The American Cancer Society produces two major publications each year that provide in-depth cancer statistics for the United States:
- Cancer Statistics: Presents the estimated numbers of new cancer cases and deaths expected in the U.S. and in each state in the current year, which are among the most widely quoted cancer statistics in the world. Published in the American Cancer Society’s journal CA: A Cancer Journal for Clinicians, this article is meant especially for clinicians.
- Cancer Facts & Figures: A companion to the Cancer Statistics article, this consumer-friendly report, published annually since 1952, also includes the projected numbers of new cancer cases and deaths for the publication year. A unique feature of this publication is the Special Section, which is an in-depth review of a timely cancer topic.
In this interview, Rebecca Siegel, MPH, the American Cancer Society’s lead author on the reports, gives insights into what the key takeaways are from this year’s statistical publications.
Q. The Cancer Statistics article reports that more than 1.5 million cancer deaths have been averted over the past two decades due to a 22% drop in cancer mortality. What led to this decline in mortality?
A. The steady decline in cancer death rates since the early 1990s is due to fewer Americans smoking and advances in cancer prevention, early detection, and treatment. For example, lung cancer death rates in men have dropped 36% since 1990 because so many fewer men smoke as a result of increased awareness of the health hazards of smoking and the implementation of tobacco control measures, such as higher cigarette taxes and smoke-free laws.
Q. What cancers have seen the least amount of improvement and why?
A. Survival rates for some cancers, such as lung, liver, pancreas, and esophagus, remain low because these cancers are usually detected at a late stage and advances in treatment have been slower than for many other cancers. However, there is hope that screening for lung cancer among long-term or heavy smokers will increase early detection and reduce lung cancer mortality.
Q. The Cancer Statistics 2015 article shows that cancer death rates continue to vary widely across states, with southern states seeing the smallest decline and northeastern states seeing the largest drop. Why is this?
A. The large geographic variation in both death rates and trends reflects differences in risk factor patterns (e.g., higher smoking and obesity rates in southern states) as well as disparities in poverty and access to health care, which have increased over time.
Q. The reports find that from 2007 to 2011 the average annual decline in cancer death rates was slightly larger among men (1.8%) than women (1.4%). Why is that?
A. This is likely due to the large declines in prostate cancer death rates in men (3.2% per year) and the larger declines in lung cancer death rates in men than in women (2.9% per year versus 1.9%) during this time period.
Q. What are the key takeaways from these reports in terms of cancer incidence rates?
A. In men, there were rapid declines in incidence rates from 2007 to 2011 for the three major cancers – prostate (2.1% per year), lung (3.0% per year), and colorectal (3.6% per year). In women, there were declines in lung and colorectal cancer incidence rates similar to those in men, but rates of invasive breast cancer were stable.
Q. Cancer Facts & Figures, 2015 contains a special section about breast cancer in situ. What are the major findings from this report?
A. An estimated 60,290 new cases of in situ breast cancer will be diagnosed in women in the U.S. in 2015, most of which (83%) will be ductal carcinoma in situ, or DCIS. While DCIS cannot spread to other organs and cause serious illness or death, it has the potential if left untreated to evolve into invasive cancer and is considered a true cancer precursor. Studies of women with DCIS that was untreated because it was originally misclassified as benign found that 20% to 53% were eventually diagnosed with an invasive breast cancer. Incidence rates of DCIS by state are strongly associated with mammography prevalence.
Q. What do these reports point to as the most important steps people can take to lower their risk of getting cancer?
A. People have more control over their risk of developing cancer than they realize. There are many things you can do to reduce your risk of cancer, including not smoking, maintaining a healthy body weight throughout life, being physically active on a regular basis, and eating a healthy diet that is low in red and processed meat and high in fruits, vegetables, and whole grains.
Q. Lastly, but importantly, what do the reports tell us about the areas of research that could have the most significant impact in cancer prevention (and/or treatment)?
A. Unfortunately, much of what we already do know about preventing cancer is not widely applied, particularly among underserved populations. Implementing targeted cancer control programs in high-poverty settings could greatly reduce the national cancer burden. In addition, further research into the how cancer develops, especially for those tumors that are less well understood, such pancreas, will help advance the development of more effective treatments and accelerate progress in reducing cancer death rates.