California Women's Chances of Getting Breast Cancer

A California woman's chance of getting breast cancer is 1 in 8. But your chance—or the chance of a woman you care about—is probably different.

If present trends continue, one out of eight California women will get breast cancer at some point in their lives. Yet a 50-year-old California woman today faces one chance out of 84 that she will develop the disease over the next five years.

The risk of getting breast cancer over a lifetime and the risk at any particular point in a woman's life are very different.

Lifetime Risk

The table below shows the lifetime risk for invasive breast cancer—the type that can spread to other parts of the body and cause death—for California women from four ethnic groups.

However, there are several reasons why these figures may not be accurate. They are based on breast cancer cases diagnosed in California between 1995 and 1999, and will only come true if the state's breast cancer rate stays the same, which is unlikely to happen over a span of more than 80 years. What's more, the figures in this table give the risk for a newborn baby girl. An adult woman's risk is not the same.

As a woman ages, her risk goes up for getting breast cancer within the next five years. But her lifetime risk drops for every year she lives without getting the disease. For example, if a California woman has lived to age 60 and not yet had breast cancer, her chance of getting it is 1 in 11, not 1 in 8.

Figure 5

Looking at Risk over the Next 5-20 Years

Another way to look at a woman's chances of getting breast cancer is to look at the risk for women of her age over a given number of years. The shorter the time period being considered, the more likely it is that the prediction based on current trends will come true.

The tables below and on the next page show the risk of getting breast cancer over the next 5, 10, or 20 years for women of various ages. They are based on cases diagnosed in California between 1995 and 1999.

Chance That California Women At Various Ages Will Be Diagnosed With Invasive Breast Cancer in the Next 5 Years

Current Age

All CA Women

White

African American

Hispanic

Asian/Pacific Islander

30

1 in 883

1 in 845

1 in 604

1 in 1,035

1 in 929

40

1 in 189

1 in 175

1 in 184

1 in 235

1 in 182

50

1 in 84

1 in 73

1 in 89

1 in 128

1 in 99

60

1 in 59

1 in 50

1 in 66

1 in 87

1 in 86

70

1 in 46

1 in 40

1 in 63

1 in 76

1 in 89

 

Chance That California Women At Various Ages Will Be Diagnosed With Invasive Breast Cancer in the Next 10 Years

Current Age

All CA Women

White

African American

Hispanic

Asian/Pacific Islander

30

1 in 271

1 in 253

1 in 219

1 in 328

1 in 270

40

1 in 71

1 in 64

1 in 73

1 in 94

1 in 74

50

1 in 38

1 in 33

1 in 42

1 in 58

1 in 46

60

1 in 28

1 in 24

1 in 33

1 in 43

1 in 44

70

1 in 24

1 in 21

1 in 31

1 in 38

1 in 47

 

Chance That California Women At Various Ages Will Be Diagnosed With Invasive Breast Cancer in the Next 20 Years

Current Age

All CA Women

White

African American

Hispanic

Asian/Pacific Islander

30

1 in 57

1 in 51

1 in 56

1 in 74

1 in 59

40

1 in 25

1 in 22

1 in 28

1 in 36

1 in 29

50

1 in 17

1 in 14

1 in 20

1 in 25

1 in 23

60

1 in 14

1 in 12

1 in 18

1 in 22

1 in 24

70

Since estimates stop at age 85, 20-year projections not possible.

 

How This Research Was Done

Researchers used information on the number of cases of breast cancer collected by the California Cancer Registry for the years 1995–1999. Information on the population figures for women of various ethnic groups, and death rates from other causes, came from the Demographic Research Unit, California Department of Finance, a part of the state government. Researchers calculated the chances that a California woman, over a period of years, would either get breast cancer or die of another cause without having gotten breast cancer. All women who were predicted to do neither of these, based on trends in 1995–1999, became part of the population at risk for breast cancer during the next time period. Information in this section comes from Chapter 6 of Breast Cancer in California, 2003, “Risk of Developing Invasive Female Breast Cancer in California,” by Cyllene R. Morris, D.V.M., Ph.D.