 hematologic toxicities during chemotherapy occurred in 8 (38%) patients.

CONCLUSION

Re-SRT and TMZ is a safe treatment offering high LC in patients with progressive APTs and PCs. The potential advantages of combined chemoradiation as up-front or salvage treatment need to be explored in prospective trials.

Definition and diagnosis of aggressive pituitary tumors

Pituitary adenomas are considered benign tumors, but approximately 10% of them can have an aggressive behavior and more rarely (0.2%) can present metastasis, being classified as pituitary carcinomas. Aggressive adenomas are generally large and invasive tumors that present unusually rapid growth and/or that grow irrespective of conventional treatment with surgery, medical therapy and radiotherapy. Nevertheless, large tumors, as well as invasive tumors are not always aggressive, with this definition being possible only after clinical follow-up of these tumors, with growth rate and response to therapies being key points to its diagnosis. The correct identification and diagnosis of aggressive adenomas is of great importance as they are associated with great morbidity and increased mortality.

Temozolomide therapy for aggressive pituitary tumours - current understanding and future perspectives

The use of temozolomide (TMZ) for the management of aggressive pituitary tumours (APT) has revolutionised clinical practice in this field with significantly improved clinical outcomes and long-term survival. Its use is now well established however a large number of patients do not respond to treatment and recurrence after cessation of TMZ is common. A number of challenges remain for clinicians such as appropriate patient selection, treatment duration and the role of combination therapy. This review will examine the use of TMZ to treat APT including mechanism of action, treatment regimen and duration; biomarkers predicting response to treatment and patient selection; and current evidence for administration of TMZ in combination with other agents.

Fertility issues in aggressive pituitary tumors

The management of aggressive pituitary adenomas represents a special clinical challenge, and usually involves a combination of surgery, radiotherapy and pharmacological agents to control tumor growth and hormone abnormalities. Fertility is commonly affected in these patients due to compressive effects of the tumor, pituitary hormone dysfunction or as a result of the multiple therapies. The initial approach to restore fertility involves the reduction of tumor volume by the use of dopamine agonists in prolactinomas and by surgery in other pituitary adenomas. Somatostatin analogues are alternative options for GH, ACTH and TSH-secreting tumors. When present, pituitary deficiencies should be appropriately treated, particularly GH deficiency that has been associated with poor pregnancy rates in hypopituitary patients. Other therapies for aggressive pituitary tumors, such as invasive surgery, radiotherapy and temozolamide, may lead to infertility. In such cases, fertility preservation strategies might be considered and discussed with the patient desiring conception before or during treatment. In men and women with hypogonadotropic hypogonadism, administration of gonadotropins or pulse GnRH has resulted in satisfactory pregnancy rates. If spontaneous gestation is not achieved, assisted reproduction techniques can be employed as the last line of treatment. In any context, pre-conception counseling and care are essential as pregnancies in women with aggressive pituitary tumors should always be considered high risk.

Aggressive pituitary tumors in the young and elderly

Aggressive pituitary tumors (APTs) represent rare pituitary adenomas (PAs) with local invasion of surrounding tissues, increased risk for multiple recurrence, rapid tumor growth, or resistance to standard therapies. The most common APTs in children and adolescents are giant prolactinomas and somatotropinomas. Few cases of Crooke's cell adenomas, silent corticotroph adenomas and pituitary carcinomas have also been reported in the literature. Pediatric patients with APTs have higher risk of harboring germline genetic defects, most commonly in the MEN1 and AIP genes. Since certain genetic defects confer a more aggressive behavior to PAs, genetic testing should be considered in tumors with young onset and positive family history. The management of pediatric APTs involves usually a combination of standard therapies (surgical, medical, radiation). Newer agents, such as temozolomide, have been used in few cases of pediatric pituitary tumors with promising results. In the elderly, PAs are more commonly non-functioning. Their management often poses dilemmas given the coexistence of age-related comorbidities. However, standard surgical treatment and temozolomide seem to be safe and well tolerated in elderly patients.

Efficacy of Temozolomide Therapy in Patients With Aggressive Pituitary Adenomas and Carcinomas-A German Survey

CONTEXT

Despite growing evidence that temozolomide (TMZ) therapy is effective for the treatment of aggressive pituitary tumors (APTs) or carcinomas (PCs), individual therapy decisions remain challenging.

OBJECTIVE

We therefore aimed to report on clinical characteristics leading to initiation of TMZ therapy and to add evidence on TMZ long-term effectiveness.

DESIGN AND SUBJECTS

Retrospective survey on TMZ treatment in patients with APTs or PCs. TMZ therapy was initiated in 47 patients (22 females) with APTs (n = 34) or PCs (n = 13). Mean age at diagnosis was 45 ± 15 years. The immunohistochemical subtypes were corticotroph (n = 20), lactotroph (n = 18), and nonfunctioning (n = 9) tumors. TMZ therapy started 8 years after initial diagnosis using a standard regimen (median 6 cycles) for the majority of patients.

