Pituitary adenomas are currently classified by histological, immunocytochemical and numerous ultrastructural characteristics lacking unequivocal prognostic correlations. We investigated the prognostic value of a new clinicopathological classification with grades based on invasion and proliferation. This retrospective multicentric case-control study comprised 410 patients who had surgery for a pituitary tumour with long-term follow-up. Using pituitary magnetic resonance imaging for diagnosis of cavernous or sphenoid sinus invasion, immunocytochemistry, markers of the cell cycle (Ki-67, mitoses) and p53, tumours were classified according to size (micro, macro and giant), type (PRL, GH, FSH/LH, ACTH and TSH) and grade (grade 1a: non-invasive, 1b: non-invasive and proliferative, 2a: invasive, 2b: invasive and proliferative, and 3: metastatic). The association between patient status at 8-year follow-up and age, sex, and classification was evaluated by two multivariate analyses assessing disease- or recurrence/progression-free status. At 8 years after surgery, 195 patients were disease-free (controls) and 215 patients were not (cases). In 125 of the cases the tumours had recurred or progressed. Analyses of disease-free and recurrence/progression-free status revealed the significant prognostic value (p < 0.001; p < 0.05) of age, tumour type, and grade across all tumour types and for each tumour type. Invasive and proliferative tumours (grade 2b) had a poor prognosis with an increased probability of tumour persistence or progression of 25- or 12-fold, respectively, as compared to non-invasive tumours (grade 1a). This new, easy to use clinicopathological classification of pituitary endocrine tumours has demonstrated its prognostic worth by strongly predicting the probability of post-operative complete remission or tumour progression and so could help clinicians choose the best post-operative therapy.
Temozolomide treatment may be an effective option for some aggressive pituitary tumors or carcinomas. Response to a trial of three cycles of treatment seems sufficient to identify responders and more reliable than patient MGMT status.
Objective: Silent corticotroph adenomas (SCAs) are rare pituitary tumours immunoreactive for ACTH, but without clinical evidence of Cushing's disease. We characterized SCAs based on clinical, hormonal and molecular data, and compared the characteristics of these tumours with those of macro (MCA)-and micro (mCA)-ACTH adenomas with Cushing's disease. Methods: Fifty ACTH adenomas (14 SCAs, 15 MCAs and 21 mCAs) with complete corresponding clinical, radiological and biochemical data were selected. Histological corticotroph differentiation; immunostaining for ACTH, b-endorphin and b-LPH; and mRNA expression levels of TPIT, POMC, GRa, prohormone convertase 1/3 (PC1/3) and galectin-3 were compared in 21 representative tumours. Results: Despite the absence of clinical hypercortisolism in patients with SCA, elevated plasma ACTH levels that were similar to those associated with mCA were observed. The cortisol/ACTH ratio was similar between SCA and MCA groups and lower than that found with mCA (P!0.05). This dissociation could be explained by lower expression of PC1/3 in SCA and MCA than in mCA (P!0.05). After an i.v. dexamethasone suppression test, ACTH levels were significantly higher in patients with MCA than in those with mCA (P!0.05). Cytological and immunocytochemical analyses as well as mRNA expression levels of TPIT, POMC and GRa confirmed corticotroph differentiation in both mCAs and MCAs and in half of the SCAs, with a strong correlation between TPIT and POMC mRNA expression levels in SCAs (R 2 Z0.72; P!0.01) and in MCAs (R 2 Z0.65; P!0.05). Conclusions: Despite the absence of hypercortisolism, SCAs exhibit histological, biochemical and molecular corticotroph differentiation. SCA and MCA show hormonal and molecular similarities differentiating them from mCA.
Our data suggest that classification of PitNETs into five grades is of prognostic value to predict postoperative tumor behavior and identifies patients who have a high risk of early recurrence or progression. It therefore will allow clinicians to adapt their therapeutic strategies and stratify patients in future clinical trials.
Summary 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.
Objectives Only few retrospective studies have reported an efficacy rate of temozolomide (TMZ) in pituitary tumors (PT), all around 50%. However, the long-term survival of treated patients is rarely evaluated. We therefore aimed to describe the use of TMZ on PT in clinical practice and evaluate the long-term survival. Design Multicenter retrospective study by members of the French Society of Endocrinology. Methods Forty-three patients (14 women) treated with TMZ between 2006 and 2016 were included. Most tumors were corticotroph (n = 23) or lactotroph (n = 13), and 14 were carcinomas. Clinical/pathological characteristics of PT, as well as data from treatment evaluation and from the last follow-up were recorded. A partial response was considered as a decrease in the maximal tumor diameter by more than 30% and/or in the hormonal rate by more than 50% at the end of treatment. Results The median treatment duration was 6.5 cycles (range 2–24), using a standard regimen for most and combined radiotherapy for six. Twenty-two patients (51.2%) were considered as responders. Silent tumor at diagnosis was associated with a poor response. The median follow-up after the end of treatment was 16 months (0–72). Overall survival was significantly higher among responders (P = 0.002); however, ten patients relapsed 5 months (0–57) after the end of TMZ treatment, five in whom TMZ was reinitiated without success. Discussion Patients in our series showed a 51.2% response rate to TMZ, with an improved survival among responders despite frequent relapses. Our study highlights the high variability and lack of standardization of treatment protocols.
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