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PubMedDate not supplied

Correlation of behavior with brain damage after in utero exposure to toxic agents.

Early postnatal behaviors involving sensorimotor integration were measured along with thickness of the sensorimotor cortex in rats irradiated with 1.0 Gy on gestational day 11 or 17. Body weight and morphology of anterior pituitary cells were recorded. Irradiation on day 17 was more effective in reducing cortical thickness and body weight and performance on behavioral tests and less effective in altering pituitary cells than irradiation on day 11. Prediction of behavioral effects, using cortical layers, body weight and pituitary morphology as predictors in stepwise multiple regression, was measured in both irradiated and control rats. Cortical Layer V more than I more than IV and VI as significant predictors of behavior. The best predictions accounted for about half of the variance in the data. When behavioral data were used to predict brain damage, the best predictor was negative geotaxis. Significant association of behavior with Layers V and VI was found. These experiments show the difficulties in correlating complex behaviors with specific brain areas and, at the same time, implicate especially Layer V of the sensorimotor cortex in these behaviors.

Animals↗

PubMed1991

Thyroid function after treatment of brain tumors in children.

In 134 children who had been treated for a brain tumor not involving the hypothalamic-pituitary axis, thyroid function was assessed up to 24 years after treatment with cranial or craniospinal irradiation. In addition, 78 children received up to 2 years of cytotoxic chemotherapy. Of 85 children who received craniospinal irradiation, 30 (35%) had abnormalities of thyroid function, and 10 (20%) of 49 who received cranial irradiation had such abnormalities. Frank hypothyroidism developed in three children and thyrotoxicosis in one. Thirty-six children had an elevated thyroid-stimulating hormone level in the presence of a normal thyroxine level; in 16 of them the thyroid-stimulating hormone level subsequently returned to normal. Twenty-eight children who were treated between 1960 and 1970 were excluded from the analysis. Of 34 children who received cranial irradiation, five had thyroid dysfunction and 24 of 72 who received craniospinal irradiation had such dysfunction (p = 0.013). Thyroid dysfunction was present in 4 of 35 children who received no chemotherapy and in 25 of 71 who received chemotherapy (p = 0.014). Direct irradiation plus chemotherapy was more damaging than irradiation alone. These data confirm the high incidence of thyroid dysfunction when the thyroid gland is included in the radiation field. However, in a high proportion, the thyroid abnormalities are minor and revert to normal with time; life-long replacement therapy with thyroxine may be unnecessary.

Adolescent↗

PubMed1985

Cushing's syndrome.

Cushing's syndrome remains one of the most challenging problems in clinical endocrinology. Cushing's disease is caused in the majority of cases by basophil pituitary microadenomas which may be successfully treated by trans-sphenoidal hypophysectomy. Treatment with metyrapone or o,p'-DDD can always induce a clinical remission but not a cure, and neurotransmitter therapy may be effective in a minority of cases. Pituitary irradiation cures about half of cases in the long-term and may be used for surgical failures. Tumours producing ectopic ACTH are frequently benign, small and occult and may produce a syndrome clinically indistinguishable from Cushing's disease. Biochemical investigations cannot absolutely distinguish pituitary from ectopic sources of ACTH and therefore body CT scanning and percatheter venous sampling are essential diagnostic investigations. Tumour localization may result in resection and complete cure, although even small tumours may have a malignant potential. Adrenal tumours are readily diagnosed by plasma ACTH measurement and adrenal CT scanning. Adrenal adenomas are cured by adrenalectomy. Carcinomas may be treated by a combination of adrenalectomy, radiotherapy and o,p'-DDD, but long-term prognosis is poor.

Adrenal Cortex Hormones↗

PubMedDate not supplied

[Endocrine sequela of radiation treatment of extracranial head and neck tumors].

A study of the thyroid and hypothalamo-pituitary functions was undertaken in 14 children having been irradiated for tumors of the neck and head. The following anomalies were found: S.T.H. deficiency: 8 cases, A.C.T.H. deficiency: 2 cases, T.S.H. deficiency: 4 cases, primary thyroid insufficiency: 4 cases. Growth was severely impaired since the height of 10 out of 14 patients was less than or equal to 2 S.D. These results emphasize the frequency of endocrine lesions related to radiotherapy, as the lesions were essentially extracranial. They also show a repercussion on growth, which worsen the long-term prognosis of these diseases.

