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Results for “Randomized trial”

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PubMed1986

Levamisole therapy in chronic type B hepatitis. Results of a double-blind randomized trial.

A double-blind, randomized, controlled trial has been undertaken to evaluate treatment of chronic hepatitis type B with levamisole. Ten patients received levamisole (150 mg/day, 3 days/wk) and 10 received placebo until seroconversion to antibody to hepatitis B e antigen eventually occurred, or for a maximum of 18 mo. Final evaluation at 24 mo after starting treatment revealed that 60% of the patients in the levamisole group had become hepatitis B e antigen negative, 90% were hepatitis B virus-deoxyribonucleic acid negative in serum, and 8 of 9 (89%) patients had cleared hepatitis B core antigen from the liver. On the other hand, in the placebo group only 4 of the 10 subjects (40%) were hepatitis B e antigen and hepatitis B virus-deoxyribonucleic acid negative in serum and 3 of 8 (37.5%) of them became hepatitis B core antigen free in the liver. Moreover, in 8 patients of the treated group and in 4 of the control cases aminotransferase activities fell into the normal range. A liver biopsy specimen was obtained after treatment in 17 patients and 7 of 9 levamisole recipients showed marked improvement in hepatic histology, compared with 3 of 8 placebo recipients. These data show that patients treated with long-term levamisole therapy have a tendency toward normalization of aminotransferase activities and suppression of hepatitis B virus replication, suggesting that the drug may be of benefit in chronic hepatitis B e antigen-positive hepatitis.

Adolescent↗

PubMed2001

Accurate in vivo dosimetry of a randomized trial of prostate cancer irradiation.

PURPOSE: To guarantee an accurate dose delivery, within +/- 2.5%, in a Phase III randomized trial of prostate cancer irradiation (68 vs. 78 Gy) by means of a comprehensive in vivo dosimetry program. METHODS AND MATERIALS: Prostate patients are generally treated in our clinic with a 3-field isocentric technique: an 8-MV anteroposterior beam and 2 18-MV wedged laterals. All fields are shaped conformally to the PTV. Patients were randomized between two dose levels of 68 Gy and 78 Gy. During treatment, the entrance and exit dose were measured for each patient with diodes. Special 2.5-mm thick steel build-up caps were applied to make the diodes appropriate for measurements in 18-MV photon beams as well. Portal images were used to verify the correct position of the diodes and to detect and correct for gas filling in the rectum that may influence the exit dose reading. Entrance and exit dose measurements were converted to midplane dose, which was used in combination with a depth dose correction to obtain the dose at the specification point. An action level of 2.5% was applied. RESULTS: The added build-up for the diodes in the 18-MV beams resulted in correction factors that were only slightly sensitive to changes in beam setup and comparable to the corrections used in the 8-MV beams for diodes without extra build-up. The calibration factor increased almost linearly with cumulative dose: 0.7%/kGy for the 8-MV and 1.2%/kGy for the 18-MV photon beams. The introduction of average correction factors made the analysis easier, while keeping the accuracy within acceptable limits. In a period of 3 years, 225 patients were analyzed, from which 8 patients needed to be corrected. The average ratio of measured and prescribed dose was 1.009 (standard deviation [SD] 0.012) for the total group treated on two linear accelerators. When the results were analyzed per accelerator, the ratios were 1.002 (SD, 0.001) for Accelerator A and 1.015 (SD, 0.001) for Accelerator B. This difference could be attributed to the cumulative effect of three small imperfections in the performance of Accelerator B that were well within the limits of our quality assurance program. CONCLUSION: Diodes can be used for accurate in vivo dosimetry during prostate irradiation in high-energy photon beams. The dose delivery in this randomized trial is guaranteed within the 2.5% limits on an individual patient basis. This could not be achieved without the in vivo dosimetry program, despite our high-standard quality assurance program of treatment delivery.

Algorithms↗

PubMed1990

N of 1 randomized trials for investigating new drugs.

Presently, in the process of new drug development, large sample parallel group randomized trials are often begun without the detailed knowledge of optimal dose, most responsive patient group, and optimal outcomes which would be desirable. We propose that randomized trials in individual subjects (N of 1 RCTs) could be used to elucidate these issues at an early stage of drug development. In appropriate conditions N of 1 RCTs can be used to define the rapidity with which a drug begins and ceases its clinical action, the likely range of the optimal drug dose, and the optimal outcomes on which subsequent trials should focus. N of 1 RCTs can also generate initial estimates of the proportion of patients who respond to a new agent and for determining sample size, inclusion criteria, and dosage regimen(s) for subsequent parallel group trials. We provide an example of 14 N of 1 RCTs of amitriptyline in fibrositis that illustrate the ways in which N of 1 RCTs can elucidate these issues. The multiple uses of N of 1 RCTs suggest that the method has immense potential for use in the early phases of drug development programs.

