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Biomedical subjects

G Ioannidis

Publications and source records attributed to G Ioannidis.

29 records · Page 2Linked to original sources
PubMed2000

Navigation system for interstitial brachytherapy.

PURPOSE: To develop a computed tomography (CT) based electromagnetic navigation system for interstitial brachytherapy. This is especially designed for situations when needles have to be positioned adjacent to or within critical anatomical structures. In such instances interactive 3D visualisation of the needle positions is essential. METHODS AND MATERIALS: The material consisted of a Polhemus electromagnetic 3D digitizer, a Pentium 200 MHz laptop and a voice recognition for continuous speech. In addition, we developed an external reference system constructed of Perspex which could be positioned above the tumour region and attached to the patient using a non-invasive fixation method. A specially designed needle holder and patient bed were also developed. Measurements were made on a series of phantoms in order to study the efficacy and accuracy of the navigation system. RESULTS: The mean navigation accuracy of positioning the 20.0 cm length metallic needles within the phantoms was in the range 2.0-4.1 mm with a maximum of 5.4 mm. This is an improvement on the accuracy of a CT-guided technique which was in the range 6.1-11.3 mm with a maximum of 19.4 mm. The mean reconstruction accuracy of the implant geometry was 3.2 mm within a non-ferromagnetic environment. We found that although the needles were metallic this did not have a significant influence. We also found for our experimental setups that the CT table and operation table non-ferromagnetic parts had no significant influence on the navigation accuracy. CONCLUSIONS: This navigation system will be a very useful clinical tool for interstitial brachytherapy applications, particularly when critical structures have to be avoided. It also should provide a significant improvement on our existing technique.

Brachytherapy↗
PubMed2000

Etridronate therapy in the treatment and prevention of osteoporosis.

Etidronate disodium is an oral bisphosphonate compound known to reduce bone resorption through the inhibition of osteoclastic activity. This article is a review of its efficacy and safety in the treatment and prevention of postmenopausal and corticosteroid-induced osteoporosis. In general, studies of cyclical etidronate therapy (400 mg daily for 2 wk every 3 mo) have found a significant improvement in bone density. These studies have not been powered to study fracture incidence, but a reduced fracture rate has been found in some of the studies reviewed. Studies examining cyclical etidronate in the prevention of osteoporosis indicate it prevents early menopausal bone loss and is free of significant side effects. In both prevention of corticosteroid-induced osteoporosis and treatment of patients who have been on long-term corticosteroid therapy, cyclical etidronate appears to increase bone density and prevent further loss of bone. In summary, a review of available literature pertaining to the use of etidronate in prevention and treatment of primary and secondary osteoporosis has been presented. This review suggests etidronate, used as a cyclical therapy, is a safe and effective therapy. The weight of evidence suggests it is capable of reducing fracture risk in patients with osteoporosis. Increases in bone density at the spine and hip are not as pronounced as with some other bisphosphonates, particularly alendronate, but no direct clinical comparison trials of significant size or duration have been undertaken.

Adrenal Cortex Hormones↗
PubMed2000

A pooled data analysis on the use of intermittent cyclical etidronate therapy for the prevention and treatment of corticosteroid induced bone loss.

OBJECTIVE: To conduct a pooled data analysis in a group of patients defined by sex, menopausal status, and underlying disease in order to examine the effect of intermittent cyclical etidronate in the prevention and treatment of corticosteroid induced osteoporosis. METHODS: We selected 5 randomized, placebo controlled studies that examined the efficacy of intermittent cyclical etidronate therapy in which the raw data were available for analysis. Three were prevention studies and 2 treatment studies. The primary outcome was the difference between treatment groups in the percentage change from baseline in lumbar spine bone density. Secondary outcomes included the difference between treatment groups in the percentage change from baseline in femoral neck and trochanter bone density, and vertebral fracture rates. RESULTS: Results are separately pooled for the prevention and treatment studies. The prevention studies had significant mean differences (95% CI) between groups in mean percentage change from baseline in lumbar spine, femoral neck, and trochanter bone density of 3.7 (2.6 to 4.7), 1.7 (0.4 to 2.9), and 2.8% (1.3 to 4.2) after one year of treatment, in favor of the etidronate group. The treatment studies displayed a mean difference between groups in mean percentage change from baseline in lumbar spine bone density of 4.8 (2.7 to 6.9) and 5.4% (2.5 to 8.4) after one and 2 years of therapy. In the prevention studies, a reduced fracture incidence was observed in the etidronate group compared with the placebo group (relative risk 0.50; CI 0.21 to 1.19). CONCLUSION: Etidronate therapy was effective in preventing bone loss in the prevention studies and in preventing or slightly increasing bone mass in the treatment studies. A fracture benefit was observed in postmenopausal women treated with etidronate in the prevention studies.

Adult↗
PubMed1999

Development and validation of the mini-osteoporosis quality of life questionnaire (OQLQ) in osteoporotic women with back pain due to vertebral fractures. Osteoporosis Quality of Life Study Group.

