SEARCH · Search PubMed

Results for “multicenter”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 181 records · Page 10Linked to original sources

PubMed2006

Accreditation and quality assurance for Radiation Therapy Oncology Group: Multicenter clinical trials using Stereotactic Body Radiation Therapy in lung cancer.

Starting in 2002, the Radiation Therapy Oncology Group in North America began the process of developing multicenter prospective trials in lung cancer using Stereotactic Body Radiation Therapy (SBRT). Much of the work was based on the prospective single institution trials from Indiana University that had been presented and published. In late 2004, RTOG 0236 using SBRT for medically inoperable patients with clinical stage I non-small cell lung cancer (NSCLC) was activated for accrual. Prior to activation, representatives from the Lung, Image-Guided Therapy, Physics, and Radiobiology Committees met on regular occasions to design the multicenter study and quality assurance measures. SBRT is not a black box, and the essence of the therapy had to be distilled via guidelines. Issues related to patient selection, method of dosimetry construction, equipment requirements, motion assessments and control, site accreditation, data exchange, and follow-up policies were worked out by compromise and consensus. RTOG 0236 has nearly completed its accrual. The Lung Committee has initiated the development of several other trials, each building on the last, to investigate the therapy in central tumors, in combinations with systemic therapy, in operable patients, and in lung metastases patients. The guidelines developed for RTOG 0236 will be refined to take advantage of more modern innovations including heterogeneity corrections and intensity modulation when appropriate. The development of RTOG 0618 using SBRT in operable patients with early stage NSCLC is a testament to both the enthusiasm from already published works and prospective multicenter clinical testing using SBRT techniques.

Accreditation↗

PubMed2001

Variability among institutional review boards' decisions within the context of a multicenter trial.

BACKGROUND: Institutional review boards (IRBs) are given discretion to interpret and apply the federal regulations governing the protection of human subjects in research. OBJECTIVE: To determine the extent of the variability among different IRBs on their approved research practices and informed consent forms within the context of a multicenter trial that used a common protocol. DESIGN: Descriptive analysis of survey information and informed consent forms. SETTING AND PARTICIPANTS: Sixteen IRBs from the institutions participating in a multicenter trial comparing lower vs. traditional tidal volume ventilation in patients with acute lung injury. MEASUREMENTS: Analysis of survey information on IRBs' approved research practices. Analysis of informed consent forms for the presence and the adequacy of description of each basic element of informed consent specified in the federal regulations. Reading levels of informed consent forms. MAIN RESULTS: Surveys and IRB-approved consent forms were obtained from all of the contacted IRBs (n = 16). Variability was observed among several of the research practices; one IRB waived the requirement for informed consent, five IRBs permitted telephone consent, and three IRBs allowed prisoners to be enrolled. Three consent forms contained all of the basic elements of informed consent outlined in the federal regulations, and 13 forms had varying numbers of these elements absent (six forms without one element, four without two, one without three, and two without four). Reading levels of the consent forms ranged from grades 8.2 to 13.4 (mean +/- sd was 11.6 +/- 1.2 grade level). CONCLUSIONS: Within a multicenter trial, IRBs reviewing a common protocol varied in several of their approved research practices and in the extent to which the basic elements of informed consent were included in their consent forms.

Clinical Protocols↗

PubMedDate not supplied

A multicenter clinical trial to evaluate the topical hemostatic efficacy of fibrin sealant in burn patients.

Current surgical management of deep partial-thickness and full-thickness burn wounds involves early excision and grafting. Blood loss during these procedures can be profound, thus prompting the use of topical hemostatic agents to control and minimize hemorrhage during grafting. The primary endpoint of this multicenter trial was to evaluate the efficacy of fibrin sealant as a topical hemostatic agent during skin grafting. The secondary endpoint was to obtain data to support the existing safety profile of a human fibrin sealant (FS) in participating patients as indicated by the type, severity, and frequency of any adverse events within the 24-hour postoperative period. A multicenter prospective, open label, Phase III multicenter, randomized, comparative clinical trial evaluated the use of fibrin sealant in burn patients undergoing skin graft procedures. Each patient served as his or her own control in this randomized, unblinded study of the effect on time to hemostasis in donor sites treated with the investigational FS product. At operation, 1 contiguous donor skin harvest site was bisected into 2 equal halves, 1 of which was then randomly selected and treated with fibrin sealant. At the end of the fibrin sealant application, the time to hemostasis in each of the donor site halves was identified by the operating surgeon and recorded by the research coordinator. The use of any other topical hemostatic agents was prohibited. A significant difference (P < .001) was demonstrated in the mean time to hemostasis between the fibrin sealant treated donor sites when compared painwise to the control sites. The significant difference was consistent across the 6 participating study centers. There were no adverse events associated with the use of fibrin sealant. The investigational FS product was shown to be efficacious, because it significantly decreases the time to hemostasis at the donor skin harvest site in patients undergoing skin grafting and was noted not to cause any adverse reactions.

