Overall and progression-free survival and visual and endocrine outcomes for patients with parasellar lesions treated with intensity-modulated stereotactic radiosurgery

Radiotherapy-induced Hypothalamic-Pituitary axis dysfunction in adult Brain, head and neck and skull base tumor patients - A systematic review and Meta-Analysis

Background and purpose

Radiotherapy for brain, head & neck (HN), and skull base (SB) tumors may deliver significant radiation dose to the hypothalamic-pituitary axis (HPA), leading to impaired functioning of this region and hence, to endocrine disorders. The purpose of this systematic review and meta-analysis is to investigate literature on HP dysfunction after radiation for non-pituitary brain, HN, or SB tumors at adult age, aiming to give insight in the prevalence of HP dysfunction related to radiation dose.

Materials and methods

Literature search of the PubMed database was performed for HP dysfunction after radiotherapy in adult patients. A risk of bias assessment was performed to rate the quality of the included papers. Besides clinical and treatment variables, reported insufficiencies for adrenocorticotrophic hormone, thyroid stimulating hormone, growth hormone, prolactin and follicle stimulating hormone and luteinizing hormone and for insufficiency of any axis were extracted. The prevalence for hormonal insufficiency per axis and for multiple axes was calculated using a random effects meta-regression with a random effect at the study level.

Results

The literature selection process resulted in a total of 22 original papers, suitable for full assessment (n = 1,462 patients). Literature showed a wide variation in HP dysfunction, along with wide dose ranges given to the hypothalamus and pituitary, with varying follow-up times. The calculated prevalence for any pituitary insufficiency was on average 0.61 (95 % CI 0.44-0.75). For growth hormone the mean prevalence was 0.40 (95 % CI 0.22-0.61), for prolactin 0.22 (95 % CI 0.17-0.28), for gonadotropin 0.20 (95 % CI 0.14-0.28), for adrenocorticotropic hormone 0.16 (95 % CI 0.08-0.30) and for thyroid stimulating hormone 0.16 (95 % CI 0.11-0.23). The prevalence for any insufficiency of 1 axis was 0.19 (95 % CI 0.11-0.30), of 2 axes 0.22 (95 % CI 0.12-0.38), of 3 axes 0.05 (95 % CI 0.03-0.09) and of panhypopituitarism 0.17 (95 % CI 0.08-0.32). Patients irradiated for nasopharyngeal carcinoma (NPC) seemed to be at highest risk for developing any endocrine insufficiency with a mean prevalence of 0.68 (95 % CI 0.45-0.85). A significant correlation between any endocrine insufficiency and follow-up time was observed (p = 0.015). A correlation between dose to the pituitary and occurrence of insufficiency on the hormonal axes could not be observed.

Conclusion

Endocrine insufficiency is reported in over half of the patients irradiated for brain, HN and SB malignancies. The hypothalamus is likely to be more vulnerable to radiation dose compared to the pituitary gland. More research is needed to establish dose thresholds for the hypothalamus and the pituitary to minimize the risk for pituitary insufficiency. Based on this knowledge, radiotherapy and follow-up of these patient groups should be standardized to establish a normal tissue complication probability (NTCP) model for the HPA.

Clinical outcomes of benign brain tumors treated with single fraction LINAC-based stereotactic radiosurgery: Experience of a single institute

Objectives

Accelerator-based stereotactic radiosurgery (SRS) is a noninvasive and effective treatment modality widely used for benign brain tumors. This study aims to report 20-year treatment outcomes in our institute.

Materials and Methods

From May 2001 to December 2020, 127 patients treated with LINAC-based single-fraction SRS for their benign brain lesions were included. A neurosurgeon and two radiation oncologists retrospectively reviewed all data. Computed tomography (CT) simulation was performed after head-frame fixation under local anesthesia. All planning CT images were co-registered and fused with gadolinium-enhanced magnetic resonance imaging taken within 3 months for lesions targeting and critical organs delineation. The marginal dose was prescribed at 60%-90% isodose lines, respectively, to cover ≥95% planning target volume. Outcome evaluations included clinical tumor control rate (TCR), defined as the need for salvage therapy, and radiological response, defined as no enlargement of >2 cm in the maximal diameter. Overall survival (OS) and adverse reaction (defined according to CTCAE 5.0) were also analyzed.

