Trends in United States Cancer Mortality



Trends in United States Cancer Mortality


Tim E. Byers



INTRODUCTION

Cancer incidence registries now cover nearly all of the US population. State-based vital records systems and aggregate national systems regularly report trends in both cancer incidence and mortality, and national surveys routinely monitor cancer-related risk factors in the population. These surveillance systems have documented substantial changes in both risk factors for cancer and in cancer incidence and mortality rates in the United States over the past 3 decades. In 1996, the American Cancer Society (ACS) set an ambitious challenge for the United States: to reduce cancer mortality rates from their apparent peak in 1990 by 50% in the 25-year period ending in 2015.1 In 1998, the ACS then challenged the United States to also reduce cancer incidence rates from their peak in 1992 by 25% by the year 2015.2 In this chapter, we will examine trends in cancer risk factors as well as trends in cancer incidence and mortality rates in the United States over the 25-year period between 1990 and 2015.


CANCER SURVEILLANCE SYSTEMS

Collecting cancer incidence rates is largely a state-based activity in the United States, because cancer is a reportable disease in all states. The Centers for Disease Control and Prevention (CDC) organizes all state-based cancer registries within the National Program of Cancer Registries, which now reports collective data on cancer incidence from over 40 different state-based registries, providing data that meets strict quality standards.3 The National Cancer Institute has supported high-quality cancer incidence and outcomes registration in selected states and cities since 1973 within the Surveillance, Epidemiology, and End Results (SEER) Program.4 The most precise measures of long-term trends in cancer incidence come from SEER-9, a set of nine SEER registries that together include about 10% of the US population. The populations included in the SEER-9 registries document the most detailed history of cancer trends beginning in the 1970s based on highly standardized cancer case ascertainment, staging, treatment, and outcomes. Deaths from cancer are well ascertained in all states via state-based vital records, which are aggregated into annual national mortality reports by the CDC’s National Center for Health Statistics.5 Each year, the ACS, the National Cancer Institute, and the CDC publish a Report to the Nation on trends in cancer incidence and mortality in the United States.6 Trends in the prevalence of behavioral factors that affect cancer risk are tracked by the Health Interview Survey, an ongoing, in-person interview of a nationally representative sample of adults, and in annual reports by the Behavioral Risk Factor Surveillance System, a continuously operating telephone-based survey operated by state departments of health and organized by the CDC.7


MAKING SENSE OF CANCER TRENDS

Understanding the reasons for cancer trends requires understanding trends in cancer-related risk factors. For factors like tobacco, relating trends in exposure to trends in rates is easy, because those effects are large and single. However, for many other cancer risk factors, because effects are much smaller and multifactorial, simple correlations over time are less apparent. In most situations, all that maybe possible are crude qualitative relationships between temporal trends in cancer risk factors and subsequent trends in cancer rates. Statistical methods such as linear regression joinpoint analysis can tell us when inflections in cancer trends occur, but accounting for the precise reasons for changing rates is often impaired by our incomplete knowledge about the interacting impacts of variations in cancer screening, diagnosis, and treatment, and by uncertainties about latencies between interventions and outcomes.8


TRENDS IN CANCER RISK FACTORS AND SCREENING

Trends in major cancer risk factors have been mixed (Table 12.1). Although the downward trends in tobacco smoking among adults that began in the 1960s slowed after 1990, there has been a continuing downward trend in the number of cigarettes smoked per day by continuing smokers.9 Obesity trends have been adverse among both men and women since the 1970s, with more than a doubling of the prevalence of obesity between 1990 and 2010. Long-term trends in the use of hormone replacement therapy (HRT) are not routinely monitored in the Behavioral Risk Factor Surveillance System (BRFSS), but HRT use increased substantially in the last 2 decades of the 20th century. Then, following the 2002 publication of the Women’s Health Initiative trial, which showed clear adverse effects of HRT, there was a rapid and substantial drop in HRT use.10,11 The use of endoscopic screening for colorectal cancer (sigmoidoscopy or colonoscopy) has increased substantially in recent years, approximately doubling since the mid 1990s, so that, as of 2010, about two-thirds of Americans age 50 and older reported ever having had an endoscopic examination. Mammography use increased progressively through the 1990s, but mammogram rates then leveled off after 2000.12 Widespread prostate-specific antigen (PSA) testing began in the mid to late 1980s, then increased substantially during the 1990s. By 2002, a majority of US men age 50 and older reported having been tested.


