Breast Cancer in California

Every two hours, on average, a California woman dies of breast cancer.

During 2000, an estimated 20,000 California women were diagnosed with the disease.Nearly 200,000 women in our state are living with a past or present diagnosis of breast cancer. While many are long-term survivors, some are battling a recurrence and others are fighting for their lives. Today, no woman who has survived breast cancer can be guaranteed that it won't return.

Because of early detection through widespread mammogram screening, a California woman diagnosed with breast cancer today has a better chance of surviving than in the past. Since 1973, the breast cancer death rate in our state has dropped 20%. However, California women are more likely to get breast cancer today than in 1973. The breast cancer rate for our state rose alarmingly until 1988, and has gone down only slightly since.

Are Rates of Breast Cancer Really Going Down?

The rate of breast cancer was rising in California and in the U.S. about 1% every year throughout most of the last century. In the 1990's, however, cancer registries started reporting that the rate of breast cancer was leveling off, and then that it was beginning to fall. However, while the rates of invasive breast cancer were decreasing, the rates of pre-cancerous lesions called "ductal carcinoma in situ" (DCIS) were increasing.

Scientists believe that breast cancer takes years to develop, and that there are many changes that happen on the route from normal breast cell to breast cancer. One of the stages on the path to breast cancer is DCIS. DCIS is considered "pre-cancer," rather than cancer, because it does not leave the breast ducts. This was once a very rare diagnosis because DCIS does not form lumps, and cannot be detected by breast examination. More women are being diagnosed with DCIS because more women are receiving mammograms, and DCIS can appear as an abnormality on a mammogram. Although the diagnosis of DCIS was very rare before mammography became widespread, autopsies on women who died of other causes indicate that 5-20% of women probably have undiagnosed DCIS with no symptoms when they die.

In past years, when DCIS was not often detected, an unknown percentage of the women with this condition went on to develop breast cancer. Their numbers added to the numbers of women then being counted as having breast cancer in California. Today, women with DCIS are being diagnosed and treated before they develop breast cancer and these diagnoses are not counted as invasive breast cancer. It turns out that the rate of DCIS has increased over the past 10 years by the same amount that breast cancer has decreased over the same time period. Thus, the rate of invasive breast cancer has decreased, but the rate of DCIS plus breast cancer has remained constant. There has been a shift in the diagnosis of the disease to earlier in the disease process.

This is both good news and bad news. One of our goals must be to detect and treat breast abnormalities before they turn into cancer. And the shift in rates from invasive breast cancer to DCIS indicates that we are beginning to do this. On the other hand, the treatment for DCIS is the same as the treatment for early stage breast cancer (surgery with either removal of the lesion and the surrounding tissue or removal of the entire breast). So the rate of women undergoing surgery for breast cancer or pre-cancer is remaining constant. Thus this shift from invasive breast cancer to DCIS makes little difference in the physical and mental repercussions of diagnosis.

Regardless of whether California's breast cancer rate has changed, the numbers are much too high. If present trends continue, 1 out of 8 California women will have breast cancer at some point in her lifetime. This relentless toll underlines the urgent need for more research into prevention. Keeping breast cancer from happening in the first place is the best way to save lives. This is why the California Breast Cancer Research Program makes prevention research a priority.

Not an Equal Opportunity Killer

When it comes to breast cancer in California, ethnicity makes a difference. White women are most likely to get the disease, followed closely by black women, then Asian/ Pacific women, with the lowest rate among Hispanic women. Although the death rate has dropped in the last 12 years, most of the gains have come for white women. Black women have the highest death rate, even though they are less likely than white women to get the disease. Death rates for Asian/Pacific and Hispanic women, although they were lower to begin with, have not improved in recent years. Income level also matters. Low-income women are less likely to survive breast cancer, in part because their tumors are more likely to be caught later, when treatment is less successful.

The number of precancerous breast conditions being caught through mammogram screening has consequences beyond throwing into question California's breast cancer rate. Early detection also has consequences for California women's lives. It saves some, but leads to others receiving disfiguring and unnecessary treatment.

Catching precancerous breast conditions early saves some women's lives, because it keeps their cancer from progressing to a stage where treatment is less effective. But there's currently no way to tell whether a precancerous condition will turn into cancer. So some women who would have remained cancer-free, and unaware of any problems throughout their lives, are being treated, solely as a result of early detection.

Precancerous conditions are frequently found in more than one place in the breast, so the treatment is often removal of the entire breast. Women who have a small cancer may only have the lump removed, while a woman with DCIS often receives the more disfiguring treatment. It may have prevented her having cancer, or she may not have needed it at all.

Similarly, the breast cancer death rate is going down at the cost of unnecessarily treating large numbers of women, simply because there is no way to identify who will be helped by treatment and who will not. One example is the current treatment for women with Stage 2 breast cancer (breast cancer is classified from Stages 1 to 4, each progressively more serious and life-threatening).

A women under age 50 with a Stage 2 tumor has a 71% chance of surviving without chemotherapy. With chemotherapy, her odds rise to 78%. This means that for every 100 women who get chemotherapy, 22 will die anyway, 71 would have survived without it, and only 7 will be helped. To keep 7 women alive, 93 others receive an often debilitating treatment that does not help them, but can cause long-term health damage.

If there were a way to test those 100 women with Stage 2 breast cancer and pinpoint which 7 would benefit from chemotherapy, it would be a big advance. This is just one example of the fairly crude state of today's breast cancer treatment. Individual women with individual cancers are all given the same treatment, although some don't need it and others won't be helped. This is why the California Breast Cancer Research Program funds research into possible new methods for identifying which women will be helped by which treatment, and for more effective new treatments. It's why we encourage researchers to take risks and investigate new approaches. We're working toward a future where any woman who has breast cancer can receive treatment with confidence that the treatment is needed and effective against the disease in her individual case.

Men and Breast Cancer
Breast Cancer is rare among men. In California this year, 130 men were diagnosed with the disease, and 35 men died. Breast cancer in men is almost always due to inherited abnormal genes.

References:
Rates of breast cancer and DCIS in California: Kwong SL, Perkins CI, Morris CR, Cohen R, Allen M, Schlag R, Wright WE. Cancer in California: 1988-1998. Sacramento, CA: California Department of Health Services, Cancer Surveillance Section, December 2000. Survival rates with and without chemotherapy: Polychemotherapy for early breast cancer: an overview of the randomised trials. Early Breast Cancer Trialists' Collaborative Group. Lancet 1998 Sep 19;352(9132):930-42