Cancer rates are on the rise in younger populations; here’s why

By Kristen Fuller, MD | Medically reviewed by Jeffrey A. Bubis, DO, FACOI, FACP
Published June 15, 2023

Key Takeaways

  • A new study has shown that the incidence of cancer is increasing in younger individuals—those under 50 years of age.

  • The specific etiology of why this phenomenon is occurring is unclear, but researchers believe that unhealthy lifestyle factors such as poor diet and low levels of physical activity are likely contributing factors. 

  • Physicians can advise their patients to adopt healthier lifestyle habits while encouraging early screenings and self-exams—these are especially useful for younger patients to help prevent an early onset cancer diagnosis.

Many people operate under the assumption that cancer primarily affects individuals of older age, but new research has shown that cancer is becoming more prevalent in younger people. To uncover the reasons behind this, researchers from Brigham and Women's Hospital looked at 14 types of cancers that are increasing in frequency in individuals under age 50.

Results of the study reveal the incidence of early onset cancers has dramatically increased, globally, since 1990.[]

New recommendations for colorectal cancer screening 

In 2021, the US Preventive Services Task Force and the Multisociety Task Force on Colorectal Cancer recommended that most Americans be screened for colorectal cancer at age 45; this is 5 years earlier than their previous recommendations.

Related: Overcoming patients’ barriers to colorectal cancer screening

An article published by Yale Medicine emphasized the increase in incidence of colorectal cancer in young patients: Seven patients were diagnosed with colorectal cancer in one week, all under 36, including a father of four who thought his rectal bleeding was due to hemorrhoids; the youngest patient was 18.[]

The Yale Medicine article notes statistics from the American Cancer Society (ACS), which reported that  20% of diagnoses in 2019 were in patients under age 55—double the rate in 1995, 26 years earlier.

Additionally, ACS found that rates of advanced disease increased by about 3% annually in people younger than 50, and estimated that 19,550 diagnoses and 3,750 deaths would be in people younger than 50 in 2023. 

The microbiome's link to early onset cancer

Eight out of the 14 early-onset cancers studied at Brigham and Women’s Hospital were related to the digestive system. Some experts believe this relates to the gut’s microbiome. The microbiome is strongly affected by what an individual ingests, including alcohol, food, tobacco, and medications (such as antibiotics). 

The study’s authors also noted that obesity and type 2 diabetes are on the rise in younger populations, potentially due to the Western-style diet, including high consumption of processed foods and sugary drinks, and sedentary lifestyles. 

They tie these factors to early onset cancers, especially digestive system-related cancers, due to the change in the gut’s microorganisms.

Increasing rates of premenopausal breast cancer 

According to the Brigham and Women’s Hospital study, breast cancer has been on the rise in premenopausal women. The authors noted that an increase in premenopausal breast cancer could be due to earlier detection and screening with mammography and self-breast exam. 

“Enhanced screening and detection have probably contributed to an increased incidence of premenopausal breast cancer in countries with certain screening programs, albeit to an unknown extent,” the study authors wrote. 

Of note, the increased rate of premenopausal cancer in women younger than the screening age (40 years) has increased alongside rates of premenopausal breast cancer in women outside of the US who do not have similar access to breast cancer screening tools.

Therefore, early detection and screening programs are most likely not the only culprit of increased breast cancer rates in premenopausal women. 

The Brigham researchers found that additional factors may contribute to early onset breast cancer, including being of a younger age at menarche, oral contraceptive use, nulliparity, older age at first birth, and never breastfeeding.

Effects of cancer diagnosis at an early age

Being diagnosed with cancer at an earlier age can bring about a unique set of challenges, distinct from those faced by older patients.

Cancer early in life can interrupt careers that are not yet established and damage personal finances. In addition, it can negatively affect fertility outcomes; therefore, individuals undergoing treatments must make quick decisions about preserving eggs or sperm. 

Cancer can also affect an individual’s sexual performance and body type, impacting younger individuals and their current and future relationships. (While these effects are also experienced by older people, younger women are more susceptible to the negative effects of low self-esteem.)

In addition, “considering the substantial environmental changes that have occurred since the mid-20th century, an improved understanding of the effects of exposures in the lived environment (such as air and water pollution) is also crucial,” the Brigham researchers note, referencing the fact that younger individuals have experienced higher rates of pollution than older individuals, making them more susceptible to early onset cancer. 

Looking forward

The Brigham researchers believe that early age cancers are more likely to be advanced and have worse outcomes than cancers that develop later in life.

Primary prevention, early detection, and specific treatments for early onset cancers are needed now more than ever. In addition, early lifestyle interventions starting in childhood need to be adopted. 

“We must raise awareness, among both the public and health-care professionals, of the rising incidence of early-onset cancer and aim to increase primary, secondary and tertiary prevention efforts,” the study authors state. Some of these efforts include discouraging smoking and alcohol consumption and adopting a healthy diet and exercise routine. In addition to personal prevention efforts, early screening recommendations and the regulation of industries that produce tobacco, processed food, and sugary beverages could affect cancer risk, according to the study authors. 

"We call for collaborations of researchers, health-care providers, public health practitioners, policymakers and the public to address the rising incidence of early-onset cancer."

Brigham and Women’s Hospital study authors

One thing is for certain—we’re all in this together. 

What this means for you

Research shows that cancer in younger generations is on the rise, potentially due to lifestyle choices and environmental factors. As a physician, this means prevention in the form of patient education and patient lifestyle changes is paramount. Taking time during each patient encounter to discuss your patient’s lifestyle and to encourage healthier habits may help decrease cancer rates. However, it is ultimately up to collaboration between the general public, physicians, and policy makers to address this issue head on.

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