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Pituitary Tumors
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Stereotactic radiosurgery XVI: a treatment for previously
irradiated pituitary adenomas.
Swords FM, Allan CA, Plowman PN, Sibtain A, Evanson J, Chew SL, Grossman
AB, Besser GM, Monson JP.
Department of Endocrinology, St. Bartholomew's and The Royal London School
of Medicine, London EC1A 7BE, United Kingdom.
We report the use of stereotactic radiosurgery delivered through an adapted
linear accelerator [stereotactic multiple arc radiation therapy (SMART)]
for pituitary adenomas not cured by conventional therapy. All 21 patients
had undergone conventional radiotherapy (45-50 Gy); 18 had also undergone
prior surgery. This cohort comprised 13 patients with somatotrope adenomas,
four with corticotrope adenomas, one with a lactotrope adenoma, and three
with nonfunctioning pituitary adenomas (median follow-up: 33 months, range:
3-72 months). SMART has proven effective, safe, and rapidly acting. We observed
an accelerated reduction in GH and IGF-I levels in acromegaly, with normalization
of GH and IGF-I levels in 58%. Mean GH fell from 21.1 mU/liter to 7.9 mU/liter
(7 ng/ml to 2.6 ng/ml, P < 0.01, median 25 months) faster than our predicted
fall to 50% at 2 yr with conventional radiotherapy. Mean IGF-I fell from
624 ng/ml to 384 ng/ml (P < 0.001). Tumor growth was controlled in two
of three nonfunctioning pituitary adenomas, and three of four corticotrope
adenomas. There were no adverse effects from SMART. Notably there have been
no visual sequelae or further loss of anterior pituitary function in this
heavily pretreated group. Our data indicate that SMART is an effective complementary
therapy for pituitary adenomas that have displayed a suboptimal response
to conventional therapy including external irradiation.
Publication Types:
PMID: 14602770 [PubMed - indexed for MEDLINE]
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Stereotactic radiosurgery as an alternative to fractionated
radiotherapy for patients with recurrent or residual nonfunctioning pituitary
adenomas.
Pollock BE, Carpenter PC.
Department of Neurological Surgery, Mayo Clinic and Foundation, Rochester,
Minnesota 55905, USA. pollock.bruce@mayo.edu
OBJECTIVE: To evaluate tumor control rates and complications after stereotactic
radiosurgery for patients with nonfunctioning pituitary adenomas. METHODS:
Between 1992 and 2000, 33 patients underwent radiosurgery for treatment of
nonfunctioning pituitary adenomas. Thirty-two patients (97%) had undergone
one or more previous tumor resections. Twenty-two patients (67%) had enlarging
tumors before radiosurgery. The median tumor margin dose was 16 Gy (range,
12-20 Gy). The median follow-up period after radiosurgery was 43 months (range,
16-106 mo). RESULTS: Tumor size decreased for 16 patients, remained unchanged
for 16 patients, and increased for 1 patient. The actuarial tumor growth
control rates at 2 and 5 years after radiosurgery were 97%. No patient demonstrated
any decline in visual function. Five of 18 patients (28%) with anterior pituitary
function before radiosurgery developed new deficits, at a median of 24 months
after radiosurgery. The actuarial risks of developing new anterior pituitary
deficits were 18 and 41% at 2 and 5 years, respectively. No patient developed
diabetes insipidus. CONCLUSION: Stereotactic radiosurgery safely provides
a high tumor control rate for patients with recurrent or residual nonfunctioning
pituitary adenomas. However, despite encouraging early results, more long-term
information is needed to determine whether radiosurgery is associated with
lower risks of new endocrine deficits and radiation-induced neoplasms, compared
with fractionated radiotherapy.
PMID: 14580275 [PubMed - indexed for MEDLINE]
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A study on the radiation tolerance of the optic nerves
and chiasm after stereotactic radiosurgery.
Stafford SL, Pollock BE, Leavitt JA, Foote RL, Brown PD, Link MJ, Gorman
DA, Schomberg PJ.
