Early onset cancer trends and the persistently higher burden of cancer in young women

Although there are many favorable cancer trends including decreases in overall incidence and mortality, there remains substantial heterogeneity in these trends by race, ethnicity, and age.In particular, there are well-documented and major health disparities, particularly in higher cancer mortality, seen for Black, Hispanic, and Indigenous Americans compared to White Americans. 1More recently, there has been growing recognition of the increasing incidence rates of cancers in adults under the age of 50 years (hereafter referred to as early onset cancer). 2 What is less discussed are the sex differences in the early onset cancer burden.The International Agency for Research on Cancer estimated that currently 2/3 of all cancers diagnosed under age 50 years in the world are diagnosed in women. 3However, since this estimate is based on cross-sectional data, it is unclear how the female-to-male incidence ratio has changed over time due to varying incidence rates for many cancer types.In this commentary, we present an overview of the current evidence on early-onset cancer incidence trends.Using the latest data from the Surveillance Epidemiology and End Results (SEER) and United States Cancer Statistics (USCS) public use databases, we analyze sex-specific trends in early-onset cancer, overall, and for the top 10 cancer sites in the United States.We conclude by discussing the potential public health and clinical implications of these trends.