What to Know About Rising Rates of 'Early-Onset' Cancer

[Originally published: March 4, 2024. Updated: August 1, 2024]

Many people think of the first few decades of adulthood as a time of exploration—to focus on a career, make new friends (or even find a spouse), travel the world, or just have fun. Whichever path they choose, the last thing on their mind is cancer. But cancer is occurring in more adults at younger ages—before they turn 40 or 50 and sometimes even earlier.

These are called “early-onset” cancers, which are diagnosed in adults between the ages of 18 and 49. Because advancing age is the top risk factor for cancer in general, the recent rise in early-onset cancers is worrisome.

Many individuals in this age group are too young for recommended routine cancer screenings—for example, mammography screening typically starts at age 40 and colonoscopies at age 45. And busy lives make it difficult to keep up with routine primary care visits, where family history might prompt a doctor to suggest an earlier screening. Others may not go to the doctor because they have limited or no health insurance—or they believe their health problems are not serious enough to warrant a visit. This can result in diagnosis delays, which raise the risk of cancer potentially being diagnosed at a more advanced stage, which may be harder to treat.

Why are younger people getting cancer? “It's such an important question, and it points to the need for more research in all kinds of domains—in population science, behavioral health, public health, and basic science as well,” says Veda Giri, MD, a Yale Medicine medical oncologist and director of Yale Cancer Center’s Early-Onset Cancer Program at Smilow Cancer Hospital, which brings together such components as research, clinical services, and care from psycho-oncologic specialists, including psychiatrists and social workers.

“So, right now, we are focusing on recognizing that early-onset cancer is a different type of cancer and providing more support for these younger patients,” Dr. Giri says.

Below, Yale Medicine specialists who care for patients with early-onset cancer answer questions about the uptick in diagnoses and the importance of family history.

Age itself is the first and obvious difference. “Early-onset” can be defined in various ways based on the cancer type. “For example, early-onset breast cancer refers to a diagnosis in someone younger than age 45, while early-onset colorectal cancer is a diagnosis that occurs in someone younger than 50,” says Dr. Giri. “To be as inclusive as possible, the Early-Onset Cancer Program at Yale is addressing the needs of patients diagnosed with cancer between the ages of 18 and 49.”

At age 50, cell damage begins to build up in the body, and the rate of cancer incidence climbs steeply through the following decades. A cancer diagnosis before age 50 is not uncommon, but it’s also not the trajectory most people expect, considering the median age for a cancer diagnosis is 66 years old.

Another difference is that certain cancers, such as breast cancer, tend to be more aggressive in younger adults, says Yale Medicine’s Mariya Rozenblit, MD, a medical oncologist.

“While older women are more likely to be diagnosed with slow-growing, estrogen-positive tumors, younger women have more triple-negative and human epidermal growth factor receptor 2 [HER2] breast cancers, which are more aggressive types,” Dr. Rozenblit says. The latter cancers often require more aggressive treatments, especially if the cancer is already spreading in the body, and those treatments can have significant side effects, she adds.

“Younger women diagnosed with breast cancer are also more likely to have a genetic mutation than older women,” says Dr. Rozenblit. But she cautions that while genetics are getting more attention, mutations like BRCA only account for about 20% of early-onset breast cancers. “So, there are clearly other contributing factors that we don’t yet know,” she says. “The good news is that once breast cancer is diagnosed, the prognosis is usually very good. The treatments can be long, but we still have very high cure rates, and these younger women often end up doing extremely well.”

Jeremy Kortmansky, MD, a Yale Medicine medical oncologist specializing in gastrointestinal cancers, also sees differences when younger adults are diagnosed with colorectal cancer. “Some of the molecular characteristics and pathways of how something becomes cancerous are different between the older and younger groups,” he says. “Younger adults tend to have a more aggressive-appearing cancer. They also tend to present at a more advanced stage that is not solely explained by a delay in diagnosis.”

Some of this may be explained by the fact that they are too young for routine screening, but there's probably more to the story. We just don’t have answers yet, he adds.

While some cancers have been declining in older people, various reports and studies have shown that cancer is on the rise in younger adults. One recent large study, published in The Lancet Public Health in July 2024, analyzed differences among adults born in the U.S. between 1920 and 1999, and found incidence rates rose in successively younger generations—particularly in Generation Xers and Millennials—in 17 of 34 cancer types, including breast, pancreatic, and gastric cancers. Mortality rates for several types of cancers increased as well. The study was led by the American Cancer Society (ACS).

Another recent one is Cancer Statistics, 2024, an ACS annual report on cancer facts and trends. Published in January, the report revealed that while cancer deaths are falling, new cases are ticking upwards—from 1.9 million in 2022 to over 2 million in 2023.

More of those new cases involve younger people. The ACS annual report showed younger adults to be the only age group with an increase in overall cancer incidence between 1995 and 2020—the rate has risen by 1% to 2% each year during that time period.

The ACS annual report also showed continued increases in such common cancers as breast, prostate, and endometrial in young adults, as well as colorectal and cervical cancers. Colorectal cancer, while still overwhelmingly a disease that affects older people, is now the leading cause of cancer death in men younger than 50 and second in women in that age group. The numbers have been rising steadily in people 55 and younger since the mid-1990s, according to the ACS.

