10 Years' Experience of Using Low-Field Intraoperative MRI in Transsphenoidal Surgery for Pituitary Adenoma: Results of the Swiss Pituitary Registry (SwissPit)

Letrozole Decreased Testosterone-Induced Cell Proliferation and Prolactin Secretion also Increased Apoptosis in MMQ and GH3 Rat Prolactinoma Cell Lines

Aromatase enzyme plays an essential role in estrogen-induced tumorigenesis. It is expressed in the normal pituitary and more significantly in prolactinoma tissues. The aim of this study was to investigate the effects of an aromatase inhibitor, letrozole, on MMQ and GH3 rat prolactinoma cell lines and evaluate the possible mechanism of action. MMQ and GH3 cells were characterized with demonstrating aromatase enzyme and estrogen receptor alpha expression by PCR and immunofluorescence staining. After dose optimization for testosterone (T) and letrozole (L), four groups were established: only the testosteron-treated group (T) to detect cell proliferation; only letrozole-treated group (L) to investigate apoptotic effects; testosterone and letrozole concomitant-treated group to demonstrate inhibition of testosterone induced cell proliferation with letrozole treatment s(T + L) and control group (C) with no treatment. The proliferation rate of cells was determined by WST-1. For the detection of apoptotic and necrotic cells, Annexin V and caspase-3 labeling was used. Prolactin and estrogen levels were measured with ELISA, and the mRNA expression of aromatase and Esr1 was also determined. Testosterone induced the proliferation of MMQ and GH3 cells and further increased prolactin and estradiol levels. Adding letrozole to testosterone resulted in decreased cellular proliferation and even induced apoptosis. Also, letrozole administration significantly decreased prolactin and estradiol levels. However, letrozole alone had no effects on proliferation and apoptosis. Gene expression of aromatase and Esr1 was also significantly decreased by letrozole treatment. This in vitro study demonstrated that treatment of testosterone proliferating cells with letrozole resulted in decreased prolactin levels and cell proliferation and induced apoptosis, and further loss of aromatase and Esr1 mRNA expression were observed. Although this is an in vivo study, the results showed unique and novel findings which may easily be adapted to clinical use for further verification.

The Value of Intraoperative Magnetic Resonance Imaging in Endoscopic Endonasal Resection of Pituitary Adenoma

Background  Intraoperative magnetic resonance images (iMRIs) have been variably adopted by some centers to help increase the rate of gross total resection (GTR) of pituitary adenomas. In this comparative study, we report our institution's experience with using iMRIs for endoscopic endonasal approach (EEA) pituitary adenoma resection to better elucidate its role and potential value for pituitary surgery. Methods  All adult patients who underwent EEA for a pituitary adenoma from January 2013 to September 2021 were retrospectively reviewed. GTR was defined as no residual tumor or recurrence on postoperative imaging within 6 months. Univariate analysis followed by multivariate analysis was performed with GTR as the categorical endpoint. To measure the independent effect of iMRI on GTR, propensity score matching was then performed. Results  A total of 351 pituitary adenoma patients who underwent EEA were identified. The mean age was 51.2 (range: 18-90) years and 196 (55.8%) patients were female. iMRI was utilized in 87 (24.8%) cases. The overall rate of GTR was 69.2%. On multivariate analysis, low Knosp grade, low tumor volume, and the use of iMRI were predictive of GTR. There was no difference in the need for desmopressin or hydrocortisone at 90 days postoperatively. Conclusion  At our institution, we report a significant absolute increase in GTR rates of 16.4% for patients undergoing an iMRI. Among iMRI patients who did not have GTR, the majority of residuals were intentionally left behind after being deemed too risky to pursue. Overall, this study suggests the high value that iMRI adds to endoscopic pituitary adenoma surgery.

Impact of Intraoperative Magnetic Resonance Imaging on Short-Term and Long-Term Outcomes After Transsphenoidal Resection of Pituitary Adenoma: A Systematic Review and Meta-Analysis

BACKGROUND

Intraoperative magnetic resonance imaging (iMRI) allows for greater tumor visualization and extent of resection. It is increasingly used in transsphenoidal surgeries but its role is not yet established.

OBJECTIVE

We aimed to clarify the usefulness of iMRI in transsphenoidal surgery using direct statistical comparisons, with additional subgroup and regression analyses to investigate which patients benefit the most from iMRI use.

METHODS

Systematic searches of PubMed, Embase, and Cochrane Central were undertaken from database inception to May 2020 for published studies reporting the outcomes of iMRI use in transsphenoidal resection of pituitary adenoma.

