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Biomedical subjects

M Brada

Publications and source records attributed to M Brada.

At least 109 records · Page 6Linked to original sources
PubMed1993

The long-term efficacy of conservative surgery and radiotherapy in the control of pituitary adenomas.

OBJECTIVES: We assessed the long-term efficacy and toxicity of conservative surgery and radiotherapy in the control of pituitary adenomas. DESIGN: Retrospective study of patients treated at the Royal Marsden Hospital. PATIENTS: Four hundred and eleven patients with pituitary adenomas treated with conventional external beam radiotherapy at the Royal Marsden Hospital between 1962 and 1986. Two hundred and fifty-two patients had clinically non-functioning pituitary adenomas, 131 had hormone secreting tumours and in 28 patients the secretory status was not known. Three hundred and thirty-eight patients had surgical intervention of whom only 11 had complete tumour excision. All patients received conventional fractionated external beam radiotherapy to a dose of 45-50Gy in 25-30 fractions. MEASUREMENTS: Actuarial progression free survival and overall survival and assessment of toxicity, particularly in terms of vision, requirement for hormone replacement therapy and incidence of second tumours. RESULTS: The actuarial progression free survival was 94% at 10 years and 88% at 20 years for all patients and 97% at 10 years and 92% at 20 years for patients with clinically non-functioning adenomas. Only secretory status was an independent prognostic factor for disease control. The 10 and 20-year survivals for all patients were 77 and 58% respectively. When compared with the normal population the relative risk of death was 1.76 (P < 0.001) and no prognostic factors for survival were identified. The morbidity of radiotherapy was low. Visual deterioration, assumed to be radiation induced, occurred in 1.5% of patients and the risk of second brain tumour was 1.9% at 20 years. Fifty per cent of patients received hormone replacement therapy by 19 years. CONCLUSION: Conventional external beam radiotherapy as described here combined with conservative surgery is safe and effective in the control of pituitary adenomas. These results should form a baseline for comparison with new treatment strategies.

Adenoma↗
PubMed1993

Feasibility of patient immobilization for conventional cranial irradiation with a relocatable stereotactic frame.

The precision of patient repositioning and the firmness of immobilization are among the major determinants of the accuracy of radiation treatment delivery. A relocatable Gill-Thomas localizer (GTL) developed for neurosurgery and stereotactic radiotherapy achieves highly accurate relocation and immobilization and has been used successfully for fractionated stereotactic radiotherapy of intracranial lesions. The feasibility of using GTL for immobilization in conventional fractionated external beam radiotherapy was assessed by comparison with conventional Cabulite shell head fixation. The GTL was well tolerated at the time of preparation and during a 5 week course of radiotherapy. The principal advantage was superior relocation accuracy maintained throughout the course of treatment, high precision of field set-up and markedly reduced production time. In addition the time taken to position the patient in the treatment room was also marginally shortened. GTL is therefore a feasible method of head fixation for conventional cranial irradiation providing patients have adequate dentition. With further development the relocatable method of immobilization originally designed for stereotactic radiotherapy may become the preferred technique particularly in situations where high accuracy is desirable, such as stereotactically guided conformal radiotherapy.

Adenoma↗
PubMed1993

Management of spinal astrocytoma with conservative surgery and radiotherapy.

Twenty-seven patients with histologically verified spinal astrocytoma were treated at the Royal Marsden Hospital with postoperative radiotherapy. All patients had previous surgery; 10 had partial resection and 17 biopsy alone. All patients received involved field radiotherapy to a median dose of 50 Gy in 33 fractions. Overall 5- and 10-year survival was 59 and 52%, and progression free survival was 38 and 26% at 5 and 10 years, respectively, at a median follow-up of 6.5 years. Following radiotherapy, eight patients showed functional improvement, 15 were unchanged and two deteriorated. Sixteen patients relapsed, eleven at the primary site and five elsewhere in the CNS. Low grade histology, female gender and the presence of intramedullary cysts were favourable prognostic factors for survival on univariate analysis. The extent of surgery was not a significant predictor of survival. It is not possible to define the precise role of radiotherapy. However, all patients had residual tumour prior to irradiation, and 53% of low grade and 33% of high grade gliomas remained controlled locally at 3 years with stabilization or improvement in neurological function in all but two patients. This suggests that radiotherapy may result in temporary disease control analogous to cerebral gliomas.

Adolescent↗
PubMed1992

Risk of second brain tumour after conservative surgery and radiotherapy for pituitary adenoma.