As for cervical cancer, the ACS annual report had both good and bad news. Rates of cervical cancer dropped significantly in women in their 20s, who were among the first to get the human papillomavirus (HPV) vaccine, which can prevent more than 90% of HPV-attributable cancers. But for women ages 30 to 44, rates rose 1.7% each year from 2012 through 2019. The increase highlights the need for more screening in younger women and a broader uptake for the vaccine, according to the ACS report.

Because doctors and researchers don’t yet know why early-onset cancers are increasing, they are focusing on efforts to diagnose these cancers early, when they are typically more treatable. And family history has emerged as a key factor in early diagnosis.

This is partly because young adults don’t always meet the recommended age for routine screenings that are available for some of these cancers. For instance, because colonoscopy screening typically starts at age 45, most cases in adults younger than 45 are not identified until they start noticing signs and symptoms.

But talking to a doctor about a family history of colorectal cancer could prompt a screening referral at a younger age. “If there is a family history of either cancer or polyps, we usually start colonoscopy screening 10 to 15 years before the family member who had it was diagnosed,” says Dr. Kortmansky. “So, if a first-degree relative was diagnosed with cancer at 45, you would start screening at 30.”

Likewise, women who are at average risk for breast cancer may start biennial mammography screening at age 40, according to U.S. Preventive Services Task Force (USPTF) recommendations updated in 2024. But women with a family history of breast cancer are generally advised to start when they are 10 years younger than the first-degree relative (a mother and/or sister) was at their time of diagnosis.

“We’re beginning to recognize that family history is very important,” says Dr. Rozenblit. “For young women who have a significant family history of cancer in the family, we are starting to refer them to a high-risk clinic—even if the cancer in their family is not breast cancer.”

Depending on family history, calculators can be used to further estimate a patient's cancer risk, and advanced screening like MRIs or other diagnostic procedures may be offered, adds Dr. Giri.

“Family history can inform genetic testing to find out whether a person has a mutation that makes them predisposed to developing a certain type of cancer,” she says. “But even if patients test negative for genetic mutations, family history may be a reason to follow them more closely.”

Nancy Borstelmann, PhD, MPH, LCSW, co-director of Yale’s Early-Onset Cancer Program, says that while a cancer diagnosis and treatment are challenging for most people, there are some heightened and unique concerns for someone in their 20s, 30s, or 40s.

One key example is family planning, since some cancers and treatments can create challenges with being able to become pregnant or produce sperm. “It depends on each person’s situation—for example, their age, type of cancer, and treatment plan. But patients may face a decision about freezing eggs or embryos, or whether to consider sperm banking,” Borstelmann says. “Reproductive concerns can add to the distress that cancer patients are already experiencing, and they are important issues for patients and their doctors to discuss. Additional challenges include worries about insurance coverage and the financial impact of taking steps related to family planning.”

Younger women may also be concerned that cancer treatment could pose a risk of early menopause. Chemotherapy may induce menopause, or, in some cases, hormonal treatments are part of a treatment plan specifically designed to produce an early menopause. Whatever the cause, Borstelmann notes, early menopause shortens a person’s fertility window and can have other effects on their overall physical and emotional well-being.

Body image is yet another concern. There are many aspects to body image, but, for some, a clearly visible issue to manage is hair loss, which can be a side effect of chemotherapy, Borstelmann says. “For some, it's very distressing.”

Sexual function and sexual health issues are also common and can range from changes in bodily sensation (for example, for a woman who has had a mastectomy) to erectile dysfunction (for example, after prostate cancer treatment). Younger individuals diagnosed with any type of cancer, however, may struggle with the direct or indirect impact of cancer on their sexual health and how they feel about their bodies. Some describe a sense of loss and fear related to developing or sustaining intimate relationships.

What’s more, because cancer is happening at such young ages, even after treatment, there is the possibility that the cancer could come back, which is especially difficult for survivors who still have decades of life ahead of them. This is a particular concern for those with thyroid cancer, who face a risk of recurrence that is highest in the first five years after diagnosis and treatment, but persists throughout their lifetime, says Yale Medicine endocrine surgeon Courtney Gibson, MD, MS. “Since the life expectancy of young adults remains largely unchanged after a thyroid cancer diagnosis, the fact that recurrence can happen at any time is very unsettling,” she says. “However, we can provide reassurance that if it returns, we still have effective ways to treat it.”

The advice on the topic—for everyone—remains the same: Pay attention to exercise and nutrition, don’t smoke or drink too much alcohol, and be aware of family history and share it with a primary care physician, the doctors say.

Following up with a doctor and fully checking out any unusual symptoms can be critical, Dr. Kortmansky adds. “There is often a delay between the onset of symptoms and the actual diagnostic procedure to find the cancer,” he says. “Some of that may be driven by patients who think, ‘I'm only 40—it's probably not cancer, right?’ Other times, a physician may think rectal bleeding in a young patient is just a sign of hemorrhoids, so it’s important to advocate for yourself.”

At the same time, no patient should feel guilty or ashamed if they are diagnosed with cancer, Dr. Giri and Borstelmann say, describing two common reactions they say some of their young patients have. “It can be a human response to ask, ‘Did I do something wrong?’” Dr. Giri says. “I've seen this in some incredibly health-conscious patients who ate well and exercised. They feel completely thrown by this and need to know it’s not their fault.”

Each patient is different, and a key component of the Early-Onset Cancer Program at Yale is to ensure that patients have a place where they can talk about their feelings and experiences, Dr. Giri says. “Young people need to feel supported and holistically cared for through the course of their cancer and beyond,” she says.