Annual Report to the Nation on the Status of Cancer, 1975–2010, Featuring Prevalence of Comorbidity and Impact on Survival Among Persons with Lung, Colorectal, Breast or Prostate Cancer: Questions and Answers
1. What is the purpose of this report and who created it?
This report provides a yearly update of cancer incidence (new cases), mortality (death) rates, and trends in these rates in the United States. The special feature section of this year’s Report highlights the prevalence of comorbidity and its impact on survival among persons 66 years of age and older who were diagnosed with lung, colorectal, breast or prostate cancer. Comorbidities are defined as coexisting medical conditions that are distinct from the principal cancer diagnosis.
The American Cancer Society (ACS), the Centers for Disease Control and Prevention (CDC), the National Cancer Institute (NCI), part of the National Institutes of Health, and the North American Association of Central Cancer Registries (NAACCR) have collaborated since 1998 to produce the Annual Report to the Nation on the Status of Cancer.
2. What are the sources of the data?
Cancer mortality information in the U.S. is based on causes of death reported by physicians on death certificates and filed by each state’s vital statistics offices. The mortality information is processed and consolidated in a national database by the CDC through the National Vital Statistics System, which covers the entire United States.
Information on newly diagnosed cancer cases occurring in the U.S. is based on data collected by registries in the NCI's Surveillance, Epidemiology, and End Results (SEER) Program and CDC's National Program of Cancer Registries (NPCR). NAACCR evaluates data annually from the registries of both programs and provides combined data for this analysis.
Long-term (1992-2010) overall incidence trends for all cancer sites combined, childhood cancers, and for the 15 most common cancers were based on SEER incidence data covering about 13 percent of the U.S. population. Data from combined SEER and NPCR population-based cancer registries were used to estimate cancer incidence rates and short-term (2001-2010) trends for five major racial and ethnic groups: white, black, Asian and Pacific Islander, American Indian/Alaska Native, and Hispanic. For the time period 2006-2010, 46 registries (covering 90.1 percent of the U.S. population) met NAACCR data quality criteria, and for the time period 2001-2010, 42 registries (covering 85.4 percent of the U.S. population) met these criteria.
3. Which reporting periods were chosen as a main focus of the report?
The period from 2006-2010 was used for describing the U.S. burden of cancer (rates), and the period from 2001-2010 was used for describing trends in cancer incidence and death rates for five major racial and ethnic groups. The period from 1975-2010 was chosen to provide the best perspective on long-term trends in cancer death rates among all races combined, while the period from 1992-2010 was chosen to provide the best perspective on long-term incidence trends.
4. What is detailed in the special feature section of this year’s report?
In this year’s special feature section, the authors highlight the prevalence of comorbidity among older persons and its impact on survival among persons diagnosed with lung, colorectal, breast or prostate cancer. For cancer patients, survival and the probabilities of dying of their cancer and of other causes by comorbidity level, age, and stage were calculated. The comorbidity index score in this report used claims from SEER-Medicare cancer patients diagnosed from 1992 through 2005.
Update on Incidence and Mortality Trends for All Cancer Sites Combined and the Most Common Cancers
5. What is happening with cancer incidence trends overall?
Incidence rates represent the number of reported new cases over a period of time per 100,000 people in the general population. From 2001-2010, age-adjusted incidence rates for all cancers combined declined 0.6 percent per year among men, were stable among women, and increased by 0.8 percent per year among children 14 years and under as well as for children 19 years of age and younger (see Table 1 of the Report).
While declines in cancer mortality rates are always good news, changes in incidence rates may represent both good and bad news. Declines in cancer incidence rates that occur as a result of decreased modifiable risk factors or increased use of screening tests (colorectal and cervical cancer screening) that allow the detection and removal of precancerous lesions are good news. However, a drop in screening rates can also make it appear that incidence rates are lower while in fact some cancers will not be detected early and may not be discovered until they are at a more advanced stage.