Administration, Topical↗

PubMed1998

Centralized echocardiogram quality control in a multicenter study of regression of left ventricular hypertrophy in hypertension.

OBJECTIVE: To test the feasibility and utility of instituting centralized echocardiographic quality control during a multicenter study of regression of left ventricular hypertrophy in hypertension. DESIGN AND METHODS: The LIVE (Left Ventricular Hypertrophy: Indapamide Versus Enalapril) study is an ongoing multicenter, double-blind, controlled study of regression of echocardiographic left ventricular mass index in hypertensive patients with left ventricular hypertrophy (left ventricular mass indexes > 100 g/m2 for women and > 120 g/m2 for men) treated for 1 year with 1.5 mg indapamide sustained-release coated tablets versus 20 mg enalapril. A centralized evaluation committee has validated a prestudy sample echocardiogram from each center, and is now reviewing all videotapes recorded during this study for quality control; final results will be based on a further randomized blinded analysis by this centralized evaluation committee. RESULTS: Since December 1994, 878 patients have been preselected (videoechocardiographic recordings sent for assessment), 645 selected (videoechocardiographic recordings validated), and 576 randomly allocated to treatment. After preliminary quality control, 27% (233) of baseline echocardiograms were rejected by our centralized evaluation committee, and 22% (142) of postinclusion echocardiographic measurements had to be repeated, mainly because they were of poor echogenic quality. Analysis of approved baseline echocardiograms for the first 274 randomly allocated patients with digitized data showed that there was a significant correlation between centralized evaluation committee and investigator calculations of left ventricular mass index (r = 0.76, P < 0.001), with consistently higher values for investigator calculations, independently of level of left ventricular mass index (correlation between difference and mean of investigator and centralized evaluation committee measurements, r = 0.08, P = 0.28). The mean difference was 8 +/- 20 g/m2 (P < 0.001). CONCLUSION: Early results of the LIVE study quality control showed that real-time 'live', centralized echocardiographic reading was not only feasible, but also useful for avoiding unquantifiable echocardiograms and overestimation of left ventricular mass index. Thus, real-time, centralized echocardiographic quality control should be recommended for multicenter studies of regression of left ventricular hypertrophy.

Adult↗

PubMed2005

A prospective, randomized, multicenter Food and Drug Administration investigational device exemptions study of lumbar total disc replacement with the CHARITE artificial disc versus lumbar fusion: part I: evaluation of clinical outcomes.

STUDY DESIGN: A prospective, randomized, multicenter, Food and Drug Administration-regulated Investigational Device Exemption clinical trial. OBJECTIVES: The purpose of this study was to compare the safety and effectiveness of lumbar total disc replacement, using the CHARITE artificial disc (DePuy Spine, Raynham, MA), with anterior lumbar interbody fusion, for the treatment of single-level degenerative disc disease from L4-S1 unresponsive to nonoperative treatment. SUMMARY OF BACKGROUND DATA: Reported results of lumbar total disc replacement have been favorable, but studies have been limited to retrospective case series and/or small sample sizes. METHODS: Three hundred four (304) patients were enrolled in the study at 14 centers across the United States and randomized in a 2:1 ratio to treatment with the CHARITE artificial disc or the control group, instrumented anterior lumbar interbody fusion. Data were collected pre- and perioperatively at 6 weeks and at 3, 6, 12, and 24 months following surgery. The key clinical outcome measures were a Visual Analog Scale assessing back pain, the Oswestry Disability Index questionnaire, and the SF-36 Health Survey. RESULTS: Patients in both groups improved significantly following surgery. Patients in the CHARITE artificial disc group recovered faster than patients in the control group. Patients in the CHARITE artificial disc group had lower levels of disability at every time interval from 6 weeks to 24 months, compared with the control group, with statistically lower pain and disability scores at all but the 24 month follow-up (P < 0.05). At the 24-month follow-up period, a significantly greater percentage of patients in the CHARITE artificial disc group expressed satisfaction with their treatment and would have the same treatment again, compared with the fusion group (P < 0.05). The hospital stay was significantly shorter in the CHARITE artificial disc group (P < 0.05). The complication rate was similar between both groups. CONCLUSIONS: This prospective, randomized, multicenter study demonstrated that quantitative clinical outcome measures following lumbar total disc replacement with the CHARITE artificial disc are at least equivalent to clinical outcomes with anterior lumbar interbody fusion. These results support earlier reports in the literature that total disc replacement with the CHARITE artificial disc is a safe and effective alternative to fusion for the surgical treatment of symptomatic disc degeneration in properly indicated patients. The CHARITE artificial disc group demonstrated statistically significant superiority in two major economic areas, a 1-day shorter hospitalization, and a lower rate of reoperations (5.4% compared with 9.1%). At 24 months, the investigational group had a significantly higher rate of satisfaction (73.7%) than the 53.1% rate of satisfaction in the control group (P = 0.0011). This prospective randomized multicenter study also demonstrated an increase in employment of 9.1% in the investigational group and 7.2% in the control group.

