- Clinical trials are studies involving people that help make progress in preventing, diagnosing, and treating cancer.
- Each clinical trial follows a set of rules called a protocol that describes who can participate in the study and how the treatment will be given and monitored.
- Governmental and non-governmental organizations may sponsor clinical trials, and people may participate in a clinical trial at a variety of hospitals and doctors offices. It's important to talk with your doctor about the costs you'll need to pay in a clinical trial because they can vary.
To make scientific advances, doctors perform research studies involving people, called clinical trials. Many clinical trials evaluate new treatments to find out whether they are safe, effective, and possibly better than the current (standard) treatment. There are many different types of clinical trials. Some studies test different combinations of existing treatments, new approaches to radiation therapy or surgery, and new methods of treatment. In clinical trials, the different treatment groups are sometimes called arms.
Some clinical trials, called placebo-controlled clinical trials, compare a new treatment with a placebo (an inactive drug or treatment). The use of placebos alone in cancer clinical trials is rare; they are used when there is no effective, standard treatment available, or they are given in addition to standard treatment. When a placebo is used in a study, it is done with the full knowledge of the participants. Find out more about placebos in cancer clinical trials .
There are also clinical trials that study new ways to ease symptoms and side effects during treatment and manage the late effects that may occur after treatment. In addition, there are ongoing studies about ways to prevent cancer.
The importance of clinical trials
Cancer clinical trials have led to scientific advances that have increased doctors' understanding of how and why tumors develop and grow. This knowledge has helped doctors make progress  in preventing cancer, diagnosing cancer, slowing or stopping the development of cancer, and finding cancers that have come back after treatment. Because clinical trials may involve hundreds or even thousands of people, it often takes a long time to find out the results. Still, clinical trials remain the most reliable and only accepted scientific method to find out if a new treatment works better than the current standard of care.
Despite the promise offered by clinical trials, less than 5% of adults with cancer enroll in them. This lack of participation slows progress in the development of new, more effective therapies. By contrast, more than 60% of children with cancer are enrolled in clinical trials. Approximately three-quarters of children with cancer survive long-term, compared with half of adults. The increased survival rate for children can be directly linked to their higher rate of participation in cancer clinical trials. Read stories on patients who have participated in clinical trials  and find out what led them to participate.
How clinical trials are set up
All clinical trials have requirements about who can participate, called inclusion and exclusion criteria. These criteria are based on a person's age, type of disease, medical history, and current health.
Inclusion criteria help make sure that all the people in the clinical trial are medically similar. For example, the inclusion criteria may require that each participant have the same kind of cancer or same stage of disease (such as stage IIA colorectal cancer). If the people have too many medical differences, the doctors will have more difficulty interpreting the results.
Likewise, exclusion criteria help keep people safe. For example, it is often not safe for patients with a severe heart condition or kidney failure to receive some cancer treatments, so they may be excluded from clinical trials. Exclusion criteria are not used to reject people personally.
Each clinical trial follows a set of rules called a protocol. A protocol describes inclusion and exclusion criteria; the schedule of tests, procedures, medications, and doses; and the length of the study.
While in a clinical trial, the research team monitors the health of the participants to determine the safety and effectiveness of the treatment. The research team  includes doctors, nurses, social workers, and other health care professionals. They will check the person's health at the beginning of the clinical trial, give specific instructions for participating in the clinical trial, monitor the person carefully during the clinical trial, and stay in touch with the person after the study. A person's participation will be most successful if they carefully follow the instructions given to them by the research team and stay in contact with the research staff.
Sponsorship and insurance coverage
Clinical trials are sponsored by government agencies such as the National Institutes of Health (NIH), including the National Cancer Institute (NCI), pharmaceutical companies, individual doctors, health care centers such as health maintenance organizations (HMOs), and organizations that develop medical devices or equipment. Clinical trials can take place in hospitals, universities, doctor's offices, or community clinics.
One effective way to operate clinical trials is through an NCI-funded cooperative group. Cooperative groups are large networks of doctors and other health care professionals from many different centers that develop and coordinate clinical trials. Cooperative groups are funded by the NCI. Because so many doctors and institutions are involved, the clinical trials sponsored by cooperative groups can enroll more people than a single clinical trial at one hospital. Also, the cooperation makes it easier for people from different parts of the country to enroll in a clinical trial. Find a cancer center or cooperative group .
Laws regarding the coverage of clinical trial costs differ by state. Medicare covers routine costs related to clinical trials intended to treat the cancer, called therapeutic intent. Learn about the different phases of clinical trials . Some clinical trials offer payment, while others do not. In some programs, trial sponsors will reimburse for expenses associated with participating in the research, such as transportation, childcare, meals, and accommodations.
In March 2010, the Patient Protection and Affordable Care Act - often called simply Health Reform - was signed into law, changing several rules regarding health care insurance coverage in the United States. As of January 1, 2014, insurers will not be allowed to limit or drop coverage to an individual choosing to participate in a clinical trial. This applies to clinical trials to treat cancer, in addition to other life-threatening diseases. Learn more about the 2010 Health Reform Law and costs of cancer .
Clinical Trials 
National Cancer Institute: Clinical Trials 
ClinicalTrials.gov: Understanding Clinical Trials