6. What is happening with long-term incidence trends for the most common cancers?
From 2001-2010, age-adjusted incidence rates decreased for six of the 17 most common cancers among men (prostate, lung, colon and rectum, stomach, brain and other nervous [brain], and larynx). In contrast, incidence rates increased among men for eight cancers (kidney and renal pelvis [kidney], pancreas, liver and intrahepatic bile duct [liver], non-Hodgkin lymphoma [NHL], thyroid, leukemia, melanoma of the skin [melanoma], and myeloma) during the same time period (see Table 1 of the Report).
Among women, incidence rates from 2001-2010 decreased for six of the 18 most common cancers (colon and rectum, urinary bladder [bladder], cervix uteri [cervix], oral cavity and pharynx [oral], ovary, and stomach), and increased for eight cancers (thyroid, melanoma, kidney, pancreas, leukemia, liver, myeloma, and corpus and uterus NOS [uterus]).
Note that findings are presented for the top 17 cancers among men and 18 cancers among women in order to accommodate the top 15 cancers for all races and ethnicities combined, and for each major racial and ethnic group. Cancer represents over a hundred different types of diseases, based on where it occurs in the body as well as the biological features of the tumor. The Report uses broad groupings to present cancer statistics on rates and trends; however, reports for more specific types of cancer require customized analyses. As the understanding of the biological and genetic features of cancers evolve and are reported in medical records, experts may revise how cancers are grouped for statistical reporting (see Table 3 of the Report).
7. What is happening with cancer mortality trends overall?
Overall age-adjusted cancer death rates continued to decline, a trend that began in the early 1990s. From 2001-2010, death rates decreased by 1.8 percent per year among men, by 1.4 percent per year among women, by 1.9 percent per year among children ages 0-14, and by 2.1 percent per year among children 0-19 years (see Table 2 of the Report). Age-adjusted death rates are the best indicator of progress against cancer, although other measures, such as quality of life, are also important.
8. What is happening with death rates for the most common cancers among men and women?
During the most recent 10-year period (2001-2010), death rates among men decreased for 11 of the 17 most common cancers (lung, prostate, colon and rectum, leukemia, non-Hodgkin lymphoma, esophagus, kidney, stomach, myeloma, oral cavity and pharynx, and larynx) and increased for four others (cancer of the pancreas, liver, melanoma, and soft tissue including heart) (see Table 2 of the Report).
During the same period, death rates among women decreased for 15 of the 18 most common cancers (lung, breast, colon and rectum, ovary, leukemia, non-Hodgkin lymphoma, brain and other central nervous system, myeloma, kidney, stomach, cervix, bladder, esophagus, oral cavity and pharynx, and gallbladder) and increased for cancers of the pancreas, liver, and uterus.
9. If cancer death rates continue to fall, does that mean the number of people dying from cancer will also continue to fall?
Not necessarily. The data described in the report are rates (number of deaths per 100,000 persons in the U.S.) and are adjusted for age so they can be compared across groups that vary by factors such as race, time period, and regions with different age structures (i.e., some areas have higher concentrations of older people while others have more young people). The actual number of people dying from cancer (sometimes called the count) can be influenced by several factors, including the growth in the number of older people in the U.S. (cancer is primarily a disease of aging), as well as an increase in the size of the population.
Therefore, although the cancer death rate may go down during a particular period, the actual number of cancer deaths could go up because the number of older Americans is increasing and the overall size of the population is increasing,
10. What is happening with childhood cancer rates?
Cancer incidence rates increased 0.8 percent each year from 1992-2010 among children ages 14 or younger and also ages 19 or younger. However, considerable progress has been seen for many types of childhood cancers, resulting in very long-term overall declines in death rates for cancer among children. In the most recent 10-year period, cancer death rates among children ages 0 to14 declined 1.9 percent and children ages 0 to 19 declined 2.1 percent per year; for a more recent period (2006-2010), the decline was 2.4 percent per year.
Comorbidity and Survival of Cancer Patients
11. Why is measuring comorbidity important?
Comorbidity is the condition of having two or more diseases at the same time. Measures of comorbidity contribute to understanding how multiple diseases affect an individual’s health status, impact medical management and treatment decisions, and predict outcomes. Incorporating comorbidity measures into treatment decisions may allow for more accurate assessment of risks and benefits of different forms of treatment because cancer patients and survivors with multiple comorbidities likely require coordinated care and support.