Adolescent↗

PubMed1989

Allogenic bone marrow transplantation in adults: endocrine sequelae after 1-6 years.

Twenty-three patients (13 females, 10 males) with panmyelopathy (N = 9), chronic leukemia (N = 5), and acute leukemias (N = 9) were studied 1 to 6 years following allogenic bone marrow transplantation. All patients had received conditioning treatment with cyclophosphamide prior to aBMT, and 2 of the patients with bone marrow aplasia and all of the leukemia patients had been given radiotherapy. An endocrine assessment was performed by means of TRH, GnRH, oCRF and GHRH tests and estimation of thyroid and gonadal hormones. Whereas pituitary-adrenal function appeared to remain stable, there was a 17.4% incidence of subclinical hypothyroidism (25% of the irradiated patients). Growth hormone reserve was diminished, and ovarian failure occurred in all female patients after radiotherapy, whereas in the men, only a moderate elevation of gonadotropins was observed. Our results warrant observation of thyroid and gonadal function, and in children of growth hormone secretion, after allogenic bone marrow transplantation. They also show that replacement therapy may be needed in some patients.

Adolescent↗

PubMed2006

A prospective analysis of 151 cases of patients with acromegaly operated by one neurosurgeon: a follow-up of more than 23 years.

BACKGROUND: Transsphenoidal adenomectomy has been the accepted surgical management for treatment of growth hormone (GH)-secreting pituitary adenomas. Although the goal of treatment might be to keep the GH level in the reference range, the actual definition of success in control of acromegaly is not yet clear. METHODS: The aim of this study was to analyze prospectively the result of transsphenoidal adenoctomy performed over 23-year period by a single neurosurgeon in one center. The analysis has been performed to determine which preoperative factor could significantly influence the long term outcome. This series consisted of 151 patients. The preoperative hormonal studies documenting the high GH and/or insulin-like growth factor were available in all the cases. At least 1 laboratory report documenting the postoperative level of hormones was also available for all of them. Transsphenoidal microsurgical adenomectomy was performed in all the cases. RESULTS: There were 90 patients with pure GH-secreting adenoma (59.6%) with the highest GH level of 235 mU/L. A second group of 12 patients had normal GH level but elevated serum level of insulin-like growth factor 1 (8%). The group with mixed secretion of GH and prolactin included 49 cases (32.4%). There was no postoperative mortality. Cerebrospinal fluid leakage occurred in 12 patients. Transient diabetes insipidus was encountered in 19 cases (12.6%) and long lasting diabetes insipidus in 2 patients (1.3%). Early and minor hypopituitarism was encountered in 14 patients, whereas a persistent condition occurred mainly after irradiation in 14 other cases. Normal postoperative serum GH level could be achieved in 98 patients (94.2%) of 104 cases with full follow-up. CONCLUSION: In the developing countries, early diagnosis and proper surgical extirpation of the GH-secreting adenoma by an experienced and dedicated pituitary surgeon is mandatory to reduce the mortality and increase the chance of cure of this rather mortal endocrionopathy.

Acromegaly↗

PubMed1984

High-dose radiation and the emergence of thyroid nodular disease.

High-dose radiation (in excess of 2500 rads or centiGray) to the head and neck area is reputedly infrequently associated with the emergence of thyroid nodular disease. Thirty-three patients who underwent high-dose radiation and who developed thyroid nodular disease have been described. Radiation was originally administered for hyperthyroidism in 11 patients, postmastectomy in five, oral cancer in three, Hodgkin's disease in three, facial hirsutism in three, hemangioma in three, cancer of the larynx in one, skin cancer in one, desmoid tumor of the neck in one, Ewing's tumor in one, and pituitary tumor in one. Treatment included radioiodine in 11, external radiation in 21, interstitial radiation in one, and combined radiation in one. Associated head and neck neoplasms included four parathyroid tumors, one osteogenic sarcoma of the maxilla, two basal cell cancers of the facial skin, and one parotid gland carcinoma. The study group consisted of five men and 26 women varying in age from 22 to 75 years, with a duration of latency of effect varying from 1.5 to 50 years. Thyroid disease consisted of 21 cancers, six adenomas, four colloid goiters, and two cases of thyroiditis resulting in four deaths caused by cancer, for a 20% mortality rate. Consideration of radiation beam behavior showed that isodose curve, penumbra effect, back scatter, and special field resulted in the thyroid gland receiving a low dose, namely under 2500 rads. Clinical factors such as an overlooked goiter, coincidental carcinoma, error in presumption of dose, and second primary malignancy were also considerations. True biologic radiation oncogenesis may have been seen in our radioiodine-treated group with hyperthyroidism as well as the group with Hodgkin's disease who underwent mantle irradiation. It is apparent that for whatever reason and by whatever means and by whatever mechanism, high-dose radiation to the head and neck area can result in significant thyroid disease, and patients undergoing such radiation should be followed with this in mind and considered for thyroid feeding on a prophylactic basis.

