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Are there risks or side effects in clinical trials

Yes. The treatments used in clinical trials can cause side effects and other health risks depending on the type of treatment and the patient's condition. Side effects vary from patient to patient.

Because clinical trials are research into new areas of treatment, the risks involved are not always known ahead of time, though efforts have been made to find out what they might be. For this reason, trials can carry unknown dangers and side effects as well as hoped-for benefits.

Patients need to know what is involved in the study -- what side effects may be expected -- and, as much as possible, what unknowns or uncertainties they may be facing.

A doctor or nurse will tell you about the treatments being tested and will give you a form to read that discusses the risks and hoped-for benefits. If you agree to take part, you will be asked to sign a form, called the informed consent form. Before you sign, be sure to understand what risks you face. Ask the doctor or nurse to explain any parts of the form or trial that are not clear. If you do not want to be in the trial, you may refuse. Even if you sign the form, you are free to leave the trial at any time and can receive other available medical care.

In clinical trials, most side effects are temporary and will gradually go away once treatment is stopped. For example, some anticancer drugs cause hair loss and nausea and some do not. They can also affect the bone marrow which produces blood cells. During treatment, the number of blood cells, called blood counts, may fall too low. Since this could lead to possible infection or other problems, patients have their blood counts checked often. Luckily, bone marrow has a great ability to replace blood cells, so that blood counts can usually return to normal.

Some side effects in clinical trials can be permanent and serious, even life-threatening. Also, certain side effects may not occur until later, after the treatment itself is over. These "late" effects may include damage to a major organ like the heart, lungs or kidneys; sterility; or a second cancer. Many cancer patients are living longer, largely because of better treatments. Researchers are concerned and trying to prevent late complications of treatments.

As a patient, it can be hard to decide about your treatment. There are a number of things to consider. Cancer is a life-threatening disease which causes symptoms of its own which are not related to treatment. In each case, the unavoidable risks of the cancer itself, and your condition, should be weighed against the potential risks and benefits of new research treatment. Standard treatments, as well as treatments in clinical trials, can also cause side effects and risks.

Why does cancer treatment have side effects?

Any medical treatment can carry the potential for side effects in some patients. Cancer treatment is particularly powerful, because it is designed to destroy constantly dividing cancer cells. It can also affect healthy dividing cells and this can cause side effects. The challenge to researchers has been to develop treatments that destroy cancer cells but do not harm healthy cells.

What is being done to lessen the side effects of treatment?

Cancer researchers are trying to make cancer treatment more effective and lessen its side effects for cancer patients. Results of such research efforts include:

  • new anticancer drugs with fewer side effects,
  • better antinausea medicine,
  • some shorter periods of time on anticancer drugs,
  • special ways to protect normal tissues during radiation therapy,
  • new methods of surgery that are less extensive and less damaging to the body, and
  • psychological support programs and information on ways to cope during difficult times.
The above information is taken from "What Are Clinical Trials All About?" published by the National Institutes of Health, National Cancer Institute