RESULTS

Long-term radiological response to TMZ after a median follow-up of 32 months with 4 patients still on TMZ therapy was tumor regression for 9 (20%), stable disease for 8 (17%), and tumor progression for 29 patients (63%) (outcome data available for 46 patients). Progression occurred 16 months after initiation of TMZ. Median estimated progression-free survival was 23 months. Disease stabilization and median progression-free survival did not differ between patients with APTs or PCs. Predictors of tumor response were not identified. Overall, TMZ was well tolerated.

CONCLUSION

We performed a nationwide survey on TMZ therapy in patients with APTs and PCs. While early response rates to TMZ are promising, long-term outcome is less favorable. Prolonged TMZ administration should be considered. We were not able to confirm previously reported predictors of tumor response to TMZ.

Dopamine agonist resistant prolactinomas: any alternative medical treatment?

Consensus guidelines recommend dopamine agonists (DAs) as the mainstay treatment for prolactinomas. In most patients, DAs achieve tumor shrinkage and normoprolactinemia at well tolerated doses. However, primary or, less often, secondary resistance to DAs may be also encountered representing challenging clinical scenarios. This is particularly true for aggressive prolactinomas in which surgery and radiotherapy may not achieve tumor control. In these cases, alternative medical treatments have been considered but data on their efficacy should be interpreted within the constraints of publication bias and of lack of relevant clinical trials. The limited reports on somatostatin analogues have shown conflicting results, but cases with optimal outcomes have been documented. Data on estrogen modulators and metformin are scarce and their usefulness remains to be evaluated. In many aggressive lactotroph tumors, temozolomide has demonstrated optimal outcomes, whereas for other cytotoxic agents, tyrosine kinase inhibitors and for inhibitors of mammalian target of rapamycin (mTOR), higher quality evidence is needed. Finally, promising preliminary results from in vitro and animal reports need to be further assessed and, if appropriate, translated in human studies.

Malignant Prolactinoma With Liver Metastases Masquerading as Metastatic Gastrointestinal Stromal Tumor: A Case Report and Literature Review

Pituitary carcinomas are rare diseases defined as pituitary tumors with metastases. In this report, we describe a case of malignant prolactinoma with liver metastases masquerading as metastatic gastrointestinal stromal tumor (GIST). A 54-years-old woman received dopamine agonists for macroprolactinoma for 2 years, followed by transsphenoidal surgery due to a poor response to medical therapy. Despite the continuation of dopamine agonist after surgery, serum prolactin level progressively increased to above 8,000 ng/ml in 5 years. There was no evidence of disease recurrence on sella magnetic resonance imaging (MRI). She stopped medical therapy. Meanwhile, she was diagnosed with GIST accompanied by liver and peritoneal metastases. After a 2-months treatment with imatinib, she suddenly presented with headache and visual impairment. Sella MRI showed a 3.3-cm sized pituitary mass, and serum prolactin levels were still high. For the recurred mass, she underwent a second surgery followed by radiation therapy. During the imatinib treatment for GIST, main mass and peritoneal metastases were dramatically decreased, but liver metastases were markedly aggravated. Liver masses were eventually confirmed as metastases from prolactin-producing pituitary carcinoma and not from GIST by percutaneous biopsy. Unfortunately, she died 6 months after the second surgery due to acute renal failure and sepsis. This case suggests that highly sustained serum prolactin levels during the dopamine agonist may indicate prolactin-producing pituitary carcinomas with hidden metastases.

Medical Management of Cushing's Syndrome: Current and Emerging Treatments

Endogenous Cushing's syndrome is a chronic disease associated with increased morbidity and mortality if not appropriately treated. Recurrence and/or persistence of hypercortisolemia after surgical treatment, especially for Cushing's disease, are high, and long-term medical treatment is used to decrease cortisol levels and risk of metabolic comorbidities. Medical treatment is also often required while waiting for radiation effects to take place. In some cases, severe or life-threatening hypercortisolism must be urgently and medically treated, via intravenous medications or with combination therapy, before patients can undergo surgery. In the last decade, medical treatment has progressed from a few steroidogenesis inhibitors to three novel drug groups: new inhibitors for steroidogenic enzymes with possibly fewer side effects, pituitary-directed drugs that aim to inhibit the pathophysiological pathways of Cushing's disease, and glucocorticoid receptor antagonists that block cortisol's action. Understanding the pathophysiology of Cushing's syndrome has also led to the identification of potential targets that may decrease adrenocorticotrophic hormone and/or cortisol excess, and/or decrease tumor cell proliferation, and induce senescence or apoptosis. We provide here a review of current and near-future medical options to treat Cushing's syndrome, and discuss updates on clinical trials and the efficacy and safety of novel or in-development drugs, as well as future potential targets.