Division of Radiation Oncology, Mayo Clinic and Foundation, Rochester,
MN 55905, USA. stafford.scott@mayo.edu
PURPOSE: To evaluate the risk of clinically significant radiation optic neuropathy
(RON) for patients having stereotactic radiosurgery of benign tumors adjacent
to the optic apparatus. METHODS AND MATERIALS: We reviewed the dose plans
and clinical outcomes of 218 gamma knife procedures (215 patients) for tumors
of the sellar and parasellar region (meningiomas, n = 122; pituitary adenomas,
n = 89; craniopharyngiomas, n = 7 patients). Previous surgery or radiation
therapy was performed in 156 (66%) and 24 (11%) patients, respectively. Median
follow-up was 40 months (range 4-115). RESULTS: The median maximum radiation
dose to the optic nerve was 10 Gy (range 0.4-16.0). Four patients (1.9%)
developed RON at a median of 48 months after radiosurgery. All had prior
surgery, and 3 of 4 had external beam radiotherapy (EBRT) in their management
either before (n = 2) or adjuvantly (n = 1). The risk of developing a clinically
significant RON was 1.1% for patients receiving 12 Gy or less. Patients receiving
prior or concurrent EBRT had a greater risk of developing RON after radiosurgery
(p = 0.004). CONCLUSION: RON occurred in less than 2% of our patients, despite
the majority (73%) receiving more than 8 Gy to a short segment of the optic
apparatus. Knowledge of the dose tolerance of these structures permits physicians
to be more aggressive in treating patients with sellar or parasellar tumors,
especially those with hormone-producing pituitary adenomas that appear to
require higher doses to achieve biochemical remission.
Publication Types:
PMID: 12654424 [PubMed - indexed for MEDLINE]
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Late bilateral temporal lobe necrosis after conventional
radiotherapy.
Hoshi M, Hayashi T, Kagami H, Murase I, Nakatsukasa M.
Department of Neurosurgery, Saiseikai Utsunomiya Hospital, Utsunomiya,
Tochigi, Japan.
A 63-year-old woman presented with radionecrosis in the bilateral temporal
lobes manifesting as dementia about 30 years after undergoing conventional
radiotherapy for pituitary adenoma. Computed tomography and magnetic resonance
(MR) imaging showed edema and cystic lesions in both temporal lobes. The
mass in the left temporal lobe was excised. MR imaging 12 days after surgery
showed reduced edema. Her dementia had improved. Radionecrosis usually
occurs between several months and a few years after radiotherapy. The incidence
of radionecrosis is estimated as 5%, but may be higher with longer follow-up
periods. Clinical reports have suggested that larger total doses of radiation
are associated with earlier onset of delayed necrosis and the fractional
dose is the most significant factor causing cerebral radionecrosis. Radionecrosis
can occur long after conventional radiotherapy or stereotactic radiosurgery
using a linac-based system or a gamma knife unit.
Publication Types:
PMID: 12760503 [PubMed - indexed for MEDLINE]
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The role of gamma knife radiosurgery in the management
of pituitary adenomas.
Thoren M, Hoybye C, Grenback E, Degerblad M, Rahn T, Hulting AL.
Department of Endocrinology and Diabetology, Karolinska Hospital and Institute,
Stockholm, Sweden.
No treatment modality has been entirely successful in the management of
pituitary adenomas. Although most patients with pituitary microadenomas
can be cured by transsphenoidal surgery, the results are less satisfactory
in macroadenomas in particular with suprasellar and/or parasellar extension.
Additional treatment is then called for. Conventional fractional radiotherapy
can often control tumour growth but is limited to 45-50 Gy with a very
slow reduction in elevated pituitary hormones and a high incidence of pituitary
insufficiency. Stereotactic radiosurgery allows the delivery of radiation
with high precision to the target with low doses to the surrounding tissues
permitting higher radiation doses. Gamma knife radiosurgery using photon
energy with gamma beams from multiple cobalt 60 radiation sources is now
used in many centers. It can be carried out in an outpatient setting with
one single treatment. A more rapid normalization of pituitary hormone hypersecretion
than with conventional radiation can be achieved as well as arrest of tumour
growth and reduction of tumour mass. We therefore consider gamma knife
radiosurgery as a valuable compliment to pituitary surgery. Long-term prospective
studies are needed to evaluate the frequency of pituitary insufficiency
in patients where the target area is determined with stereotactic magnetic
resonance imaging (MRI).
Publication Types:
PMID: 11761436 [PubMed - indexed for MEDLINE]
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Fractionated stereotactically guided radiotherapy and
radiosurgery in the treatment of functional and nonfunctional adenomas
of the pituitary gland.
Milker-Zabel S, Debus J, Thilmann C, Schlegel W, Wannenmacher M.
Department of Clinical Radiology, Radiation Therapy, University of Heidelberg,
Heidelberg, Germany. Stefanie_Milker-Zabel@med.uni-heidelberg.de
PURPOSE: We evaluated survival rates and side effects after fractionated
stereotactically guided radiotherapy (SCRT) and radiosurgery in patients
with pituitary adenoma. METHODS AND MATERIALS: Between 1989 and 1998, 68
patients were treated with FSRT (n = 63) or radiosurgery (n = 5) for pituitary
adenomas. Twenty-six had functional and 42 had nonfunctional adenomas. Follow-up
included CT/MRI, endocrinologic, and ophthalmologic examinations. Mean follow-up
was 38.7 months. Seven patients received radiotherapy as primary treatment
and 39 patients received it postoperatively for residual disease. Twenty-two
patients were treated for recurrent disease after surgery. Mean total dose
was 52.2 Gy for SCRT, and 15 Gy for radiosurgery. RESULTS: Overall local
tumor control was 93% (60/65 patients). Forty-three patients had stable disease
based on CT/MRI, while 15 had a reduction of tumor volume. After FSRT, 26%
with a functional adenoma had a complete remission and 19% had a reduction
of hormonal overproduction after 34 months' mean. Two patients with STH-secreting
adenomas had an endocrinologic recurrence, one with an ACTH-secreting adenoma
radiologic recurrence, within 54 months. Reduction of visual acuity was seen
in 4 patients and partial hypopituitarism in 3 patients. None of the patients
developed brain radionecrosis or radiation-induced gliomas. CONCLUSION: Stereotactically
guided radiotherapy is effective and safe in the treatment of pituitary adenomas
to improve local control and reduce hormonal overproduction.
Publication Types:
PMID: 11483339 [PubMed - indexed for MEDLINE]
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Stereotactic radiosurgery for pituitary adenoma invading
the cavernous sinus.
Shin M, Kurita H, Sasaki T, Tago M, Morita A, Ueki K, Kirino T.
Department of Neurosurgery, The University of Tokyo Hospital, Japan. shinmasa@ka2.so-net.ne.jp
OBJECT: The purpose of this study is to determine the efficacy of gamma knife
radiosurgery (GKS) treatment of pituitary adenomas that have invaded the
cavernous sinus. METHODS: Sixteen patients were treated with GKS: three with
nonfunctional adenomas and 13 with hormone-secreting (seven growth hormone
[GH] and six adrenocorticotropic hormone [ACTH]) adenomas. More than 16 Gy
and 30 Gy were delivered to the tumor margin for nonfunctioning tumors and
functioning tumors, respectively, keeping the dose to the optic pathways
below 10 Gy. The median follow up was 3 years. Tumor growth control was achieved
in all cases. In GH-producing tumors, four of six cases evaluated were endocrinologically
normalized (serum GH < 10 mIU/L, somatomedin C < 450 ng/ml), and the
remaining two cases also showed a steady decrease in the GH and somatomedin
level. In ACTH-producing tumors, three of six cases were endocrinologically
normalized (24-hour urinary-free cortisol < 90 mg/day), two were unchanged,
and one showed hormonal recurrence 3 years after radiosurgery. Notably, there
were no cases of permanent hypopituitarism or visual symptoms caused by radiosurgery.
CONCLUSIONS: The authors data indicate that GKS can be a safe salvage therapy
for invading pituitary adenomas, with effectiveness equivalent to conventional
radiation therapy but with less risk of causing radiation-induced injury
to the surrounding structures.
PMID: 11143249 [PubMed - indexed for MEDLINE]
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The efficacy of conventional radiation therapy in the
management of pituitary adenoma.
Sasaki R, Murakami M, Okamoto Y, Kono K, Yoden E, Nakajima T, Nabeshima
S, Kuroda Y.
Department of Radiology, Tenri Hospital, Nara, Japan. rsasaki@med.kobe-u.ac.jp
PURPOSE: To evaluate the efficacy of conventional radiotherapy for reducing
tumor size and endocrine hypersecretion of pituitary adenomas. METHODS AND
MATERIALS: We reviewed the records of 91 patients with pituitary adenoma,
who were first treated between 1969 and 1994 and had been followed for more
than 2 years (median, 8.2 years.) Of these patients, 86 had received postoperative
radiotherapy, and 5 had received radiotherapy alone. The median total dose
was 51 Gy. Clinical symptoms related to mass effects or endocrine hypersecretion
were assessed. The efficacy of radiotherapy was evaluated before treatment
and during the follow-up period (1-14 years; median, 3 years) by estimating
tumor size on computed tomography or magnetic resonance imaging in 56 patients,
as well as by endocrine testing in the 22 patients who had secreting adenomas.
Local control rate, prognostic factors, and side effects were analyzed. RESULTS:
Mass-effect symptoms improved in 72% and 79% of patients who had such symptoms
due to nonsecreting adenomas and secreting adenomas, respectively. Symptoms
of endocrine hypersecretion abated in 67% of patients who had such symptoms.
Excessive hormone levels normalized in 74% of patients who showed endocrine
hypersecretions. The greatest size reduction was seen 3 years after the completion
of radiotherapy (24% CR, 62% PR, 12% NC, and 3% PD in nonsecreting adenomas,
and 32% CR, 36% PR, 27% NC, and 5% PD in secreting adenomas). Three patients
with secreting adenomas (2 with prolactinoma and 1 with Cushing's disease)
showed a mismatch between reduction in tumor size and normalization of endocrine
hypersecretion. The 10-year local control rates were 98%, 85%, 83%, and 67%
for nonsecreting adenoma, growth-hormone-secreting adenoma, prolactinoma,
and Cushing's disease, respectively. Univariate analyses showed that disease
type and radiation field size were significant prognostic factors. Brain
necrosis occurred in 1 patient who received a 60-Gy dose of irradiation.
CONCLUSION: We conclude that conventional external radiotherapy with 50 Gy
is safe and sufficient to control pituitary adenoma. Careful observation
is required in the management of secreting adenomas because the effects on
tumor size and endocrine hypersecretion may be mismatched in some secreting
adenomas.
PMID: 10889388 [PubMed - indexed for MEDLINE]
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Stereotactic conformal radiotherapy for pituitary adenomas:
technique and preliminary experience.
Jalali R, Brada M, Perks JR, Warrington AP, Traish D, Burchell L, McNair
H, Thomas DG, Robinson S, Johnston DG.
Department of Physics, The Institute of Cancer Research and The Royal Marsden
NHS Trust, London, UK.
OBJECTIVE: Stereotactic conformal radiotherapy (SCRT) is a high precision
technique of fractionated radiotherapy which ensures accurate delivery
of radiation with reduction in the volume of normal tissue irradiated as
compared to conventional external beam radiotherapy. We describe the technique
and preliminary experience of SCRT in patients with residual and recurrent
pituitary adenomas. PATIENTS AND METHODS: Between February 1995 and March
1999, 22 patients (mean age: 45.3, range: 20-67 years) with residual or
recurrent pituitary adenomas (13 nonfunctioning, nine secretory) were treated
with SCRT. All were immobilized in a relocatable Gill-Thomas-Cosman (GTC)
frame and tumour was localized on a postcontrast planning computerized
tomography (CT) and MRI scan. The gross tumour volume (GTV) and the critical
structures were outlined on contiguous 2-3 mm separated slices. A margin
of 5 mm (12 patients) to 10 mm (10 patients) was grown around GTV in three-dimensions
(3-D) to generate the planning target volume (PTV). The treatment was delivered
by three (five patients) and four (17 patients) maximally separated conformal
fixed fields with each field conformed to the shape of the tumour using
customized lead alloy blocks (19 patients) or multileaf collimator (three
patients). The patients were treated on a 6-MV linear accelerator to a
dose of 45 Gy in 25 fractions (18 patients) and 50 Gy in 30 fractions (four
patients). RESULTS: The technique of SCRT has become a part of the routine
work of the radiotherapy department. The treatment was well tolerated with
minimal acute toxicity. One patient developed transient quadrantanopia
2 weeks after treatment with full recovery after a short course of corticosteroids.