Adenocarcinoma↗

PubMed1990

Radiation and hypothalamic-pituitary function.

In adults, hypopituitarism is a common consequence of external radiotherapy. The clinical manifestations may be subtle and develop insidiously many years after radiotherapy. Anterior pituitary deficiencies can therefore only be detected by regular testing, including dynamic tests of GH and ACTH reserve. Although the deficiencies most commonly develop in the order GH, gonadotrophins, ACTH then TSH, this sequence may not be predictable in an individual patient and comprehensive testing is therefore required. The tests should ideally be performed annually for at least 10 years after treatment or until deficiency has been detected and treated. It is not only the patients with pituitary disease who are at risk of developing hypopituitarism after radiotherapy. Any patient who receives a total dose of irradiation of 20 Gy or more to the hypothalamic-pituitary axis is at risk of hypopituitarism, although the threshold dose may be lower than this. This is particularly important in the long-term survivors of malignant disease in whom endocrine morbidity may be relatively common and in whom this can be easily treated, with consequent improvement in quality of life. Whilst patients who receive a high total dose of irradiation are at increased risk of developing multiple deficiencies, a higher fraction size also increases the risk of anterior pituitary failure. There is good evidence that the earliest damage to the hypothalamic-pituitary axis after external radiotherapy is at the level of the hypothalamus. However, patients who undergo pituitary ablation with interstitial radiotherapy or heavy particle beams are likely to sustain direct damage to the pituitary. In these patients, the sequence in which individual pituitary hormone deficiencies develop is generally the same as that observed with the hypothalamic damage after conventional external radiotherapy. The increasing use of radiotherapy as a means of treatment for malignant disease means that new groups of patients with potential for endocrine dysfunction are emerging. Whole body irradiation in the preparation for bone marrow transplant is one such treatment and although hypothalamic-pituitary damage appears to be confined to GH deficiency in children, longitudinal experience is limited to date, particularly in adults. The treatment of malignant disease in childhood is of particular importance in terms of the delayed endocrine sequelae. The hypothalamic-pituitary axis may not be the only endocrine tissue damaged by treatment in these patients and management is therefore more complicated. In the growing child, the potential association of growth hormone deficiency, gonadal failure or premature puberty and thyroid dysfunction mean that expert endocrine supervision is essential for optimum long-term outcome.

Dose-Response Relationship, Radiation↗

PubMed1978

Feedback control by the testis of gonadotrophin secretion: an examination of the inhibin hypothesis.

Spermatogenesis in rats was interrupted by local X-irradiation, heat or ligation of the testicular efferent ducts. A significant and specific rise in the serum level of FSH occurred 5--8 days after ligation of the efferent ducts, reaching twice the value observed in sham-operated controls by 21 days after the operation. After the testes were heated to 43 degrees C for 30 min, the serum levels of both LH and FSH were raised within 3 days and remained so up to 50 days after treatment. After X-irradiation, no changes in the concentration of FSH were observed in the first 21 days after treatment, but the serum levels of both gonadotrophins were increased at 49 days. By comparing the relative increases in the concentrations of FSH and LH after germ cell damage with those occurring after castration, it was evident that testicular androgens could account for only part of the normal feedback control of FSH secretion; at least one third of the inhibition of FSH secretion appeared to be due to non-androgenic sources, presumably 'inhibin'.

Animals↗

PubMed1983

Covalent linking of photoreactive gonadotropin-releasing hormone to gonadotropes produces a prolonged signal.

A bioactive, photoreactive derivative of gonadotropin-releasing hormone (GnRH; gonadoliberin), [azidobenzoyl-D-Lys6]GnRH, was shown to bind covalently to dispersed pituitary cells after irradiation. Approximately 7% of the total cell-associated radioactivity was covalently bound to the receptors. Photolysis of cultured pituitary cells in the presence of the photoreactive derivative resulted in persistent activation of luteinizing hormone (LH; lutropin) release. This persistent response was time dependent and concentration dependent. No increase in the basal rate of LH release was observed with cells incubated in the presence of photoreactive GnRH analog and maintained in the dark or with hormone derivatives that lack the photoreactive azido group. These results suggest that only the covalently bound cell surface receptors account for the persistent activation of LH release after photolysis.