Amitriptyline↗

PubMed2003

Off-pump versus on-pump coronary artery bypass: meta-analysis of currently available randomized trials.

BACKGROUND: Off-pump coronary artery bypass (OPCAB) challenges the conventional on-pump coronary artery bypass grafting (CABG) as the standard of surgical therapy for coronary disease. The aim of this study is to assess the differences in clinical outcomes between CABG and OPCAB by meta-analysis of data published in randomized trials. METHODS: A literature search (Medline, Pubmed, Cochrane Controlled Trials Register, and the Cochrane Medical Editors Trial Amnesty of unpublished clinical trials) was done for the period starting from January 1990 until May 2002 and was supplemented with a manual bibliographic review for all peer-reviewed English language publications. A systematic overview (meta-analysis) of the randomized trials was done to define the risk of the composite end point (death, stroke, or myocardial infarction) in CABG versus OPCAB. RESULTS: A literature search yielded nine comparable randomized studies, for a total of 1090 patients, of whom 558 and 532 were randomly assigned to CABG and OPCAB, respectively. Meta-analysis of these studies showed a trend, albeit not statistically significant, toward reduction in the risk of the composite end point for patients who had OPCAB (odds ratio 0.48; 95% confidence interval 0.21 to 1.09; p = 0.08). CONCLUSIONS: Cumulative analysis of the few prospective randomized studies currently available found a potential clinical benefit of OPCAB, indicating that the avoidance of extracorporeal circulation might result in improved clinical outcomes. Further evidence, however, from large randomized trials is needed to assess potential advantages of OPCAB in terms of early outcomes.

Aged↗

PubMed2005

Increasing the degrees of freedom in existing group randomized trials: the df* approach.

This study describes a method for incorporating external estimates of intraclass correlation to improve the precision for the analysis of an existing group-randomized trial. The authors use a random-effects meta-analytic approach to pool the information across studies, which takes into account any interstudy heterogeneity that may exist. This approach can be used in several different situations to estimate the degrees of freedom available for an adjusted test of the intervention effect in a study where the challenges of group-randomized trials were not fully considered when the study was planned. The authors discuss the limitations of this approach and the circumstances in which it is likely to be helpful.

Humans↗

PubMed2003

Factors associated with failure to publish large randomized trials presented at an oncology meeting.

CONTEXT: Large clinical trials are the criterion standard for making treatment decisions, and nonpublication of the results of such trials can lead to bias in the literature and contribute to inappropriate medical decisions. OBJECTIVES: To determine the rate of full publication of large randomized trials presented at annual meetings of the American Society of Clinical Oncology (ASCO), quantify bias against publishing nonsignificant results, and identify factors associated with time to publication. DESIGN: Survey of 510 abstracts from large (sample size, > or =200), phase 3, randomized controlled trials presented at ASCO meetings between 1989 and 1998. Trial results were classified as significant (P< or =.05 for the primary outcome measure) or nonsignificant (P>.05 or not reported), and the type of presentation and sponsorship were identified. Subsequent full publication was identified using a search of MEDLINE and EMBASE, completed November 1, 2001; the search was updated in November 2002, using the Cochrane Register of Controlled Trials. Authors were contacted if the searches did not find evidence of publication. MAIN OUTCOME MEASURES: Publication rate at 5 years; time from presentation to full publication. RESULTS: Of 510 randomized trials, 26% were not published in full within 5 years after presentation at the meeting. Eighty-one percent of the studies with significant results had been published by this time compared with 68% of the studies with nonsignificant results (P<.001). Studies with oral or plenary presentation were published sooner than those not presented (P =.002), and studies with pharmaceutical sponsorship were published sooner than studies with cooperative group sponsorship or studies for which sponsorship was not specified (P =.02). These factors remained significant in a multivariable model. The most frequent reason cited by authors for not publishing was lack of time, funds, or other resources. CONCLUSIONS: A substantial number of large phase 3 trials presented at an international oncology meeting remain unpublished 5 years after presentation. Bias against publishing nonsignificant results is a problem even for large randomized trials. Nonpublication breaks the contract that investigators make with trial participants, funding agencies, and ethics boards.