OBJECTIVE: To assess the risk of second brain tumour in patients with pituitary adenoma treated with conservative surgery and external beam radiotherapy. DESIGN: Long term follow up of a cohort of patients with pituitary adenoma and comparison of tumour occurrence with population incidence rates. SETTING: The Royal Marsden Hospital. SUBJECTS: 334 patients with pituitary adenoma treated with conservative surgery and radiotherapy (median dose 45 Gy) and followed up for 3760 person years. MAIN OUTCOME MEASURES: Second intracranial tumour and systemic malignancy. RESULTS: Five patients developed a second brain tumour: two had astrocytoma, two meningioma, and one meningeal sarcoma. The cumulative risk of developing a second brain tumour over the first 10 years after treatment was 1.3% (95% confidence interval 0.4% to 3.9%) and over 20 years 1.9% (0.7% to 5.0%). The relative risk of a second brain tumour compared with the incidence in the normal population was 9.38 (3.05 to 21.89). There was no excess risk of any other type of second primary malignancy. CONCLUSIONS: There is an increased risk of second intracranial tumour in patients with pituitary adenoma treated with surgery and radiotherapy. Although radiation is likely to be the most important factor contributing to the excess risk, further study is required in a cohort of similar patients not receiving radiation.

Adenoma↗
PubMed1992

Intracranial ependymoma: long-term results of a policy of surgery and radiotherapy.

Ninety-three patients with primary intracranial ependymoma were treated at the Royal Marsden Hospital, between 1952 and 1988, with postoperative radiotherapy. The survival probability at 5, 10, and 15 years was 51%, 42% and 31%, respectively, and the corresponding progression free survival (PFS) probability, 41%, 38%, and 30%. Tumor grade was the single most important prognostic factor for survival and PFS with gender of lesser prognostic significance. Treatment parameters were stratified for grade. In patients with low grade tumors survival and PFS were better following complete macroscopic excision compared to incomplete surgery. The extent of resection had no significant influence on survival or PFS in patients with high grade tumors. Extent of irradiation did not influence PFS, irrespective of tumor grade, while patients with high grade tumors had marginally better survival following extensive irradiation compared to more limited radiotherapy. The main problem in the treatment of ependymoma remains local progression which was the cause of death in all but two patients. New treatment strategies should focus on improvement of local control, especially in incompletely resected low grade tumors and all high grade tumors. The use of spinal irradiation is unlikely to significantly improve treatment results.

Adolescent↗
PubMed1992

A comparison of gallium-67 single photon emission computed tomography and computed tomography in mediastinal Hodgkin's disease.

The role of gallium-67 single photon emission computed tomography (Ga-67 SPECT) in the assessment of mediastinal Hodgkin's disease was evaluated prospectively. Ga-67 SPECT and computed tomography (CT) were compared and correlated with clinical findings at initial presentation in 30 patients, 6 weeks after treatment, and 6 months later in 20 of the 30 patients. At initial presentation, active disease was detected on both imaging modalities on all occasions. 6 weeks after treatment CT showed residual mediastinal abnormality in 7 patients, whereas Ga-67 SPECT showed abnormal mediastinal tracer uptake in 3 patients. 6 months later CT showed residual mediastinal abnormality in 5 patients whereas all the Ga-67 SPECT studies were negative. Ga-67 SPECT imaging is a useful tool in assessing response to therapy in mediastinal Hodgkin's disease.

Adult↗
PubMed1992

Intracranial germ cell tumour in association with cryptorchidism.

An intracranial germ cell tumour (GCT) in a patient with cryptorchidism is presented. The known association between testicular GCTs and cryptorchidism suggests a possible common predisposition for gonadal and extragonadal tumours. To confirm this the frequency of the reported association needs to be defined.

Adolescent↗
PubMed1992

Radiotherapy for the treatment of recurrent craniopharyngioma.

Twenty-five patients with craniopharyngioma received radiotherapy at the time of recurrence. The 10-year progression free survival and survival from the time of recurrence were 72% and 77% respectively. Nineteen patients underwent surgery prior to radiotherapy (6 partial excision, 4 decompression and 9 cyst aspiration). The extent of resection at the time of recurrence did not influence the outcome. Apart from pituitary failure there was no serious morbidity associated with this approach. The results of radiotherapy at recurrence are similar to those of conservative surgery and radiotherapy at the time of presentation. It suggests that radiotherapy remains an effective treatment modality at the time of recurrence of craniopharyngioma and it may therefore be delayed in situations where immediate radiation is not advisable. However, the high recurrence rate in incompletely excised craniopharyngioma, together with the potential risk of additional morbidity and mortality from undiagnosed progressive tumour and salvage surgery, would argue for a policy of radiotherapy as part of the initial treatment of incompletely excised craniopharyngioma.

Adolescent↗
PubMed1992

Salvage radiotherapy in recurrent Hodgkin's disease.

