Radiosurgery For Pituitary Adenomas Research Articles

Hypopituitarism after gamma knife radiosurgery for pituitary adenomas: long-term results from a single-center experience

ObjectiveThe aim of this study was to investigate the incidence and risk factors of new-onset hypopituitarism after gamma knife radiosurgery (GKRS) for pituitary adenomas in a single center.MethodsIn this retrospective study, 241 pituitary adenoma patients who underwent GKRS from 1993 to 2016 were enrolled. These patients had complete endocrine, imaging, and clinical data before and after GKRS. The median follow-up time was 56.0 (range, 12.7–297.6) months.ResultsFifty patients (20.7%) developed new-onset hypopituitarism after GKRS, including hypogonadism (n = 22), hypothyroidism (n = 29), hypocortisolism (n = 20), and growth hormone deficiency (n = 4). The median time to new-onset hypopituitarism was 44.1 (range, 13.5–141.4) months. The rates of new-onset hypopituitarism were 7%, 16%, 20%, 39%, and 45% at 1, 3, 5, 10, and 15 years, respectively. For those patients treated with a single GKRS, sex (p = 0.012), suprasellar extension (p = 0.048), tumor volume (≥ 5 cm3) (p < 0.001), tumor progression (p = 0.001), pre-existing hypopituitarism (p = 0.011), and previous surgery (p = 0.009) were significantly associated with new-onset hypopituitarism in univariate analysis. In the multivariate analysis, tumor volume (≥ 5 cm3) and tumor progression were associated with new-onset hypopituitarism (hazard ratio [HR] = 3.401, 95% confidence interval [CI] = 1.708–6.773, p < 0.001 and HR = 3.594, 95% CI = 1.032–12.516, p = 0.045, respectively). For patients who received 2 or more times GKRS, no risk factors associated with new-onset hypopituitarism were found.ConclusionNew-onset hypopituitarism was not uncommon after GKRS for pituitary adenomas. In this study, large tumor volume (≥ 5 cm3) and tumor progression were associated with new-onset hypopituitarism after a single GKRS.

Stereotactic radiosurgery for pituitary adenoma

Stereotactic radiosurgery for pituitary adenoma

Effect of distance from target on hypopituitarism after stereotactic radiosurgery for pituitary adenomas.

Delayed hypopituitarism is the most common complication after stereotactic radiosurgery (SRS) for pituitary adenomas. The aim of this study was to investigate the relationship between the distance from the hypothalamic-pituitary axis to the treatment target and anterior pituitary function preservation after SRS. Between 2007 and 2020, consecutive adult patients who underwent single-session SRS for non-functioning or hormone-secreting pituitary adenomas with ≥ 6months of follow-up were included. Distance measurements between hypothalamic-pituitary axis structures and the SRS target volume were quantified on MRI. The primary outcome was anterior pituitary function preservation. Outcomes were compared using multivariable regression and area under the receiver operator characteristic curve (AUROC) analyses. The study cohort comprised 224 patients, who were categorized by preservation (n = 168) and no preservation (n = 56) of anterior pituitary function after SRS. The mean and median clinical follow-up durations were 53.7 (38.0) and 46.0 (17.0-75.0) months, respectively. Independent predictors of anterior pituitary function preservation were a greater distance between the center of the pituitary gland and center of the SRS target [OR 1.101 (1.000-1.213), p = 0.050], and a shorter clinical follow-up duration [OR 0.985 (0.977-0.993), p < 0.0001]. The adjusted AUROC for the distance from the center of the pituitary gland and center of the SRS target in predicting anterior pituitary function preservation was 0.595. The sensitivity, specificity, positive predictive value and negative predictive value in predicting anterior pituitary function preservation at the optimal cut-off distance of 15mm were 30.0, 88.0, 89.9 and 26.2%, respectively. Greater distance between the normal pituitary gland and the SRS target is associated with anterior pituitary function preservation and increasing this distance should be a goal of adenoma resection. Larger prospective, multi-center studies are necessary to corroborate this finding and establish the effects of distance on hypopituitarism after SRS for pituitary adenomas.

