Introduction

Each year, breast cancer strikes more than 25,000 California women and kills over 4,000. Breast Cancer in California: A Closer Look summarizes information from Breast Cancer in California, 2003, a special report on breast cancer, published in 2004 by the California Cancer Registry. The Registry's report is written in scientific terms. The California Breast Cancer Research Program has produced this booklet because we wanted to make the Registry's research findings available to a wider public.

The California Cancer Registry

The California Cancer Registry, a state government program, collects information about every case of breast cancer, and several other types of cancer, reported in California. It does not collect tissue samples of tumors. Physicians, hospitals, and other health care providers send information about every cancer case they diagnose to one of nine regional cancer registries, which in turn pass the information on to the statewide Registry in Sacramento. The Registry makes the information available to researchers and the public, but it also has strict safeguards to protect the privacy of cancer patients. As a result, the California Cancer Registry is one of the world's leading cancer registries, and its data meet the highest standards for quality and completeness.

The Importance of Collecting Information About Breast Cancer in California

Collecting information—about who gets breast cancer, their tumors, and the results of their treatments—is important for several reasons. Information can help scientists understand how the disease develops and how to better treat it. Information can help scientists figure out if a strategy, such as the widespread use of mammograms to detect cancer, is saving lives. Information can help pinpoint which women aren't getting medical services that could help them survive the disease, and can also help women make decisions about their own health.

Because California has a diverse population—both urban and rural, with many ethnic groups—information from our state can identify differences in breast cancer rates and survival between different groups of people, which may provide clues to causes and progression of breast cancer.

The California Cancer Registry has been collecting data on breast cancer statewide since 1988. The facts in Breast Cancer in California: A Closer Look are drawn from the years 1988–1999. During those twelve years, over 250,000 California women learned they had breast cancer, and 50,556 died from the disease.

Why the Information Here Stops in 1999

There are several reasons why the information presented here is not more current. Physicians and hospitals have up to six months after diagnosis to report cancer cases. Then the Registry staff must compile and analyze the data. After that, the scientists who produced the information in this booklet needed time to do their research. Also, starting in the year 2000, cancer statistics in the U.S. are calculated with a different standard for the population as a whole. The new standard better matches the current age distribution of the U.S. population, but it makes comparisons between the years before and after 2000 less accurate.

Looking at Breast Cancer in Our State from a Variety of Angles

The information we present here is based on research into the California Cancer Registry's data by more than 15 scientists. The scientists used a variety of ways of dividing the information into categories and a variety of statistical methods. This allowed them to better understand breast cancer in California from different angles. We interpreted some of their research further. Breast cancer is a complex disease. Having different experts look at it from different angles gives a fuller picture of this medical puzzle.