Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2023 Winter;50(4):123-137.

The Burden of Rare Cancers in North America

Brenda M Hofer  1 , Hannah K Weir  2 , Angela Eckstrand  3 , Keisha Musonda  4 , Recinda Sherman  2
Affiliations

The Burden of Rare Cancers in North America

Brenda M Hofer et al. J Registry Manag. 2023 Winter.

Abstract

Background: Rare cancers are difficult to study owing to their infrequent diagnosis. Using aggregate incidence data from population-based cancer registries in Europe, the Surveillance of Rare Cancers in Europe project compiled a list of clinically relevant, topography and morphology defined rare cancers operationally defined as having a crude annual incidence rate of <6 per 100,000 persons. In 2020, this list of rare cancers was updated. The objective of this study was to assess the utility of a rare cancer recode variable for use in the Cancer in North America (CiNA) dataset and to provide a first look at the burden of rare cancers in Canada and the United States.

Methods: Data were obtained from 62 registries in Canada and the United States that met North American Association of Central Cancer Registries (NAACCR) high-quality data standards. The list of rare cancers was programmed as a Rare Cancer Classification variable within SEER*Stat. SEER*Stat was used to estimate case counts and crude and age-specific incidence rates per 100,000 for cancers diagnosed 2015-2019 by age at diagnosis, country, and country-specific geographic regions in Canada and the United States, and by race/ethnicity in the United States.

Results: In Canada and the United States, 21% and 22% of all invasive cancers were classified as rare, respectively. The percentage of rare cancers ranged between 18% to 21% across geographic regions in Canada and the United States. Children (aged 0-14 years) had the highest percentage and lowest incidence rates of rare cancers. The percentage of rare cancers decreased, and incidence increased with increasing age. In the United States, Hispanics had the highest percentage (27%) and non-Hispanic Whites and non-Hispanic Blacks the lowest percentage (21%) of rare cancers.

Conclusions: While individual rare cancers are infrequently diagnosed, in aggregate, they account for a substantial percentage of all cancers diagnosed in the population and pose a substantial public health burden. We report variations in percentage of rare cancers by age, and race/ethnicity (United States only). Such variations in the burden of these cancers may suggest possible areas for public health research.

Keywords: North American Association of Central Cancer Registries (NAACCR); cancer registries; rare cancers; surveillance.

PubMed Disclaimer

Figures

Figure 1
Figure 1
Percent of All Rare Cancers Among All Invasive Cancers and Age-Specific Incidence Rates of Rare Cancers by Age Group, North America, 2015–2019
Figure 2
Figure 2
Percent of Rare Cancers Among All Invasive Cancers by Geographic Region, North America, 2015–2019
Figure 3
Figure 3
Percent of Rare Cancers Among All Invasive Cancers by Race/Ethnicity, United States, 2015–2019
See this image and copyright information in PMC

References

    1. Greenlee RT, Goodman MT, Lynch CF, Platz CE, Havener LA, Howe HL.. The occurrence of rare cancers in U.S. adults, 1995-2004. Public Health Rep. 2010;125(1):28–43. doi: 10.1177/003335491012500106 - DOI - PMC - PubMed
    1. Gatta G, van der Zwan JM, Casali PG, et al. ; RARECARE working group . Rare cancers are not so rare: the rare cancer burden in Europe. Eur J Cancer. 2011;47(17):2493–2511. doi: 10.1016/j.ejca.2011.08.008 - DOI - PubMed
    1. DeSantis CE, Kramer JL, Jemal A.. The burden of rare cancers in the United States. CA Cancer J Clin. 2017;67(4):261–272. doi: 10.3322/caac.21400 - DOI - PubMed
    1. Walker EV, Maplethorpe E, Davis FG.. Rare cancers in Canada, 2006-2016: A population-based surveillance report and comparison of different methods for classifying rare cancers. Cancer Epidemiol. 2020;67:101721. doi: 10.1016/j.canep.2020.101721 - DOI - PubMed
    1. Bilkey GA, Trevithick RW, Coles EP, Girschik J, Nowak KJ.. Descriptive epidemiological study of rare, less common and common cancers in Western Australia. BMC Cancer. 2021;21(1):779. - PMC - PubMed