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

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. 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. 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 22.6Gy (range, 6-49), maximum dose 50Gy (range, 25-90), and isodose line 50% (range, 9-100%). Median maximum point doses were 9Gy (range, 0.5-25) to the pituitary stalk, 7Gy (range, 1-38) to the optic apparatus, and 5Gy (range, 0.4-12.3) to the optic chiasm. Pooled 5year 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 45months (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%). 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.

Stereotactic Radiosurgery for pituitary adenomas: A review of literature.

Stereotactic radiosurgery (SRS) is a choice of treatment for pituitary adenomas (PA), particularly for residual or recurrent disease, apart from surgery. It has a progression free survival and endocrine remission rate comparable to surgery, with fewer side effects, making it an ideal tool for dealing with PA. In this review, we have discussed the role of SRS for primary as well as post-operative residual/ recurrent PA, and have assessed its safety and outcomes.

Biological Effective Dose as a Predictor of Hypopituitarism After Single-Fraction Pituitary Adenoma Radiosurgery: Dosimetric Analysis and Cohort Study of Patients Treated Using Contemporary Techniques

Graffeo, Christopher S MD, MS; Perry, Avital MD; Link, Michael J MD; Brown, Paul D MD; Young, William F MD; Pollock, Bruce E MD

Aneurysmal formation of internal carotid artery after a long time stable disease by gamma knife radiosurgery for pituitary adenomas

Aneurysmal formation of internal carotid artery after a long time stable disease by gamma knife radiosurgery for pituitary adenomas

Biological Effective Dose as a Predictor of Hypopituitarism After Single-Fraction Pituitary Adenoma Radiosurgery: Dosimetric Analysis and Cohort Study of Patients Treated Using Contemporary Techniques.

Hypopituitarism is the most frequent complication after pituitary adenoma stereotactic radiosurgery (SRS) and is correlated with increasing radiation to the pituitary gland. Biological effective dose (BED) is a dosimetric parameter that incorporates a time component to adjust for mechanisms of deoxyribonucleic acid repair activated during treatment. To assess mean gland BED as a predictor of post-SRS hypopituitarism, as compared to mean gland dose, in a contemporary cohort study of patients undergoing single-fraction SRS for pituitary adenoma. Cohort study of 97 patients undergoing single-fraction SRS from 2007 to 2014. Eligible patients had no prior pituitary irradiation, normal pre-SRS endocrine function, and >24mo of endocrine follow-up. Cox proportional hazards analysis was used to assess mean gland dose and BED as predictors of new post-SRS hypopituitarism. Median post-SRS follow-up was 48 mo (interquartile range [IQR], 34-68). A total of 27 patients (28%) developed new hypopituitarism at a median 22 mo (IQR, 12-36). Actuarial rates of new endocrinopathy were 17% at 2 yr (95% CI 10%-25%) and 31% at 5 yr (95% CI 20%-42%). On univariate analysis, sex (P=.02), gland volume (P=.03), mean gland dose (P<.0001), and BED significantly predicted new hypopituitarism (P<.0001). After adjusting for sex and gland volume, BED>45 Gy2.47 and mean gland dose>10Gy were significantly associated increased risk of hypopituitarism (hazard ratio [HR]=14.32, 95% CI=4.26-89.0, P<.0001; HR=11.91, 95% CI=3.54-74.0, P<.0001). BED predicted hypopituitarism more reliably than mean gland dose after pituitary adenoma SRS, but additional studies are needed to confirm these results.

Internal carotid artery stenosis and risk of cerebrovascular ischemia following stereotactic radiosurgery for recurrent or residual pituitary adenomas.