One patient had a transient visual deterioration 7 months after treatment
due to cystic degeneration of the tumour which fully recovered following
surgical decompression. Nine of the 15 patients presenting with visual
impairment had improvement after treatment and the visual status remained
stable in all others. One patient with acromegaly and one with a prolactinoma
achieved normalization of elevated hormonal abnormality four and 10 months
after SCRT, respectively. The remaining seven patients with a secretory
adenoma had declining hormone levels at last follow-up. Newly initiated
hormone replacement therapy was required in five patients. At a median
follow-up of 9 months (range 1-44 months), the 1 and 2 year actuarial progression
free and overall survival were 100%. CONCLUSION: Stereotactic conformal
radiotherapy is a high precision technique suitable for the treatment of
pituitary adenomas requiring radiotherapy. Preliminary results suggest
effective tumour control and low toxicity within the range expected for
conventional external beam radiotherapy. While the technique is of potential
benefit in reducing the volume of normal brain irradiated, the advantages
in terms of sustained tumour control and reduced toxicity over conventional
radiotherapy need to be demonstrated in long-term prospective studies.
PMID: 10848873 [PubMed - indexed for MEDLINE]
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Postoperative radiation therapy for pituitary adenoma.
Isobe K, Ohta M, Yasuda' S, Uno T, Hara R, Machida N, Saeki N, Yamaura
A, Shigematsu N, Ito H.
Department of Radiology, Chiba University, School of Medicine, Japan.
BACKGROUND: We evaluated the efficacy of postoperative radiation therapy
(RT), prognostic factors for local control probability, dose response relationship
and treatment sequelae in 75 patients with pituitary adenoma. MATERIALS
AND METHODS: A total dose of 48-60 Gy (median: 50 Gy) was delivered with
a conventional fractionation schedule after surgery. Of 75 patients, 55
(73%) were followed for more than 5 years and 27 (36%) were followed for
more than 10 years with a median of 95 months. RESULTS: Five- and 10-year
local control probabilities were 87.1% and 85.0%, respectively. Univariate
analysis revealed that age (p = 0.007), tumor volume smaller than 30 cm3
(p = 0.018) and the absence of prolactin secretion (p = 0.003) were significantly
favorable prognostic factors for local control probability. After multivariate
analysis combining these 3 factors, tumor volume smaller than 30 cm3 (p
= 0.017) and age (p = 0.039) were statistically significant. Patients with
prolactinoma greater than 30 cm3 showed particularly poor local control
rates. No significant improvement of the local control rate was detected
with increasing total irradiation doses between 48 and 60 Gy (p = 0.29).
The most common side effect was hypopituitarism, and there were no severe
sequelae such as optic neuropathy or brain necrosis. CONCLUSION: Except
with prolactinoma, the dose of postoperative RT for pituitary adenoma should
not exceed 50 Gy. Large prolactinoma, however, was very difficult to control
with the irradiation doses between 50 and 60 Gy, and would be good candidates
for stereotactic radiosurgery or stereotactic radiation therapy.
Publication Types:
PMID: 11083077 [PubMed - indexed for MEDLINE]
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Octreotide may act as a radioprotective agent in acromegaly.
Landolt AM, Haller D, Lomax N, Scheib S, Schubiger O, Siegfried J, Wellis
G.
Neurosurgery Section, Klinik im Park, Zurich, Switzerland. 100023.1666@compuserve.com
Clinical experience shows that an increasing number of patients undergoing
radiation treatment for recurring acromegaly or acromegaly persisting after
surgery are treated with octreotide. We, therefore, performed a follow-up
study of patients undergoing stereotactic radiosurgery (Gamma Knife) to determine
whether this medication has an influence on the ultimate result of radiation
therapy in either a positive or negative sense. It has been suggested that
the combination of radiation with antisecretory drugs may increase the effectiveness
of radiation. A follow-up study of 31 patients suffering from recurrent acromegaly
and acromegaly persisting after surgery, and who had been treated with stereotactic
radiosurgery, showed that patients treated with octreotide at the time of
radiation application simultaneously reached a normal level of growth hormone
and insulin-like growth factor-I only after a significantly longer interval
than patients who did not receive the drug. The two groups of patients did
not demonstrate significant differences in the main clinical findings (age,
sex, target volume, radiation dose, baseline growth hormone, and baseline
insulin-like growth factor-I).
