An illustration of four doctors examining a molecule on a board.
A clinical trial for cancer is an approach at trying new types of therapies to treat or prevent cancer.

Clinical Trials for Cancer

Clinical trials for cancer are systemic studies in which participants receive an intervention based on a research plan. The intervention may be a certain medication, medical device, medical procedure, or behavioral change. Clinical trials are the best way to identify whether a new drug, vaccine, medical device or procedure, or lifestyle change can be safely administered to patients without causing severe side effects.

How Are Clinical Trials Used for Cancer?

Clinical trials for cancer are aimed at identifying new approaches to therapy by comparing treatments that are most effective for a specific stage or type of cancer. This process can lead to the innovation of a new drug or combination of drugs, or improvement of established therapies. Cancer researchers also use clinical trials to develop new and improved surgical techniques and radiation therapy protocols.

Researchers have been working on clinical trials for every type of cancer. Although most of these trials focus on late-stage cancers, research is being carried out in other areas:

  • Preventing cancer
  • Diagnosing cancer early
  • Preventing remission
  • Reducing treatment side effects
  • Improving palliative care

How Clinical Trials Are Approved

Before applying for Food and Drug Administration (FDA) approval, scientists perform thorough laboratory tests and apply new drugs or therapies on animals to understand their efficacy and safety. A cancer drug is tested for at least six years on average before making it to the clinical trial stage. Out of all the substances and therapies that are tested, only a few prove to be promising enough to be tested on humans.


All clinical trials follow guidelines to determine which volunteers are selected. For example, some clinical trials may look for people with a specific type or stage of cancer. For cancer trials, there may also be other eligibility criteria:

  • Medical history
  • Previous treatments
  • Length of treatment
  • Previous history of other cancers
  • The activity level of the volunteer

The volunteer’s age, sex and some other factors are also part of eligibility criteria. Online advertisements may not include all of the criteria. If you are looking at a particular clinical trial, it is best to get in touch with someone from the study to determine your eligibility.

Phases of Clinical Trials

Clinical trials investigating drugs are often described by phase.

Phase I

Once a drug gets the green light to be tested on humans, it is administered to a small group (20 to 80 participants) of volunteers to determine the optimal safe dosage. This stage of the clinical trial typically involves patients with different types of cancer.

Phase II

Phase II of the trial focuses more on the effectiveness of the treatment and can last for several years. It’s carried out on more people (100 to 300 participants). The goal of this stage is to identify optimal dosage, and to assess whether the drug works or not. It continues to monitor short-term side effects.

Phase III

Phase III of the trial starts once the previous phases report promising results. Phase III is conducted on a larger group of people, ranging from a few hundred to several thousand. For cancer trials, patients with specific types and stages of cancer are selected. These trials provide definitive evidence about whether it should receive FDA approval or not.

Phase IV

The research enters stage IV after receiving FDA approval and this phase is often referred to as post-marketing trials. The effectiveness and side effects of the drug are monitored among a diverse, large population. Sometimes, the side effects of a drug do not become apparent until administered to a larger population.

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Risks vs Benefits of Clinical Trials

Before signing up for a clinical trial, you should discuss the potential benefits and risks with your doctor. Although the risks and opportunities are different for each trial, they have certain things in common. Some of the potential benefits of a clinical trial:

  • You are helping someone who has the same disease by aiding the research process.
  • You will have special access to drugs or other forms of treatments that are not available to regular patients.
  • It will increase your treatment options.
  • You will be more in control of your situation by actively participating in the trials.
  • Clinical trial participants tend to get more attention from their doctors and caregivers.
  • You may get a partial or full payment waiver (some clinics pay people for participating in their drug trials).

You should also be aware of the possible downsides of clinical trials:

  • The drug under trial may have unknown side effects that are worse than existing medicines. People in the early phases of a trial are more at risk.
  • Like any other form of treatment, the new drugs or therapy may not work for you even if it helps other patients.
  • You may need to visit the clinic or research lab frequently.
  • In the case of a randomized trial, you may not receive the intervention, but rather a placebo treatment.
  • Your insurance provider may not bear all the costs of the clinical trial.

Finding a Clinical Trial That Is Right for You

Most people hear about clinical trials from their doctors. If you are looking to broaden your treatment options, you can look for clinical trials online. The National Cancer Institute (NCI) has a list of active research. The National Institute of Health (NIH) has an even larger database of clinical trials. Private pharmaceutical and biotech companies publish their ongoing trial list on their websites. Additionally, many organizations have developed an algorithm to match patients with research that might help them. In many cases, these services are offered online.

In Conclusion

Before registering for a clinical trial, it is vital to make sure that the potential benefits outweigh the risks. Make sure to ask all the right questions. A few years back, clinical trials were only conducted at major medical centers. Now, patients have more options and flexibility. Informed decision making has helped many patients overcome their diseases through clinical trial participation.