Adult↗

PubMed2001

Osseotite implant: 3-year prospective multicenter evaluation.

PURPOSE: This prospective multicenter study evaluates the cumulative success rate of the Osseotite implant after 3 years of prosthetic loading. MATERIALS AND METHODS: A total of 413 Osseotite implants (Implant Innovations) were placed in 142 patients (completely or partially edentulous) in five dental offices exclusively devoted to implants. The average age of the patients was 58.3 years. Of the 413 implants, 191 were placed in the maxilla and 222 in the mandible; 271 (65.6%) were posterior implants and 142 (34.4%) were anterior implants. Clinical and radiographic evaluations were made after completion of the prosthetic restoration, after 6 months of loading, at 1 year, and at 3 years. RESULTS: A cumulative success rate of 95.3% was obtained after 3 years of prosthetic loading. The success rate was similar in both arches: 95.1% in the maxilla and 96.8% in the mandible. Early failures (before prosthetic loading) were greater (n = 12) than late failures (n = 2). After 3 years of prosthetic loading, the marginal bone level of 385 (93.2%) implants were evaluated radiographically. Bone level was at the first thread for 91.4% of the implants. A slightly increased loss was observed around 26 implants (6.7%). Including survival implants, the cumulative implant success rate after 3 years was 96%. A success rate of 98.4% was obtained with 187 short implants (8, 5 and 10 mm) reported in this multicenter evaluation. CONCLUSION: This multicenter evaluation demonstrates excellent predictability for Osseotite implants.

Adult↗

PubMed2003

Multicenter evaluation of the VERSANT HCV RNA qualitative assay for detection of hepatitis C virus RNA.

We report the results of a multicenter evaluation of a new assay for the detection of hepatitis C virus (HCV) RNA in human serum or plasma based on transcription-mediated amplification (HCV TMA). Analysis of combined data obtained from 15 independent sites, including 4 sites in the United States and 11 in Europe, by using preproduction kits showed a limit of detection of 9.8 IU/ml and an overall mean specificity of 97.9%. In addition, assay runs and samples were valid consistently (97.8% of assay runs and 98.0% of specimen results). Of the 15 sites that participated in the multicenter evaluation, 2 subsequently carried out additional performance studies with production kits in support of the assay's registration in France. Comparison of the findings from these two sites during the multicenter evaluation and during the registration studies showed an overall improvement in assay performance. A statistically significant (P < 0.001) improvement was achieved for both specificity and specimen validity in the registration studies, which were 99.4 and 98.1%, respectively. Combined data from the two sites showed a lower limit of detection of approximately 2.4 IU/ml and an improved assay validity of 100%, although the sample size was too small to show statistical significance at the 0.05 level. In summary, the performance characteristics of HCV TMA indicate that this assay is a reliable tool for the detection of HCV RNA in serum or plasma. Improvement in assay performance has been demonstrated with refinement of assay reagents, instrumentation, and operator experience.

Genotype↗

PubMed1994

Ensuring reliability of outcome measures in multicenter clinical trials of treatments for acute ischemic stroke. The program developed for the Trial of Org 10172 in Acute Stroke Treatment (TOAST).