Affinity Labels↗

PubMed1993

Stereotactically guided radiosurgery using the linear accelerator.

Leksell initiated the concept of stereotactic radiosurgery in 1951. This last decade has seen a rapid proliferation in the development of the methodology which is certainly related in part to the simultaneous growth of high-resolution neuro-imaging techniques. By focusing the beams of 201 hemispherically arrayed cobalt 60 sources, the gamma-knife delivers a high dose of radiation to a small target. Another possibility proposed by several authors is the bragg peak cyclotron-generated irradiation with accelerated protons or helium ions. In Lille, since 1988, we have chosen to develop stereotactic radiosurgery, according to the system of Betti, by the association of Talairach's stereotactic methodology and external single-dose encephalic irradiation with high energy X-rays, delivered by means of a linear accelerator. The major indication for the use of this method is an arteriovenous malformation. Stereotactic radiosurgery may be proposed alone or in combination with surgery and embolisation. It has been shown to be a potentially effective treatment and an attractive alternative in carefully selected patients with intracranial tumours: slow-growing, well limited, deep-seated tumours, such as some gliomas, acoustic neurinomas, skull base meningiomas, pituitary adenomas. This treatment is also used to deliver a focal boost of radiation to previously administered fractionated radiotherapy in patients with small gliomas and solitary brain metastases.

Adenoma↗

PubMed1989

Hypopituitarism following external radiotherapy for pituitary tumours in adults.

The development of anterior pituitary hormone deficiencies has been studied in a group of 165 patients who underwent external radiotherapy for tumours of the pituitary or closely related anatomical sites, and who have been observed for up to 10 years. One hundred and forty had undergone pituitary surgery before radiotherapy. All patients received external radiotherapy by a three-field technique, giving 3750-4250 cGy in 15 or 16 fractions over 20-22 days. A combined test of anterior pituitary function using insulin hypoglycaemia or glucagon stimulation in conjunction with thyrotrophin and gonadotrophin releasing hormone tests and basal estimations of prolactin, thyroid hormones and testosterone or oestradiol was performed before radiotherapy. This was repeated six and 12 months later and subsequently annually. Before radiotherapy, 18 per cent of patients had normal growth hormone secretion, 21 per cent had normal gonadotrophin secretion, 57 per cent had normal corticotrophin reserve and 80 per cent had normal thyrotrophin secretion. Life table analysis demonstrated increasing incidences of all anterior pituitary hormone deficiencies with time: by five years all patients were growth hormone deficient, 91 per cent were gonadotrophin deficient, 77 per cent were corticotrophin deficient and 42 per cent were thyrotrophin deficient. At eight years, respective incidences of deficiencies were 100, 96, 84 and 49 per cent. Radiation-induced hyperprolactinaemia was seen in 73 patients; mean serum prolactin concentration rose from 227 +/- 11 mU/l to a peak of 369 +/- 60 mU/l at two years and subsequently declined towards the basal value. The primary diagnosis, patient age, sex, irradiated tissue volume and previous surgery were examined as variables that might influence the rate of development of anterior pituitary hormone deficiencies, but none of these factors had a significant effect. The radiation induced hyperprolactinaemia was however more marked in female patients. Although anterior pituitary hormone deficiencies most commonly developed in the order growth hormone, gonadotrophin, corticotrophin, thyrotrophin (61 per cent of patients), other sequences were evident. Most notably corticotrophin deficiency occurred before gonadotrophin deficiency. There is a high incidence of anterior pituitary hormone deficiencies in patients treated surgically for pituitary tumours and the incidence increases after external radiotherapy. Deficiencies may occur in an unpredictable sequence and endocrine testing is recommended on an annual basis.

Adolescent↗

PubMed2003

No damaging effect of chemotherapy in addition to radiotherapy on the thyroid axis in young adult survivors of childhood cancer.

