What Are Preliminary Estimates?
Every April, the NCI releases official updated cancer statistics. However, statistical modeling and early access to data enable the Surveillance Research Program (SRP) to generate preliminary estimates of the statistics before the April release. This website provides these preliminary estimates, including age-adjusted 5-year rates, 5-year trends, and long-term trends. Preliminary estimates predict the rates and trends that will become available once the data are released in April.
Why Use Preliminary Estimates?
Trends in cancer incidence can help us understand the impact that changes in risk factors, early detection and diagnostic technologies, and other cancer control interventions are having at the population level. Preliminary estimates can help to identify these impacts earlier than we would otherwise, and can help guide research and facilitate more prompt attention to areas of concern. SRP continues to work on minimizing the delay in reporting to allow for official statistics to be available more quickly; the availability of these preliminary estimates demonstrates progress on such efforts.
What Cautions Should Be Considered in Using Preliminary Estimates?
Please note that because SRP is releasing these early estimates based on less complete data, they are preliminary and therefore subject to change. The official statistics released in April will reflect new cases that were not yet available at the time of early data access. Modeling adjusts for the undercount of cases based on historical data related to the delayed submission of cases by cancer registries. Even with this adjustment, it is uncertain whether the official statistics reported in April will differ from the preliminary estimates. While past publications have generally shown good agreement between the preliminary estimates based on the February submission and the official estimates based on the November submission, appropriate caution is needed when interpreting these preliminary estimates. For background publications on preliminary estimates, see References.
This website contains the following sections:
- Preliminary Estimates for 2017 – Estimates of preliminary 5-year trends (2013-2017), preliminary 5-year rates (2013-2017), and long-term trend comparisons (2000-2016 vs 2000-2017)
- February Delay-Adjustment – Information about the modeling that adjusts for the undercount of cases based on historical data related to the delayed submission of cases by cancer registries
- Validation – Information about the agreement between rates and trends based on preliminary estimates from the February submission and the official estimates based on the November submission
- Archive - Earlier Preliminary Estimates datasets, plus the Validation and Reference for each dataset
When using these estimates, please refer to them as preliminary and reference them as suggested below.
SEER Preliminary Cancer Incidence Rate Estimates for 2017, and diagnosis years 2000 to 2017, SEER 18, National Cancer Institute. Bethesda, MD, https://seer.cancer.gov/statistics/preliminary-estimates/, based on the February 2019 SEER data submission and the November 2018 SEER data submission. Posted to the SEER web site, September 2019.