The objective of the study was to evaluate a shortened osteoporosis quality of life questionnaire (OQLQ) in osteoporotic women with back pain due to vertebral fractures. From the longer 30-item OQLQ (four to nine items per domain) we created the mini-OQLQ by choosing the two items with the highest impact in each of five domains (symptoms, physical function, activities of daily living, emotional function, leisure). We administered the OQLQ, the Sickness Impact Profile, the SF-36 and the Brief Pain Index to patients at baseline, after 2 weeks and after 6 months. The intraclass correlations between baseline and the 2-week follow-up for the five mini-OQLQ domains ranged from 0.72 to 0.86. Cross-sectional correlations between the domains of the mini-OQLQ and other health instruments were moderate to large (0.35-0.80) and greater than predicted. The mini-OQLQ items showed moderate to large correlations with items omitted from the shortened questionnaire (0. 44-0.88). Correlations between the OQLQ domains and the other three instruments were greater than those of the mini-OQLQ, and partial correlations between OQLQ items omitted from the mini-OQLQ and the other three instruments after considering mini-OQLQ items were substantial (0.19-0.71) and statistically significant. Sample sizes of less than 200 per group should be required to detect minimally important differences in parallel-group clinical trials. Longitudinal correlations between the mini-OQLQ and the other measures were often significant but generally lower than predicted (0.10-0.49). The partial correlations revealed that the omitted items explained a significant portion of the longitudinal variance in each domain. We conclude that in a selected group of patients with back pain caused by vertebral fractures, the mini-OQLQ demonstrated good discriminative and adequate evaluative properties. The mini-questionnaire should be useful in clinical settings.

Aged↗
PubMed1999

Calcium and vitamin D therapy in corticosteroid-induced bone loss: what is the evidence?

Corticosteroid-induced osteoporosis (CIO) is a serious disorder that results in significant long-term morbidity. Increased bone resorption is caused by decreased Ca absorption and increased urinary Ca excretion leading to secondary hyperparathyroidsim. Calcium prophylaxis alone, when patients start corticosteroids, is associated with rapid rates of spinal bone loss and offers only partial protection from corticosteroid-induced spinal bone loss. Though calcium supplementation may have some benefit, it clearly cannot completely prevent corticosteroid-induced bone loss. At most, Ca therapy should only be considered adjunctive therapy in the treatment or prevention of corticosteroid-induced bone loss and should be administered in combination with other treatments. Earlier work demonstrated increases in forearm bone mineral density (BMD) with the use of Ca and vitamin D in patients with established CIO. However, caution should be taken when interpreting these results, since bone loss generally tapers or plateaus after the first 12 months of corticosteroid treatment; as such, any therapy might show benefit. In addition, bone density was only taken at the radius and not the spine where most of the bone loss takes place. Nonetheless, in recent trials of at least 2-year duration in which calcium and vitamin D therapy served as placebos, the result indicated that bone mass was maintained at the spine and hip throughout treatment in patients who had used chronic corticosteroids. In primary prevention trials, the amount of bone loss observed in the spine after therapy with Ca and vitamin D combinations is similar to that observed in other prevention studies in the Ca alone-treated control groups. Furthermore, Ca and vitamin D therapy appears to be less effective than other agents in the prevention of corticosteroid-induce bone loss. Although several studies do not report side effects that may be associated with Ca and vitamin D therapy, the few that do frequently report hypercalciuria. In the absence of other studies that support the use of Ca and vitamin D in the prevention of CIO, the data are too limited to generally recommend them alone as a preventative therapy. Activated vitamin D may be of greater benefit.

Adrenal Cortex Hormones↗
PubMed1999

36 month intermittent cyclical etidronate treatment in patients with established corticosteroid induced osteoporosis.

OBJECTIVE: To determine the longterm safety and efficacy of etidronate therapy in patients in whom corticosteroid induced bone loss has already occurred. METHODS: We performed a 36 month observational cohort study in which all data were obtained from Canadian Database of Osteoporosis and Osteopenia (CANDOO) patients. The etidronate group consisted of 24 patients who received 400 mg of etidronate disodium for 14 days, followed by 76 days of calcium carbonate (500 mg of elemental calcium), repeated every 3 mo; the control group included 37 patients who received calcium carbonate 500 to 1000 mg daily. Outcome measurements included changes within groups from baseline and differences between groups in the bone mineral density (BMD) of the lumbar spine, femoral neck, and trochanter at 12, 24, and 36 months. The incidence of vertebral fractures was also determined. RESULTS: Etidronate therapy resulted in a meaningful percentage increase from baseline in lumbar spine BMD, primarily during the first 24 months of treatment, and this increase was sustained for the remainder of the 36 month study period (5.2%; p = 0.016). Analysis of covariance revealed a significant percentage difference (SD) between groups in lumbar spine BMD at 12 [5.5 (13.5) percent; p = 0.003] and 24 months [6.0 (17.4) percent; p = 0.011] in favor of the etidronate group. After 3 years of therapy, one patient (4%) experienced one vertebral fracture in the etidronate group, whereas 3 patients (8%) experienced 5 vertebral fractures in the control group. CONCLUSION: Etidronate treatment administered for 36 months reversed lumbar spine bone loss, and appeared to be safe in patients with established corticosteroid induced osteoporosis.