CANCER INCIDENCE AND MORTALITY

In this chapter, we describe and discuss cancer trends for the time period 1990 through 2010 using cancer incidence data from the SEER-9 registry (Table 12.2 and Fig. 12.1) and US cancer mortality data from the National Center for Health Statistics (Table 12.3).4,5 All rates were age-adjusted to the US 2000 standard population by the direct method, using 10-year age intervals.


Lung Cancer

The lung is the second leading site for cancer incidence and the leading site for cancer death among both men and women in the
United States.6 There are now more deaths from lung cancer in the United States than from the sum of colorectal, breast, and prostate cancers. Trends in lung cancer incidence and mortality have been nearly identical because there are few effective treatments for lung cancer, and survival time remains short. Lung cancer trends follow historic declines in tobacco use, lagged by about 20 years.13 Between 1965 and 1985, tobacco use among US adults dropped substantially, and more in men than in women. Lung cancer mortality rates began to decline among men in 1990, but rates increased among women throughout the 1990s. The stabilization of lung cancer incidence trends among women from 2000 to 2005 and the beginning of a decline in the period 2005 to 2010 foretells a coming persistent decline in lung cancer mortality among women in the United States.








TABLE 12.1 Trends in Risk Factors and Cancer Screening Practices in the United States, 1990-2010a





























































































































































































Men


Women


Both Genders



Smoking


PSA Screening


Smoking


Mammography


Obesity


CRC Screening


1990


24.9



21.3


58.3


11.6



1991


25.1



21.3


62.2


12.6



1992


24.2



21.0


63.1


12.6



1993


24.0



21.1


66.5


13.7



1994


23.9



21.6


66.6


14.4



1995


24.8



20.9


68.6


15.8


29.4


1996


25.5



21.9


69.2


16.8



1997


25.4



21.1


70.3


16.6


32.4


1998


25.3



20.9


72.3


18.3



1999


24.2



20.8


72.8


19.7


43.7


2000


24.4



21.2


76.1


20.1



2001


25.4



21.2



21.0



2002


25.7


53.9


20.8


75.9


22.1


48.1


2003


24.8



20.2





2004


23.0


52.1


19.0


74.7


23.2


53.0


2005


22.1



19.2



24.4



2006


22.2


53.8


18.4


76.5


25.1


57.1


2007


21.2



18.4



26.3



2008


20.3


54.8


16.7


76.0


26.6


61.8


2009


19.5



16.7



27.1



2010


18.5


53.2


15.8


75.2


27.5


65.2


CRC, colorectal cancer; PSA, prostate-specific antigen.


aMedian percent of the population across all states in the Behavioral Risk Factor Surveillance System. The survey covered such areas as body mass index and was based on self-reported height and weight. Questions included: Are you a regular cigarette smoker? Have you ever had a sigmoidoscopy or proctoscopic examination? For women age 40 and older, the following question was included: Have you had a mammogram in the past 2 years? For men aged 50 and older, the following question was included: Have you had a PSA test in the last 2 years? (From Centers for Disease Control and Prevention. Behavioral Risk Factor Surveillance System Web site. http://cdc.gov/brfss.)


The effectiveness of annual examinations by use of chest radiographs in reducing lung cancer mortality was studied as part of the Prostate, Lung, Colorectal, Ovary (PLCO) trial, and the effectiveness of annual screening by low-dose computed tomography (LDCT) of the lung fields was studied in the National Lung Screening Trial (NLST).14,15 In brief, screening with standard chest radiography finds more cancers earlier but does not affect mortality, whereas screening with LDCT reduces the risk of death from lung cancer by at least 20%.14,15 Therefore, both the ACS and the US Preventive Services Task Force have issued recommendations that favor informed decision making for lung cancer screening using LDCT.16,17

Only gold members can continue reading. Log In or Register to continue

Stay updated, free articles. Join our Telegram channel

Jun 28, 2016 | Posted by in ONCOLOGY | Comments Off on Trends in United States Cancer Mortality

Full access? Get Clinical Tree

Get Clinical Tree app for offline access