Prevalence of Rare Cancer Survivors in the United States.

[BACKGROUND] The purpose of this study was to estimate the prevalence of rare cancer survivors in the United States.

[METHODS] A rare cancer was defined as one in which the age-adjusted incidence is less than 15 cases per 100,000 individuals in the population. The prevalence of survivors of 24 rare cancer types was estimated using data from the Surveillance, Epidemiology, and End Results program as of January 1, 2022. Prevalence data for each cancer type were also generated by attained age and number of years from diagnosis. Incidence, mortality, and five-year survival trends were assessed utilizing joinpoint regression models.

[RESULTS] There were an estimated 4,979,791 survivors with a history of a rare cancer diagnosis in the United States as of January 1, 2022, 53.3% of whom were female. Overall, 69.9% of rare cancer survivors were long-term survivors (5 or more years from diagnosis) and 49.5% were very long-term survivors (10 or more years from diagnosis). The most common rare cancer types were thyroid cancer, leukemia, and rectal cancer. Across the rare cancer survivor population, the highest percentage was in the attained age category of 40 to 64 years (39.4%). Five rare cancer types had increasing rates of both incidence and survival: stomach, pancreas, anus, small intestine, and bones and joints.

[CONCLUSIONS] There are almost 5 million survivors with a history of a rare cancer diagnosis living in the United States.

[IMPACT] Rare cancer survivors represent 27.7% of the US cancer survivor population. Additional research is needed to address the survivorship needs of these individuals.