Results

The present study included 76 female and 51 male patients for analysis. The median age was 59 years (range, 20-88 years). Their diagnoses were vestibular schwannoma (VS, n = 54), nonvestibular cranial nerve schwannoma (n = 6), meningioma (n = 50), and pituitary adenoma (n = 17). Totally 136 lesions were treated in a single fraction, predominantly skull base tumors, accounting for 69.1%. Median and mean follow-up duration was 49 and 61 months (range, 1-214 months), Overall TCR was 92.9%. The 5-year disease-specific TCR for VS, nonvestibular schwannoma, meningioma, and pituitary adenoma were 97.4%, 91.7%, 93.8%, and 83.3%. Salvage therapy was indicated for eight patients at 4-110 months after SRS. Among symptomatic patients, post-SRS symptom(s) was improved, stable, and worse in 68.2%, 24.3%, and 3.6%, respectively. Radiological response rate for 111 evaluable patients was 94.6% (shrinkage, 28.8%; stable, 65.8%). OS was 96.1% without treatment-related mortality. One patient with post-SRS cranial nerve injury (0.8%, involving the trigeminal nerve, grade 2 toxicities). No grade 3-4 acute or late toxicity was found.

Conclusion

Our results suggested that LINAC-based SRS effectively controls tumor growth and tumor-related neurological symptoms for patients with benign brain tumors. SRS is less aggressive, associated with low neurological morbidity and no mortality. Continuous follow-up is indicated to conclude longer outcomes.

Visual Symptoms Outcomes in Cavernous Sinus Radiosurgery and a Systematic Review

Introduction

The complex anatomy of the cavernous sinus confers a true challenge when it comes to safe tumor resection. Due to its non-invasive nature, stereotactic radiosurgery (SRS) is expected to have lower mortality and morbidity rates than microsurgery. The purpose of this study was to evaluate clinical results regarding visual symptoms after SRS for benign tumors invading the cavernous sinus. We also conducted a systematic literature review to provide a robust analysis regarding visual outcomes.

Methods

The study included 58 patients (43 women and 15 men; mean age: 52 years) with benign tumors invading the cavernous sinus (27 pituitary adenomas and 31 meningiomas) who underwent SRS with different platforms between August 2011 and December 2021. Of these, 26 patients underwent surgery before SRS, and the remaining 32 had SRS as first-line therapy. We identified symptoms involving cranial nerves (CN) II, III, IV, and VI in 38 patients at the time of SRS. We conducted a systematic review to identify all original studies assessing visual outcomes. We searched PubMed, the Latin American and Caribbean Health Sciences Literature index, and Google Scholar using the Medical Subject Heading search terms “radiosurgery” and “cavernous sinus” for valid studies published until January 31, 2022.

Results

Regarding pituitary adenomas, median tumor volume was 2.05 cc, 3.12 cc, and 2.39 cc for Gamma Knife (GK), CyberKnife (CK), and tomotherapy (Tomo), respectively. Median doses were 14 Gy for GK, 17 Gy for CK, and 15 Gy for Tomo. For meningiomas, median tumor volume was 10.2 cc, 2.62 cc, and 16.3 cc for GK, CK, and Tomo, respectively. The median dose was 14 Gy for GK, 14 Gy for CK, and 14.5 Gy for Tomo. The overall tumor control rate was 100% with a median follow-up of 33 months (range: 6-128 months). A reduction of >30% in total tumor size per the Response Evaluation Criteria in Solid Tumors (RECIST) classification was documented in seven patients (RECIST II; 12.1%), 51 patients (87.9%) had stable disease (RECIST III), and no increase in tumor volume was documented in any patient. Visual symptoms improved in 51.7% of patients. In the systematic review, the mean visual improvement was 36% (range: 25.8-42.5%).

Conclusion

SRS is an effective treatment for benign tumors invading the cavernous sinus. In this series, patients who underwent SRS as a primary treatment showed improvement in pre-existing cranial neuropathy and visual symptoms. Given the natural history of these tumors, which tend to grow and cause visual alternations, treating asymptomatic patients is a feasible approach worth considering for the appropriate patients.