To evaluate the incidence of internal carotid artery (ICA) stenosis and cerebrovascular accident in a series of patients treated with stereotactic radiosurgery (SRS) for recurrent or residual pituitary adenoma. All patients treated with single fraction SRS in our institution for recurrent or residual non-functioning-, growth hormone- and ACTH-secreting pituitary adenomas were retrospectively identified and reviewed. A comprehensive literature review to identify studies reporting on ICA steno-occlusive disease following SRS for pituitary adenomas and compare the risks of carotid stenosis and ischemic stroke in the SRS treated group to the general population figures. 528 patients [312 women and 216 men; median age at SRS 46years old (range 12-80years)] treated with SRS at our institution met study inclusion criteria. Mean clinical and radiologic follow-ups were 68.87 (SD ± 43.29) and 55.99months (SD ± 38.03), respectively, and there were no clinically evident cerebral ischemic events noted. Asymptomatic, post-SRS, ICA stenosis occurred in two patients. A total of eight patients with ICA steno-occlusive disease following pituitary adenoma radiosurgery have been reported. Two of them suffered from ischemic stroke with however excellent recovery. As compared to the general population, SRS for pituitary adenomas does not seem to confer appreciable increased risk for ICA steno-occlusive disease and ischemic stroke. However, post-SRS radiation vessel injuries do occur and physicians should be aware about this rare event. Prompt identification and management according to current guidelines are essential to prevent ischemic strokes.

Gamma Knife Radiosurgery for Pituitary Adenomas Invading the Cavernous Sinus: Tokyo Women's Medical University Experience.

Total surgical removal of a pituitary adenoma (PA) invading the cavernous sinus (CS) is challenging and carries a significant risk of postoperative complications. As an alternative treatment strategy, after incomplete resection, such tumors may undergo stereotactic radiosurgery-in particular, Gamma Knife surgery (GKS). Treatment planning based on advanced neuroimaging (e.g., thin-slice 3-dimensional postcontrast constructive interference in steady state (CISS) images) allows clear visualization of the target microanatomy, which results in highly conformal and selective radiation delivery to the lesion with preservation of adjacent functionally important neurovascular structures. In the Tokyo Women's Medical University experience of GKS for 43 nonfunctioning and 46 hormone-secreting PA invading the CS, with a minimum follow-up period of 5years (mean 76months, range 60-118months), the tumor control rate has reached 97%, and a significant volume reduction (≥50%) has been seen in 24% of lesions. In cases of hormone-secreting neoplasms, normalization (in 18 patients; 39%) or improvement (in 22 patients; 48%) of endocrinological function has been noted. Importantly, such effects have been sufficiently durable. Complications have been extremely rare and limited to transient cranial nerve palsy (in 2% of cases). Notably, no patient in our series has had a new pituitary hormone deficit after irradiation. Thus, subtotal resection followed by GKS may be considered a valuable alternative to aggressive surgery for a PA invading the CS.

Pituitary adenoma treatment plan quality comparison between linear accelerator volumetric modulated arc therapy and Leksell Gamma Knife® radiosurgery.

The aim of this study was to compare radiosurgical treatment plan quality of a linear accelerator with Leksell Gamma Knife (LGK) for pituitary adenoma irradiation. Thirty pituitary adenoma patients were evaluated in this study. Treatment plans were prepared on LGK and stereotactic linear accelerator Varian TrueBeam STx. Volumetric Modulated Arc Therapy (VMAT) plans (21 plans with 2 coplanar arcs and 9 plans with 4 non-coplanar arcs) were calculated for linear accelerator. All the plans were evaluated in terms of conformity, selectivity, gradient index and organ at risk (OAR) sparing. VMAT produced dosimetrically comparable treatment plans to LGK regarding conformity and selectivity (New Conformity Index (NCI): 1.76 ± 0.65 for 4 arc VMAT, 2.33 ± 1,16 for 2 arc VMAT and 1.96 ± 0.71 for LGK; Selectivity Index (SI): 0.63 ± 0.16 for 4 arc VMAT, 0.51 ± 0.16 for 2 arc VMAT and 0.58 ± 0.17 for LGK). Gradient index (GI) was superior for LGK plans (GI: 2.74 ± 0.20 for LGK and 5.28 ± 2.29 for 4 arc VMAT). OAR sparing for optics, brainstem, and hypophysis was similar for both modalities while target volume coverage was maintained the same. Finally, treatment time resulted in favor of VMAT plans (in this study VMAT plans were almost 5 times faster than LGK treatment regarding beam on time). According to the results of this study stereotactic linear accelerator with VMAT treatment could be used as a reasonable alternative to LGK for pituitary adenoma radiosurgery but only if the same head fixation method accuracy and target volume delineation are maintained for both modalities.