Bias↗

PubMed2003

Feasibility of a randomized trial on adjuvant radio-iodine therapy in differentiated thyroid cancer.

BACKGROUND: Justification for adjuvant radio-iodine (I-131) therapy in differentiated thyroid cancer (DTC) is purely based on retrospective data. This is true for ablative therapy and even more so for high-dosage adjuvant schedules. Randomized trials on the latter application are considered impossible due to anticipated formidable sample sizes required in a disease with an overall excellent prognosis like DTC. OBJECTIVE: To develop and validate a model that could stratify for risk of recurrence, rather than survival, as is usually done in prognostic indices, and secondly, to use this model to estimate the sample size required for a randomized trial. DESIGN, PATIENTS AND RESULTS: From databases of three large Dutch centres, we identified 342 consecutive patients without known residual DTC after (near-) total thyroidectomy. Using Cox proportional hazards analysis, a model was validated that clearly distinguished risk categories of recurrence using commonly available baseline variables. The model included age, N stage at presentation and T stage in papillary carcinoma. According to this stratification, a subset of patients at substantial risk for relapse (30-40%) was identified. They could be eligible for a trial assessing the impact of high-dose adjuvant I-131 on recurrence rates. Assuming a clinically relevant effect of 30% reduction of relapses, 290 patients would have to be entered in either arm (alpha 0.05, power 80%). CONCLUSION: We conclude that even though a randomized trial on this issue will be difficult to design and conduct, sample size is not the main problem.

Adult↗

PubMed2001

Extending the CONSORT statement to cluster randomized trials: for discussion.

The need for clear reporting of randomized controlled trials has been emphasized recently. The CONSORT Statement has made evidence-based suggestions for a checklist and a patient flow diagram. Adapting this for cluster randomized controlled trials presents particular challenges. Simple changes in the checklist and diagram for the completely randomized two level cluster randomized trials are suggested for discussion. An example taken from an unpublished trial demonstrates that these changes are less simple to implement, although extensions to electronic publications may be helpful. These suggestions should be formally evaluated. Further work is required to consider the cases of more levels and of stratified or pair-matched cluster randomized trials.

Cluster Analysis↗

PubMed1989

Chinese herb "destagnation" series I: Combination of radiation with destagnation in the treatment of nasopharyngeal carcinoma (NPC): a prospective randomized trial on 188 cases.

The results of a prospective randomized trial on 188 patients with NPC is reported to evaluate the validity of Chinese herbal medicine-Destagnation combined with radiotherapy. Ninety patients were allotted to the Destagnation group (radiation plus Destagnation) and 98, to the control group (radiation only). The 5-year success rate (number surviving minus number recurred but salvaged by re-treatment) of the Destagnation group is 53% (48/90) in comparison to 37% (36/98) of the control group (p less than 0.05). Minor complications of Destagnation included occasional anorexia and frequency of bowel movement. The reduced rate of local recurrence at the primary site in the Destagnation group (14%-13/90) as compared to that of the control group (29%-28/98) (p less than 0.05) suggests that Destagnation may be a radiosensitizer. The similar metastatic rates in both groups; 21% (19/90) in the Destagnation group and 21% (21/98) in the control group may refute the belief that Destagnation enhances hematogenous spread.

Adult↗

PubMed1993

Randomized trial of drainage of colorectal anastomosis.

A prospective randomized trial was carried out to determine whether use of a high-pressure closed-suction intraperitoneal drain was associated with a reduction in morbidity rate after colorectal resection and to examine the influence of drainage on postoperative fluid collections. A consecutive series of 148 patients who underwent colonic or colorectal resection were randomized to receive no drain (n = 51) or a high-pressure closed-suction drain for either 3 (n = 47) or 7 (n = 47) days. Three patients were excluded. All patients underwent abdominal ultrasonography on days 3 and 7 and those undergoing left-sided colorectal resection (n = 96) received a water-soluble contrast enema on day 7. The three groups of patients were similar in age, sex, diagnosis and the numbers of sutured and stapled anastomoses. The presence of a drain did not influence the postoperative morbidity or mortality rate. If the anastomosis leaked, neither faeces nor pus emerged from the drain. Ultrasonographic detection of a fluid collection was of no value: such collections bore no relationship to radiological or clinical leaks or the postoperative course. Routine use of a high-pressure suction drain after colorectal resection appears to be unnecessary.

Aged↗

PubMedDate not supplied

Statistical reanalysis of four recent randomized trials of acupuncture for pain using analysis of covariance.

