Adjuvant Gamma Knife radiosurgery in non-functioning pituitary adenomas; low risk of long-term complications in selected patients

OBJECTIVEGamma Knife radiosurgery (GKRS) provides a safe and effective management option for patients with all types of pituitary adenomas. The long-term adverse effects of targeted radiation to the hypothalamic-pituitary axis in relationship to radiation dose remain unclear. In this retrospective review, the authors investigated the role of differential radiation doses in predicting long-term clinical outcomes and pituitary function after GKRS for pituitary adenomas.METHODSA cohort of 236 patients with pituitary tumors (41.5% nonfunctioning, 58.5% functioning adenomas) was treated with GKRS between 1998 and 2015. Point dosimetric measurements, with no minimum volume, to 14 consistent points along the hypothalamus bilaterally, pituitary stalk, and normal pituitary were made. Statistical analyses were performed to determine the impact of doses to critical structures on clinical, radiological, and endocrine outcomes.RESULTSWith a median follow-up duration of 42.9 months, 18.6% of patients developed new loss of pituitary function. The median time to endocrinopathy was 21 months (range 2–157 months). The median dose was 2.1 Gy to the hypothalamus, 9.1 Gy to the pituitary stalk, and 15.3 Gy to the normal pituitary. Increasing age (p = 0.015, HR 0.98) and ratio of maximum dose to the pituitary stalk over the normal pituitary gland (p = 0.013, HR 0.22) were independent predictors of new or worsening hypopituitarism in the multivariate analysis. Sex, margin dose, treatment volume, nonfunctioning adenoma status, or ratio between doses to the pituitary stalk and hypothalamus were not significant predictors.CONCLUSIONSGKRS offers a low rate of delayed pituitary insufficiency for pituitary adenomas. Doses to the hypothalamus are low and generally do not portend endocrine deficits. Patients who are treated with a high dose to the pituitary stalk relative to the normal gland are at higher risk of post-GKRS endocrinopathy. Point dosimetry to specific neuroanatomical structures revealed that a ratio of stalk-to-gland radiation dose of 0.8 or more significantly increased the risk of endocrinopathy following GKRS. Improvement in the gradient index toward the stalk and normal gland may help preserve endocrine function.

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Initial Gamma Knife radiosurgery for nonfunctioning pituitary adenomas

Journal of Neurosurgery ◽

10.3171/2013.11.jns131757 ◽

2014 ◽

Vol 120 (3) ◽

pp. 647-654 ◽

Cited By ~ 30

Author(s):

Cheng-Chia Lee ◽

Hideyuki Kano ◽

Huai-Che Yang ◽

Zhiyuan Xu ◽

Chun-Po Yen ◽

...

Keyword(s):

Gamma Knife ◽

Pituitary Adenomas ◽

Gamma Knife Radiosurgery ◽

Outcome Data ◽

Tumor Control ◽

Surgical Removal ◽

Tumor Margin ◽

Tumor Control Rate ◽

Nonfunctioning Pituitary Adenomas

Object Nonfunctioning pituitary adenomas (NFAs) are the most common type of pituitary adenoma and, when symptomatic, typically require surgical removal as an initial means of management. Gamma Knife radiosurgery (GKRS) is an alternative therapeutic strategy for patients whose comorbidities substantially increase the risks of resection. In this report, the authors evaluated the efficacy and safety of initial GKRS for NFAs. Methods An international group of three academic Gamma Knife centers retrospectively reviewed outcome data in 569 patients with NFAs. Results Forty-one patients (7.2%) underwent GKRS as primary management for their NFAs because of an advanced age, multiple comorbidities, or patient preference. The median age at the time of radiosurgery was 69 years. Thirty-seven percent of the patients had hypopituitarism before GKRS. Patients received a median tumor margin dose of 12 Gy (range 6.2–25.0 Gy) at a median isodose of 50%. The overall tumor control rate was 92.7%, and the actuarial tumor control rate was 94% and 85% at 5 and 10 years postradiosurgery, respectively. Three patients with tumor growth or symptom progression underwent resection at 3, 3, and 96 months after GKRS, respectively. New or worsened hypopituitarism developed in 10 patients (24%) at a median interval of 37 months after GKRS. One patient suffered new-onset cranial nerve palsy. No other radiosurgical complications were noted. Delayed hypopituitarism was observed more often in patients who had received a tumor margin dose > 18 Gy (p = 0.038) and a maximum dose > 36 Gy (p = 0.025). Conclusions In this study, GKRS resulted in long-term control of NFAs in 85% of patients at 10 years. This experience suggests that GKRS provides long-term tumor control with an acceptable risk profile. This approach may be especially valuable in older patients, those with multiple comorbidities, and those who have endocrine-inactive tumors without visual compromise due to mass effect of the adenoma.

