Significant differences in age, sex, and race/ethnicity were detected when comparing cancer case data between the National Cancer Database (NCDB), Surveillance, Epidemiology, and End Results Program (SEER), and the US Cancer Statistics Public Use Database (USCS). Researchers presented their findings at the 2023 ASCO Annual Meeting.

While these national registries have been useful tools to explore data around concerns like disease incidence and treatment patterns, the research team noted the registries have also been criticized for not fully representing the general population. 

The study compared patients diagnosed with malignant or in situ breast cancer from 2010 to 2019. The data was compared between the NCDB (Fall 2022 release), SEER-22 (November 2021 release) and US Cancer Statistics Public Use Database (USCS, 2021 submission). 

Age, sex, race/ethnicity, and year of diagnosis were used to identify patient frequencies. The number of patients in the NCDB or SEER was divided by the number of patients in the USCS to estimate the percent case coverage.

A total of 3,047,509 patients were reported in the USCS database. Of these patients, 77.5% (n = 2,362,477) were included in the NCDB and 46.0% (n = 1,403,272) in SEER. Case coverage improved consistently for the NCDB between 2010 (72.8%) and 2019 (81.5%). However, only a minor increase was observed in SEER from 2010 (46.0%) to 2019 (46.6%). 

Case ascertainment was notably lower for individuals aged 50 years or older in both the NCDB and SEER (both P < .001) in comparison to the USCS. The NCDB accounted for most patients, with 81.7% of those aged less than 50, and 76.6% of those aged 50 or more. Comparatively, the SEER identified a lower percentage, with 49.4% of those under 50 and 45.3% of those aged 50 or more.

Case ascertainment varied significantly depending on the patient's sex (both P < .001). While 84.1% of male breast cancers were included in the NCDB, only 77.5% of female patients were included. On the other hand, SEER had a higher case coverage for female patients compared to male patients (46.1% and 43.5%, respectively).
Additionally, data in the registries varied significantly in terms of race/ethnicity (both P < .001). The NCDB had the highest case coverage for non-Hispanic White (78.2%), non-Hispanic Black (77.7%), and non-Hispanic Asian/Pacific Islander (72.5%) patients, while the lowest case coverage was for Hispanic (56.4%) and non-Hispanic American Indian/Alaska Native (41.1%) patients. By contrast, SEER had its highest case coverage in non-Hispanic Asian/Pacific Islander (78.1%) and Hispanic (69.6%) patients, with considerably lower coverage in non-Hispanic Black (44.8%), non-Hispanic White (42.4%), and non-Hispanic American Indian/Alaska Native (36.6%) patients.

“National US tumor registries provide data for a large sampling of breast cancer patients, and case coverage has improved over time,” said researchers. “However, significant differences in case coverage were observed based on age, sex, and race/ethnicity, suggesting that analyses using these data sets should be interpreted with caution.”

Reference: 
Plichta JK, Thomas SM, Record S, et all. Comparison of incident breast cancer cases in the largest national US tumor registries. J Clin Oncol. 2023;41(suppl 16; abstr 6512). doi:10.1200/JCO.2023.41.16_suppl.6512