OBJECTIVES: Acupuncture has been promoted for the treatment of chronic pain. Though many randomized trials have been conducted, these have been criticized for deficiencies of methodology, acupuncture technique, and sample size. Somewhat less emphasis has been placed on methods of statistical analysis. This paper describes 4 recent randomized trials of acupuncture for musculoskeletal or headache pain. Each trial used statistical methods that did not adjust for baseline pain scores and were thus of suboptimal power. The objective of this study is to reanalyze the trials using analysis of covariance (ANCOVA). METHODS: Raw data for the 4 trials were obtained from the original authors. Data were reanalyzed by ANCOVA. RESULTS: For 2 trials--acupuncture versus placebo for chronic headache and acupuncture versus transcutaneous electric nerve stimulation for back pain--reanalysis did not change the conclusion of no difference between groups, but showed that clinically significant differences between groups could not ruled out. Reanalysis of a trial of acupuncture versus placebo for shoulder pain slightly strengthened the evidence of acupuncture effectiveness. Reanalysis of the fourth trial, which compared acupuncture to placebo acupuncture and massage for neck pain, reversed the results of the original paper: reanalysis found acupuncture to be effective and that its effectiveness could not be ascribed to a placebo effect. DISCUSSION: Future trials of acupuncture and other modalities for pain should use efficient statistical methods. ANCOVA is more efficient than unadjusted analysis where used appropriately.

Acupuncture↗

PubMed2003

Phase III multicenter randomized trial of amifostine as cytoprotectant in first-line chemotherapy in ovarian cancer patients.

BACKGROUND: A phase III multicenter randomized trial has been designed in order to address whether amifostine (WR-2721, Ethyol), an organic thiophosphate cytoprotector, can protect ovarian cancer patients from toxicity induced by carboplatin-paclitaxel chemotherapy. PATIENTS AND METHODS: Patients were randomly assigned to receive carboplatin [area under the curve (AUC) 5 mg.min/ml] and paclitaxel (175 mg/m(2)) with (arm A) or without (arm B) amifostine (910 mg/m(2)) every 21 days for six cycles. RESULTS: One-hundred and eighty-seven patients were accrued: 93 patients in arm A and 94 patients in arm B. There was no difference in terms of erythrocytopenia between the two arms; grade 3-4 thrombocytopenia was higher in arm A (3.3% versus 0.6%; P = 0.0010). There was no significant reduction of grade 3-4 leukopenia in arm A (11.8% versus 13.8%). The incidence of grade 3-4 neutropenia was lower in arm A (31.3% versus 37.9%; P = 0.03), as was the incidence of severe mucositis (4.7% versus 15.4% in arm A versus arm B, respectively; P <0.0001). Finally, amifostine appears to be protective against neurotoxicity (grade 3-4 neurotoxicity 3.7% versus 7.2%; P = 0.02). With a median follow-up of 24 months (range 2-41), time to progression was similar between the two groups. CONCLUSIONS: We showed that amifostine can exert some protection from the cumulative toxicity associated with this regimen. The results need to be confirmed in other randomized trials with this combination.

Adult↗

PubMed1994

Received dose-intensity: a randomized trial of weekly chemotherapy with and without granulocyte colony-stimulating factor in small-cell lung cancer.

PURPOSE: A prospective randomized trial to determine if granulocyte colony-stimulating factor (G-CSF) could increase the received dose-intensity (RDI) of weekly chemotherapy in patients with small-cell lung cancer (SCLC). PATIENTS AND METHODS: Forty patients with SCLC with good prognostic features (all patients with limited disease [LD], and extensive-disease [ED] patients with Eastern Cooperative Oncology Group [ECOG] 0 or 1 and plasma alkaline phosphatase levels < 1.5 times the upper limit of normal) were randomized to receive weekly chemotherapy with or without G-CSF. G-CSF (5 micrograms/kg) was self-administered subcutaneously on days when chemotherapy was not given. Chemotherapy consisted of cisplatin 50 mg/m2 intravenously (IV) on day 1 and etoposide 75 mg/m2 IV on days 1 and 2 alternating weekly with ifosfamide 2 g/m2 IV (with mesna) and doxorubicin 25 mg/m2 on day 1, for a total of 12 courses. Dose modifications (dose reductions and treatment delays) were made according to defined hematologic criteria. RESULTS: Dose reductions were made at some point during treatment in 12 of 17 patients in the control arm and in 11 of 23 patients in the G-CSF arm (P = .20). The proportion of patients experiencing dose reductions due to leukopenia was significantly higher in the control arm (nine of 17) compared with the G-CSF arm (four of 23, P < .04). Cycle delays due to leukopenia were similar in both arms of the study. The RDI was 82% of projected in the control arm (95% confidence interval [CI], 79% to 84%) and 84% in patients receiving G-CSF (95% CI, 82% to 87%) (P value not significant). CONCLUSION: In this randomized trial, G-CSF significantly decreased dose reductions due to neutropenia. However, administration of G-CSF did not decrease dose reductions or treatment delays to a level that would allow an increase in received dose-intensity. Nonhematologic toxicities such as increased creatinine concentration also prevented an increase in the RDI in the G-CSF arm.