Role of Stereotactic Radiosurgery in Pituitary Adenomas.

Pituitary adenomas are one of the common indications for gamma knife radiosurgery. Gamma knife enables one to deliver a very high radiation dose to the target in a single fraction. Due to steep radiation fall out of Gamma Knife, the adjacent visual apparatus gets minimal radiation. The aim of stereotactic radiosurgery for pituitary adenomas is to stop tumor growth, normalize hormonal hypersecretion, preserve pituitary function, and protect important surrounding structures. Surgery is the treatment modality of choice in the management of pituitary adenomas and gamma knife radiosurgery is restricted for residual or recurrent lesions only. The acceptable marginal dose for non-functional adenomas is 12 Gy. Control rates varies from 76-87% at 10 years are described in non-functional pituitary adenomas. In functional adenomas, to achieve hormonal remission a higher marginal dose up to 25 Gy is needed. However, primary gamma knife radiosurgery is needed in some situations - for instance, when the patient is unfit for surgery due to various reasons or surgical difficulties like the presence of kissing carotids.

Hypopituitarism after Gamma Knife radiosurgery for pituitary adenomas: a multicenter, international study.

Recurrent or residual adenomas are frequently treated with Gamma Knife radiosurgery (GKRS). The most common complication after GKRS for pituitary adenomas is hypopituitarism. In the current study, the authors detail the timing and types of hypopituitarism in a multicenter, international cohort of pituitary adenoma patients treated with GKRS. Seventeen institutions pooled clinical data obtained from pituitary adenoma patients who were treated with GKRS from 1988 to 2016. Patients who had undergone prior radiotherapy were excluded. A total of 1023 patients met the study inclusion criteria. The treated lesions included 410 nonfunctioning pituitary adenomas (NFPAs), 262 cases of Cushing's disease (CD), and 251 cases of acromegaly. The median follow-up was 51 months (range 6-246 months). Statistical analysis was performed using a Cox proportional hazards model to evaluate factors associated with the development of new-onset hypopituitarism. At last follow-up, 248 patients had developed new pituitary hormone deficiency (86 with NFPA, 66 with CD, and 96 with acromegaly). Among these patients, 150 (60.5%) had single and 98 (39.5%) had multiple hormone deficiencies. New hormonal changes included 82 cortisol (21.6%), 135 thyrotropin (35.6%), 92 gonadotropin (24.3%), 59 growth hormone (15.6%), and 11 vasopressin (2.9%) deficiencies. The actuarial 1-year, 3-year, 5-year, 7-year, and 10-year rates of hypopituitarism were 7.8%, 16.2%, 22.4%, 27.5%, and 31.3%, respectively. The median time to hypopituitarism onset was 39 months.In univariate analyses, an increased rate of new-onset hypopituitarism was significantly associated with a lower isodose line (p = 0.006, HR = 8.695), whole sellar targeting (p = 0.033, HR = 1.452), and treatment of a functional pituitary adenoma as compared with an NFPA (p = 0.008, HR = 1.510). In multivariate analyses, only a lower isodose line was found to be an independent predictor of new-onset hypopituitarism (p = 0.001, HR = 1.38). Hypopituitarism remains the most common unintended effect of GKRS for a pituitary adenoma. Treating the target volume at an isodose line of 50% or greater and avoiding whole-sellar radiosurgery, unless necessary, will likely mitigate the risk of post-GKRS hypopituitarism. Follow-up of these patients is required to detect and treat latent endocrinopathies.