Radiotherapy as a tool for the treatment of Cushing's disease

Treatment of Cushing's disease (CD) is one of the most challenging tasks in endocrinology. The first-line treatment, transsphenoidal pituitary surgery, is associated with a high failure rate and a high prevalence of recurrence. Re-operation is associated with an even higher rate of a failure and recurrence. There are three main second-line treatments for CD - pituitary radiation therapy (RT), bilateral adrenalectomy and chronic cortisol-lowering medical treatment. All these treatments have their limitations. While bilateral adrenalectomy provides permanent cure of the hypercortisolism in all patients, the unavoidable chronic adrenal insufficiency and the risk of development of Nelson syndrome are of concern. Chronic cortisol-lowering medical treatment is not efficient in all patients and side effects are often a limiting factor. RT is efficient for approximately two-thirds of all patients with CD. However, the high prevalence of pituitary insufficiency is of concern as well as potential optic nerve damage, development of cerebrovascular disease and secondary brain tumours. Thus, when it comes to decide appropriate treatment for patients with CD, who have either failed to achieve remission with pituitary surgery, or patients with recurrence, the pros and cons of all second-line treatment options must be considered.

Single- and Multi-Fraction Stereotactic Radiosurgery Dose Tolerances of the Optic Pathways

PURPOSE

Dosimetric and clinical predictors of radiation-induced optic nerve/chiasm neuropathy (RION) after single-fraction stereotactic radiosurgery (SRS) or hypofractionated (2-5 fractions) radiosurgery (fSRS) were analyzed from pooled data that were extracted from published reports (PubMed indexed from 1990 to June 2015). This study was undertaken as part of the American Association of Physicists in Medicine Working Group on Stereotactic Body Radiotherapy, investigating normal tissue complication probability (NTCP) after hypofractionated radiation.

METHODS AND MATERIALS

Eligible studies described dose delivered to optic nerve/chiasm and provided crude or actuarial toxicity risks, with visual endpoints (ie, loss of visual acuity, alterations in visual fields, and/or blindness/complete vision loss). Studies of patients with optic nerve sheath tumors, optic nerve gliomas, or ocular/uveal melanoma were excluded to obviate direct tumor effects on visual outcomes, as were studies not specifying causes of vision loss (ie, tumor progression vs RION).

RESULTS

Thirty-four studies (1578 patients) were analyzed. Histologies included pituitary adenoma, cavernous sinus meningioma, craniopharyngioma, and malignant skull base tumors. Prior resection (76% of patients) did not correlate with RION risk (P = .66). Prior irradiation (6% of patients) was associated with a crude 10-fold increased RION risk versus no prior radiation therapy. In patients with no prior radiation therapy receiving SRS/fSRS in 1-5 fractions, optic apparatus maximum point doses resulting in <1% RION risks include 12 Gy in 1 fraction (which is greater than our recommendation of 10 Gy in 1 fraction), 20 Gy in 3 fractions, and 25 Gy in 5 fractions. Omitting multi-fraction data (and thereby eliminating uncertainties associated with dose conversions), a single-fraction dose of 10 Gy was associated with a 1% RION risk. Insufficient details precluded modeling of NTCP risks after prior radiation therapy.

CONCLUSIONS

Optic apparatus NTCP and tolerance doses after single- and multi-fraction stereotactic radiosurgery are presented. Additional standardized dosimetric and toxicity reporting is needed to facilitate future pooled analyses and better define RION NTCP after SRS/fSRS.

[Retrospective analysis to evaluate efficacy and safety of stereotactic radiosurgery in Cushing's disease: 24 cases and a review]

BACKGROUND

In the past few years, stereotactic radiosurgery (SRS) has been suggested as a good alternative, second line therapy for the management of patients with ACTH-secreting pituitary adenomas. A retrospective study has been conducted in order to evaluate the efficacy and safety of this treatment in these patients.

MATERIAL AND METHODS

Data were collected on all patients treated with SRS for an ACTH-secreting pituitary adenoma between 1996 and 2008, and with at least one year of follow-up. An analysis was carried out by analysing the return to normal of the hormone levels and clinical improvement rates (including Cushing signs, arterial hypertension), as well as adverse effects, and disease relapse. A return to normal of the 24 hour urinary free cortisol (24-UFC) levels (<100 μg/day) without any ACTH-secretion suppressor drug treatment, was considered as cure or improvement.