RESULTS

Thirty-three studies reporting 2106 transsphenoidal surgeries in 2099 patients were included. Of these surgeries, 1487 (70.6%) were for nonfunctioning pituitary adenomas, whereas 619 (29.4%) were for functioning adenomas. Pooled gross total resection (GTR) was 47.6% without iMRI and 66.8% with iMRI (risk ratio [RR], 1.32; P < 0.001). Subgroup and meta-regression analyses demonstrated comparable increases in GTR between microscopic (RR, 1.35; P < 0.001) and endoscopic (RR, 1.31; P < 0.001) approaches as well as functioning and nonfunctioning adenomas (P = 0.584). The pooled rate of hypersecretion normalization was 73.0% within 3 months and 51.7% beyond 3 months postoperatively. The pooled rate of short-term and long-term improvement in visual symptoms was 96.5% and 84.9%, respectively. The incidence of postoperative surgical complications was low. The pooled reoperation rate was 3.8% across 1106 patients.

CONCLUSIONS

The use of iMRI as an adjunct significantly increases GTR for both microscopic and endoscopic resection of pituitary adenomas, with comparable benefits for both functioning and nonfunctioning adenomas. Satisfactory endocrinologic and visual outcomes were achieved.

Prevalence and outcome of comorbidities associated with acromegaly

BACKGROUND

Acromegaly is associated with various comorbidities, such as arterial hypertension (aHT), type 2 diabetes mellitus (DM2), obstructive sleep apnoea syndrome (OSAS), carpal tunnel syndrome (CTS) and polyposis coli. For therapeutic decisions, it is essential to know if, and to what extent, these associated morbidities are reversible or preventable. The aim of this study is to assess the prevalence and course of aHT, obesity, OSAS, CTS, DM2 and polyposis coli in acromegalic patients.

METHODS

The following criteria for inclusion in this database study were used: treatment for acromegaly at the authors' institutions; full endocrinological and radiological work- and follow-up; screening for aHT, DM2, CTS, OSAS, obesity and polyposis coli. All patients were followed-up for > 3 months, and treatments were indicated with the intent of biochemical remission (normal IGF-1 and random growth hormone level).

RESULTS

Sixty-three patients were included. Twelve (19%), 45 (71%) and 6 (10%) patients harboured micro-, macro- and giant adenomas, respectively. Nineteen tumours (30%) invaded the cavernous sinus. Mean tumour volume was 5.4 cm³. Mean follow-up time was 42 months. Sixty-one (97%) patients had transsphenoidal surgery; two patients only had drug therapy. Surgery led to remission in 31 (51%) patients. Intracavernous growth and larger tumour volume were negative predictors for cure. Drug therapy lead to remission in 22 (73%) patients within a mean follow-up of 54 months. The pretherapeutic prevalence of associated morbidities was as follows: aHT, 56%; DM2, 25%; OSAS, 29%; CTS, 29%; polyposis coli, 5%. There were neither age nor gender preferences for the respective prevalences. Surgery leads to remission of aHT and DM2 in 6% and 25%, respectively. Additional drug therapy resulted in remission of aHT, DM2 and CTS in 17%, 14% and 14%, respectively. Other associated morbidities persisted regardless of therapeutic efforts. Even if criteria for remission were not met, no new comorbidities of acromegaly developed during follow-up.

CONCLUSIONS

Treating acromegaly may relieve threatening associated morbidities such as aHT and DM2; nevertheless, only few comorbidities are reversible, which highlights the importance of treating acromegaly as early as possible.

Impact of intraoperative magnetic resonance imaging on gross total resection, extent of resection, and residual tumor volume in pituitary surgery: systematic review and meta-analysis

BACKGROUND

Residual tumor tissue after pituitary adenoma surgery, is linked with additional morbidity and mortality. Intraoperative magnetic resonance imaging (ioMRI) could improve resection. We aim to assess the improvement in gross total resection (GTR), extent of resection (EOR), and residual tumor volume (RV) achieved using ioMRI.

METHODS

A systematic review was carried out on PubMed/MEDLINE to identify any studies reporting intra- and postoperative (1) GTR, (2) EOR, or (3) RV in patients who underwent resection of pituitary adenomas with ioMRI. Random effects meta-analysis of the rate of improvement after ioMRI for these three surgical outcomes was intended.

RESULTS

Among 34 included studies (2130 patients), the proportion of patients with conversion to GTR (∆GTR) after ioMRI was 0.19 (95% CI 0.15-0.23). Mean ∆EOR was + 9.07% after ioMRI. Mean ∆RV was 0.784 cm3. For endoscopically treated patients, ∆GTR was 0.17 (95% CI 0.09-0.25), while microscopic ∆GTR was 0.19 (95% CI 0.15-0.23). Low-field ioMRI studies demonstrated a ∆GTR of 0.19 (95% CI 0.11-0.28), while high-field and ultra-high-field ioMRI demonstrated a ∆GTR of 0.19 (95% CI 0.15-0.24) and 0.20 (95% CI 0.13-0.28), respectively.

CONCLUSIONS

Our meta-analysis demonstrates that around one fifth of patients undergoing pituitary adenoma resection convert from non-GTR to GTR after the use of ioMRI. EOR and RV can also be improved to a certain extent using ioMRI. Endoscopic versus microscopic technique or field strength does not appear to alter the impact of ioMRI. Statistical heterogeneity was high, indicating that the improvement in surgical results due to ioMRI varies considerably by center.