You are at lunch with your friends. The person to your right says, “I hate October. All this fuss about breast cancer when over 90% of patients survive. Why don’t they have ribbons for the really deadly diseases?”
Your friend on the left says, “Forty thousand people die from breast cancer every year, and that hasn’t changed for years. All those pink ribbons haven’t done a bit of good.”
Your friends stare daggers at each other. Then either a loud argument ensues or an icy silence falls. You go home and look up the statistics they quoted. Both of your friends are right. How can that be?
Understanding statistics can be complicated. Every October news reports and fund-raising letters from cancer charities throw numbers at you. But how can you make sense of them?
The American Cancer Society reports an estimated 232,570 new cases of invasive breast cancer in 2013 with 62,570 estimated new cases of non-invasive breast cancer (carcinoma in situ). They say that 39,620 people died from breast cancer in 2013. In 2003, the number of deaths was 39,800. So for the last ten years about 40,000 people died from breast cancer annually.
The Center for Disease Control reports that from 2001-2010 the incidence level of breast cancer for all women has remained level. They say the rate of death during that same period has decreased by 2% per year.
How can the death rate be going down while the number of deaths is 40,000 year in and year out? Our population is growing, and people are living longer. Two important terms to look for when you see a chart showing statistics about health problems are “cases per 100,000” and “age-adjusted.”
When public health officials want to know if a health problem is getting better, they look at the number in units of 100,000. Because the characteristics of a population change over time, statisticians can also adjust their numbers based on those changes. For breast cancer, the most important factor to adjust for is age. Age and being female are the main risk factors for getting breast cancer. The population in the United States is getting older, so naturally there will be more cases. Some numbers you see may say “age-adjusted” and others may just give you the total number of cases.
Keeping those factors in mind, here are some important numbers to know about breast cancer.
Breast cancer is the second most common cancer in women, right after skin cancers, and only lung cancer causes more cancer deaths in women. It is a big public health problem. Currently there are about 2,800,000 breast cancer survivors in the United States many of whom will have continuing health problems related to their cancer or its treatment.
The median age at diagnosis for all types of breast cancer is 61 years, and the median age at death is 68 years. A median is a type of average that means half the cases were above it and half below it. Breast cancer rates have fluctuated over the years, but since doctors reduced the use of hormone replacement therapy, the rate has gone down.
Survival rates are getting better. in 1975, 75.2% of all breast cancer patients lived five years. By 1990 that rate had improved to 84.6%, and in 2006, 90.6%. Public health officials attribute this improvement to earlier detection and to improved treatment. However, breast cancer tends to be a slow-growing type of cancer, so many people who survive five years will recur much later. The 20-30% of breast cancer patients who recur usually don’t show up in the five-year statistics. They are part of the approximately 160,000 living with metastatic breast cancer in the United States.
It is also important to consider the stage and type of cancer when looking at survival rates. For localized cancer that hasn’t spread to any lymph nodes, there is a 98.5% five-year survival. This is the cheerful number that you will hear at many breast cancer rallies during October. This is also the number that has lulled many people into thinking that breast cancer isn’t a big deal anymore. If the cancer has spread to the lymph nodes, the rate is 85.6% five-year survival. If the cancer has metastasized to distant organs, it drops to 25% five-year survival.
Survival rates also vary according to the hormone and Her2 status of a tumor. Survival rates for triple negative and inflammatory breast cancer are lower than for other types. Cancer incidence and survival rates also vary according to race, ethnic background, and location. For example, African-American women have a lower incidence of breast cancer, but a higher mortality rate. They tend to have the more aggressive types of breast cancer like inflammatory and triple negative, and they have less access to treatment.
The American Cancer Society is one of several excellent sources for looking at cancer stats from different perspectives. You can check out how your state compares to others. You can see how common breast cancer is in your age and ethnic group. The National Cancer Institute is another good source for accurate cancer numbers. One tool they have that can help you visualize what has been happening with cancer is an animation tool that shows changes over time.
What does all of this mean to you? As a predictor of what will happen to you, nothing. Even if you are in a high-risk age and ethnic group living in a state with a high incidence of breast cancer, that doesn’t mean that you will get it. If you appear to have no risk factors, you must still be vigilant. These numbers are useful for public health officials. They are part of how researchers figured out that hormone replacement therapy was a big risk factor for breast cancer. But they have no value in predicting outcomes for individuals.
However, It’s important to have a sense of how breast cancer fits into the overall picture of health issues. It is a major cause of death for women right after heart disease and lung cancer. Knowing this can help you make decisions about how you want to spend your money and time. If you live in a state with a higher than average death rate from breast cancer, you may want to investigate why and get involved in changing the conditions in your area that have led to high mortality.
Many people will be asking you for money during October. You can read charitable appeals carefully and make sure that you are giving to groups that will make a real difference in research and support for people with breast cancer.
When you understand the breast cancer numbers, you can be both encouraged that progress is being made and aware that much more remains to be done. Then you can take action to make a difference.
Breast Cancer Statistics. Center for Disease Control. Accessed from http://www.cdc.gov/cancer/breast/statistics/index.htm Oct. 1, 2014.
Breast Cancer Facts and Figures. American Cancer Society. Accessed from http://www.cancer.org/research/cancerfactsstatistics/breast-cancer-facts-figures Oct. 1, 2014.
Breast Cancer Facts and Figures 2013-2014. American Cancer Society. Accessed from http://www.cancer.org/acs/groups/content/@research/documents/document/acspc-042725.pdf Oct. 1, 2014.
Cancer Statistics Animator. U. S. Mortality by Age Group Animated from 1969-2011. National Cancer Institute. Accessed from http://seer.cancer.gov/canstat/animator/#v1=040001;o=0011633;y=2011f Oct. 1, 2014.
Published On: October 01, 2014