RESULTS

A total of 30 patients were treated with SRS, of which 24 were included in the analysis. They all had high 24-UFC levels before the treatment. Cure was achieved in 12 (50%) in a mean of 28 months, and in other 3 patients 24-UFC levels returned to normal with treatment with ketoconazole after the SRS. Cushing signs improved in all cases, as well as arterial hypertension in 13 out of 14 cases. There were relapses after cure consolidation. As far as adverse effects, it should be mentioned that there were 9 cases of new pituitary hormonal dysfunction (the most frequent being hypothyroidism), one radionecrosis, and one case of visual field defect impairment. Radiation-related neoplasm was not detected in any of the cases.

CONCLUSIONS

SRS is an effective treatment for those patients with ACTH-secreting pituitary adenoma in whom surgery has failed, or in those that are not good candidates for it. It showed good rates of hormone levels returning to normal, as well as clinical disease control and a low level of adverse effects.

Visual outcome after fractionated stereotactic radiation therapy of benign anterior skull base tumors

To determine visual outcome including the occurrence of radiation induced optic neuropathy (RION) as well as tumor control after fractionated stereotactic radiation therapy (FSRT) of benign anterior skull base meningiomas or pituitary adenomas. Thirty-nine patients treated with FSRT for anterior skull base meningiomas and 55 patients treated with FSRT for pituitary adenomas between January 1999 and December 2009 with at least 2 years follow-up were included. Patients were followed up prospectively with magnetic resonance imaging scans, visual acuity and visual field examinations. RION was found in four (10%) patients with anterior skull base meningiomas and seven patients (13%) with pituitary adenomas. The five-year actuarial freedom from 25% RION visual field loss was 94% following FSRT. Actuarial 2-, 5- and 10-year tumor control rates were 100, 88.4 and 64.5% for anterior skull base meningiomas and 100, 98.2 and 94.9% for pituitary adenomas, respectively. Patients with an impaired visual field function pre-FSRT were more likely to experience worsened function (p = 0.016). We found that RION, was a relatively uncommon event, in a large prospective cohort of patients that were systematically monitored following FSRT of benign anterior skull base tumors. Long term tumor control was favorable, especially for pituitary adenomas.

Hypothalamic/pituitary morbidity in skull base pathology

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

McCune-Albright syndrome: surgical and therapeutic challenges in GH-secreting pituitary adenomas

McCune-Albright syndrome (MAS) is a postzygotic (non-germline) disorder characterized by polyostotic fibrous dysplasia, cafe-au-lait macules and hypersecretory endocrinopathies. A significant percentage of MAS patients have pituitary adenomas that are either growth hormone (GH) or mixed GH/prolactin (PRL)-producing. Surgical excision may be challenging-or even impossible-due to the associated severe fibrous dysplasia of the skull base. Treatment relies on an interdisciplinary, multi-modal approach from endocrinologists, neurosurgeons and radiation oncologists. We present two cases of women with MAS and GH-secreting pituitary adenomas, encountered in our 30-year experience with pituitary diseases. The first patient successfully underwent transsphenoidal surgical resection for a pituitary microadenoma in 1997 (at age 18) and again in 2009 for recurrent disease, with a significant reduction in IGF-1 level. Immunohistochemistry (IHC) and electron microscopy (EM), performed on both specimens, showed a mammosomatotroph adenoma with GH, PRL, alpha subunit (+) IHC, with increased fibrous bodies developing over the 13-year interval. Focal hyperplasia could be discerned. EM in 1997 showed an admixture of mammosomatotrophs, mature lactotrophs and somatotrophs, with a bimodal population identified in 2009. The second MAS patient had long-standing polyostotic fibrous dysplasia, but was only recently diagnosed with GH excess and a pituitary adenoma, at the age of 29 years. Surgical resection was not advised in this patient because of the massive obstructive skull-base fibrous dysplasia. Medical therapy was initiated with somatostatin analogues, although responses in both patients have been suboptimal to date. We review the literature on GH excess in MAS to highlight its surgical and medical challenges.