http://health.medscape.com/cx/viewarticle/401725_print

Posted On Site: May 2001
Elizabeth Tracey, Medical Writer

Introduction

Like many men his age, William Harn, 72, a machinist living north of Baltimore, has had a bout with prostate cancer. "I was diagnosed when I was 68," he recalls. "But they caught it early enough that my treatment wasn't that bad, and I haven't had any problems since."

Harn's treatment involved a couple of hormone injections, followed by radioactive material implanted in the prostate gland itself. Together, these therapies resulted in shrinkage of the gland and a sharp drop in a blood marker for prostate cancer called prostate-specific antigen--PSA, for short. "At my last checkup a few months ago, my doctor was very happy with how things are going, and I feel great," Harn says.

He owes much of his treatment success to therapies that were developed and tested about 10 years ago in clinical trials. Clinical trials are carefully designed experiments in which new therapies are tested in human volunteers, and they are a critical part of the process of advancing knowledge and success in cancer treatment.

"We've made great strides in the early detection and treatment of many cancers," says Leslie Ford, MD, associate director for clinical research at the National Cancer Institute. "Now we are turning our attention to investigating prevention of cancer as well. To continue to make strides in all these areas, clinical trials are really key."

Even though clinical trials are so important, only about 3% of the people who are eligible to enroll in one do so, according to a recent Harris survey. And 85% of those people say they didn't even know that a trial was available to them. Why?

Barriers to Enrollment

"There are many barriers to participation in clinical trials that we need to examine more closely," says Ford. "One is that many people simply don't know how many trials are out there or how they can participate." To help solve this problem, the National Institutes of Health, of which the National Cancer Institute is a part, maintains a Web site at www.clinicaltrials.gov. (Potential participants can also call 1-800-411-1222.)

A possible benefit of participation in a clinical trial is access to the latest techniques and therapies, often provided by leading physicians at top-notch medical centers. Participants can also feel good about helping others with the disease. What's more, clinical trials may offer the only hope for those in an advanced stage of cancer. But those who take part may have to travel to a center where they would not ordinarily seek care, and their treatment may be limited to the therapy under investigation. These problems can make some people resist the idea of being part of a clinical trial.

Another potential downside is that really new drugs and therapies are being used, and all of the possible side effects may not yet be known. "It can take years to really assess the long-term impact of a drug or treatment," says Adrian Dobs, MD, director of the Johns Hopkins Clinical Trials Unit. "Patients are followed very closely during trials, but there's still the risk that an adverse event might take place."

Dobs says that people who join trials must accept the fact that they will not receive other treatments for their condition. This may seem like a big problem, but she says that everyone in a trial is given standard treatment with the expectation that if a really promising treatment emerges, it will be offered to everyone.

Barbara Brenner, executive director of Breast Cancer Action, a national breast cancer advocacy group based in San Francisco, offers this caveat about taking part in a clinical trial: "I have seen women who are desperately ill cling to false hope based on their participation, so I would say, 'Try to be realistic.' It's also necessary to clearly understand the question the trial is attempting to answer. Phase I trials, for example, are about safety, not efficacy. There is no question in my mind that we need clinical trials and we need people to enroll in them, but we need things to be explained better to participants."

Ford says resistance on the part of physicians is one barrier to participation in clinical trials. Taking part requires additional recordkeeping and sticking to a specific treatment program on the physician's part, which may be confining. Many doctors who practice in community hospitals or on their own may not have the support they need to encourage their patients to participate.

"My own personal bias is to work through community doctors as much as possible," says Ford. "We have developed a network called the Community Clinical Oncology Programs, which is intended to reach groups of doctors in the community setting."

As more doctors outside large university-affiliated or regional hospitals take part in clinical trials, Ford hopes that trials will see more diversity in their study populations, which she says is important in proving that the study results are valid. Minorities and lower-income people do not often participate in trials, and they are sorely needed, Ford says.

What to Expect

So let's say you're convinced that clinical trials are a good idea, and you'd like to enroll. What can you expect? First, you'll be given a document called an "informed consent." This document will detail the purpose of the trial, its possible risks, and what you will need to do to participate and for how long. Before you sign, make sure you understand the document, and keep a copy for your records. Remember that you have the right to withdraw from a trial whenever you wish.

The trial will be in one of four phases:

• Phase I looks at the safety of a medicine or therapy.