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Clinical trials for cancer – explained simply
 

  • Clinical trials test new cancer treatments and diagnostic procedures for safety and efficacy – in clearly defined phases and under strict ethical and legal guidelines.
  • Participation, procedures and rights are clearly regulated: eligibility is determined using trial specific medical criteria; participation is voluntary, closely monitored and can be withdrawn at any time.
  • Weighing the opportunities and risks: trials offer participants new possibilities for the diagnosis and treatment of their cancer, but risks cannot always be ruled out. Doctors can provide information about potential opportunities and risks.

What is a clinical trial for cancer?

In clinical trials, researchers test new procedures or drugs for the early detection, diagnosis and/or treatment of cancer in humans to determine whether they are safe and effective. 

They follow strict legal and international standards. 

Only when clinical trials provide convincing data is it possible for new therapies be approved and new diagnostic methods be used in everyday clinical practice.

Clinical trials, for example of new drugs, are usually divided into four phases, each with its own objective:

  • Phase I: First use in humans. Small groups of patients, focus on safety and tolerability.
  • Phase II: Testing of efficacy and optimal dosage, 50 to 200 participants.
  • Phase III: Comparison of new treatments with standard therapies. Large studies with several hundred to thousands of participants. Often conducted at different study centres, these studies form the basis for the approval of drugs.
  • Phase IV: Long-term observation after drug approval to detect rare side effects, interactions and suitability for everyday use.

Good to know:
So-called epidemiological studies are not clinical studies – they "observe" population groups without testing new therapies.

Further reading
The phases of clinical trials are also explained in detail in the text Cancer research explained simply.

Who can participate in a clinical trial?

Whether a study is suitable depends on clearly defined inclusion criteria and exclusion criteria specified in the study protocol. Examples include:

  • type and stage of the disease
  • physical condition
  • previous treatments
  • age and comorbidities

Doctors work with patients to assess whether participation in a study is medically appropriate.

How does a clinical trial work?

All procedures are specified in a study protocol – from the conditions of participation to the treatment regimen. 

There are often several patient groups. Normally, one group receives the new therapy (treatment or verum group) and other groups receive the standard treatment or a placebo (control group).

Various methods ensure that the results are objective and scientifically reliable. These include:

  • Randomisation: If a trial is "randomised", patients are randomly assigned to the treatment and control group.
  • Blinding: If a study is "blinded", patients do not know whether they are receiving the new therapy or the control treatment. If the treatment team does not know either, the study is referred to as being "double-blind".

In clinical studies, participants are often divided into different groups so that new treatments or methods can be reliably compared.

  • Treatment group: receives the new therapy or method.
  • Control group: receives the proven standard treatment or – rarely in cancer medicine – an inactive treatment (placebo).

Good to know
In cancer medicine, a placebo is never given as a substitute for effective therapy, and no one is left without medically necessary care.

Control groups are important because only comparison can show whether a new treatment really works better or whether changes in the course of the disease could have other causes. To ensure that the results remain objective, participants, and often also the treatment team, do not know who is assigned to which group (blinding).

Important to know: Those in a control group also receive effective treatment and are cared for just as carefully as those in the treatment group.

How do I find a suitable study?

The search for a clinical trial ideally begins with the treating physicians. You can:

  • Check current study registries.
  • Contact study centres.

If you search for studies yourself on the internet, you should also discuss the results of your search with your doctors. They can help assess whether the study is suitable for your individual medical situation. 

Cancer centres and specialist clinics regularly conduct studies and often know where suitable opportunities exist and whether studies are still accepting participants.

Typical procedure:

  • Consult with your treating doctor to determine whether participation in the study is advisable and which study might be suitable.
  • If there is a suitable study, your doctor will contact the study centre. Alternatively, you can do this yourself.
  • During an initial consultation, a study doctor will examine you and provide you with comprehensive information about the study.
  • If you wish to participate and meet the requirements, you will need to sign a written consent form.

Important to know
Participation in a study is always voluntary. You can withdraw from the study at any time.

What are the advantages of participating?

Study participants receive close support, benefit from the expertise of specialised centres and gain access to promising new therapies. 

The objectives may include: 

  • longer survival
  • fewer side effects
  • better quality of life

Despite strict safety requirements, uncertainties remain – especially in the early stages. New therapies may have different effects than expected or cause unknown side effects.

However, every study is reviewed and monitored by ethics committees and other healthcare related authorities to ensure the greatest possible safety.

Further reading
In the text Cancer research explained simply, you can find out how safety and ethical standards are guaranteed in studies and what role the ethics committee plays in this.

What are my rights and obligations in a study?

Your rights:

  • You will receive comprehensive information.
  • You have the right to have your data protected – studies must comply with strict guidelines in this regard.
  • There is a trial participant insurance policy that covers the risk of any health impairments resulting from participation in the study.
  • You can withdraw from a study at any time without disadvantage.

Your obligations:

  • You must keep appointments and, if necessary, attend the study centre regularly.
  • You must provide honest information about your health.
  • You must inform the study staff about any additional medications or treatments.

Do I have to pay to participate in a clinical study?

As a rule, the study provider covers all treatment costs. Any expenses not covered, such as travel costs, must be clearly stated by the providers in advance. 

Health insurance companies do not normally cover study costs, as the effectiveness of the new therapy is still being tested.

Sources

This text is based on sources and information from the text Clinical Trials for Cancer: Your Questions – Our Answers from the Cancer Information Service at the German Cancer Research Centre.