Radiosurgery as primary management for acromegaly

Efficacy and safety of radiosurgery in acromegaly

Stereotactic radiosurgery (SRS) more and more frequently plays a crucial role in the treatment of acromegaly. We provide a systematic review of the literature and meta-analysis, according to PRISMA, on SRS for the management of growth hormone (GH)-secreting pituitary adenomas, including several radiosurgical techniques, with the aim of describing efficacy and safety of this treatment. A weighted random effects model was used to calculate pooled outcome estimates. From 346 abstract reviews, 27 retrospective studies were included. Despite the variability in hormonal remission criteria and the heterogeneity between treatment guidelines among included studies, most of them reported an endocrine remission rate between 40% and 60%. Random effects meta-analysis for overall endocrine remission and 5-year probability of remission estimate after SRS were 46% (95% CI: 39-53%) and of 48% (95% CI: 38-57%), respectively. Random effects meta-analysis for new hypopituitarism estimate after SRS was 23% (95% CI: 17-29%). Furthermore, incidence of radiation induced optic neuropathy after SRS ranged between 0% and 6% This meta-analysis confirms and quantifies safety and effectiveness of SRS to achieve endocrine remission after surgical management in acromegaly.

Gamma Knife Radiosurgery for Cushing's Disease: Evaluation of Biological Effective Dose from a Single-Center Experience

Objective: Gamma knife radiosurgery (GKRS) has served as an adjunctive treatment in Cushing's disease (CD) for decades and has become a vital part of therapy in the management of CD. Biological effective dose (BED) is a radiobiological parameter with time correction, considering the cellular deoxyribonucleic acid repairment. We aimed to investigate the safety and efficacy of GKRS for CD and evaluate the association of BED and treatment outcome. Methods: A cohort study of 31 patients with CD received GKRS in West China Hospital between June 2010 and December 2021. Endocrine remission was defined as normalization of 24 h urinary free cortisol (UFC) or serum cortisol ≤ 50 nmol/L after a 1 mg dexamethasone suppression test. Result: The mean age was 38.6 years old, and females accounted for 77.4%. GKRS was the initial treatment for 21 patients (67.7%), and 32.3% of patients underwent GKRS after surgery due to residual disease and recurrence. The mean endocrine follow-up duration was 22 months. The median marginal dose was 28.0 Gy, and the median BED was 221.5 Gy_2.47. Fourteen patients (45.1%) experienced control of hypercortisolism in the absence of pharmacological treatment, and the median duration to remission was 20.0 months. The cumulative rates of endocrine remission at 1, 2, and 3 years after GKRS were 18.9%, 55.3%, and 72.21%, respectively. The total complication rate was 25.8%, and the mean duration from GKRS to hypopituitary was 17.5 months. The new hypopituitary rate at 1, 2, and 3 years were 7.1%, 30.3%, and 48.4%, respectively. A high BED level (BED > 205 Gy_2.47) was associated with better endocrine remission than a low BED level (BED ≤ 205 Gy_2.47), while no significant differences were found between the BED level and hypopituitarism. Conclusions: GKRS was a second-line therapeutic option for CD with satisfactory safety and efficacy. BED should be considered during GKRS treatment planning, and optimization of BED is a potentially impactful avenue toward improving the efficacy of GKRS.

Endocrine disorders after primary gamma knife radiosurgery for pituitary adenomas: A systematic review and meta-analysis

PURPOSE

Gamma Knife radiosurgery (GKRS) is feasible for pituitary adenomas, but post-surgery GKRS may cause severe hormone deficits. We reviewed the literature on primary GKRS for pituitary adenoma focusing on radiation-induced hormone deficiencies.

METHODS

PubMed, Web-of-Science, Scopus, and Cochrane were searched upon the PRISMA guidelines to include studies describing primary GKRS for pituitary adenomas. Pooled-rates of GKRS-induced hormone deficiencies and clinical-radiological responses were analyzed with a random-effect model meta-analysis.