Publication Types:
PMID: 10720077 [PubMed - indexed for MEDLINE]
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Comment in:
Fractionated stereotactic radiotherapy (FSRT) for optic
glioma.
Debus J, Kocagoncu KO, Hoss A, Wenz F, Wannenmacher M.
Department of Clinical Radiology, University of Heidelberg, Germany.
PURPOSE: To determine efficacy and toxicity of fractionated stereotactic
radiotherapy (FSRT) in patients with optic glioma. METHODS AND MATERIALS:
Ten patients suffering from optic glioma were treated by FSRT between December
1990 and December 1995 at the German Cancer Research Center (DKFZ) in Heidelberg.
Eight patients were treated for progressive recurrent tumor following partial
tumor resection and 2 patients were treated postoperatively. Dose distributions
were calculated by a 3D treatment planning system (Voxelplan, Heidelberg).
Patients were treated with a noninvasive repeatable stereotactic fixation
system using a manually driven midsize multileaf collimator attached to
a linear accelerator. We applied a median prescribed total dose to the
isocenter of 52.4 Gy with a median daily fraction size of 1.8 Gy. RESULTS:
All patients treated by definitive radiotherapy remained free from local
tumor progression during the follow-up period (range 12-72 months) except
the 1 patient treated for recurrence after previous radiotherapy. A complete
remission was achieved in 3 patients with subsequent improvement of visual
acuity. None of the patients with locally controlled tumor experienced
any further impairment of vision. One patient developed new ACTH deficiency.
No other clinically significant late effects attributable to radiotherapy
were observed. CONCLUSION: FSRT permits treatment of optic glioma with
excellent tumor control and without clinically relevant morbidity. Compared
to conventional techniques there is the potential of sparing the pituitary
gland in chiasmatic lesions.
PMID: 10760415 [PubMed - indexed for MEDLINE]
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Radiotherapy for nonfunctional pituitary adenoma: analysis
of long-term tumor control.
Breen P, Flickinger JC, Kondziolka D, Martinez AJ.
Department of Radiation Oncology, University of Pittsburgh School of Medicine,
Pennsylvania, USA.
OBJECT: The authors studied outcomes in patients who had undergone radiotherapy
for nonfunctional pituitary adenoma to assess long-term tumor control and
to identify factors affecting tumor control such as higher radiation doses,
improved imaging, and histological characteristics of the tumor. METHODS:
In this retrospective study, the authors evaluated 120 patients who received
radiotherapy for nonfunctional pituitary adenomas between 1960 and 1991.
The median follow-up period was 9 years (range 1 month-32 years). Radiation
doses varied between 37.6 and 65.6 Gy (median 46.7 Gy). Tumors progressed
in 15 of the 120 patients by 1 to 25 years after radiotherapy. Actuarial
tumor control rates at 10, 20, and 30 years were 87.5+/-3.6%, 77.6+/-6.3%,
and 64.7+/-12.9%, respectively. Tumor progression after radiotherapy occurred
significantly more often (p=0.0397) in patients with oncocytoma than in
patients with nononcocytic null cell adenoma. No other factors correlated
significantly with tumor control. One case of optic and oculomotor neuropathy
developed 4.5 years after a maximum dose of 50 Gy in 25 fractions. Radiation-induced
neoplasms (meningioma and glioblastoma multiforme) developed at a rate
of 2.7% at 10 and 30 years. CONCLUSIONS: The oncocytic variant of null
cell pituitary adenoma appears less sensitive to control by radiotherapy
than nononcocytic undifferentiated cell adenoma. A follow-up period extending
beyond 20 years is needed adequately to assess the efficacy of radiotherapy
for tumor control. Doses of 40 or 45 Gy in 20 or 25 fractions, respectively,
appear optimal.
