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How do you know if I’ve had cancer?

Knowing when our participants are diagnosed with cancer is a top research priority of the California Teachers Study – it is what makes all the other research possible!

Because this question is so important—and because so many participants have asked this crucial question—we want to clarify our process for collecting and using information about participant diagnoses.

Q: You didn’t ask about my cancer history on the most recent questionnaire. How does the California Teachers Study know if I’ve had cancer?

The California Cancer Register (CCR) is an important partner in cancer research. By collaborating with the CCR, the CTS receives cancer diagnosis details for each study participant who is diagnosed in California. You can learn more about cancer notifications by clicking here.

Q: How does the CCR get cancer information?

In 1985, California passed legislation to make cancer a “reportable disease.” This means that hospitals, physicians, and treatment facilities in the state are legally required to report every cancer diagnosis that occurs in the state. Three years after this law went into effect, the California Cancer Registry (CCR) was established as the State’s cancer surveillance program. The CCR is responsible for receiving and recording each reported cancer diagnosis. Today the CCR is recognized as one of the top-notch cancer registries in the nation and is one of the leading cancer registries worldwide. It has collected detailed information on more than 7 million cancer cases among Californians. Each year 175,000 new cancer cases are added to this state-of-the-art cancer surveillance program. To learn more about the CCR, please visit their website at

Q: Why is this important?

CTS researchers use CCR data to monitor the rates of cancers and deaths from those cancers within our study; to look at differences between groups of women in relation to their cancer risk, their treatment, and overall survival rates; and to help determine the possible causes of many types of cancer. Have you ever wondered if there is a cancer cluster in your neighborhood? Does your hospital want to do a study about risk factors for the cancers they are treating? CCR data makes investigating this possible. You can learn more about how CCR data are used at

Q: How do I know my information is kept private?

Researchers must go through a rigorous application and approval process with the State’s Committee for the Protection of Human Subjects (CPHS) Institutional Review Board before the CCR will release any cancer data and other personal information to those researchers. CPHS thoroughly reviews and evaluates each research proposal that is submitted to them to ensure patients’ rights are protected and the proposed research is justified.

Q: If the California Teachers Study is getting information from the CCR, how do you keep my data secure?

The CCR and the CTS follow very strict procedures to ensure your data is shared and stored with the highest degree of confidentiality. When we receive data from the California Cancer Registry, we are only permitted to use that information for research purposes. In addition, we separate all of those data from the other identifying information about participants, such as their name or address. That enables researchers to use the cancer data they need without seeing any of the personally identifying information about the patient in whom the cancer was diagnosed.

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