Adult↗

PubMed1993

Are borderline tumors of the ovary overtreated both surgically and systemically? A review of four prospective randomized trials including 253 patients with borderline tumors.

The optimal treatment of early-stage ovarian borderline tumors is controversial. Only a few randomized trials evaluating adjuvant treatment for this disease have been published. Between 1970 and 1988 four consecutive randomized trials, including patients with ovarian borderline tumors, were conducted at the Norwegian Radium Hospital. After surgery, 253 stage I-II borderline tumors without residual disease were randomly allocated to these protocols. The adjuvant treatment in the four trials consisted of [1] external irradiation (Ext) combined with intraperitoneal instillation of radioactive gold (198Au) or Ext alone, [2] intraperitoneal radioactive therapy followed by thio-TEPA or no further treatment, [3] thio-TEPA or no adjuvant therapy, and [4] cisplatin or 32P treatment. The patients were equally distributed according to prognostic variables within the eight randomization groups. The overall corrected and crude survival were 99 and 94%, respectively. In 83% of the patients a hysterectomy, bilateral salpingo-oophorectomy, and omentectomy was performed. None of the patients with less extensive surgery relapsed. Adjuvant therapy did not seem to improve the overall corrected survival. On the contrary, toxicity was added with small bowel complications after radiation therapy, neurotoxicity after cisplatin treatment, and bone marrow toxicity after thio-TEPA therapy. It is concluded that stage I borderline tumors should not receive any adjuvant treatment.

Adult↗

PubMed1994

Randomized trials of directional coronary atherectomy: implications for clinical practice and future investigation.

OBJECTIVES: This study compared and contrasted the randomized trials of directional atherectomy and coronary angioplasty for de novo native coronary artery lesions. BACKGROUND: The results of two randomized trials, the Coronary Angioplasty Versus Excisional Atherectomy Trial (CAVEAT) and the Canadian Coronary Atherectomy Trial (CCAT), comparing initial and intermediate-term outcome of directional coronary atherectomy and conventional coronary angioplasty in de novo native vessels, have been reported. In CAVEAT any coronary artery segment that could be treated by either technique was included; in CCAT only nonostial proximal left anterior descending coronary artery stenoses were studied. METHODS: The primary end point was 6-month angiographic restenosis. Clinical outcome end points at 6 months included death, myocardial infarction, emergency bypass surgery and abrupt closure. RESULTS: Initial angiographic success rates were significantly improved with directional coronary atherectomy compared with conventional angioplasty (89% vs. 80% for CAVEAT; 98% vs. 91% for CCAT). Also, the initial improvement in minimal lumen diameter and final immediate postprocedural residual diameter stenosis were better with atherectomy. In CCAT, there was no difference in initial complications; in CAVEAT, non-Q wave myocardial infarction rates and abrupt closure were increased with atherectomy. Despite improved success rates and better lumen achieved with atherectomy, in CCAT there was no difference in angiographic restenosis (46% for directional atherectomy vs. 43% for angioplasty). In CAVEAT, in a prespecified subset analysis involving the proximal left anterior descending coronary artery, restenosis was both significantly and clinically less for directional atherectomy (51% vs. 63%). For non-left anterior descending coronary artery segments, there was no difference. CONCLUSIONS: These studies document the difference between achievement of an excellent initial angiographic result and the longer term issue of clinical restenosis. Widespread use of directional coronary atherectomy to treat lesions that would be well treated by angioplasty in an attempt to decrease restenosis rates substantially does not appear indicated by the data. In individual lesions, directional atherectomy should be selected with the view toward optimizing initial results. Further trials are needed to determine whether more aggressive or better targeted directional coronary atherectomy may improve not only the initial gain but the long-term outcome as well.