PMID: 9833818 [PubMed - indexed for MEDLINE]
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Initial clinical results of LINAC-based stereotactic
radiosurgery and stereotactic radiotherapy for pituitary adenomas.
Mitsumori M, Shrieve DC, Alexander E 3rd, Kaiser UB, Richardson GE,
Black PM, Loeffler JS.
The Brain Tumor Center of the Brigham and Women's Hospital, Dana Farber
Cancer Institute, Harvard Medical School, Boston, MA, USA.
PURPOSE: To retrospectively evaluate the initial clinical results of stereotactic
radiosurgery (SRS) and fractionated stereotactic radiotherapy (SRT) for
pituitary adenomas with regard to tumor and hormonal control and adverse
effects of the treatment. SUBJECTS AND METHODS: Forty-eight patients with
pituitary adenoma who underwent SRS or SRT between September 1989 and September
1995 were analyzed. Of these, 18 received SRS and 30 received SRT. The
median tumor volumes were 1.9 cm3 for SRS and 5.7 cm3 for SRT. Eleven of
the SRS and 18 of the SRT patients were hormonally active at the time of
the initial diagnosis. Four of the SRS and none of the SRT patients had
a history of prior radiation therapy. Both SRS and SRT were performed using
a dedicated stereotactic 6-MV linear accelerator (LINAC). The dose and
normalization used for the SRS varied from 1000 cGy at 85% of the isodose
line to 1500 cGy at 65% of the isodose line. For SRT patients, a total
dose of 4500 cGy at 90% or 95% of the isodose line was delivered in 25
fractions of 180 cGy daily doses. RESULTS: Disease control-The three year
tumor control rate was 91.1% (100% for SRS and 85.3% for SRT). Normalization
of the hormonal abnormality was achieved in 47% of the 48 patients (33%
for SRS and 54% for SRT). The average time required for normalization was
8.5 months for SRS and 18 months for SRT. Adverse effects-The 3-year rate
of freedom from central nervous system adverse effects was 89.7% (72.2%
for SRS and 100% for SRT). Three patients who received SRS for a tumor
in the cavernous sinus developed a ring enhancement in the temporal lobe
as shown by follow-up magnetic resonance imaging. Two of these cases were
irreversible and were considered to be radiation necrosis. None of the
48 patients developed new neurocognitive or visual disorders attributable
to the irradiation. The incidence of endocrinological adverse effects were
similar in the two groups, resulting in 3-year rates of freedom from newly
initiated hormonal replacement of 78.4% (77.1% for SRS and 79.9% for SRT).
CONCLUSION: Considering the relatively high incidence of morbidity observed
in the SRS group, we recommend SRT as the primary method of radiation therapy
for pituitary tumors. When treating a lesion in the cavernous sinus with
SRS, special attention should be paid to dose distribution in the adjacent
brain parenchyma. Longer follow-up is necessary before drawing any conclusions
about the advantages of these techniques over conventional external beam
radiation therapy.
PMID: 9806517 [PubMed - indexed for MEDLINE]
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Multiple radiation-induced intracranial lesions after
treatment for pituitary adenoma. Case report.
Alexander MJ, DeSalles AA, Tomiyasu U.
Division of Neurosurgery, University of California at Los Angeles Medical
Center, 90095-6901, USA.
This 53-year-old man presented with a syncopal episode 31 years after undergoing
craniotomy and external-beam radiation for a pituitary macroadenoma. A gadolinium-enhanced
magnetic resonance (MR) image of the brain demonstrated a 2.5-cm enhancing
mass in the right caudate region that had not been seen on previous studies.
A stereotactically guided biopsy procedure was performed to obtain specimens
from the mass, which were consistent with ependymoma. The MR image also revealed
two additional lesions that appeared to be within the radiation fields: a
right temporal meningioma and a left frontal cavernous malformation. A review
of the literature found three previous reports in which ependymomas presented
after radiation therapy.
Publication Types:
- Case Reports
- Review
- Review of Reported Cases
PMID: 9420081 [PubMed - indexed for MEDLINE]
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