Background: About 483,000 new cancer cases were estimated in Brazil 2023–2025, with breast, prostate, and colorectal cancers being the most common. Increasing cancer incidence among young adults underscores the need for surveillance and improved understanding of early-onset cancer epidemiology.
Objectives: To assess temporal trends in cancer incidence for selected topography in Brazil overall and by early- and late-onset strata.
Methods: A time-series study using data from Brazilian population-based cancer registries, covering seven cancer groups (breast [BC], endocrine system [EC], gastrointestinal [GC], head and neck [HNC], reproductive system [RSC], thoracic [TC], and urinary [UC]). Age–period–cohort and average annual percent change (AAPC) analyses were conducted.
Results: There were 583,818 cancers cases. For BC Relative risk (RR) increases over the period among early-onset, RR 1.19 [2015]. The oldest-cohorts [1920-1950] showed an increase in RR, and subsequent increase from 1980-onward, RR 1.38 [1995-cohort]. For EC, Increasing trend among women (AAPC 4.17) and men (AAPC 4.70), highest <50-years women (AAPC 5.12), men (AAPC 7.21). RR increases over the period among women (+68%), men (+91%), more in early-onset RR 2.05/2.71. RR reduction among women from the 1920-1970-cohorts, followed by increase, RR 1.75 [1995-cohort]. Men, increase from the 1970-cohort onward, RR 2.05 [1995-cohort]. For GC, RR increases among early-onset women, RR 1.13 [2015]. RR reduction in women 1920-1955-cohorts, and increase from 1970-cohort onward, +22% [1955-cohort]. For HNC, Women/men showed decreasing trends (AAPC −1.80; -2.00), highest men <49-years (AAPC −2.91). RR reduction (-26%) over the period, highest early-onset men, RR 0.70 [2015]. For RSC, decreasing trend in women (AAPC −2.04), smallest <50-years (AAPC −1.33); increasing men <50-years (AAPC 1.05). RR reduction between 2000-2015 among women, more in late-onset, RR 0.70. RR increases in men early-onset, RR 1.21 [2015], and reduction in late-onset (RR 0.89). RR increases among women from the 1980-cohort onward, 50% increase [1995-cohort]. Men increase was 74% [1995-cohort]. For TC, increasing trend in women (AAPC 0.53); decreasing men, (AAPC −2.60), major reduction <50-years (AAPC −5.36). 41% RR reduction in men over the period. RR increased among women/men from 1920-cohort to 1960-cohort, followed by a reduction up to 1980-cohort. For UC, RR increases over the period among women, RR 1.24 [2015], more in early-onset RR 1.49, and increases in men early-onset, RR 1.29 [2015]. Persistence of increase in women from the 1985-cohort onward, RR 1.23 [1985-cohort].
Conclusions: Cancer incidence trends in Brazil are heterogeneous across cancer sites, with rising early-onset incidence observed for BC, EC, UC, and RSC. Further analyses are warranted to clarify early- and late-onset cancer patterns and their determinants in the Brazilian population.