Human studies

The data in this section come from 2 main types of research studies:

• Observational studies (cohort or case-control)
• Randomized controlled trials  

The goal of these studies is to give information that helps support or disprove an idea about a possible link between an exposure (such as alcohol use) and an outcome (such as breast cancer) in people.

Although they have the same goal, observational studies and randomized controlled trials differ in:

• The way they are conducted
• The strength of the conclusions they reach

Learn more about different types of research studies.

Animal studies

Animal studies add to our understanding of how and why some factors cause cancer in people.

However, there are many differences between animals and people, so it makes it hard to translate findings directly from one to the other.

Animal studies are also designed differently. They often look at exposures in larger doses and for shorter periods of time than are suitable for people.

While animal studies can lay the groundwork for research in people, we need human studies to draw conclusions for people.

All data presented within the About Breast Cancer section of this website come from studies of people.

Finding information on risk factors

Susan G. Komen^® has up-to-date information on many established, probable and possible risk factors for breast cancer (and information on many factors not related to risk).

Other organizations conduct research and/or prepare detailed summary reports of research on certain factors shown to have a link (or no link) to breast cancer and other types of cancer, including:

• International Agency for Research on Cancer (IARC)
• Centers for Disease Control and Prevention (CDC)
• National Toxicology Program (NTP)
• U.S. Food and Drug Administration (FDA)

IARC is a part of the World Health Organization. The CDC, NTP and FDA are all part of the U.S. Department of Health and Human Services.