Adrenal Cortex Hormones↗
PubMed1998

A conformal index (COIN) to evaluate implant quality and dose specification in brachytherapy.

PURPOSE: To propose a new index (COIN) that can be easily understood and computed to assess high dose rate (HDR) brachytherapy interstitial implant quality and dose specification and is an improvement on existing indexes. METHODS AND MATERIALS: The COIN index is based on an extension of dose-volume histograms and employs an analogous concept to that of cost-benefit analysis, which has already been applied to quality-of-life assessments for two alternative treatment protocols. The COIN index calculation methodology is shown for two cases: with and without critical structures. An analysis is given of dose distributions for two planning treatment volumes (PTV) of simple geometrical shape, applying both the rules of the Paris system and that of the "Offenbach" system. 40 patients who have received interstitial implants form the clinical material. With current HDR brachytherapy technology both for dose delivery, using remote afterloaders, and for three-dimensional (3D) treatment planning, it is now possible to relatively easily plan conformal brachytherapy treatments that would have been impossible with manual afterloading techniques and two-dimensional (2D) treatment planning. RESULTS: Examples of the use of the COIN index are presented for experimental and clinical data. CONCLUSIONS: The results show that COIN is a useful and practical index to improve the quality of treatment of interstitial brachytherapy implants. Further work will be undertaken with a larger population of implanted cancer patients and a subdivision of the results by treatment site.

Algorithms↗
PubMed1997

Fluoride therapy in prevention of rheumatoid arthritis induced bone loss.

OBJECTIVE: To determine the efficacy of sodium fluoride (40 mg/day) in preventing rheumatoid arthritis (RA) induced bone loss, which may lead to osteoporosis. METHODS: We conducted an 18 month, randomized, double blind, placebo controlled trial in 38 patients with RA. The primary outcome measure was the difference in the percentage change between groups in lumbar spine bone mineral density (BMD) from baseline values after 18 months of therapy. The secondary outcome measures were the differences in the percentage change between groups in femoral neck, Ward's triangle, trochanter, and total body BMD from baseline after 18 months of therapy. RESULTS: There was a significant percentage difference (SD) between groups of 6.2% (7.3%) (p = 0.0005) in lumbar spine BMD after 18 months of treatment in favor of the fluoride group. The fluoride group experienced a 5.2% (8.4%) (p = 0.0125) increase, whereas the placebo group showed a 1.0% (4.8%) (p = 0.8015) decrease in lumbar spine BMD after treatment. No significant differences were found for the femoral neck, Ward's triangle, trochanter, and total body BMD in terms of the percentage changes from baseline within each treatment group or in the differences in the degree of change between groups after therapy. Lumbar spine BMD increased in about 80% of patients treated with fluoride (responders) compared to 44% of patients treated with placebo. CONCLUSION: The results showed that fluoride therapy was well tolerated and increased vertebral bone mass in patients with RA.

Administration, Oral↗
PubMedDate not supplied

First-line chemotherapy with fluorouracil-epirubicin-navelbine (FEN) combination in advanced breast cancer.

BACKGROUND: A phase II study was carried out to determine the safety and efficacy of the combination of vinorelbine, epirubicin and 5-fluorouracil (FEN) as first-line chemotherapy in advanced breast cancer (BC). PATIENTS AND METHODS: Thirty-four women with advanced BC, aged 32-75 years (median 59), previously untreated for recurrence, were enrolled in the study. The treatment consisted of fluorouracil 600 mg/m2 on day 1, epirubicin 75 mg/m2 on day 1 and vinorelbine 25 mg/m2 on days 1 and 8, every 3 weeks, up to a maximum of 9 cycles. RESULTS: The efficacy appeared favourable with 18 objective responses (3 complete and 15 partial) and 9 disease stabilizations, giving an overall response rate of 53% (95% CI: 36-70). The median progression-free and overall survival was 6 and 18 months, respectively (95% CI: 4.8-7.8 and 16.2-22.2, respectively). Toxicity was acceptable; the main grade 3/4 toxicity was alopecia in 94% of patients, neutropenia in 44% and less frequently gastrointestinal toxicity (9%), anaemia (6%), mucositis (6%), thrombocytopenia (3%) and diarrhoea (3%). No treatment-related death occurred, CONCLUSION: Our results suggest that FEN, as first-line chemotherapy, is an active and well-tolerated treatment for patients with advanced breast cancer.

Adult↗