TUESDAY, Oct. 21, 2025 (HealthDay News) -- From 2003 to 2017, cancer incidence rates increased for several cancer types, with increases in younger and older adults for many cancers, according to a study published online Oct. 20 in the Annals of Internal Medicine.Amy Berrington de Gonzalez, D.Phil., from The Institute of Cancer Research and Imperial College London in the United Kingdom, and colleagues compared international cancer incidence trends in younger adults (aged 20 to 49 years) and older adults (aged 50 years and older) from 42 countries in Asia, Europe, Africa, North and South America, and Australasia with annual cancer incidence data from 2003 to 2017. The average annual percentage change (AAPC) in cancer incidence rates was estimated for 13 cancer types.The researchers found that in younger adults, incidence rates increased in most (>75 percent) countries for six of the 13 cancer types: thyroid cancer, breast cancer, colorectal cancer, kidney cancer, endometrial cancer, and leukemia (median AAPC, 3.57, 0.89, 1.45, 2.21, 1.66, and 0.78 percent, respectively). For these cancer types, incidence rates also increased in older adults in most countries (median AAPCs, 3, 0.86, 1.65, 1.20, and 0.61 percent for thyroid, breast, kidney, endometrial cancer, and leukemia, respectively); colorectal cancer only increased in older adults in about half of the countries (median AAPC, 0.37 percent), while in 69 percent of the countries, the AAPC was greater in younger than older adults. In more than half the countries, rates decreased in younger adults for liver, oral, esophageal, and stomach cancer."Formal analysis of obesity or other risk factors in these increasing cancer rates is warranted and requires long-term national survey data," the authors write.Abstract/Full Text (subscription or payment may be required)Editorial (subscription or payment may be required)