Forty-four patients with Hodgkin's disease (HD) which relapsed after chemotherapy were treated with salvage radiotherapy (S-RT) with curative intent. Patients were aged 7 to 80 years (median 32 years) at the time of S-RT and the median follow-up from S-RT was 5 years (1-15). Nine patients had recurrent HD following first-line chemotherapy and thirty five patients had refractory HD. Salvage therapy consisted of radiotherapy alone in 25 and combined chemotherapy and radiotherapy in 19 patients. The overall CR rate of salvage therapy was 66%. The overall median survival of 44 patients was 4.6 years from S-RT with 46% 5 year and 40% 10 year survivals. Age (greater than 40 years) and progression free interval (less than or equal to 1 year) were adverse independent prognostic factors for survival on multivariate analysis. The 5 and 10 year progression free survivals were 38% and 23% respectively. Adverse independent prognostic factors for progression-free survival were extranodal site of recurrence and short progression free interval (less than or equal to 1 year). We conclude that radiotherapy with or without chemotherapy has a role in the salvage of patients failing chemotherapy, particularly in those with nodal disease and progression-free interval greater than 1 year.

Adolescent↗
PubMed1992

Failure of conventionally fractionated radiotherapy to decrease the risk of hemorrhage in inoperable arteriovenous malformations.

Twenty-six patients with arteriovenous malformations (AVMs) were treated between 1965 and 1986 with conventional fractionated radiotherapy at the Royal Marsden Hospital. There were 14 male patients and 12 female, aged 11 to 57 years (median, 24 yr). Twenty-five patients completed radiotherapy with a localized treatment target volume of a dose of 40 to 54 Gy. The median follow-up was 14.5 years. Eleven patients had an additional hemorrhage. The actuarial annual risk of bleeding was 2.3%, which is similar to that found in untreated patients. Follow-up angiograms were performed in 11 patients, and 10 showed persistence of AVM. The results suggest that fractionated radiotherapy in conventional doses does not make a large impact on the risk of hemorrhage in patients with inoperable AVMs, and, where possible, stereotactic external beam radiotherapy/radiosurgery should be employed.

Actuarial Analysis↗
PubMed1991

A comparison of techniques for stereotactic radiotherapy by linear accelerator based on 3-dimensional dose distributions.

In order to establish the appropriate beam arrangement for use in stereotactic radiotherapy using a linear accelerator, dose volume distributions were calculated for a number of spherical targets in a head phantom and assessment was made by dose sparing of normal tissue outside the target volume. Using a single isocentre, fixed beam arrangements were compared with single and multiple non-coplanar isocentric arc rotations at target sizes from 10 to 55 mm diameter on a 6 MV Philips linear accelerator. From the dose-volume histograms produced, an arrangement of 3 or 4 arcs of rotation proved most suitable, in terms of sparing of normal tissue outside the target volume to high dose irradiation, across the range of target sizes studied. There was little further benefit with increasing the number of arcs beyond this. At target sizes greater than 20 mm diameter an arrangement of 6 static non-coplanar beams achieved sparing equivalent to multiple arc rotations and may have considerable advantages in the treatment of irregular volumes where customised beam shaping could be employed.

Humans↗
PubMed1991

A non-invasive, relocatable stereotactic frame for fractionated radiotherapy and multiple imaging.

A non-invasive relocatable stereotactic frame has been developed for fractionated stereotactic external beam radiotherapy (SRT) by linear accelerator. Fixation is via the upper dentition and tests of repositioning have shown mean antero-posterior and lateral displacements of 1.0 mm. The relocatable frame allows accurate 3-dimensional target localisation by CT, MRI, PET and cerebral angiography and precise isocentric positioning for radiotherapy. This method of immobilisation is ideal for fractionated SRT as well as for other techniques requiring high precision localisation and treatment delivery.

Animals↗
PubMed1991

Measurements of blood-brain barrier permeability in patients undergoing radiotherapy and chemotherapy for primary cerebral lymphoma.

Positron emission tomography (PET) has been used to measure changes in regional blood-brain barrier (BBB) permeability in patients with primary cerebral lymphoma undergoing radiotherapy and chemotherapy. The method employed is to measure the rate of wash-out of a radioactive tracer (68Ga-EDTA) from blood into brain tissue using time-sequence PET imaging. Preliminary studies carried out on patients with more common primary cerebral tumours show that time-activity data are reproducible to approximately 10%. Measurements made in 2 patients with primary cerebral lymphoma treated with initial chemotherapy showed significant changes in permeability in the region of the tumour. Within 5 weeks of the start of treatment, permeability values reached the levels of normal brain. No changes in BBB permeability in normal brain were seen immediately after radiotherapy.

Adult↗
PubMed1991

Relocatable frame for stereotactic external beam radiotherapy.

A non-invasive head fixation system is described which is accurately relocatable and enables the transfer of stereotactic positions between a variety of radiodiagnostic images and therapeutic procedures. The system can be simply and repeatedly applied for planning stereotactic radiation therapy from one or more diagnostic images and for repeated treatment with a conventional linear accelerator. In addition, the long-term effects of therapy can be objectively monitored by relocating the frame and repeating images in an identical way, months or years later.

Radiotherapy↗