How are clinical trials conducted
The doctors who conduct a clinical trial follow a carefully designed treatment plan called a "protocol." This spells out what will be done and why. Studies are planned to safeguard the medical and psychological health of patients as well as answer research questions.
Some clinical trials test one research treatment in one group of patients. Other trials compare two or more treatments in separate groups of patients who are similar in certain ways, such as the extent of the disease. This way, treatment groups are alike and the results from each can be validly compared.
One of the groups may receive standard (and most accepted) treatment so the new treatments can be directly compared to it. The group receiving the standard treatment is called the "control" group. For example, one group of patients (the control group) may receive the usual surgical treatment for a certain cancer, while another patient group with the same type of cancer may receive surgery plus radiation therapy to see if this improves disease control.
Sometimes, no standard treatment yet exists for certain cancer patients. In drug studies for such cases, one group of patients might receive a new drug and the control group, none. But no patient is placed in a control group without treatment if there is any known treatment that would benefit the patient. The control group is followed as often and carefully as the "treatment" group.
One of the ways to prevent the bias of a patient or doctor from influencing study results is "randomization." If a patient agrees to be randomized, this means he or she is selected by chance to be in one group or another. The researchers do not know which treatment is best. From what is known at the time, any one of the treatments chosen could be of equal benefit to the patient.
If the treatment in a trial is not helping the patient, the patient's doctor can decide to take him or her out of the study. Of course, the patient can decide to leave as well, and still receive other medical care. There are regular reviews of the results of the trial and the information is shared. This is important, because if a treatment is found to be too harmful or not effective, it is stopped. Also, when there is firm evidence that one method is better than the others in a study, the trial is stopped and all patients in the trial are given the benefit of the new information. Such information may help present and future patients.
Throughout a clinical study, a patient's personal doctor will be kept informed of the patient's progress. Patients are encouraged to maintain contact with their referring doctors.
The above information is taken from "What Are Clinical Trials All About?" published by the National Institutes of Health, National Cancer Institute