RESULTS

We included 24 studies comprising 1381 patients. Prolactinomas were the most common (34.2%), and 289 patients had non-functioning adenomas (20.9%). Median tumor volume was 1.6cm³ (range, 0.01-31.3), with suprasellar extension and cavernous sinus invasion detected in 26% and 31.1% cases. GKRS was delivered with median marginal dose 22.6 Gy (range, 6-49), maximum dose 50 Gy (range, 25-90), and isodose line 50% (range, 9-100%). Median maximum point doses were 9 Gy (range, 0.5-25) to the pituitary stalk, 7 Gy (range, 1-38) to the optic apparatus, and 5 Gy (range, 0.4-12.3) to the optic chiasm. Pooled 5 year rates of endocrine normalization and local tumor control were 48% (95%CI 45-51%) and 97% (95%CI 95-98%). 158 patients (11.4%) experienced endocrinopathies at a median of 45 months (range, 4-187.3) after GKRS, with pooled 5-year rates of 8% (95%CI 6-9%). GKRS-induced hormone deficiencies comprised secondary hypothyroidism (42.4%) and hypogonadotropic hypogonadism (33.5%), with panhypopituitarism reported in 31 cases (19.6%).

CONCLUSION

Primary GKRS for pituitary adenoma may correlate with lower rates of radiation-induced hypopituitarism (11.4%) than post-surgery GKRS (18-32%). Minimal doses to normal pituitary structures and long-term endocrine follow-up are of primary importance.

Long-term safety of gamma knife radiosurgery (SRS) for acromegaly

PURPOSE

Acromegaly has high morbidity and mortality when growth hormone secretion remains uncontrolled. Stereotactic radiosurgery (SRS) may be used when pituitary surgery is not suitable or unsuccessful, but there are few very long-term safety data available, especially for significant adverse events such as stroke.

METHODS

118 patients with acromegaly were treated with SRS between 1985 and 2015, at the National Centre for Stereotactic Radiosurgery, Sheffield, UK. Data were gathered from case notes, hospital databases, and patient questionnaires. Stroke incidence in comparison to the normal population was quantified using the standardised incidence ratio (SIR), and visual complications assessed.

RESULTS

88% (104/118) had complete morbidity follow up data for analysis. The mean follow-up was 134 months, and median SRS dose was 30 Gy. 81% of tumours had cavernous sinus invasion. There was no excess stroke rate relative to that seen in two age- and sex-matched large population studies (SIR = 1.36, 95% CI 0.27-3.96; SIR = 0.52, 95% CI 0.06-1.89). In 68/104 patients who had MRI-guided SRS with no further radiation treatment (SRS or fractionated radiotherapy) there was no loss of visual acuity and 3% developed ophthalmoplegia. There was a positive correlation between > 1 radiation treatment and both ophthalmoplegia and worsening visual acuity.

CONCLUSION

Stroke rate is not increased by SRS for acromegaly. Accurate MRI-based treatment planning and single SRS treatment allow the lowest complication rates. More than one radiation treatment (SRS or fractionated radiotherapy) was associated with increased visual complications.

Stereotactic radiosurgery for acromegaly: an international systematic review and meta-analysis of clinical outcomes

INTRODUCTION

We performed a systematic review and meta-analysis of clinical outcomes for patients with acromegaly treated with stereotactic radiosurgery (SRS).

METHODS

Primary outcomes were 5- and 10-year endocrine remission (ER) and endocrine control (EC). Secondary outcomes were 10-year radiographic local control (LC), visual toxicity, and hypopituitarism rates. Weighted random effects meta-analyses using the DerSimonian and Laird methods were conducted to characterize and compare effect sizes. Mixed effects regression models were used to examine correlations between potential prognostic factors and primary and secondary outcomes.

RESULTS

In total, 1533 patients across 20 published studies with acromegaly treated with SRS were included. At 5-years, estimated ER and EC rates were 43.2% (95% CI 31.7-54.6%) and 55.0% (95% CI 27.6-82.4%), respectively. At 10-years, estimated ER and EC rates were 56.9% (95% CI 47.5-66.4%) and 69.7% (95% CI 47.7-91.8%), respectively. The estimated 10-year LC rate was 92.8% (95% CI 83.0-100%). Visual toxicity and hypopituitarism following SRS were estimated to be 2.7% (95% CI 1.3-4.2%) and 26.8% (95% CI 16.9-36.7%), respectively. Every 1 Gy increase in margin prescription dose beyond 17 Gy was estimated to result in a 0.41% increased risk of visual toxicity (p = 0.03). No prognostic factors were associated with EC, ER, LC, or hypopituitarism.

CONCLUSIONS

SRS was well-tolerated in the management of pituitary acromegaly resulting in gradually improving ER and EC rates over time that approached 60% and 70%. SRS-related visual loss is an uncommon treatment-related side effect, and patient-specific clinical decision making remains critical.