Scientists are working on finding the causes of this new anomaly in cancer research. The rate of early-onset cancers—cancer which affects those under 50—has exponentially increased since the 1990s.
Cancer is a disease that typically affects older people, with 88% of cancer patients in the U.S. over 50. Older people are usually at a higher risk for cancer due to various factors throughout their lives that may contribute to later health problems in the many years they have spent living. This, however, is changing with new studies observing the rise of diagnoses in younger people and of certain cancers. A study by the BMJ Oncology Journal found a global increase of 79.1% in early-onset cancer between 1990 and 2019, with the most concerning cancers in terms of mortality being early-onset breast, tracheal, bronchus and lung, stomach, and colorectal cancers. These findings align with the Lancet Public Health, which has been finding a steady rise in 17 of 34 cancer types in the U.S., most affecting men and women after 20.
Early-onset cancer may be progressing faster in young adults than typical cancers in older adults. While this could explain why younger people are commonly diagnosed with cancer at a late stage, young people are still often not suspected of cancer. Early-onset cancers are still not yet normally considered, causing earlier cancer symptoms in young adults to be often attributed to and misdiagnosed as more benign health issues. In a U.S. survey of nearly 900 people with early-onset colorectal cancer, 54% were initially misdiagnosed with hemorrhoids. “Thirty-six percent of patients saw three or more doctors before receiving a diagnosis of colorectal cancer,” says Michael Sapienza, CEO of nonprofit Colorectal Cancer Alliance.
Some possible risk factors for cancer include chronic inflammation, healthcare disparities, and gut microbiome changes, as reported by UChicago Medicine. “If there had been one risk factor, we would have identified it at this point. Make you think that it’s probably a combination of a number of different factors,” says Dr. Sonia Kupfer, gastroenterologist and cancer expert at the University of Chicago Medical Center. Kupfer and many other researchers are looking into modern changes in lifestyle, comparing how younger generations are living and the world around them are different to that of past generations. The leading hypothesis for the sudden rise in younger cases is that younger people may be more exposed to certain environmental and lifestyle factors than previous generations born before 1990. These factors include microplastics and the spread of the Western diet, both of which are being researched for possible links to cancer.
Environmental exposures to microplastics and polyfluoroalkyl substances (PFAS) have risen in the last couple of decades with “weak but increasing” links to cancer, according to Dr. Frank Frizelle, a colorectal surgeon at the University of Otago in New Zealand. Since 1990, global plastic production has increased from about 120 million metric tons to over 460 million tons in 2023, as found in a study on plastic pollution, which coincides with the increase in cases of early-onset cancers. When plastic degrades, it breaks down into micro- and nanoparticles of plastic that can be ingested and inhaled by humans. PFAS are also being consumed as they are widely used in textiles and food packaging. Both microplastics and PFAS have been found in human organs and cancer tumors “in higher levels than normal tissue,” says Frizelle. While a direct link between microplastics and cancer has yet to be found, environmental exposure to microplastic may be contributing to less diverse gut microbiomes, one of the risk factors for cancer. Changes to gut microbiomes that affect the network of bacteria could potentially lay the ground for tumors to grow.
Obesity, highly processed foods, and a sedentary lifestyle are linked to chronic inflammation, one of the risk factors for cancer. Obesity is attributed to the Western diet of high intakes of processed foods and sugar, a diet that is prevalent among younger generations. A 2022 review study in Frontiers in Nutrition linked a diet high in fat, deep-fried foods, and sugary drinks and desserts with higher rates of colorectal cancer in young adults. That same study observed a “protective effect” among those who maintained healthy diets with high amounts of micronutrients from fruits and vegetables.
Despite these concerning statistics, cancer research has progressed tremendously in recent years to improve screenings and treatment methods that have reduced overall cancer mortality. In the 2025 American Cancer Society annual report, mortality rates are reported to have declined by 34% from 1991 to 2022 in the U.S., “averting approximately 4.5 million deaths.” The same report has also reported a 70% drop in mortality rates among children and 63% in adolescents since 1970, “largely because of improved treatment for leukemia.” Some preventative measures that can be taken include staying up to date with vaccinations, such as HPV and Hepatitis B, which have been linked to cervical, throat, and liver cancers. Cancer research will only continue to grow, and until it can be effectively treated in all forms, maintaining a healthy lifestyle with balanced diets, regular exercise, and limiting the use of substances and sun exposure are the best preventions for reducing the risk of cancer.