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Long-term results of gamma knife stereotactic radiosurgery for non-functioning pituitary adenomas

International Journal of Radiation Oncology*Biology*Physics ◽

10.1016/j.ijrobp.2004.07.524 ◽

2004 ◽

Vol 60 (1) ◽

pp. S551 ◽

Cited By ~ 1

Author(s):

Y. Kwok ◽

N. Murali ◽

L. Chin ◽

M. Bangalore ◽

P. Amin ◽

...

Keyword(s):

Stereotactic Radiosurgery ◽

Gamma Knife ◽

Pituitary Adenomas ◽

Long Term Results ◽

Gamma Knife Stereotactic Radiosurgery ◽

Non Functioning Pituitary Adenomas

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Long-Term Follow-Up Studies of Gamma Knife Radiosurgery for Postsurgical Nonfunctioning Pituitary Adenomas

World Neurosurgery ◽

10.1016/j.wneu.2019.01.009 ◽

2019 ◽

Vol 124 ◽

pp. e715-e723 ◽

Cited By ~ 2

Author(s):

Shibin Sun ◽

Ali Liu ◽

YaZhuo Zhang

Keyword(s):

Gamma Knife ◽

Pituitary Adenomas ◽

Gamma Knife Radiosurgery ◽

Nonfunctioning Pituitary Adenomas ◽

Follow Up Studies ◽

Long Term Follow Up

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Long-term Outcomes After Gamma Knife Stereotactic Radiosurgery for Nonfunctional Pituitary Adenomas

Neurosurgery ◽

10.1227/neu.0b013e318222afed ◽

2011 ◽

Vol 69 (6) ◽

pp. 1188-1199 ◽

Cited By ~ 72

Author(s):

Kyung-Jae Park ◽

Hideyuki Kano ◽

Phillip V. Parry ◽

Ajay Niranjan ◽

John C. Flickinger ◽

...

Keyword(s):

Radiation Therapy ◽

Stereotactic Radiosurgery ◽

Gamma Knife ◽

Pituitary Adenomas ◽

Tumor Volume ◽

Gamma Knife Radiosurgery ◽

Tumor Control ◽

Long Term Outcomes ◽

Nonfunctional Pituitary Adenomas

Abstract BACKGROUND Nonfunctional pituitary adenomas (NFPAs) represent approximately 50% of all pituitary tumors. OBJECTIVE To evaluate the long-term outcomes of stereotactic radiosurgery for NFPAs. METHODS We evaluated the management outcomes of Gamma Knife radiosurgery in 125 patients with NFPAs over an interval of 22 years. The median patient age was 54 years (range, 16-88 years). One hundred ten patients (88%) had residual or recurrent tumors after ≥ 1 surgical procedures, and 17 (14%) had undergone prior fractionated radiation therapy. The median target volume was 3.5 cm3 (range, 0.4-28.1 cm3), and the median tumor margin dose was 13.0 Gy (range, 10-25 Gy). RESULTS Tumor volume decreased in 66 patients (53%), remained stable in 46 (37%), and increased in 13 (10.4%) during a median of 62 months (maximum, 19 years) of imaging follow-up. The actuarial tumor control rates at 1, 5, and 10 years were 99%, 94%, and 76%, respectively. Factors associated with a reduced progression-free survival included larger tumor volume (≥ 4.5 cm3) and ≥ 2 prior recurrences. Of 88 patients with residual pituitary function, 21 (24%) suffered new hormonal deficits at a median of 24 months (range, 3-114 months). Prior radiation therapy increased the risk of developing new pituitary hormonal deficits. One patient (0.8%) had a decline in visual function, and 2 (1.6%) developed new cranial neuropathies without tumor progression. CONCLUSION Stereotactic radiosurgery can provide effective management for patients with newly diagnosed NFPAs and for those after prior resection and/or radiation therapy.

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