Hypopituitarism After Single-Fraction Pituitary Adenoma Radiosurgery: Dosimetric Analysis Based on Patients Treated Using Contemporary Techniques

Toanalyze factors associated with post-stereotactic radiosurgery (SRS) hypopituitarism among radiation-naïve patients with pituitary adenomas who underwent single-fraction SRS between 2007 and2014. This was a retrospective review of 97 patients having single-fraction SRS from 2007 until 2014. Eligible patients had no history of prior radiation, normal age- and sex-specific pituitary function before SRS, and at least 24months of endocrine follow-up. Forty patients (41%) had hormone-secreting tumors; 57 patients had nonsecreting tumors (59%). The median prescription isodose volume was 2.8cm3 (interquartile range [IQR], 1.3-4.7); the median tumor margin dose was 20Gy (IQR, 15-25Gy). The median follow-up after SRS was 48months (IQR, 34-68months). Twenty-seven patients (28%) developed pituitary insufficiency at a median of 22months (IQR, 12-36months) after SRS. The rate of new endocrine deficits was 17% at 2years (95% confidence interval [CI] 10%-25%) and 31% at 5years (95% CI 20%-42%). Male sex (hazard ratio [HR] 2.38, 95% CI 1.05-5.26, P=.04), smaller pituitary gland volume (HR 0.99, 95% CI 0.99-0.99, P=.01), and higher mean pituitary gland dose (HR 1.31, 95% CI 1.16-1.47, P<.001) were associated with post-SRS hypopituitarism in multivariable analysis. The rate of hypopituitarism for patients with a mean gland dose of <11.0Gy at 2years was 2% (95% CI 0%-4%) and at 5years was 5% (95% CI 0%-11%), whereas rate of hypopituitarism for patients with a mean gland dose of ≥11.0Gy at 2years was 31% (95% CI 17%-43%) and at 5years was 51% (95% CI 34%-65%). Hypopituitarism after pituitary adenoma SRS increases in a time- and dose-dependent manner. Reducing the radiation exposure to the identifiable gland to a mean dose < 11.0Gy whenever feasible may lower the incidence of new hormonal deficits after pituitary adenoma SRS.

Hypopituitarism after gamma knife radiosurgery for pituitary adenoma

ABSTRACTPurpose: The aim of the study was to investigate the incidence of and risk factors for hypopituitarism after gamma knife radiosurgery (GKRS) for pituitary adenoma. Materials and Methods: We conducted a retrospective analysis of the pituitary function of 90 patients who underwent GKRS for pituitary adenoma at the University Hospital Centre Zagreb between 2003 and 2014. Twenty seven of them met the inclusion criteria and the others were excluded from the study due to pituitary insufficiency which was present before GKRS. Eighteen patients had non-functioning and 9 patients had secretory adenomas. Median patients’ age was 56 years (24–82). GKRS was performed using the Leksell gamma knife Model C. The median prescription radiation dose was 20 Gy (15–25) and the median tumor volume size was 3.4 cm3 (0.06–16.81). New onset hypopituitarism was defined as a new deficit of one of the three hormonal axes (corticotroph, thyreotroph, or gonadotroph) ≥3 months following GKRS. SPSS was used for statistical analysis, with the significance level at P<0.05. Results: During the median follow-up period of 72 months (range 6–144), 30% of patients developed new hypopituitarism after GKRS. This corresponds to incidence of one new case of hypopituitarism per 15 patient-years. Age, gender, tumor function, tumor volume, suprasellar extension, prescription dose of radiation, as well as dose-volume to the pituitary gland, stalk and hypothalamus were not predictive factors for the development of hypopituitarism. Conclusions: In our cohort of patients with pituitary tumors who underwent GKRS, 30% developed new hypopituitarism during the follow-up period.

Frequency, pattern, and outcome of recurrences after gamma knife radiosurgery for pituitary adenomas.