12. How were cancer survival estimates determined when looking at comorbidities?
Investigators linked SEER cancer registry data with Medicare claims from the Center for Medicare and Medicaid Services (CMS) that reported on the presence or absence of comorbidities among patients at age 66 or older, one year prior to their cancer diagnosis. This data was then used to calculate survival estimates that were based upon comorbidity levels and cancer stage at diagnosis. Cancer stage was included in this survival model because patients with advanced stage cancer have higher mortality rates than those diagnosed with earlier stage cancer, even after accounting for comorbidity status.
Specifically, for every cancer patient in the study, the authors looked at three outcomes: if a patient was still alive; if they died of their diagnosed cancer; or if they died of some other cause. They characterized each cancer patient by their type of cancer, stage (extent of disease), age, and comorbidity level.
Relative survival, a complex mathematical calculation that takes into account various factors in the general population, is typically presented in cancer statistical reports. In this Report, the authors present crude survival measurements that take into account the risks of dying from non-cancer causes as well as the risks of dying of cancer, as these are more useful for clinical purposes.
Survival measures in this Report are presented as survival (due to any cause of death), probabilities of dying of causes due to the specific cancer, and probabilities of dying of other causes. In general, age and the presence of comorbidities in the year prior to diagnosis influence the probability of dying of other causes while stage of the disease (how advanced is the cancer) is more predictive of the probability of dying of cancer.
13. What cancer types showed the highest prevalence of comorbidities from 2001-2010?
Among the top four cancers occurring in over half of older patients, the prevalence of comorbidities was:
- Lung cancer: 52.9 percent
- Colorectal cancer: 40.7 percent
- Breast cancer: 32.2 percent
- Prostate cancer: 30.5 percent
One or more comorbidities were present in 31.8 percent of non-cancer patients (see Table 5).
14. What comorbidities were identified in patients in the year prior to cancer diagnosis?
The comorbidities identified in patients in the year prior to cancer diagnosis were based on Medicare claims reports, and included (see Table 5):
- Acute myocardial infarction (heart attack)
- Acquired immunodeficiency syndrome (AIDS)
- Cerebrovascular disease (stroke)
- Chronic renal failure (chronic kidney disease)
- Cirrhosis/chronic hepatitis
- Congestive heart failure
- Chronic obstructive pulmonary disease (COPD, lung disease)
- Diabetes or diabetes with sequelae
- History of myocardial infarction (irreversible heart disease)
- Liver disease
- Rheumatologic disease (arthritis)
- Ulcer disease
- Vascular disease
15. What comorbidities were most prevalent among cancer patients?
Among the comorbidities identified, the most common types were (see Table 5):
- Diabetes: 16.0 percent
- COPD: 15.5 percent
- Congestive heart failure: 9.7 percent
- Cerebrovascular disease: 6.0 percent
16. How were comorbidities ranked for severity?
Comorbidities were grouped into three levels using scores calculated from claims data and statistical models for older persons in the SEER-Medicare linked database:
- Low comorbidity conditions usually do not require adjusting cancer treatment. Conditions associated with low comorbidity include ulcer or rheumatologic disease (ulcer, arthritis or other rheumatic disease).
- Moderate comorbidity conditions that may require modifying cancer treatment. Conditions include diabetes, vascular disease, paralysis, and AIDS.
- Severe comorbidity involves severe illness that always requires adjusting cancer treatment. Conditions associated with severe comorbidity include chronic obstructive pulmonary disease (COPD), liver dysfunction, chronic renal failure, dementia and congestive heart failure. Patients in the severe group generally have multiple comorbidities.
17. How does comorbidity influence the survival of breast cancer patients?
For women with breast cancer diagnosed at an early stage of the disease, 5-year survival varied by age and comorbidity level. For example, for women ages 66-74 with early stage disease, the probability of death for low or moderate comorbidity levels was almost double the probability of death compared to women with no comorbidity, while for women with severe comorbidity levels, the likelihood of dying was nearly triple compared to women with no comorbidity.
Comorbidity levels were associated with a similar impact on 5-year survival among men ages 66-74 with prostate cancer diagnosed at an early stage. By contrast, comorbidity levels had relatively little or modest impact on the survival of women diagnosed with advanced breast cancer or men with advanced prostate cancer.
