Clinical Trials are the best way to investigate whether proposed new treatments are better than existing treatments, which are considered the standard of care. People who are diagnosed with any disease should expect to be treated with the best standard of care. Standard of care changes only after strong evidence from clinical trials confirms that the proposed new treatment works better than the current standard of care.

Decades ago, thousands of selfless women participated in a clinical trial that compared survival rates in women diagnosed with breast cancer who would undergo the then standard of surgical care, mastectomy, to survival rates in those who were treated instead with lumpectomy in combination with radiation therapy. Those courageous women agreed to be randomized to either standard of care or the newer breast conserving option in order to determine which treatment would be best for women who came after them. The result of this trial gave many women the choice of breast conserving surgery followed by radiation therapy or mastectomy.

When you participate in a clinical trial you are usually agreeing to be randomized, sometimes blindly, to the control group or the investigational treatment group so that researchers can compare the new investigational intervention to the standard of care. Patients in clinical trials may not receive any additional benefit than they would from standard of care. They can hope that the newer treatment is better, but there is no guarantee and investigators must make it clear to them that the trial is being done in order to understand which treatment will be better for women in the future.

Types of Trials:

Randomized clinical trials are studies that blindly assign participants to separate groups in order to compare different treatments. The Principal Investigators and the participants do not have any choice about which participant gets which intervention. When patients participate in randomized clinical trials they are being randomly assigned the standard of care treatment or the new investigational drug or treatment. This eliminates bias and allows investigators to observe which treatment is more effective, including consideration of side effects.

Non randomized clinical trials allow investigators to assign participants to a treatment arm or participants themselves can select which group they want to be in. Both the researcher and the patient know which intervention they are using.

Observational studies occur when a research team follows individuals or groups of individuals in order to measure certain outcomes. There is no control group and no attempt is made to change the outcome by intervention.

Retrospective cohort studies or historical cohort studies, are carried out by examining medical files in order to see a pattern of medical events or outcomes. A group of patient files are selected based upon exposure status or disease outcome. Exposure and behaviors which were measured in the past are reconstructed for analysis. The primary disadvantage of this study design is the limited control the investigator has over data collection. The existing data may be incomplete, inaccurate, or inconsistently measured between subjects. However, because of the immediate availability of the data, this study design is comparatively less costly and shorter than prospective cohort studies.

Prospective observational studies or prospective cohort studies observe groups of people from today on into the future and are designed with specific data collection methods. A study like this has the advantage of being tailored to collect specific exposure data and is likely more complete and accurate than retrospective trials. Disadvantages of a prospective cohort study are the often long follow-up period while waiting for events or diseases to occur and potential cost.

Clinical Trial Phases:

Phase I trials are designed to test the safety of a new drug or treatment in humans. They measure the best way to give an experimental drug (i.e. delivery and dosage). The trial usually seeks to measure the highest dose that can be given which will not cause adverse effects. Because so little is yet known about the intervention, this phase is usually limited to a small number of patients who have not had success with standard of care and other treatments. It is designed to test how much harm a treatment might cause.

Phase II trials will test whether the new intervention has a positive effect on helping to fight the disease. In cancer, investigators would want to see tumor shrinkage or another measureable outcome that indicates that the drug works against the disease.

Phase III trials would compare the results of people taking a new treatment with the results of people taking standard treatment. (It could measure which treatment yields better survival rates and fewer adverse effects.) Phase III trials happen only after successful completion of Phase I and II trials. These trials need to be done on hundreds of people in order to have results that are generalizable to the intended population.

Phase IV trials take place after a drug or treatment has been approved by the FDA. This Phase is meant to evaluate all side effects which may not have been seen in earlier phase trials. Thousands of people likely participate.

A Pilot Study is a small test study used to inform a larger clinical trial study. It provides information about the feasibility of accrual (enrolling sufficient patients), the goals of the trial, methods of gathering data and the quality of that data. It is not meant to measure the benefits or risks of the intervention, but rather will allow for adjustment in the planned research methods to be used in the trial.


If you are interested in participating in a clinical trial, talk to your doctor, gather all your medical records and use the following websites to find the best trials for you and then talk to your doctor again.

The following websites might offer you more information and webinars about Clinical trials: 


Consumers United for Evidence Based Healthcare has an amazing webinar series about evidence based healthcare, quality of evidence and participation in clinical trials.


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