Angioplasty, Balloon, Coronary↗

PubMed1990

Computerized tabulation of cine coronary angiograms. Its implication for results of randomized trials.

The quality of cine angiography is excellent in our days, and as a consequence some of the pitfalls encountered in previous randomized trials are not currently present. An example can be found in the CASS analysis of the reproducibility of coronary arteriographic reading by the Quality Control Committee Sessions: "There is an indication that different clinics" involved in the CASS trial "can reduce the variability between their readings by concerted effort to improve both the quality and the completeness of the angiographic examination." The introduction of electronic calipers to judge the severity of the obstruction can eliminate human errors. The computerized protocol has the disadvantage that it takes longer to tabulate cine coronary angiography and it will depend on its pattern, but it certainly will not be as long as filling in the CASS protocol. However, this effort is justified because it will enrich our knowledge of coronary arteriosclerosis. As a result, patients will be divided into proximal (1, 2, 12, 13, and 19), middle (mainly, 3, 14, and 20), and distal (remainder) segments. Sometimes midsegments can be important. For example, in the report from CASS related to the left main equivalent lesions, the 5-year survival rate was 48% if the obstruction on the left anterior descending was proximal and increased to 71% if it was more distal. Several randomized studies to compare PTCA with CABG as suggested by Gruentzig et al in 1979 are underway, and it is hoped that the data will be properly analyzed. However, if cine coronary angiography and the status of the left ventricle are not carefully tabulated (classification of patients into left main trunk or one-, two-, or three-vessel disease is not sufficient), the results of the randomized trials comparing PTCA with CABG will add more confusion instead of clarifying proper therapeutic implications.

Angioplasty, Balloon, Coronary↗

PubMed2005

Parametric versus non-parametric statistics in the analysis of randomized trials with non-normally distributed data.

BACKGROUND: It has generally been argued that parametric statistics should not be applied to data with non-normal distributions. Empirical research has demonstrated that Mann-Whitney generally has greater power than the t-test unless data are sampled from the normal. In the case of randomized trials, we are typically interested in how an endpoint, such as blood pressure or pain, changes following treatment. Such trials should be analyzed using ANCOVA, rather than t-test. The objectives of this study were: a) to compare the relative power of Mann-Whitney and ANCOVA; b) to determine whether ANCOVA provides an unbiased estimate for the difference between groups; c) to investigate the distribution of change scores between repeat assessments of a non-normally distributed variable. METHODS: Polynomials were developed to simulate five archetypal non-normal distributions for baseline and post-treatment scores in a randomized trial. Simulation studies compared the power of Mann-Whitney and ANCOVA for analyzing each distribution, varying sample size, correlation and type of treatment effect (ratio or shift). RESULTS: Change between skewed baseline and post-treatment data tended towards a normal distribution. ANCOVA was generally superior to Mann-Whitney in most situations, especially where log-transformed data were entered into the model. The estimate of the treatment effect from ANCOVA was not importantly biased. CONCLUSION: ANCOVA is the preferred method of analyzing randomized trials with baseline and post-treatment measures. In certain extreme cases, ANCOVA is less powerful than Mann-Whitney. Notably, in these cases, the estimate of treatment effect provided by ANCOVA is of questionable interpretability.

Analysis of Variance↗

PubMed1990

Randomized trial comparing single dose versus fractionated irradiation for prevention of heterotopic bone: a preliminary report.

Radiation therapy has been shown to prevent heterotopic bone formation in high risk patients undergoing total hip replacement. A number of doses have been used without a randomized trial comparing one dose regimen against another. A prospective randomized trial was undertaken comparing 10 Gy in 5 fractions versus 8 Gy in 1 fraction. Forty-seven patients have been randomized at the time of this evaluation with 37 patients eligible for analysis. The pre-operative, immediate post-operative and 2 month post-operative radiographs were graded. At the time of this analysis, 17 patients were randomized to the 8 Gy arm with 20 patients in the 10 Gy arm. Patients were treated with limited fields so as to only cover the area at risk for development of heterotopic bone to prevent adverse effects on biologic fixation of uncemented implants. When comparing the pre-operative, operative, and 2 month post-operative radiographs, only four patients (1 patient in the 8 Gy arm and 3 patients in the 10 Gy arm), had an increase in the score. No patient had an increase in score to a clinically significant level, usually grade 3 or 4. These preliminary results appear to show that 8 Gy in a single fraction can be as effective as 10 Gy in 5 fractions in preventing heterotopic bone in susceptible individuals. Further follow-up of the remaining patients may confirm this.

Female↗