Blog Post featuring Types of Cancer Clinical Trials

All About Cancer Clinical Trials: Types of Trials

There are many different types of clinical trials and research studies, which can be intimidating for someone new to research. The wide clinical trial variety is a good thing, however, because it means there is likely a clinical trial for everyone! Learn all about clinical trial basics and the different types of trials people volunteer to participate in below. To learn other clinical trial basics and frequently asked questions, make sure you’re following MNCCTN on Facebook and Instagram where we share all kinds of education about clinical trials every week!

What Are Clinical Trials?

Clinical trials are research studies that look to answer questions about diseases such as cancer. People volunteer to participate in trials. Clinical trials are most associated with finding new treatments for diseases. In fact, all of today’s treatments for diseases were developed through clinical trials. Clinical trials can also study how to screen for and detect diseases, reduce symptoms of diseases or side effects from treatments, and improve quality of life for survivors. Other trials study how to prevent diseases. 

Interventional and Observational Trials

Research studies fall under two broad categories: interventional and observational trials. In interventional trials, researchers intervene to observe a specific change, like a new treatment. For example, an interventional study may assign one group to receive a new chemotherapy pill and the other to receive the standard chemotherapy. Researchers then observe and measure outcomes for the participants to see if the intervention is more effective than standard of care.

Observational trials, on the other hand, observe processes and outcomes that are already occurring organically. Researchers don’t try to make one outcome occur or change any exposures. Instead, they observe and do not intervene. For example, researchers may observe people who already eat a plant-based diet versus those who already eat a traditional Western diet over time and record which people develop cancer and those who do not. Researchers will analyze these observations and outcomes to determine if relationships exist between exposures (like diet) and outcomes (developing cancer).

Preclinical Laboratory Studies

Before drugs, treatments, procedures, or other clinical elements are tested on people in clinical trials, they are studied in the lab. These studies can include animal or cell studies. These preclinical studies give researchers a better understanding of how a treatment or other clinical component will translate to people and how safe it is. 

Treatment Trials

While clinical trials are broadly considered either interventional or observational, that is just one classification trials can fall under. Trials can also be grouped by the trial’s goal. Treatment trials study whether a new treatment is safe, effective, and/or superior to existing treatments. Treatment trials often study new drugs. However, other treatment trials can study devices, surgical procedures, radiation therapy, etc. Treatment trials are further categorized by stage, or phase. 


Diagnostic Trials

Diagnostic trials study methods to diagnose diseases. Diagnostic methods typically include specific tests or procedures. For cancer, this could include a scan to detect a tumor or a biopsy to look at tumor cells and determine if it is cancerous or not. 

Prevention Trials

Cancer prevention trials study ways to prevent someone from getting cancer or to lower their risk of developing cancer. Unlike treatment trials where participants already have cancer or another disease, people who participate in prevention trials are healthy volunteers. In cancer prevention trials, this means people who participate do not have cancer. Participants may or may not have an increased risk for cancer and/or a family history of cancer depending on the study and its goals. 

In a cancer prevention trial, some participants will be asked to take an action to see if it will prevent cancer or lower risk. The action depends on the study, but it could be exercising, taking medicine, following a specific diet, or something else. This group of participants is usually compared to another group of people who take a different action. All participants will be observed over a period of time. After the study period, participants’ health outcomes will be compared to see if one prevention strategy was more effective than the other.

Learn more about prevention trials, benefits and risks, and what it’s like to participate in a previous MNCCTN blog post

Screening Trials

Screening trials study methods to test for early signs of a disease like cancer. Screening is especially important for certain cancers that are more treatable when detected early. Screening trials will see if there is a benefit to detecting the disease early and if the screening method’s benefits outweigh potential risks. These studies may also compare a new screening method to an existing one. Screening trials also help determine the best screening guidelines and schedules, such as age to begin screening and an annual or every other year schedule for example. Examples of screening methods for cancer include colonoscopies for colorectal cancer and mammograms for breast cancer. Similar to prevention trials, screening trials often include the general population and healthy volunteers. Some screening trials may focus on people with increased risk of developing a disease, like having a family history of a disease or a genetic or inherited syndrome that is linked to a disease, like the BRCA gene for breast cancer. 

Supportive Care Trials

Supportive care trials focus on quality of life. These studies seek to improve day to day life and comfort for people with chronic diseases or conditions, like cancer survivors. These trials could study ways to reduce symptoms of treatments or slow the decline of one’s health. Supportive care trials can also focus on caregivers and end of life care. 

Other Trials & Where to Learn More About Clinical Trials

There are many other types of clinical trials that don’t fit under these categories. Learn more about other clinical trial types and information in the following resources:

NIH Clinical Research Trials & You

FDA Clinical Trials: What Patients Need to Know

NCI Clinical Trial Information

ACS Clinical Trials: What You Need to Know