Gamma Knife radiosurgery is often used in pituitary adenomas. Aim of our study is to describe the characteristics and long-term outcome of patients with adenoma recurrence after Gamma Knife radiosurgery. We conducted a retrospective analysis of patients with pituitary adenoma treated by Gamma Knife radiosurgery between 1994 and 2014. Tumor recurrence was labeled as "in field" when the tumor growth occurred adjacent or within the prescribed isodose, whereas it was classified as "out of field" when the tumor growth occurred outside the prescribed isodose. Five hundred forty-three patients were included, 272 (50.1 %) had a nonfunctioning pituitary adenoma (NFPA) and 271 (49.9 %) patients had a hormone secreting-pituitary adenoma. The median follow-up after GKRS was 78 months (IQR, 36-125 months). Thirty-nine patients (7.2 %) had recurrence of disease and it was more frequent in patients with NFPA than in patients with hormone secreting adenomas (9.6 % vs. 4.8 %). The 10-yr progression-free survival in patients with NFPA was 78.7 % (95 % CI 69.5 - 87.9 %), as compared with 93.3 % (95 % CI 89.3 - 97.3 %; p < 0.01) in hormone secreting adenomas. Tumor recurrence was "in field" in 17 cases (43.6 %) and "out of field" in 22 cases (56.4 %). Seven of the 39 patients with recurrence died despite further treatments. Six of these patients had an "in field" recurrence. Recurrence of a pituitary adenoma after GKRS may occur several years after initial treatment. Distinction between "in field" and "out of field" tumor recurrence probably reflects two different pathophysiological mechanisms and may have prognostic importance.

Effect of treatment modality on the hypothalamic-pituitary function of patients treated with radiation therapy for pituitary adenomas: hypothalamic dose and endocrine outcomes.

Background: Both fractionated external beam radiotherapy and single fraction radiosurgery for pituitary adenomas are associated with the risk of hypothalamic–pituitary (HP) axis dysfunction.Objective: To analyze the effect of treatment modality (Linac, TomoTherapy, or gamma knife) on hypothalamic dose and correlate these with HP-axis deficits after radiotherapy.Methods: Radiation plans of patients treated post-operatively for pituitary adenomas using Linac-based 3D-conformal radiotherapy (CRT) (n = 11), TomoTherapy-based intensity modulated radiation therapy (IMRT) (n = 10), or gamma knife stereotactic radiosurgery (n = 12) were retrospectively reviewed. Dose to the hypothalamus was analyzed and post-radiotherapy hormone function including growth hormone, thyroid stimulating hormone, adrenocorticotropic hormone, prolactin, and gonadotropins (follicle stimulating hormone/luteinizing hormone) were assessed.Results: Post-radiation, 13 of 27 (48%) patients eligible for analysis developed at least one new hormone deficit, of which 8 of 11 (72%) occurred in the Linac group, 4 of 8 (50%) occurred in the TomoTherapy group, and 1 of 8 (12.5%) occurred in the gamma knife group. Compared with fractionated techniques, gamma knife showed improved hypothalamic sparing for DMax Hypo and V12Gy. For fractionated modalities, TomoTherapy showed improved dosimetric characteristics over Linac-based treatment with hypothalamic DMean (44.8 vs. 26.8 Gy p = 0.02), DMax (49.8 vs. 39.1 Gy p = 0.04), and V12Gy (100 vs. 76% p = 0.004).Conclusion: Maximal dosimetric avoidance of the hypothalamus was achieved using gamma knife-based radiosurgery followed by TomoTherapy-based IMRT, and Linac-based 3D conformal radiation therapy, respectively.

