Keeping Tabs on Cancer Rates

Three women huddled around a computer screen, surrounded by SEER publications

Credit: NCI (Ernie Branson, photographer)

The Annual Report to the Nation on the Status of Cancer that was released today shows continued declines in both the rate of new cancer cases (incidence) and the rate of cancer deaths (mortality) in the United States over the past several years.  The report, which is produced by the National Cancer Institute (NCI), the Centers for Disease Control and Prevention (CDC), the American Cancer Society (ACS) and the North American Association of Central Cancer Registries (NAACCR), utilizes a variety of data sources in order to track national trends in cancer rates.

“This is a report that provides a lot of information related to all the efforts that are going on to actually improve and reduce the cancer burden in the U.S.,” said Dr. Brenda K. Edwards, Associate Director of NCI’s Surveillance Research Program in the Division of Cancer Control and Population Sciences.  “It also characterizes a lot of work that’s going on in the research and clinical communities and by those who are working to educate and inform individuals about what they can do to reduce their own risk or get access to care.”

The incidence data used in the report were gathered from population-based cancer registries that participate in the NCI’s Surveillance, Epidemiology and End Results (SEER) program, and/or the CDC’s National Program of Cancer Registries (NPCR).  Information on mortality rates comes from CDC’s National Center for Health Statistics (NCHS).

“A cancer registry is a group that collects data on a defined population according to specific rules, aggregates those data, and report on cancer from that data base,” said Edwards. “A registry is a fundamental component for cancer control.  It’s essential to measure how many people are getting cancer, whether they are surviving, etc. These data are basic fundamental measures of the cancer burden and the progress that is being made to reduce the burden.”

Medical facilities report data on almost all cancer cases and deaths to a central cancer registry in each state, and in turn, the state-based cancer registries report the information to the NPCR and/or SEER.  Hospitals, physician offices, radiation treatment facilities, surgical centers and pathology laboratories all send information to these state-based, central cancer registries.  Cancers that are not captured by all registries include basal cell and squamous cell carcinoma of the skin (non-melanoma skin cancer), and pre-invasive cervical cancer.  In addition to being valuable research tools, the data collected by cancer registries helps to guide the planning and evaluation of cancer control programs and set priorities for allocating cancer care resources.

See Dr. Edwards discuss the report, and the data collection behind it:

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The National Cancer Act of 1971 mandated the collection, analysis, and dissemination of data useful in the prevention, diagnosis, and treatment of cancer, leading to the establishment of the SEER program in 1973.  The initial SEER program included nine registry sites and collected data for three racial groups: white, black and other.  The program was later expanded to include more geographical sites, and provide for greater socioeconomic representation (see below).

By 1992, only 38 states had established cancer registries and many of them collected data on only part of their population.  In order to provide for nationwide data collection, Congress enacted the Cancer Registries Amendment Act, which established the National Program of Cancer Registries, as part of the Center for Disease Control and Prevention (CDC). This program makes grants to states, or academic and nonprofit organizations designated by the state, to support the operation of population-based, statewide cancer registries to collect, manage and analyze data on cancer cases and deaths.  By law, these programs are designed to supplement, not supplant, the work done by the SEER program, and are meant to coordinate with the SEER program.


The SEER program currently has 17 registry sites, located in 13 states, which covers 26 percent of the U.S. population, and is largely representative of the population in terms of race, poverty, education, and other socioeconomic variables.  The SEER program collects data on patient demographics, primary tumor site, tumor morphology (structure) and stage at diagnosis, first course of treatment, and follow-up for vital status (i.e. whether or not they were still alive).  SEER is the only data source of its kind to include both stage of cancer at the time of diagnosis and patient survival data for all cancer cases.   In addition, the SEER program does collect information on some of the pre-cancerous lesions and benign brain tumors that are not commonly collected by other registries.  The SEER program imports mortality data from the NCHS, and population data from the U.S. Census Bureau.

SEER began collecting data on cancer cases in 1973, and by 1975 there were nine registry sites (Atlanta, Connecticut, Detroit, Hawaii, Iowa, New Mexico, San Francisco-Oakland, Seattle-Puget Sound, and Utah).  By 1992 it had expanded to 13 registry sites, adding Los Angeles, San Jose-Monterey, rural Georgia, and the Alaska Native Tumor Registry, in order to improve the racial diversity of the sample and insure that the population covered by SEER is comparable to the general U.S. population.  In 2001, the program was expanded once again, with a combination of SEER and NPCR funds, to include Kentucky, greater California, New Jersey, and Louisiana.

The SEER program sets high standards for data quality within its registries.  “We’re looking for 98 [percent] completeness of all the cancer cases within 22 months,” said Edwards. The SEER program manages the data, uses several computer programs to analyze the data, and provides feedback to the registries about the quality of the data.

In addition to the Annual Report to the Nation, the SEER program annually publishes data from the SEER registries in the SEER Cancer Statistics Review (CSR).  The CSR includes a series of data tables with cancer statistics by race, sex, age, and year of diagnosis.  The program also maintains several web-based systems for the public to access and analyze this information, including several Cancer Stat Fact Sheets, the Cancer Query System, and the State Cancer Profiles system.

Map of CDC and NCI funded cancer registries

Not shown: SEER supplemental registries in Alaska (Alaska Natives), Arizona (American Indians), Oklahoma (Cherokee Nation). Credit: National Program of Cancer Registries, CDC


The NPCR funds cancer registries in 45 states, the District of Columbia, Puerto Rico, and the U.S. Pacific Island Jurisdictions.  Together, the state-based registries funded by NPCR and the SEER-funded registries cover the entire U.S. population.

In addition to providing funding and assistance to the state-based registries, the NPCR maintains a public data set, the United States Cancer Statistics report, which is updated annually with incidence and mortality data from the state-based and SEER registries.  They are also involved in creating software programs and data systems to aid in the collection and processing of cancer data.


The NAACCR, a professional organization, works with registries from SEER and NPCR to establish and promote standards for data collection and management.   This group certifies population-based registries, and provides education and training for cancer registrars on data quality control.  All of the registries that provide data for the Annual Report to the Nation are members of the NAACCR.

The ACS, in its role as a well known and trusted, non-governmental, nation-wide, non-profit cancer organization, uses data from NAACCR, NPCR and SEER to forecast estimates of the number of new cancer cases and deaths expected to occur in the U.S. each year by applying rates to population data from the Census Bureau.  Their predictions for the current year can be found in the annual publication Cancer Facts & Figures.

“Over the years we have worked with the CDC program to combine the data and with the North American Association of Central Cancer Registries to pool the data from the high-quality registries,” explained Edwards.  “In addition, we work with the American Cancer Society, which uses this data and disseminates it to a large audience, as well as the American College of Surgeons’ Commission on Cancer, and the hospitals which serve as the building blocks for the population based cancer registries.”

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