18. How does comorbidity influence the survival of men with prostate cancer?
Men diagnosed with prostate cancer had comorbidity levels similar to those among female breast cancer patients. Between two percent to 14 percent of men diagnosed with prostate cancer at a localized stage died from their cancer, in all age and comorbidity groups. Among men diagnosed with prostate cancer at a regional stage, especially those ages 75 to 84, the probability of both cancer and non-cancer death increased with comorbidity level. Men diagnosed with prostate cancer at an advanced stage had more than a 54 percent probability of cancer death regardless of age and comorbidity level.
19. How does comorbidity influence the survival of colorectal cancer patients?
Colorectal cancer patients had a prevalence of comorbidity of 40.7 percent compared to the cancer-free group of similar age patients who had a prevalence of 31.8 percent. The prevalence of diabetes among colorectal cancer patients was 17.2 percent which was higher than the cancer free-group who had a 13.9 percent prevalence of diabetes.
Among women and men diagnosed with colorectal cancer, approximately 7 percent to 26 percent of those diagnosed at localized stages died from their cancer in all age and comorbidity groups compared with 25 percent to 44 percent of those with regional stage disease and also compared with over 80 percent of those with advanced stage disease. Overall survival and probability of non-cancer death was strongly related to comorbidity level among men and women diagnosed with colorectal cancer at a local or regional stage.
20. How does comorbidity influence the survival of lung cancer patients?
Lung cancer patients had the highest prevalence of comorbidities of all cancer types at 52.9 percent. Among lung cancer patients, the most prevalent comorbidity was COPD at 33.6 percent. The prevalence of congestive heart failure was also high in lung cancer patients at 12.4 percent.
The influence of comorbidities on the probability of both cancer and non-cancer death was smaller for lung cancer than for other cancers, due to relatively poor prognoses regardless of the stage at which lung cancer is diagnosed.
21. What else can we learn from examining comorbidity among cancer patients?
The prevalence of comorbidity helps us understand that a large proportion of recently diagnosed cancer patients have other conditions in addition to cancer and more research is needed to understand how best to treat these patients. Comorbidities also help to better quantify risk. Although cancer registries do not routinely collect data on comorbidities, registry data may be supplemented with comorbidity data from several other sources.
How to Read This Report
22. How are cancer incidence and death rates presented?
Cancer incidence rates and death rates are typically measured as the number of cases or deaths per 100,000 people per year and are age-adjusted to the 2000 U.S. standard population. When a cancer affects only one sex, for example, prostate cancer, then the number is per 100,000 persons of that sex. The numbers are age-adjusted, which allows for comparison of rates from different populations with varying age composition over time and in different regions.
23. What is annual percent change or APC?
The annual percent change (APC) is the average rate of change in a cancer rate per year in a given time frame (i.e., how fast or slowly a cancer rate has increased or decreased each year over a period of years). The APC was calculated for both incidence and death rates. The number is given as a percent, such as: an approximate 1 percent per year decrease. The APC is calculated using joinpoint regression (see below for an explanation of joinpoints).
A negative APC describes a decreasing trend, and a positive APC describes an increasing trend. In this report, all trends mentioned in the text are statistically significant unless noted otherwise. For non-statistically significant trends, terms such as “stable,” “non-significant increase,” and “non-significant decrease” were used.
24. What is average annual percent change or AAPC?
The report also uses the average annual percent change (AAPC) as an addendum to the underlying joinpoint (see below for an explanation of joinpoints) regression estimates of annual percent change (APC). This summary measure is an estimate of trends for a fixed interval of time and allows comparison of trends among many racial and ethnic groups and types of cancer.
The AAPC quantifies the average trend over a fixed period of multiple years.
Similar to the APC, a negative AAPC describes a decreasing trend, and a positive AAPC describes an increasing trend. In this report, all trends are statistically significant unless noted otherwise. For non-statistically significant trends, terms such as “stable,” “non-significant increase,” and “non-significant decrease” were used.
