Early detection trials

Early detection trials Treatment trials Quality-of-life trials... 

Those discussed above relate to conventional treatment trials, but (as listed in Table 3) there are other types of clinical trials as well. The main concepts are analogous A well-selected control group is essential, and unbiased statistical data evaluation should be provided. For example, in the case of early detection trials usually the level of a potential biomarker is determined in a group of patients and it is compared to that of the control group. In such a case it is important that the only difference between the two groups should be that of the presence of a given illness. False results may easily be obtained (and are often even reported) if, e.g., melanoma patients are compared to a group of healthy individuals. In such a case the found biomarker may be representative of very ill persons and not that of melanoma. 

Early detection of ischemic stroke can be done with the use of transcranial Doppler ultrasonography. In the Stroke Prevention Trial in Sickle Cell Anemia (STOP) study, screening with this method followed by transfusion significantly reduced the incidence of stroke.29 Screening is recommended in all patients over 2 years of age. 

First, the protocol may induce the detection of extra cases - cases that would have gone undetected if no protocol were used in the usual care of patients. These cases may be detected earlier than they would have been in usual care. In the prophylaxis example above, repeated testing of all patients is likely to increase the number of deep vein thromboses that are detected, especially if, in usual care, patients are only tested when they develop clinical signs of deep vein thromboses. This extra or early detection may also reduce the average costs for each case detected, because subclinical cases or those detected early may be less costly to treat than clinically detected cases. However, because these two potential biases - more cases, each of which may cost less -work in opposite directions, the total costs of care for patients in the trial may or may not exceed those that would occur in usual care. 

It is helpful to utilize electronic data capture when possible. Computer-assisted data entry, or electronic data capture, at the time of the subject s clinic visit or procedure makes the data entry process quicker and less susceptible to error. It also offers the chance to monitor data collection in a timely manner as the clinical trial progresses, which facilitates the opportunity to detect trends toward poor quality or unexpected data that may be the result of the investigator site failing to adhere to the protocol. Early detection and correction are much preferable to the alternative. 

Diverio D, Rossi V, Awisati G, De Santis S, PistiUi A, Pane F, et al. Early detection of relapse by prospective reverse transcriptase-polymerase chain reaction analysis of the PML/RARalpha fusion gene in patients with acute promyelocytic leukemia enrolled in the GIMEMA-AIEOP multicenter AIDA trial. GIMEMA-AIEOP Multicenter AIDA Trial. Blood 1998 92 784-9. 

One of the most important aspects of the UK regulatory system is the scheme provided by the voluntary reporting of adverse reactions to a marketed drug. As most serious ADRs are rare events, they are unlikely to be detected in early clinical trials. The problem is essentially one of numbers, as relatively small numbers of patients are exposed to a new drug before it is released on to the market. Marketing may, therefore, be the first adequate safety trial. The main functions of the adverse reactions reporting system are ... 

Signal Detection and EDA (Exploratory Data Analysis). As clinical trials progress we are increasingly awash in a continuous flow of raw data, but the early detection of signals amidst the ocean of noise receives very little attention until a signal is made obvious by... 

An immunodiagnostic technique for early detection of microsporidian Nosema infection in silkworms has been developed at MKU, Madurai and transferred to sericulturists [Dharmalingam, personal communication]. Field trials of immuno diagnostic kits developed for detection of the infectious flacherie disease of silkworm B. mori are progressing at CSRTI, Mysore. A sandwich... 

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