Late effects of treatment for childhood cancer on the thyroid axis are ascribed predominantly to radiotherapy. Whether chemotherapy has an additional detrimental effect is still unclear. Our aim was to evaluate this effect in young adult survivors of a broad spectrum of childhood cancers. The thyroid axis in 205 childhood cancer survivors was evaluated in relation to former use of chemotherapy and radiotherapy (cranial, cranio-spinal, cervical, mediastinal, or thoracic). The mean follow-up time was 17.5 yr. Damage to the thyroid axis was found in 55 patients (26.8%). Thirty-seven patients (18%) had thyroidal disease. Diagnoses varied from TSH elevation to papillary carcinoma. After multivariate analysis, high risk radiation field, irradiation dose, and the diagnosis of non-Hodgkin lymphoma/Hodgkin's disease were found to be significant risk factors for developing thyroid disease. Treatment with chemotherapy did not have an additional negative effect on the thyroid axis. For the development of central (pituitary or hypothalamic) thyroid dysfunction, patients with a brain tumor were at increased risk. Chemotherapy for childhood cancer does not contribute to the damage on the thyroid axis inflicted by radiotherapy during young adulthood.

Adolescent↗

PubMed1980

Pituitary surgery for endocrine disorders.

The use of pituitary surgery for patients with over-production of growth hormone, corticotrophin and prolactin is reviewed. The value of specialized neuroradiological techniques is discussed including computerized tomography, air-encephalography and cavernous sinus venography. The indications for transcranial as opposed to trans-sphenoidal surgery are considered. The place of trans-sphenoid surgery in the treatment of acromegaly is emphasized and the indications for surgical treatment are reviewed. The two syndromes due to over-production of ACTH are considered--Cushing's disease and Nelson's syndrome. The increasing use of pituitary surgery for the treatment of Cushing's syndrome due to increased ACTH production is noted, but a warning is given about the small ACTH-secreting pulmonary carcinoid tumour that may closely mimic Cushing's disease. The difficulties encountered in trying to treat patients with Nelson's syndrome are stressed. It is recommended that in the rate case where total adrenalectomy is required in Cushing's disease, pituitary irradiation should be given before or shortly after adrenalectomy. The present position relating to the surgical treatment of the small prolactin-secreting pituitary tumour is reviewed. Published data and personal experience suggests that for many of these patients, treatment with bromocriptine is preferable to trans-sphenoidal surgery. Large prolactinomas usually need transfrontal surgery and X-ray therapy, sometimes followed by bromocriptine treatment. The need for steroid cover for pituitary surgery is discussed and it is suggested that a glucocorticoid with less salt-retaining action than cortisol should be used. The importance of post-operative endocrine assessment is emphasized and a convenient method suggested. The incidence of complications after transsphenoidal surgery is low, although panhypopituitarism occurred in 14% of the cases reported.

Acromegaly↗

PubMed2006

Surgical remission of pituitary adenomas confined to the neurohypophysis in Cushing's disease.

CONTEXT: Partial or total removal of the pituitary cures 60-80% of patients with Cushing's disease (CD) in whom an adenoma cannot be identified at surgery. Many patients who fail complete or partial hypophysectomy are cured by sellar and parasellar irradiation. DESIGN/PATIENTS: As part of a series of prospective studies of CD, we identified 12 patients (34.5 +/- 19.9 yr; 11 females; four children) with tumors located completely within the neurohypophysis among 730 patients undergoing surgery for CD. SETTING: The study was conducted at a tertiary referral center at a clinical research hospital. RESULTS: All 12 patients had clinical and biochemically defined CD. Tumor was visible at surgery in 11 patients; all 12 tumors were positive for ACTH by immunohistochemistry. Two tumors were excised at repeat surgery because of persistent hypercortisolism within 14 d of negative exploration of the adenohypophysis. There were no long-term complications. At follow-up of 71.9 +/- 34.2 months (range, 30-138 months), all patients are in remission of CD. Adult patients have had significant improvement in weight and body mass indices, with restoration of normal menses in all women. In the four pediatric patients, height, weight, and body mass indices have been restored toward normal by surgical remission of CD. Hypopituitarism or long-term neurohypophysial dysfunction has not occurred. CONCLUSION: We report a new subset of patients with CD, ACTH-secreting adenomas that arise wholly within the posterior lobe of the pituitary gland. In cases of CD in which an adenoma is not identified in the adenohypophysis and in patients with persistent hypercortisolism after complete or partial excision of the anterior lobe, tumor within the neurohypophysis should be considered; selective adenomectomy of a neurohypophyseal, ACTH-secreting tumor can produce long-term remission.

Adenoma↗

PubMed2001

Hypothalamo-pituitary surveillance imaging in hypopituitary patients receiving long-term GH replacement therapy.