Long-term trends can obscure shorter term changes. Differences in the 5-year and 10-year AAPCs typically identify types of cancer where the 10-year average trend may mask important recent changes, which occur more often for incidence trends than for death trends. For example, in this report, the trend for lung cancer deaths and for childhood cancer deaths show a more rapid decline when looking at the 5-year AAPC than the 10-year AAPC.
25. What is joinpoint regression analysis, and how does it account for the different time periods used for trends analysis in this report?
Joinpoint regression analysis is a statistical method that describes changing trends over successive segments of time and the amount of increase or decrease within each segment. This analysis involves fitting a series of joined straight lines to the age-adjusted rates and choosing the best-fitting point or points, called joinpoints, where the rate of increase or decrease changes significantly. Thus, each joinpoint denotes a statistically significant change in trend. The resulting line segment between joinpoints can be described by an annual percent change (APC) that is based on the slope of the line segment. Joinpoint analyses were performed for incidence and mortality trends.
26. Why were rates adjusted for delays in reporting incidence data to SEER?
The report presents analyses of long-term trends in cancer incidence rates with and without adjustment for reporting delays and more complete information. Adjusting for these delays and accumulating more complete and accurate information provides the basis for a potentially more definitive assessment of incidence rates and trends, particularly in the most recent years for which data are available. Cancer registries routinely take two to three years to compile their current cancer statistics. An additional one to two years may be required to have more complete incidence data on certain cancers, such as melanomas and leukemias when they are diagnosed in outpatient settings. Cancer registries continue to update incidence rates to include these cases. Consequently, the data initially reported for certain cancer incidence rates may be an underestimate.
Long-term reporting patterns in NCI’s SEER registries have been analyzed, and it is now possible to adjust incidence rates for all cancers combined and for site-specific cancers with a correction for expected reporting delays and more complete information. However, SEER registries do not cover the entire population, thus combined data from SEER and CDC’s National Program of Cancer Registries (which is not delay adjusted) is important for assessing the incidence of cancer in the U.S. Methodologic research is in progress to adjust for reporting delays of pooled data from SEER and the National Program of Cancer Registries.
27. Why is this the second Annual Report published in 2013?
The first Annual Report published in 2013 was on January 7 in JNCI. This second Annual Report is being published online on December 16, 2013, in Cancer. Publication dates are determined by journal editors and sometimes publication is delayed for a variety of reasons, thus leading to two Annual Reports being published in the same calendar year, albeit about 12 months apart.
28. What other data issues need to be considered?
This report uses population estimates that incorporated both the 2000 and the 2010 Census results from the U.S. Census Bureau to calculate incidence and death rates. With incorporation of the 2010 census in this report, the populations for the intercensal years are more accurate than in prior reports where these data were estimated based only on the 2000 census. The official 2010 census revealed that Americans are increasingly self-identifying in ways that deviate from traditional racial and ethnic categories. Reassignment methods used for Hispanics who self-identified as “some other race” resulted in 19 percent more AI/AN, 9 percent more API, along with 31 percent more individuals of multiple races. The cancer rates for the AI/AN and API populations are lower relative to the white and black populations reported in previous years, which is likely a function of the reassignment methods rather than representing a genuine trend.
29. Where is the report published?
To view the full report Cancer, please go tohttp://onlinelibrary.wiley.com/doi/10.1002/cncr.27514/abstract .
Reference: Edwards BK, et al. Annual Report to the Nation on the Status of Cancer, 1975-2010, Featuring Prevalence of Comorbidity and Impact on Survival among Persons with Lung, Colorectal, Breast or Prostate Cancer. Cancer. Online Dec. 16, 2013. DOI: 10.1002/cncr.28509.
30. Where can I find out more about the Report?
To view the press release on the Report, go tohttp://www.cancer.gov/newscenter/newsfromnci/2013/ReportNationDec2013Release.
For Spanish translations of this press release and Q&A, go to
CDC’s Division of Cancer Prevention and Control: http://www.cdc.gov/cancer; National Program of Cancer Registries: http://www.cdc.gov/cancer/npcr; and the National Vital Statistics System:http://www.cdc.gov/nchs/nvss.htm
NCI: http://www.cancer.gov and SEER (NCI’s Surveillance, Epidemiology, and End Results program):http://www.seer.cancer.gov
NAACCR: http://www.naaccr.org .