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What is Early Onset Cancer?

Cancer is occurring in more adults at younger ages. Early onset cancers (also sometimes called early age onset cancer or cancers in younger adults) include any cancer that is diagnosed in adults between the ages of 18 and 49. Early onset cancer can be found in different parts of the body like the gastrointestinal system, breasts, reproductive organs, skin, thyroid, and blood. But being diagnosed with cancer under age 50 isn’t just about age; these cancers are sometimes more aggressive or less responsive to treatment. There can also be delays in finding the right diagnosis, or the cancer may already be at a later (more advanced) stage.

About Early Onset Cancers

Many younger adults are too young for routine screenings (unless they are at high risk), which can mean delays in diagnosis. But delays alone are not likely to be responsible for the rise in early onset cancer diagnoses. Experts at Yale Cancer Center and across the field are digging into what makes early onset cancers different. There isn’t one reason that separates early onset cancers from later onset cancers, but here are some of the important things we have learned:

  • Age

    At age 50, cell damage begins to build up in the body, and the rate of cancer incidence climbs steeply through the following decades, making cancer more common in older adults. A cancer diagnosis in an adult under age 50, on the other hand, used to be considered “unusual.” The spike in early onset diagnoses could be related to accelerated biological aging (that is, faster than chronological aging) set in motion by a variety of factors. However, researchers are still exploring exactly how age impacts cancer onset.

  • Biological Factors

    Some of the molecular characteristics and pathways of how cells become cancerous are different between the older and younger groups.

    Certain early onset cancers, such as breast cancer and colorectal cancer, can sometimes be more aggressive or less responsive to typical treatment in younger adults.

    In some cases, younger adults are diagnosed at a more advanced stage. Fast-growing cancers often also require more aggressive treatments, especially if the cancer is already spreading in the body. Those treatments can have pretty significant side effects for young adults.

  • Exposures and Lifestyle

    Some early onset cancers may be related to environmental toxins or other exposures as a young child and throughout their lifetime.

    Early onset cancers could also be associated with lifestyle choices such as eating highly processed foods, drinking sugar-sweetened beverages, smoking, and leading less active lifestyles.

  • Genetics and Inherited Cancers

    Because research into early onset cancers is relatively new, experts don’t have all the answers yet. But one thing we know is that your risk of developing an early onset cancer can be passed down from one family member to another through genes. These types of cancer are called inherited cancers.

Life Impact

Being diagnosed with cancer under the age of 50 most often comes as a shock to patients and families. Younger adults are in a unique space in their lives, and cancer throws a curve ball into an already challenging time of development.

Cancer and treatment can be difficult and often impact many areas of a person’s life, which can lead to significant life disruptions. Everyone doesn’t experience the same challenges, but some of the most common life disruptions that the Early Onset Cancer Program supports include:

  • Parenting

    Managing the demands of parenting

  • Finances

    Balancing the financial impact of cancer at a young age

  • Social Life

    Navigating social issues and challenges

  • Caregiving

    Caring for aging parents

  • School & Work

    Facing interruptions to school and work

  • Family Planning

    Wondering about the impact to fertility and family planning

Preventing Cancer

Being proactive in leading a healthy lifestyle can lower your risk of cancer. From avoiding known cancer-causing exposures to learning about your family history to discussing concerning symptoms with your doctor, you can make positive choices that lower your risk of developing an early onset cancer. Younger adults should take these steps when possible:

Cancer Prevention

  • Activity

    Stay active

  • Eat Healthy

    Avoid processed food

  • Family History

    Know your family health history, share with your doctor

  • Less Alcohol

    Drink less alcohol, less often

  • No Smoking

    Avoid or stop smoking

  • Screenings

    Get all cancer screenings on time

  • Report Symptoms

    Discuss new or concerning symptoms with your doctor

  • Vaccinations

    Stay current with cancer vaccinations

Early Detection

Because some early onset cancers are associated with your genetics, its important to know your family history and have a conversation with your healthcare provider about which cancer screenings you need and when.

You might benefit from a hereditary cancer genetics evaluation and testing if you are someone with:

  • A personal or family history of early onset cancer (age 50 years or younger)
  • Several family members on the same side of the family have cancer
  • A personal or family history of breast cancer and Jewish ancestry
  • A personal or family history of ovarian, pancreatic, triple-negative breast cancer, or metastatic prostate cancer at any age
  • A personal or family history of multiple colon polyps
  • A personal or family history of multiple cancer diagnoses within the same individual
  • A personal or family history of a rare type of cancer/tumor (breast cancer in a male, medullary thyroid cancer, sebaceous carcinoma, or adenoma)
  • A family history of a known gene pathogenic variant (such as BRCA1, BRCA2, MLH1, MSH2, etc.)
  • A person with cancer where the genetic results may help determine eligibility for targeted therapy
  • A strong personal and/or family history of cancer who has had prior negative genetic testing performed more than five years ago. Additional testing may be appropriate.

Early Onset Cancers on the Rise

The American Cancer Society’s Cancer Statistics, 2024 revealed that while cancer deaths are falling, new cases among adults under 50 are ticking upwards—from 1.9 million in 2022 to over 2 million in 2023. Recently, researchers in the US have found that adults in their 30s have seen a nearly 20% increase in cancer diagnoses since 2010.

Early onset breast cancer, or breast cancer in younger women, has been a growing concern for several years, but the recent sharp rise in younger adult gastrointestinal cancers (also called GI cancers) has sounded alarm bells for cancer specialists, researchers, and the public. Breast and GI cancers make up a large portion of what cancer specialists are seeing, but prostate, pancreatic, skin, thyroid, reproductive, and blood cancer rates are also growing.

The Early Onset Cancer Program @ Yale partners with our experts across each cancer department to support exceptional care for younger adults. Learn more about each cancer department: