Randomized versus historical controls for clinical trials

Effects of cerebrospinal fluid drainage in patients undergoing thoracic and thoracoabdominal aortic surgery

Cerebrospinal fluid (CSF) drainage has been reported to protect the spinal cord during surgical procedures requiring thoracic aortic cross-clamping. In 1986, CSF pressure monitoring and drainage was begun in an attempt to reduce the incidence of paraplegia associated with surgical repair of descending thoracic and thoracoabdominal aortic aneurysms (TAAA). These Group II patients (n = 50) were retrospectively compared to Group I patients (n = 49) who had undergone similar surgical procedures in the previous 3 years before CSF monitoring was introduced into this practice. Group II patients had intrathecal catheters placed for monitoring of CSF pressure and drainage of CSF to maintain the pressure < or = 15 mmHg. Seven patients (four in Group I, three in Group II) died before recovering from the anesthetic. Of the 47 patients in Group II who survived, none had clinically apparent complications such as an epidural hematoma or meningitis from the intrathecal catheter. The mean aortic cross-clamp time was 58.6 +/- 30.5 minutes (mean +/- SD) in Group I versus 65 +/- 42.6 minutes in Group II. Twenty-three patients in Group I and 16 patients in Group II had a shunt to the distal aorta. To maintain a CSF pressure of < or = 15 mmHg in Group II, an average of 46.9 +/- 6.9 mL of CSF was withdrawn. Of the 45 survivors in Group I, 4 developed a spinal cord deficit; the number of patients with spinal cord deficit in Group II was 4 out of the 47 who survived.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of protocol change in burn-care management using the Cox proportional hazards model with time-dependent covariates

Survival analysis methods are valuable for detecting intervention effects because detailed information from patient records and sensitive outcome measures are used. The burn unit at a large university hospital replaced routine bathing with total body bathing using chlorhexidine gluconate for antimicrobial effect. A Cox proportional hazards model was used to analyse time from admission until either infection with Staphylococcus aureus or discharge for 155 patients, controlling for burn severity and two time-dependent covariates: days until first wound excision and days until first administration of prophylactic antibiotics. The risk of infection was 55 per cent higher in the historical control group, although not statistically significant. There was also some indication that early wound excision may be important as an infection-control measure for burn patients.

Assessment of the efficacy and safety of antiarrhythmic therapy for chronic atrial fibrillation: observations on the role of trial design and implications of drug-related mortality

The findings in clinical trials of antiarrhythmic drug efficacy and safety are frequently difficult to compare, since study design often has an important effect on trial outcome. To explore this problem further, we compared three designs--randomized control, nonrandomized control, and uncontrolled--collectively enrolling 2415 patients in 21 trials reporting on the role of quinidine in the prevention of chronic atrial fibrillation. The proportion of patients remaining in sinus rhythm at 3, 6, and 12 months after cardioversion was calculated by means of Kaplan-Meier techniques, and the data were pooled for each trial design. For the randomized control trials the difference in the absolute percentage of patients remaining in sinus rhythm in the quinidine and control groups was 24% at each of the three follow-up intervals. Contrary to findings in the randomized control trials, the magnitude of the treatment benefit in nonrandomized trials was smaller and declined markedly over time. The percentage of patients remaining in sinus rhythm in the uncontrolled trials was intermediate to the percentages in the other two trial designs. When the data from all three trial designs were pooled, the crude mortality rate was 2.0% in quinidine-treated patients and 0.6% in control patients. Sudden cardiac death or ventricular fibrillation was the cause of death in 13 of 19 patients for whom the cause of death was known, highlighting the potential risk of quinidine-induced proarrhythmia. Although quinidine is effective in maintaining sinus rhythm, estimates of the treatment effect vary among trial types.(ABSTRACT TRUNCATED AT 250 WORDS)

Active immunotherapy with viral lysates of micrometastases following surgical removal of high risk melanoma

Patients who develop lymph node metastases from melanoma are known to be at risk of developing further recurrences from melanoma following surgical removal of lymph node metastases. The purpose of the present study was to examine whether immunization over a 2 year period with a vaccine made from vaccinia viral lysates of an allogeneic melanoma cell (VMCL), following surgical removal of lymph node metastases, would help prevent the development of distant metastases and improve survival from the disease. Eighty patients treated with VMCL alone and followed for a minimum of 5.5 years had improved survival compared to a historical control group of 151 patients and a concurrent non-randomized group of 55 patients. Similarly, the survival of 102 patients treated with VMCL + low dose cyclophosphamide for a minimum of 3.5 years was superior to that of the historical control group but not to that of the VMCL alone treated group. Improvement in survival was still evident when this was measured from the date of removal of the primary tumor. Analysis of subsets of patients showed that VMCL treatment appeared to benefit patients irrespective of the number of lymph nodes involved and whether surgery was carried out near to (synchronous metastases) or some time after removal of the primary (delayed metastases). Analysis of the effect of treatment on duration to development of distant metastases suggested that there was a lower proportion of metastases during treatment with VMCL compared to the historical control groups. Treatment with VMCL also appeared to be associated with a lower incidence of cutaneous metastases but a higher proportion of visceral (including liver) metastases. Treatment was not associated with prolongation of survival after development of distant metastases. The results from this prolonged follow-up provide further support for an apparent survival benefit from immunotherapy with VMCL and suggest that the duration to and site of distant metastases is altered by this treatment. A randomized control (Phase III) study based on these results is in progress.

Some problems related to the design and analysis of clinical trials

The evaluation of new cancer treatments requires demonstration of their efficacy in clinical trials. Many nonrandomized clinical series have suggested benefit of a new treatment compared with historical controls or with controls from other institutions that received standard treatment. Often, however, the new treatment is not found to be beneficial when evaluated in a subsequent randomized trial. The interpretation of clinical trials has been confounded by many problems, several of which were described or summarized in the writings of Raymond S. Bush: These include (a) invalid comparison of nonrandomized controls because of patient selection or stage migration, (b) inappropriate endpoints, and in particular the failure to evaluate quality of life and complications of treatment, (c) inadequate power to detect clinically meaningful differences in randomized trials, and (d) multiple comparisons and retrospective analysis used to make inappropriate conclusions from randomized trials. The present paper reviews briefly some of these methodological issues that may lead to inappropriate interpretation of clinical trials, with particular reference to trials of combined modality therapy.

Problems in assessing the technology of critical care medicine

Technology assessment is becoming increasingly important in the area of critical care due both to the explosion of technology associated with this discipline and to the realization that future demand for these health care resources will undoubtedly exceed the ability to pay. Technology assessment remains both confusing and controversial to many physicians. This review tries to address some of the confusion by reviewing the basic strategies involved in this process. From there, problems and prospects for the evaluation of critical care as a program are presented, followed by the assessment of components within the area of critical care. Finally, recommendations are made on how technology assessment could proceed in the future to best achieve the efficient provision of this service.

The Clinical Cooperative Trial. Guide to a critical approach

The growing difference with regard to academic and professional accountability between neurosurgeons and neuroscience is alarming. Controlled clinical trials continue to be the most scientifically valid method of evaluating standard treatments against the risks and benefits of medical innovations. Clinical research becomes more rewarding as neurosurgeons gain familiarity with the particulars of the structure and relevance of expertly designed clinical cooperative trials. The basic principles and the significance of biometrical essentials (research hypothesis, comparability, randomized and non-randomized trials, phases of studies and planning steps) are briefly discussed. A guide to the pertinent literature is provided.

Keynote address: a critical assessment of trials of neoadjuvant (preemptive) chemotherapy for bladder cancer: lesson for future studies of combined modality treatment

The 5-year survival of patients with invasive, clinically non-metastatic bladder cancer (Stages T2-4N2Mo) is less than 50%, whether treated by radical radiotherapy, radical cystectomy, or combinations of the two modalities. Cytotoxic regimens, incorporating single agents or combination protocols, produce objective response rates of 10-30 and 10-70%, respectively. Hence, it has been postulated that the use of cytotoxics before or with radiotherapy or surgery ("neoadjuvant", "preemptive", or "concurrent" chemotherapy) could improve the cure rate of invasive bladder cancer. Initial Phase I-II clinical trials have shown such approaches to be feasible, with mild to moderate toxicity. To date, few randomized trials that compare conventional treatment with these new approaches have been initiated or completed, with the majority of eligible patients being treated in increasingly complex Phase II studies. Accordingly, progress has been retarded, and after a decade of investigation, the true role of preemptive or concurrent chemotherapy for invasive bladder cancer is not known. Patients should be entered into well designed, randomized clinical trials in which new approaches to treatment are compared to standard therapy.

Efficacy of ibopamine in the treatment of heart failure

Loss of myocardial contractility, reflexly enhanced vasoconstriction, and neuroendocrine excitation are the pathophysiologic hallmarks of low-output heart failure. Drugs that counter both consequences afford considerable therapeutic potential in retarding and perhaps even in staying the consequences of the syndrome. Ibopamine possesses such potential through its unique ability to stimulate both dopaminergic- and beta-adrenoreceptors in the heart and circulatory system. Stimulation of dopaminergic- receptors and beta 2-adrenoreceptors results in vasodilatation in all regional vascular territories. beta 2-Adrenoreceptor agonist activity also affords mild positive inotropic activity in the heart, whereas stimulation of presynaptic dopaminergic- receptors (DA2) attenuates the increased sympathetic neural outflow. The drug also suppresses the renin-angiotensin-aldosterone system in addition to having a direct natriuretic activity. The pharmacodynamic effects of ibopamine, exerted through its metabolite epinine, are translated into measurable therapeutic benefits in patients with chronic heart failure. The increase in peripheral blood flow induced in all regional vascular territories, including the kidneys, is associated with increased cardiac output and stroke volume and reduction in left ventricular pressure work, wall stress, and myocardial oxygen consumption. Plasma norepinephrine, angiotensin, and aldosterone are also reduced, and renal sodium excretion is enhanced. These hemodynamic and neuroendocrine activities, which are not subject to tolerance during sustained administration of the drug, are accompanied by clinically significant improvement in symptoms, exercise tolerance, and the New York Heart Association classification of disability. More important, no proarrhythmic effects have been observed during sustained treatment, and the minimal side effects observed during long-term treatment enhance the safety profile of the drug.(ABSTRACT TRUNCATED AT 250 WORDS)

Developing improved observational methods for evaluating therapeutic effectiveness

Therapeutic efficacy is often studied with observational surveys of patients whose treatments were selected nonexperimentally. The results of these surveys are distrusted because of the fear that biased results occur in the absence of experimental principles, particularly randomization. The purpose of the current study was to develop and validate improved observational study designs by incorporating many of the design principles and patient assembly procedures of the randomized trial. The specific topic investigated was the prophylactic effectiveness of beta-blocker therapy after an acute myocardial infarction. To accomplish the research objective, three sets of data were compared. First, we developed a restricted cohort based on the eligibility criteria of the randomized clinical trial; second, we assembled an expanded cohort using the same design principles except for not restricting patient eligibility; and third, we used the data from the Beta Blocker Heart Attack Trial (BHAT), whose results served as the gold standard for comparison. In this research, the treatment difference in death rates for the restricted cohort and the BHAT trial was nearly identical. In contrast, the expanded cohort had a larger treatment difference than was observed in the BHAT trial. We also noted the important and largely neglected role that eligibility criteria may play in ensuring the validity of treatment comparisons and study outcomes. The new methodologic strategies we developed may improve the quality of observational studies and may be useful in assessing the efficacy of the many medical/surgical therapies that cannot be tested with randomized clinical trials.

An empirical study of the possible relation of treatment differences to quality scores in controlled randomized clinical trials

Meta-analytic investigations sometimes use assessments of research quality according to a formal protocol as a tool for improving research synthesis. We asked whether a particular quality scoring system could have a direct use in adjusting the summary estimates of a treatment difference. In an empirical study of the relation of quality scores to treatment differences in published meta-analyses of 7 groups of controlled randomized clinical trials comprising 107 primary studies, we found no relation between treatment difference and overall quality score. We also found no relation between quality score and variation in treatment difference. The level of quality scores has increased at a rate of 9% per decade for three decades, averaging 0.51 on a scale of 0 to 1 for the 1980s, and leaving much room for improvement. Nevertheless, attention to quality of studies by editors, reviewers, and authors may be raising both the level of research done and quality of the reports.

Problems in the use of large data sets to assess effectiveness

Large data sets are an attractive source of information for outcome assessment, but their use involves certain problems and risks. Data base evaluations are retrospective and unblinded; they often represent the result of multiple analyses of multiple endpoints, and it is difficult to identify the procedures used and analytic choices made because critical details are often omitted. While data bases can suggest problems and offer answers, they cannot prove them; data base analyses must be followed by trials.

Some statistical methods for combining experimental results

Advances in science and technology are generally the product of multiple investigations. This article discusses statistical methods for combining empirical results from a series of different experiments or clinical investigations. We delineate the steps an assessor might take in combining data from different studies and provide references for topics not discussed in detail. The article reviews some of the most commonly used statistical techniques for combining results in the medical and social sciences.

Combined modality treatment with radiotherapy and chemotherapy

Combined modality treatment with radiotherapy and chemotherapy is used increasingly for the primary management of a variety of human tumours, with the aim of improving both local and distant control. The present paper reviews methodological issues related to the evaluation of combined modality therapy. Reports that patients have superior outcome in single-arm studies as compared to historical controls treated with radiation alone have limited value because of several types of bias including patient selection, stage migration, the tendency to publish positive results, or inadequate follow-up as compared to the historical series. The observation that response to chemotherapy predicts for survival after combined treatment also conveys no proof that combined treatment is superior to radiation alone. Randomized controlled trials provide the only rigorous method for evaluating combined therapy, but are also subject to misinterpretation. The majority of published trials report negative results but are too small to detect clinically important differences in survival. Even large trials may give spurious results if they seek small benefits of treatment in a spectrum of patients with widely differing prognosis. Some randomized trials have demonstrated improved local control and increased toxicity from combined treatment, a result that might have been achieved by increasing the effective radiation dose. Ideally, combined treatment should be compared with radiotherapy alone at equal levels of normal tissue damage. A review of published data for patients with cancers of the head and neck, lung, gastrointestinal tract and bladder reveals very few trials which have adequately evaluated the role of combined modality therapy (with or without surgery). Most of the large randomized trials have demonstrated no benefit from the use of radiation and chemotherapy, although some of them suggest small therapeutic gains from using thoracic radiation with chemotherapy in small-cell-lung cancer of limited extent, or from combined modality treatment after resection of rectal cancer. Possible reasons for the failure of active drugs to lead to easily detected gains in therapeutic index include insufficient reduction in cell survival from chemotherapy, selective killing of radiosensitive subpopulations, stimulation of the proliferation of surviving cells, or enhancement of metastasis. With the possible exception of radiation and concurrent 5-fluorouracil for squamous cancers of the anal canal, there are no convincing data to mandate the routine combined use of radiotherapy and chemotherapy in any of the above sites.

Selection and evaluation of empirical research in technology assessment

Technology assessment involves application of the scientific method to the practice of medicine. Finding all of the assessment reports in a given field is not an easy task. Proper evaluation of those assessments requires the conduct of a prospective experiment in which the sources and results are blinded when the choice is made of papers to exclude and to include, and the process should be carried out in duplicate. There are several available data bases for carrying out the search, but because of indexing problems they should be supplemented by reference to the bibliographies of pertinent published articles. Clinical trials included in meta-analyses should be graded by quality and thus facilitate sensitivity analyses. Attention must be paid to the possibility of publication bias. Finally, the advent of meta-analysis makes it desirable to begin randomized controlled trials in areas of uncertainty, even when there is no possibility that individual investigators will encounter enough patients to draw valid conclusions.

A review of clinical research in orthodontics

The orthodontic journals should provide valid and reliable information that helps clinicians make appropriate decisions about patient care. The nature of the published literature has not been categorized. The American Journal of Orthodontics and Dentofacial Orthopedics (formerly the American Journal of Orthodontics) was reviewed for the years 1976, 1981, and 1986, to determine the frequency of clinical articles, the topics reported, the study designs used to obtain information, the senior author affiliation, and the major funding sources. This review demonstrates that more than half the articles in this Journal report data on patients, with the majority focusing on the evaluation or description of therapeutic interventions. Academic institutions contribute the majority of the clinical research, although only a few student theses are published. The major support for this work continues to be from departmental resources with little external funding. Despite the introduction of powerful research designs such as randomized clinical trials, these methods have not been widely adopted for orthodontic clinical research. The case report (study containing fewer than 10 patients with no control nor comparison group) continues to be the most frequently published format. Clinicians should become aware of the inherent weakness in the research designs generally used and recognize the limited information that can be obtained from such methods. Support for this research needs to be greatly expanded if the more powerful type of study required to provide valid and reliable clinical information is to be continued.

Beneficial effects of long-term diltiazem treatment in dilated cardiomyopathy

There is increasing evidence that chronic enhanced exogenous or endogenous catecholamine stimulation in patients with dilated cardiomyopathy may worsen hemodynamic status and prognosis. The cause of this deterioration may lie in myocellular calcium accumulation and microcirculatory disorders. In a prospective study, the calcium channel antagonist diltiazem was given to 22 patients with dilated cardiomyopathy (60 to 90 mg three times daily) in addition to conventional therapy of digitalis, diuretics and vasodilators. Twenty-five patients received the conventional therapy and served as historical controls. Eight additional patients who were not originally included in this control group received adjunctive diltiazem treatment after initially receiving conventional therapy alone. The three patient groups were similar in all hemodynamic and anamnestic features. Only patients with reduced myofibrillar volume fraction on myocardial biopsy were included in the trial, because they could be expected to show hemodynamic deterioration. The mean survival time was 29 months in the control group, whereas no patient in the diltiazem group died over a mean follow-up period of 15.4 months (p less than 0.001). Mean left ventricular ejection fraction increased from 0.34 to 0.44 (p less than 0.001) and New York Heart Association functional class improved significantly in the diltiazem group and during the diltiazem period in the crossover patients, but deteriorated in the control group. The results suggest that adjunctive diltiazem treatment in dilated cardiomyopathy has beneficial effects on mortality, hemodynamics and symptoms.

Hazards of inference: the active control investigation

A finding of no significant difference in seizure incidence and/or severity among groups of epileptic patients prospectively randomized to treatment with either a standard or experimental antiepileptic drug is often advanced as compelling proof of the latter's anticonvulsant efficacy. Regrettably, the finding of no difference does not, on its own at least, support such a conclusion. A finding of no difference between treatments has numerous explanations that have nothing whatsoever to do with the pharmacological actions of the experimental drug. To be clear, it is possible to argue that a pharmacological effect is the most plausible explanation for a finding of no difference in an active control study, but this argument is only supportable if it is based on additional information gathered from sources external to the study. In most circumstances, the essential external evidence is not available, and the interpretation of the null difference as a positive result turns entirely upon the truth or falsity of the sanguine assumptions made. There is a risk in inferring efficacy from the seemingly consistent results of a series of active control studies that fail to find differences. Despite the long-recognized deficiencies in the active control study design, it remains popular.

An ethical problem concerning recent therapeutic research on breast cancer

The surgical treatment of breast cancer has changed in recent years. Analysis of the research that led to these changes yields apparently good arguments for all of the following: (1) The research yielded very great benefits for women. (2) There was no other way of obtaining these benefits. (3) This research violated the fundamental rights of the women who were research subjects. This sets a problem for ethics at many levels.

Improvement in regional wall motion after percutaneous transluminal coronary angioplasty during acute myocardial infarction: utility of two-dimensional echocardiography

In the setting of acute myocardial infarction, 16 patients undergoing successful coronary angioplasty (PTCA) within 6 hours of presentation (group I) and eight patients receiving conventional medical therapy (group II) were studied by serial two-dimensional (2D) echocardiography to assess the functional recovery of myocardium. All patients underwent 2D echocardiograms within 24 hours of presentation and at a minimum of 6 days after admission. Wall motion analysis was quantified with a wall motion score index based on 16 left ventricular wall segments. Wall motion score index improved significantly from early to late echocardiographic study in the patients undergoing PTCA (1.65 +/- 0.29 to 1.40 +/- 0.30; p less than 0.001), whereas the index did not improve in the conventionally treated group (1.54 +/- 0.26 to 1.58 +/- 0.25; p = NS). One patient in group II had a greater than or equal to 10% improvement in wall motion score index compared to 11 of 16 in group I (p less than 0.01). In all cases improvement in wall motion score index was due to improvement in regional wall motion in the area of infarction. In group I, 40 of 77 (52%) infarct zone segments showed improvement of at least one grade, versus 4 of 28 (14%) segments in group II (p less than 0.001). These data indicate that regional myocardial function improves in the majority of patients undergoing successful PTCA as emergency therapy for acute myocardial infarction and that serial 2D echocardiography is an excellent means to quantify this improvement.

A randomized, double-blind, placebo-controlled trial of transfer factor as adjuvant therapy for malignant melanoma

One hundred and sixty-eight evaluable patients participated in a randomized, double-blind study of transfer factor (TF) versus placebo as surgical adjuvant therapy of Stage I and Stage II malignant melanoma. Eighty-five patients received TF prepared from the leukocytes of healthy volunteer donors; eighty-three participants received placebo. Therapy was initiated within 90 days of resection of all evident tumor and continued until 2 years of disease-free survival or the occurrence of unresectable dissemination of melanoma. Known prognostic variables were similarly distributed in the treatment and control groups, documenting the randomization efficacy. Three endpoints were analyzed: disease-free interval, time to Stage III metastasis, and survival. After a median follow-up period of 24.75 months, there was a trend in favor of the placebo group with regard to all three endpoints and this was significant (P less than or equal to 0.05) for time to Stage III metastasis. These findings indicate that TF is not effective as surgical adjuvant therapy of malignant melanoma.

Developmental pharmacology and toxicology: principles of study design and problems of methodology

Pharmacologic investigations in the fetus, neonate and child are difficult for the various reasons outlined above, ranging from ethical constraints to difficulties with microanalytic techniques. Attempts to circumvent these difficulties through animal studies, retrospective analyses, and prospective surveys have provided only partial answers. These studies have often helped to guide subsequent similar studies in humans. Results of developmental pharmacologic studies applied to the human must be conducted in humans. The alternatives to randomized, controlled trials presented above may help with these studies, but these innovative study designs must be applied carefully to avoid biasing the results. Although difficult, definitive studies in developmental pharmacology are possible with investigators willing to work within the ethical constraints outlined above, to sensitively consider the needs of perinatal and pediatric patients, and to adhere to the strictest standards of study design.

Survival of patients with primary (AL) amyloidosis. Colchicine-treated cases from 1976 to 1983 compared with cases seen in previous years (1961 to 1973)

Primary amyloidosis has a variable course, but is generally associated with a short life expectancy. To date, no specific therapy has been available. Fifty-three patients with AL amyloidosis seen between 1976 and 1983 were treated with colchicine, and their clinical course and survival were compared with that in 29 other patients seen between 1961 and 1973. Of the variables measured, the treatment, the patient's sex, and the time interval from diagnosis to referral of treatment were significantly associated with length of survival. Median survival for the colchicine-treated patients was 17 months, compared with six months for the non-colchicine-treated patients. A surprising finding was the longer life span in female patients (median eight months versus four and a half months in the non-colchicine-treated group, and 25.5 months versus 10 month in the colchicine-treated group). The study suggests that colchicine has improved the life expectancy in AL amyloidosis. Although it is not a specific therapy, it may be a reasonable form of adjunctive treatment in this complex disorder.

Meta-analyses of randomized controlled trials

A new type of research, termed meta-analysis, attempts to analyze and combine the results of previous reports. We found 86 meta-analyses of reports of randomized controlled trials in the English-language literature. We evaluated the quality of these meta-analyses, using a scoring method that considered 23 items in six major areas--study design, combinability, control of bias, statistical analysis, sensitivity analysis, and application of results. Only 24 meta-analyses (28 percent) addressed all six areas, 31 (36 percent) addressed five, 25 (29 percent) addressed four, 5 (6 percent) addressed three, and 1 (1 percent) addressed two. Of the 23 individual items, between 1 and 14 were addressed satisfactorily (mean +/- SD, 7.7 +/- 2.7). We conclude that an urgent need exists for improved methods in literature searching, quality evaluation of trials, and synthesizing of the results.

The ethics of randomized clinical trials

Randomized clinical trials pose a number of fundamental ethical problems to which morally sensitive investigators must give careful consideration. The randomized double-blind clinical trial is ethically justified and the preferred method of demonstrating therapeutic effectiveness and safety. Alternate methods such as crossover and self-controlled designs, the use of historical controls, observational methods, and practitioner's clinical trials also exist and have their place in certain circumstances. The use of randomized double-blind clinical trials must assure adequate explanation of the research plan to the patient, the documentation of informed consent, adequate consideration of safety, and an acceptably low risk/benefit ratio.

Evidence that treatment with vaccinia melanoma cell lysates (VMCL) may improve survival of patients with stage II melanoma. Treatment of stage II melanoma with viral lysates

A total of 80 patients with melanoma metastases in regional lymph nodes were treated by i.d. injections with a vaccine prepared from a vaccinia virus-infected allogeneic melanoma cell line; 39 patients have been followed for a 2-year period. Interim results from comparison of the treated group with 151 historical controls treated without the vaccine from September 1978 to December 1981 at the same institution and 56 non-randomized concurrent controls suggest that survival was significantly prolonged in the vaccinated group. At the 2-year period overall survival was 75% in the treated compared to 57% in the historical control group. Subset analysis showed a greater apparent benefit of vaccine therapy among patients who had metastases detected at the time of treatment of the primary melanoma (synchronous metastases), while therapy appeared less effective in patients with metastases detected at some time after treatment of the primary (delayed metastases). In the latter only those with one lymph node appeared to benefit from the treatment whereas in patients with synchronous metastases patients with three or more nodes as well as one node appeared to have improved survival. The survival rates at 2 years for treated patients with synchronous metastases in one, two, three or more lymph nodes was 100%, 83% and 79% respectively compared with that of 82%, 86% and 47% respectively in the equivalent control groups. Survival rates in treated patients with delayed metastases in one, two, three or more lymph nodes was 70%, 70% and 65% compared with 47%, 42% and 35% in the equivalent control groups. Treatment and control groups appeared well matched for a number of known prognostic features, including number and size of involved nodes, sex and thickness of primary tumor. Multivariate analysis indicated the effect of treatment was independent of these factors. Despite the empiricism of this approach the present results suggest that this form of therapy warrants further evaluation in a randomized controlled trial.

Using research synthesis in medical technology assessment

This article describes the use of research synthesis procedures (e.g., meta-analysis) in evaluating medical technologies. The synthesis process involves retrieval, extraction, and analysis of pertinent information from a set a research studies. There are several advantages of research synthesis: determining overall effectiveness, explaining seemingly contradictory findings, providing a standard measure of effect, and increasing statistical power. In addition, such syntheses provide timely results that can assist various policy decisions such as initiating clinical trials at NIH, reimbursement at HCFA, and answering NIH consensus conference questions. The authors' synthesis of the research literature on coronary artery bypass graft surgery (CABGS) illustrates how this method can address the various elements of a technology assessment such as safety, efficacy, and cost-effectiveness. The paper concludes by noting how research synthesis can be particularly advantageous in assessing technologies that are rapidly evolving (e.g., lytic agents for acute myocardial infarction).

Comparison of isocapnic hyperventilation and walking exercise training at home in pulmonary rehabilitation

Eighteen COPD patients enrolled in a comprehensive, multidisciplinary pulmonary rehabilitation program were randomly assigned to perform either: 1) walking, or 2) ventilatory muscle exercise training (VMT) using a prototype, portable device for isocapnic hyperventilation training. Both groups performed exercise training at home. Twelve patients completed the study and follow-up evaluation (five VMT, seven walkers). Pulmonary function did not change in either group. For the VMT patients, there were modest increases in ventilatory muscle endurance and exercise performance. VO2max and VEmax increased significantly. For the walkers, only walking endurance time increased significantly. These results indicate that isocapnic hyperventilation exercise training can be performed successfully by COPD patients in an unsupervised home setting and can lead to improvement in both ventilatory muscle endurance and exercise performance. Walking exercise training did not improve ventilatory muscle endurance.