Most cases of adult-onset (AO) GH deficiency (GHD) result from the presence of hypothalamo-pituitary tumors or their treatment. GH replacement is now widely used in adults with hypopituitarism, but its effect on hypothalamo-pituitary tumor growth or recurrence is unknown. Anecdotal evidence from early experience of GH replacement in adults documented occasional tumor recurrence, but any relationship of this to the use of GH was unclear. We have now prospectively imaged the pituitary glands of 100 consecutive patients (60 females, 40 males; mean age, 46 yr; range, 18-69 yr) who had AO-GHD after appropriate treatment for a pituitary or peripituitary tumor. External radiotherapy had been given to 91 patients. All patients were treated with a dose titration regimen to maintain serum IGF-I between the median and upper end of the age-related reference range. Pituitary imaging was performed before the commencement of GH and after 6 and 12 months of treatment in all patients, again at 2 yr in 92 patients, at 3 yr in 63 patients, and after 4 yr in 23 patients. In only one patient was there evidence of slight intrasellar tissue enlargement at 6 months; GH replacement was continued, and there was no further change between 6 and 12 months. In all other patients, either the appearances were unchanged or the amount of tissue was reduced during long-term follow-up on GH. We have shown that hypothalamo-pituitary tumor recurrence was thus very rare over this time period in this group of GH-treated patients, and this is reassuring. Similar prospective longitudinal observation of patients who have not received postoperative irradiation and comparison with rates of tumor recurrence in control series are desirable.

Adenoma↗

PubMedDate not supplied

[Heavy particle beams (proton) in oncology (35-year practice of N.N. Blokhin Cancer Research Centre)].

Clinically proved "alternative breast-preserving method" applicable for patients with locally advanced nodal breast cancer. These patients refuse to go in to surgery or have indications for surgery (183 patients--T(1-4)N(0-3)M(0-1)). This method consists of the combination of the traditional method of the whole breast and/or nodal photon irradiation with local highly concentrated proton irradiation in the dosage iso-equivalent to tumor (proton with energy from 130 to 180 MeV, with stop in the target in notice depth). We used the irradiation of the adenohypophysis with narrow proton beams energy 200 MeV. The aim of the first combination of the components is the selectively influence on the target and the channeling to the tumor and its subclinical substances the dosages sufficient for the total irradiation of tumor with sparing surrounding tissues and parts of body. The goal of irradiation of adenohypophysis with protons is the normalization of its hormonal activity and elimination of factors stimulating growth of tumor cells in case of dishormonal cancer. The suggested method didu't only improve the results of the treatment of locally advanced breast cancer, but also contributed to the reducing of the emotional stress. We received high results of the patients with locally advanced nodal breast cancer of criteria: local control rate (96%), long remission (more then 40%) and 5-year actuarial survival rate (83%). The patients examined during 5 and 18 years. It made a good cosmetic effect and high quality life of the patients with breast cancer.

Breast Neoplasms↗

PubMed1993

Eye sequelae following external irradiation.

The early reactions of the eye to radiation are conjunctivitis and, with higher doses, corneal damage. The inflammatory reactions are transient and remit within a few weeks after the end of radiotherapy. Doses above 60 Gy can produce corneal ulcerations with the risk of perforation and loss of the eye. The most frequent late reaction of the eye is cataract of the lens. The tolerance dose (about 5 Gy) is extremely low and the latent period varies from 6 months to 3 years. The lens in children has a much lower tolerance. The increasing potential for optical support and ophthalmic surgery over recent decades has reduced the fear of this complication. The most severe late complications are retinopathy (RR) and neuropathy of the optic nerve (RON), both of which are caused by radiation-induced microangiopathy. Visual loss is very frequent and complete blindness is seen with high doses in the range of 50-60 Gy. The latent period of these injuries varies widely from 1 month to 15 years, but they usually occur within 3 years of treatment. Conflicting frequencies are reported in the literature. Beyond 30 Gy, usually no RR is seen. However, the lowest recorded dose producing RR is 11 Gy. In the high dose range of 60-70 Gy RR and RON are found in 10%-100% of patients. There is a great need for prospective trials to estimate the true risk to patients with nasopharyngeal, maxillo-ethmoidal, and orbital tumors, pituitary adenomas, and tumors of the salivary glands. To minimize complications of radiotherapy to the eyes daily fractions should be reduced to 1.7-1.8Gy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