Understanding Clinical Trials

A clinical trial is a type of research study that includes people as participants. These studies explore new ways to prevent, diagnose, or treat diseases, aiming to determine whether new approaches are both safe and effective.

Joining a clinical trial can offer access to cutting-edge treatments that haven’t yet received FDA approval. There are currently many active studies focused on developing and testing new medications and combinations of treatments for prostate cancer. These trials also compare new therapies with the current most effective option, known as the standard of care, to see if improvements can be made.

Every treatment available today for prostate cancer became possible through past clinical trials and the people who volunteered for them.

Why Participate in a Clinical Trial?

You might consider taking part in a clinical trial to:

  • Try innovative treatments not yet available to the public
  • Receive regular and detailed monitoring of your prostate cancer
  • Access care from leading medical professionals
  • Contribute to medical research that may benefit others in the future

Health Equity in Clinical Trials

Clinical trials are carefully regulated to ensure participant safety and follow strict scientific and ethical standards.

However, people of color have historically been underrepresented in these studies. Ensuring diversity in trial participation is essential—it helps researchers understand how different populations may respond uniquely to the same treatments. Without inclusive participation, clinical data may not fully reflect the needs of all communities.

Learn more about clinical trials

Find more information on the types of clinical trials and how they’re conducted.

There are several types of cancer clinical trials.

  • Treatment trials: Most cancer clinical trials are treatment studies. These trials test new treatments or new ways of using existing treatments, such as new drugs, vaccines, approaches to surgery or radiation therapy, or combinations of treatments.
  • Prevention trials: Cancer prevention trials are studies involving healthy people. In most prevention trials, the participants either don’t have cancer but are at high risk for developing the disease or have had cancer and are at high risk for developing a new cancer. These studies look at cancer risk and ways to reduce that risk. There are two kinds of prevention trials:
    • Action studies (“Doing something”) focus on finding out whether actions people take—such as exercising more or eating more fruits and vegetables—can reduce the risk of getting cancer.
    • Agent studies (“Taking something”) focus on finding out whether taking certain medicines, vitamins, minerals, or dietary supplements (or a combination of them) may lower the risk of a certain type of cancer. Agent studies are also called chemoprevention studies.
  • Screening trials: The goal of cancer screening trials is to test new ways to find disease early, when it may be more easily treated. An effective screening test will reduce the number of deaths from the cancer being screened.
  • Quality-of-life trials: These trials look at ways to improve the quality of life of cancer patients, especially those who have side effects from cancer and its treatment. They find new ways to help people cope with pain, nutrition problems, infection, nausea and vomiting, sleep disorders, depression, and other health problems. Quality-of-life trials might test:
    • Drugs, such as those that help with depression or nausea.
    • Activities, such as attending support groups, exercising, or talking with a counselor.
    • Ways to help families and caregivers cope with their own needs, as well as those of the person with cancer.

Each clinical trial has its own guidelines on who can participate as part of the study protocol. These guidelines are called eligibility criteria. They describe characteristics that must be shared by all participants so they can join the clinical trial.

Common eligibility criteria for a cancer clinical trial include:

  • Having a certain type and stage of cancer
  • Treatment history
  • Age range
  • Other health conditions

Eligibility criteria can help researchers achieve accurate and meaningful results. These criteria also make certain that people who could be made worse by participating in the study are not exposed to the risk.

For a treatment to become standard, it must first go through three or four clinical trial phases. The early phases make sure the treatment is safe. Later phases show if it works better than the standard treatment.

  • A Phase 1 trial tests an experimental drug or device on a small group of people (around 20 to 80) to judge its safety, including any side effects, and to test the amount (dosage).
  • A Phase 2 trial includes more people (around 100 to 300) to help determine whether a drug is effective. This phase aims to obtain preliminary data on whether the drug or device works in people who have a certain disease or condition. These trials also continue to examine safety, including short-term side effects.
  • A Phase 3 trial gathers additional information from several hundred to a few thousand people about safety and effectiveness, studying different populations and different dosages, and comparing the intervention with other drugs or treatment approaches. If the FDA agrees that the trial results support the intervention’s use for a particular health condition, it will approve the experimental drug or device.
  • A Phase 4 trial takes place after the FDA approves the drug or device. The treatment’s effectiveness and safety are monitored in large, diverse populations. Sometimes, side effects may not become clear until more people have used the drug or device over a longer period of time.

Researchers take many years testing investigational drugs in the laboratory before the drug can be tested in humans. When the initial laboratory research is successful the drug can be moved into testing in humans through a clinical trial. All phases of clinical trials are monitored closely by the Food and Drug Administration (FDA).

Randomization is a process used in some clinical trials to prevent bias. Bias occurs when a trial’s results are affected by human choices or other factors not related to the treatments being tested. Randomization helps ensure that unknown factors do not affect trial results.

Randomization is used in all phase III and some phase II trials. These trials are called randomized clinical trials. A clinical trial consists of at least two groups depending upon the study protocol. A study protocol is a plan that describes the schedule of tests, procedures, medications and dosages, and the length of the study.

One group of patients will receive the experimental drug or treatment – this is the investigational group. One group of patients will receive either the standard of care or a placebo which has no therapeutic value – this is the control group. Placebos are almost never used in cancer treatment trials.

Comparing these groups to each other often clearly shows which treatment is more effective or has fewer side effects. If you are thinking about joining a randomized clinical trial, you need to understand that there is an equal chance you will be assigned to either group. Neither you nor your doctor chooses which group you will be in.

If you participate in such a randomized clinical trial, you will be assigned by chance to either an investigational group or a control group. Your assignment will be determined at random and no one will know which group you are in.

Regardless of which group they are in, all patients receive the same level of medical attention and care. In most clinical trials, the health of the participants is monitored both during and after the study period.

There are many patient protections and federal rules in place to ensure the safety of clinical trial participants. Such protections include:

  • Informed consent is a patient’s bill of rights. It is a critical part of ensuring patient safety in research and can help you decide whether to join. You will be provided with an informed consent document that will give you detailed facts about the trial. The informed consent will explain the purpose of the trial, tests and procedures, schedule, treatments, risks, and benefits. It should be written in everyday, plain language. If you do not understand something or have questions, be sure to ask the study doctor or nurse to explain it to you. If you decide to participate in the study, you will sign the informed consent document to acknowledge you understand and agree to all aspects of the study. You are also agreeing that you understand the potential risks and benefits that are involved.
  • You can leave the study at any time. It is your right to withdraw your consent to participate in the trial. Should you decide to leave the trial, you are not required to explain your reasons for leaving.
  • All trials must be reviewed and approved by an Institutional Review Board (IRB). An IRB is an independent committee of doctors, statisticians, community advocates, and others who ensure the clinical trial is ethical and the rights of the participants will be protected. Federal rules require that each IRB be made up of at least five people with one from outside the institution running the trial.
  • Phase III trials are monitored by Data and Safety Monitoring Boards (DSMBs). DSMBs monitor the trial to help ensure your safety. This is also an independent committee made up of statisticians, physicians, and other experts. The Board must ensure:
    • Any risk that comes from being in the study is reduced as much as possible.
    • The data is sound.
    • A trial is stopped if safety concerns come up or as soon as objectives have been met.