BACKGROUND AND PURPOSE: Ensuring the reliability and validity of outcome measures used in clinical trials is essential to the success of the trial. The Trial of Org 10172 in Acute Stroke Treatment (TOAST) is a multicenter clinical trial that is recruiting patients with acute ischemic stroke seen at medical centers across the United States. METHODS: This paper describes an approach to train physicians to use three clinical measures: the National Institutes of Health (NIH) Stroke Scale, a supplemental motor examination, and the Glasgow Outcome Scale. The program included education, certification, remediation when needed, monitoring, and reliability assessment. The goal was to ensure that interrater assessments were as equivalent to one another as possible. RESULTS: Of the first 95 clinicians who began the certification process, 75 passed during the first evaluation. Eighteen of the other physicians were able to complete the process after remediation. The intraclass correlations of both the NIH Stroke Scale and supplemental motor examination exceeded 0.95. The kappa values for the Glasgow Outcome Scale were 0.61 and 0.62 for the first and second ratings of the videotape, respectively. CONCLUSIONS: Our experience suggests that a program that includes educational and certification processes can be performed as part of the design of a multicenter clinical trial. The method of providing educational and testing videotapes to each site so that physicians can be trained and certified is an effective, inexpensive, and practical approach for enhancing and certifying the expertise of the large number of physicians involved in a multicenter study.

Brain Ischemia↗

PubMed2001

Safety and reproducibility of sputum induction in asthmatic subjects in a multicenter study.

The safety of sputum induction and the reproducibility of measurements in induced sputum in multicenter studies is unknown. We examined the safety of sputum induction in a two-visit, six-center study in 79 subjects with moderate to severe asthma (mean +/- SD FEV(1) 71 +/- 12% predicted, 67% taking inhaled corticosteroids). In addition, we compared the reproducibility of markers of inflammation in induced sputum with the reproducibility of the FEV(1) and the methacholine PC(20). The FEV(1) decreased > or = 20% from the postbronchodilator baseline in 14% of all subjects and in 25% of subjects whose initial prebronchodilator baseline was 40 to 60% of predicted. All subjects responded promptly to additional albuterol treatment, and no subject developed refractory bronchoconstriction requiring treatment other than reversal of bronchospasm in the study laboratory. The reproducibility of measurements of the eosinophil percentage, eosinophil cationic protein, tryptase, and methacholine PC(20) were similar (concordance correlation coefficients of 0.74, 0.81, 0.79, and 0.74, respectively), without any significant among-center effect. We conclude that sputum induction can be performed safely in subjects with moderate to severe asthma in multicenter clinical trials when carried out under carefully monitored conditions. Importantly, we demonstrate that measurement of markers of inflammation in induced sputum is as reproducible as methacholine PC(20) and should prove useful in the assessment of airway inflammation in multicenter clinical trials.

Aged↗

PubMed2006

Standardization and performance evaluation of mononuclear cell cytokine secretion assays in a multicenter study.

BACKGROUND: Cryopreservation of peripheral blood mononuclear cells has been used to preserve and standardize immunologic measurements for multicenter studies, however, effects of cryopreservation on cytokine responses are incompletely understood. In designing immunologic studies for a new multicenter birth cohort study of childhood asthma, we performed a series of experiments to determine the effects of two different methods of cryopreservation on the cytokine responses of cord and peripheral blood mononuclear cells. RESULTS: Paired samples of PBMC were processed freshly, or after cryopreservation in a Nalgene container (NC) or a controlled-rate freezer (CRF). Although there were some differences between the methods, cryopreservation inhibited PHA-induced IL-10 secretion and Der f 1-induced IL-2 secretion, and augmented PHA-induced IL-2 secretion and spontaneous secretion of TNF-alpha. In separate experiments, NC cryopreservation inhibited secretion of several cytokines (IL-13, IL-10, IFN-gamma, TNF-alpha) by PHA-stimulated cord blood mononuclear cells. With the exception of PHA-induced IL-13, results from fresh and cryopreserved cord blood samples were not significantly correlated. Finally, in reproducibility studies involving processing of identical cell samples in up to 4 separate laboratories, variances in cytokine responses of fresh cells stimulated at separate sites did not exceed those in cryopreserved cells stimulated at a central site. CONCLUSION: Collectively, these studies indicate that cryopreservation can affect mononuclear cell cytokine response profiles, and that IL-10 secretion and antigen-induced responses may be especially vulnerable. These studies also demonstrate that mononuclear cell responses can be standardized for performance in a small number of laboratories for multicenter studies, and underscore the importance of measuring reproducibility and of testing whether cryopreservation techniques alter specific immunologic outcomes.

Algorithms↗

PubMed2000

Pathology data in the central databases of multicenter randomized trials need to be based on pathology reports and controlled by trained quality managers.

