Current breast cancer clinical trials

The recently reported decline in breast cancer mortality in the United States and United Kingdom has been attributed to multiple factors, particularly the increased use of screening mammography, adjuvant chemotherapy and endocrine therapy with tamoxifen. These advances are directly attributable to practice standards that have been shaped by data from randomized clinical trials. The human impact of these reductions in breast cancer mortality has led to larger cooperative studies with the statistical power to detect modest, but important improvements in outcomes. A fascinating footnote is the soon-to-be-reported ATAC adjuvant trial that has about ten times as many patients as the initial adjuvant studies launched in the 1970’s.


 

 

SELECT PUBLICATIONS

Collins R, Gray R, Godwin J, Peto R. Avoidance of large biases and large random errors in the assessment of moderate treatment effects: The need for systematic overviews. Stat Med 1987;6: 245-250. Abstract

Ellis PM et al. Randomized clinical trials in oncology: Understanding and attitudes predict willingness to participate. J Clin Oncol 2001;19:3554-3561. Abstract

Giuliano AR et al. Participation of minorities in cancer research: The influence of structural, cultural and linguistic factors. Ann Epidemiol 2000;10(8 Suppl):S22-34. Abstract

Hutchins LF et al. Underrepresentation of patients 65 years of age or older in cancer-treatment trials. N Engl J Med 1999;341:2061-7. Abstract

Lara PN et al. Prospective evaluation of cancer clinical trial accrual patterns: Identifying potential barriers to enrollment. J Clin Oncol 2001;19:1728-1733. Abstract

Siminoff LA et al. Factors that predict the referral of breast cancer patients onto clinical trials by their surgeons and medical oncologists. J Clin Oncol 2000;18:1203-1211. Abstract

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HISTORICAL PERSPECTIVE
Arguably one of the most important advances during the last 50 years has been the introduction of prospectively randomized controlled trials to clinical medicine. Such trials provide information about the natural history of a disease and evaluate the worth of a particular therapy. Moreover, they allow for testing of biological hypotheses and, thus, provide a mechanism whereby the scientific method can be applied to clinical problem-solving. By replacing anecdotal information (which has influenced therapeutic decision-making in the past) with more credible and substantive data, clinical trials play a major role in transforming the practice of medicine from an art to a science. As a vital component of the “research chain,” clinical trials are an essential link between the laboratory and the clinic, providing means for determining whether the use of laboratory findings in the treatment of patients is justified. Without trials, much of the scientific information currently being reported could not be evaluated for its therapeutic worth.

—Bernard Fisher, MD
News from the Commission on Cancer of the American College of Surgeons 1991;2(2).

TRIALS AND CLINICAL DECISIONS
The randomised controlled trial has become the gold standard for evidence-based medicine; through the unbiased comparison of competing treatments it is possible to accurately quantify the cost-benefits and harm of individual treatments. This allows clinicians to offer patients an informed choice and provides the data on which purchasing authorities can make financial decisions. We, of course, subscribe to this view but also recognize this as a gross over-simplification of the power of the randomisedcontrolled trial. The randomised controlled trial is the expression of deductive science in clinical medicine. Not only is it the most powerful tool we have for subjecting therapeutic hypotheses to the hazard of refutation but also the biological fallout from such trials should allow clinical scientists to refine biological hypotheses. Trials of treatments for breast cancer have, at least twice, contributed substantially to a paradigm shift in our understanding of the disease.

—Michael Baum, ChM, FRCS;
Joan Houghton, BSc
Br Med J 1999;319:568-571. Full Text

INTERNATIONAL META-ANALYSIS
There are thousands of randomized trials in the world, which will lead to “zigs and zags” in the data. And, the “zags” are probably the ones that are going to be the most noteworthy and the most emphasized in meetings, because they look odd. So if you take lots of trials and then pick out the ones where the results look out of line with the other ones, then you’re quite likely to have something that is misleading. You’ve got to systematically bring together all the evidence in the world — look at it irrespective of what the individual study shows — see what the grand total looks like, and then you’ve got something reliable. We’ve seen too many trial results that prove to be evanescent. But if you put all of the trials together, you get reliable knowledge. If you don’t, you don’t.

—Richard Peto, FRS
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