Cyberknife® Stereotactic Radiosurgery for Pituitary Adenomas: Clinical Outcomes

AMAC: Kalinti ve/veya nuks hipofiz adenomlarinin tedavisinde stereotaktik radyocerrahi alternatif bir tedavi secenegidir. Bu yazida klinigimizde Cyberknife® stereotaktik radyocerrahi (SRC) uyguladigimiz hipofiz adenomlu hastalarin tedaviye yanitlarinin degerlendirilmesi amaclanmistir.YONTEMLER: Ankara Onkoloji Hastanesi Radyasyon Onkolojisi Kliniginde, Ocak 2010- Haziran 2013 tarihleri arasinda besi fonksiyonel ve ikisi non-fonksiyonel olmak uzere toplamda yedi hipofiz adenomlu olguya SRC uygulandi. Olgularda ortanca yas: 36 (aralik, 30-60) ve olgularin % 71'i (n=5) erkek cinsiyet idi. Hemofili hastaligi olan bir hasta disindaki tum olgulara cerrahi uygulanmis idi. Fonksiyonel adenomlu dort olgu medikal tedaviye yanitsiz idi ve yinelemis tumorlerinin olmasi nedeni ile radyocerrahi karari alindi. Iki olgu ise cerrahi sonrasi kalinti tumor nedeni ile, bir olguda cerrahi yapilamadigi icin primer olarak SRC uygulandi. Recete edilen ortanca doz, 22 Gy (aralik, 20-25 Gy), 3-5 fraksiyonda, ortanca % 84 (aralik, % 80-% 93) izodoz ile uygulandi.BULGULAR: Ortanca takip zamani: 18 ay (aralik, 14-55 ay) idi. Bir olgu (non-fonksiyonel) 55 aylik izleminde klinik ve radyolojik olarak tam yanit gosterirken, bir fonksiyonel hipofiz adenomlu olgu ise progrese oldu. Yedi olgunun 6'sinda (% 86) radyolojik olarak tumor kontrolu saglandi.SONUC: Kalinti ve/veya nuks hipofiz adenomlarinin tedavisinde stereotaktik radyocerrahi etkin ve guvenli bir tedavi secenegi olabilir.

Gamma Knife in the Treatment of Pituitary Adenomas: Results of a Single Center

Gamma Knife (GK) radiosurgery for pituitary adenomas can offer a means of tumor and biologic control with acceptable risk and low complication rates. Retrospective review of all the patients treated at our center with GK for pituitary adenomas from Nov 2003 to June 2011. We treated a total of 86 patients. Ten were lost to follow-up. Mean follow was 32.8 months. There were 21 (24.4%) growth hormone secreting adenomas (GH), 8 (9.3%) prolactinomas (PRL), 8 (9.3%) adrenocorticotropic hormone secreting (ACTH) adenomas, 2 (2.3%) follicle stimulating hormone/luteinizing hormone secreting (FSH/LH) adenomas, and 47 (54.7%) null cell pituitary adenomas that were treated. Average maximum tumor diameter and volume was 2.21cm and 5.41cm³, respectively. The average dose to the 50% isodose line was 14.2 Gy and 23.6 Gy for secreting and non-secreting adenomas respectively. Mean maximal optic nerve dose was 8.87 Gy. Local control rate was 75 of 76 (98.7%), for those with followup. Thirty-three (43.4%) patients experienced arrest of tumor growth, while 42 (55.2%) patients experienced tumor regression. Of the 39 patients with secreting pituitary tumors, 6 were lost to follow-up. Improved endocrine status occurred in 16 (50.0%), while 14 (43.8%) demonstrated stability of hormone status on continued pre-operative medical management. Permanent complications included: panhypopituitarism (4), hypothyroidism (4), hypocortisolemia (1), diabetes insipidus (1), apoplexy (1), visual field defect (2), and diplopia (1). Gamma Knife radiosurgery is a safe and effective means of achieving tumor growth control and endocrine remission/stability in pituitary adenomas.

Radiation-associated secondary brain tumors after conventional radiotherapy and radiosurgery

Although there is not enough strong molecular evidence for radiation to be a causal factor for the development of secondary brain tumors, a relationship has still been found. There is a slight but significant 2–2.7% increased risk of secondary brain tumors after conventional radiotherapy. However, this risk is small and should not preclude the use of radiotherapy as an effective treatment for uncontrolled pituitary tumors. The risk of radiosurgery-associated secondary brain tumors has not been precisely determined. Taking into account the considerable number of patients who received radiosurgery worldwide and the small number of secondary brain tumors, radiosurgery seems to be a safe treatment modality. This review summarizes the pathogenesis, prevalence and characteristics of secondary brain tumors after conventional radiotherapy and stereotactic radiosurgery for pituitary adenomas.