PURPOSE: Randomized multicenter trials form the basis of health care development. Regarding cancer research, pathology data are crucial. To maintain the quality of these trials, the auditing of subsequent processes is necessary. The aim of the present study was to examine the completeness and accuracy of data obtained from a special-purpose standardized pathology form compared with the data available through traditional hospital pathology reports. PATIENTS AND METHODS: A retrospective comparison of pathology data case record forms with hospital pathology reports was performed using the data from 300 patients with primary rectal cancer. All of these patients had been included in a large multicenter trial in the Netherlands. Three independent audits were carried out. Special attention was given to the accuracy of parameters, which are important for prognosis and treatment decisions. Furthermore, various factors that possibly influence the occurrence of errors were investigated. RESULTS: Quality control of the pathology data revealed a high accuracy of 86.5% of all data items. However, only one third of the forms were complete and correct. Missing values were most prominent in the number of lymph nodes examined, whereas most errors were made in relation to the circumferential margin. Trained review pathologists made fewer major errors. Discrepancies were detected in all control rounds. CONCLUSION: Successive rounds of quality control are required for accuracy and completeness of pathology data in multicenter trials. In addition to the special-purpose pathology forms, original pathology reports have to be collected, and the data should also be controlled by a trained pathology quality manager.

Databases, Factual↗

PubMed1997

Clinical dementia rating training and reliability in multicenter studies: the Alzheimer's Disease Cooperative Study experience.

Global ratings of dementia severity are used increasingly in clinical trials of antidementia compounds. Such ratings are clinically relevant, but their reliability in multicenter settings has not been determined. To evaluate the reliability of one global scale, the Clinical Dementia Rating (CDR), 82 investigators of the multicenter Alzheimer's Disease Cooperative Study participated in a training and reliability protocol using videotaped assessments of subjects in various stages of Alzheimer's disease. Following training, overall agreement of the investigators with "gold standard" CDR scores was 83%. These results indicate that the training protocol is useful for establishing good levels of agreement in staging dementia severity and that the CDR can be standardized as a clinical global scale for multicenter studies of Alzheimer's disease.

Alzheimer Disease↗

PubMedDate not supplied

Centralized assessment of dual-energy X-ray absorptiometry (DEXA) in multicenter studies of HIV-associated lipodystrophy.

BACKGROUND: The accurate measurement of total body and subcutaneous fat is essential if therapeutic interventions, aimed at preventing or reversing lipodystrophy syndrome, are to be adequately assessed. The aim of this study was to investigate the variability of dual-energy X-ray absorptiometry (DEXA) scans analysis performed at local sites compared to central analysis in a multicenter clinical trial. METHOD: The PIILR study was a multicenter randomized clinical trial in which 80 HIV-infected patients with physician-documented lipodystrophy had serial measurements of body composition performed with Lunar DEXA scans. Scans were analyzed at local sites and then were reanalyzed centrally. RESULTS: DEXA scans from 73 patients who completed 24 weeks study were compared. Greater variation in the locally analyzed results than in the centrally reanalyzed data was noted, with arm, leg, and combined limb fat being most divergent between the local and centralized assessments (ratio of local to central standard deviation was 1.28, 1.31, and 1.35, respectively). The magnitude of this variance was enough to alter statistically relevant differences between study populations. CONCLUSION: Quality assurance is an important issue in the use of DEXA scans to determine body fat composition in multicenter research studies. A central quality assurance site should be incorporated to reduce variability in results.

Absorptiometry, Photon↗

PubMed2005

The effect of long-term storage on measured plasma lactate concentrations and prospective lactate results from a multicenter trial of antiretroviral therapy.

Plasma lactate measurements are typically performed in real time, limiting their usefulness in multicenter or longitudinal studies. To determine the stability of lactate specimens, blood was drawn in sodium fluoride/potassium oxalate tubes from 13 volunteers before and after 5 min of handgrip exercise to intentionally increase lactate concentrations. Plasma was stored at -70 degrees C. Aliquots were assayed in real time and after 1, 3, 6, 9, 12, 18, and 24 months. Real-time lactate concentrations measured at baseline ranged from 0.52 to 2.23 mmol/L before and from 2.91 to 11.04 mmol/L after handgrip exercise. Using a linear mixed model, the estimated change from baseline at month 24 was 1.67% (95% confidence interval, -0.70% to 4.03%) for pre-exercise samples and 0.39% (95% CI, -1.13% to 1.91%) for post-exercise samples. Stored serial specimens from 232 HIV-infected subjects in a multicenter trial of antiretroviral therapy were also assayed centrally. Among those, median plasma lactate increased from baseline to 64 weeks by 0.4 mmol/L with zidovudine+lamivudine treatment and by 0.6 mmol/L with didanosine+stavudine (each p<0.001 from baseline; p=0.04 for difference between groups over time). When performed as in this study, frozen storage with central batch lactate analysis is appropriate for prospectively collected samples in multicenter trials.

Acidosis, Lactic↗

PubMed1992

Conduct of multicenter trials to test agents for treatment of periodontitis.

The conduct of multicenter trials to test agents for treatment of periodontitis is conceptually similar to that of single center trials, but the requirement that centers ultimately be combined into a single result places much more stringent requirements on uniformity and control. Multicenter trials should be considered only if numbers of subjects or the ability to generalize to other treatment settings becomes a driving theme. General guidelines for the conduct of studies of this sort are suggested and problems that occur are discussed. Despite formidable difficulties that may occur, multicenter studies provide a convincing demonstration of an agent's therapeutic efficacy for the treatment of periodontitis.

Clinical Trials as Topic↗

PubMed2001

Adjustments for center in multicenter studies: an overview.

Increasingly, investigators rely on multicenter or multigroup studies to demonstrate effectiveness and generalizability. Authors too often overlook the analytic challenges in these study designs: the correlation of outcomes and exposures among patients within centers, confounding of associations by center, and effect modification of treatment or exposure across center. Correlation or clustering, resulting from the similarity of outcomes among patients within a center, requires an adjustment to confidence intervals and P values, especially in observational studies and in randomized multicenter studies in which treatment is allocated by center rather than by individual patient. Multicenter designs also warrant testing and adjustment for the potential bias of confounding by center, and for the presence of effect modification or interaction by center. This paper uses examples from the recent biomedical literature to highlight the issues and analytic options.

Bias↗

PubMed2001

Estimation of the combined response to treatment in multicenter trials.

Analyses of multicenter trials consider the estimated treatment effect differences of the individual centers and combine them into an estimate of the overall treatment effect. There has been much debate in the literature concerning the best way to combine these treatment effect differences. We emphasize that first of all one should define the combined response to treatment (CRT), the object that has to be estimated from the results of a multicenter clinical trial. It is shown that the choice of CRT determines not only the best estimator, but also the allocation of patients among the centers that minimizes the mean squared error. A new estimator of the CRT is proposed that is based on a preliminary clustering of the centers and the use of a weighted average of the Type I estimators obtained from within each cluster. The clustering aims to minimize the bias of the combined estimator. We show via a simulation study that the simple clustering procedure provides a reasonably improved estimator. The clustering can be done on blinded data, as long as the numbers of patients on each treatment arm in each center are known. The methodology is illustrated by analyzing a multicountry, multicenter trial to compare an active treatment with placebo for the treatment of a psychiatric disorder.

Algorithms↗

PubMedDate not supplied

Inhomogeneity correction in radiotherapy for lung cancer in multicenter clinical trials.

PURPOSE: Dose distribution in patients in past multicenter clinical trials was reviewed from the perspective of clinicians to evaluate the quality of treatment and to improve the quality of future clinical trials. MATERIALS AND METHODS: Thirty patients with stage III lung cancer, who had undergone radical radiation therapy in multicenter clinical trials were retrospectively reviewed. A two-dimensional treatment planning system using Clarkson integration was used to calculate correction factors at the primary lesions and at the mediastinal lymph nodes. RESULTS: Correction factors at the primary lesions ranged from 1.00 to 1.12 (mean, 1.06) and from 1.02 to 1.14 (mean, 1.06) in the AP/PA fields and in the oblique fields, respectively. The lowest values of correction factors at the mediastinal lymph nodes on the axial plane including the primary lesions ranged from 0.93 to 1.04 (mean, 0.98) and from 0.97 to 1.10 (mean, 1.02) in the AP/PA fields and in the oblique fields, respectively. In 14 patients whose primary tumor was located in the upper lung field, the correction factors at the subcarinal lymph nodes ranged from 0.90 to 1.01 (mean, 0.96) in the AP/PA fields. CONCLUSION: Delivered doses lower than those prescribed at the mediastinal lymph nodes should be taken into consideration to improve the quality of multicenter clinical trials.

Clinical Trials as Topic↗