Potential for Cure by Stage across the Cancer Spectrum in the United States

Abstract

Abstract Background: Cure fraction—the proportion of persons considered cured of cancer after long-term follow-up—reflects the total impact of cancer control strategies, including screening, without lead-time bias. Previous studies have not reported stage-stratified cure fraction across the spectrum of cancer types. Methods: Using a mixture cure model, we estimated cure fraction across stages for 21 cancer types and additional subtypes. Cause-specific survival for 2.4 million incident cancers came from 17 US Surveillance, Epidemiology, and End Results registries for adults 40 to 84 years at diagnosis in 2006 to 2015, followed through 2020. Results: Across cancer types, a substantial cure fraction was evident at early stages, followed by either a sharp drop from stages III to IV or a steady decline from stages I to IV. For example, estimated cure fractions for colorectal cancer at stages I, II, III, and IV were 62% (95% confidence interval: 59%–66%), 61% (58%–65%), 58% (57%–59%), and 7% (7%–7%), respectively. Corresponding estimates for gallbladder cancer were 50% (46%–54%), 24% (22%–27%), 22% (19%–25%), and 2% (2%–3%). Differences in 5-year cause-specific survival between early-stage and stage IV cancers were highly correlated with between-stage differences in cure fraction, indicating that survival gaps by stage are persistent and not due to lead-time bias. Conclusions: A considerable fraction of cancer is amenable to cure at early stages, but not after metastasis. Impact: These results emphasize the potential for early detection of numerous cancers, including those with no current screening modalities, to reduce cancer death.