People 30 to 39 saw the largest increase in cancer cases, and rates increased in women but not in men.
Cancer rates in people under 50 years old are rising, according to a new study published in JAMA Network Open. Breast cancer accounted for the highest number of cancer cases in younger people, and gastrointestinal cancers, including colon cancer, saw the largest percentage increase of any type of cancer.
Researchers also found that during the same time period, 2010 to 2019, cancer rates among people 50 and older have gone down.
Healthcare professionals need to know about the increasing incidence of early-onset cancer, the authors wrote, and “investigations for possible tumours need to be considered when clinically appropriate, even in patients younger than 50 years.”
Suneel Kamath, MD, a haematologist, medical oncologist, and assistant professor of medicine at Cleveland Clinic in Ohio, agrees. “Many of the people I see told me that they saw several different doctors for many months for the same symptoms, and nobody thought of cancer. The thought was, ‘You’re too young to have cancer, so it can’t be that,’” explains Dr. Kamath, who was not involved in the research.
Not only is the study important to build awareness so that diagnoses will not be missed, but it could also lead to more funding for research to “get to the bottom of why this is happening,” Kamath says.a
Early-Onset Cancer Increased in Women but Declined in Men
The study used data from 2010 to 2019 from the National Cancer Institute Surveillance, Epidemiology, and End Results (SEER) program to analyse the incidence of early-onset cancers overall and in different organ systems, as well as patterns according to sex, age group, and race and ethnicity. The SEER database collects data on cancer cases from various locations and sources throughout the United States.
Over the 10-year period, a total of 562,145 people with early-onset cancer (cancer in people under 50 years old) were identified, and 62.5 percent were female. Overall, there was a 0.74 percent increase during the study period, with early-onset cancers in women increasing by 4.4 percent but declining by 4.9 percent among men. The increases seen among younger women were likely driven by the rise in cancers of the breast and uterus, wrote the authors.
In 2019 alone, the highest number of early-onset cases were breast cancers, with 12,649 cases, followed by thyroid cancer, with 5,869 cases.
GI Cancers the Fastest Growing Early-Onset Cancer
From 2010 to 2019, rates of gastrointestinal cancers were the fastest-rising among all early-onset cancers, increasing by almost 15 percent. In addition to colon cancer, cancers of the appendix, bile ducts in the liver, and pancreas had the fastest growth rates, according to the study results. By age, the increase in incidence was greatest in people between 30 and 39 years old.
Investigators found that early-onset cases rose 32 percent among people of Asian or Pacific Island background and nearly 28 percent among Hispanic people over the study period. Cancer rates fell nearly 12 percent among white people and 5 percent among Black Americans, though researchers note there could have been under-reporting or under-diagnosis in underserved populations.
“I think this is a really important article in a growing literature really showing that cancer is increasingly in the young. There just seems to be this rise in a number of different cancers and people even in their twenties and thirties,” says Kamath.
Not only will these findings build a greater awareness that cancer in younger people is on the rise, but it could also help identify groups at higher risk, says Kamath. “For example, people of Asian descent or Hispanic descent where there was the biggest spike may benefit from increased screening,” he says.
Early Onset Cancer Is Often More Difficult to Treat
Cancer in people under 50 tends to be more difficult to treat, and a big part of that is because these cancers are diagnosed at very late stages, so outcomes tend to be worse, says Kamath.
“The cancer diagnosis in a young adult is more devastating, when life is supposed to be full of great excitement and expectations, such as career goals and family life,” says Ning Jin, MD, a gastrointestinal medical oncologist with The Ohio State University Comprehensive Cancer Center in Columbus, who was not involved in the research.
People under 50 may have more financial stress and difficulty in balancing work, life, and medical treatment, Dr. Jin explains. “They often need to deal with acute and long-term side effects from treatment, including the pain and bowel dysfunction. If patients require radiation treatment for their rectal cancer, there will be concerns for fertility, sexual dysfunction, and colostomy management,” she adds.
In many cases, younger people have a delay in diagnosis – and therefore a delay in treatment – that can increase the likelihood of poorer outcomes, says Kamath.
Lifestyle and Early Exposure to Antibiotics May Play a Role in Cancers in Younger Adults
More research is needed to find out why cancer is on the rise in younger adults and in certain groups, according to the authors. It could be related to lifestyle changes, such as the typical Western diet (more red meat and less fibre), and food additives, says Lin.
There’s also data to suggest that antibiotic use, especially early in life, could play a role, says Kamath. “There does seem to be this birth cohort effect, where people born in a certain time frame – the 1980s until the early 2000s – may be the most impacted.”
During this period, the overprescribing of antibiotics may have had long-term impact on the microbiome and may be related to more cancer onset later in life, he says.
Why the Decrease in Cancer Rates in Older Adults?
It may be that screenings such as mammograms or colonoscopies could be helping reduce the cancer incidence in some cases, says Kamath.
“If you think about mammograms for example, if you detect a precancerous lump before it turns into cancer and it gets removed, you can stop a cancer from happening. In a colonoscopy, if polyps are identified and removed, you’re actually stopping people from ever developing colon cancer,” he says.
And although screening is certainly making a dent in reducing the number of older adults with cancer, some of the reduction is caused by the people who would have developed cancer in their fifties and sixties getting it earlier, says Kamath. “Someone that may have gotten cancer later, at age 65, is getting it at age 45,” he says.
Younger People With Unexplained Symptoms May Benefit From a Second Opinion
There is research showing that people in their twenties and thirties who are eventually diagnosed with cancer saw several doctors over the 6 to 12 months prior to their diagnosis, says Kamath. “And it wasn’t as if their symptoms really changed during that time. They were basically the same, but it ultimately took a different doctor coming across them to realise that something more serious was going on,” he says.
Getting a second opinion and going to a hospital where there is more specialisation and more awareness is important, says Kamath. “I think it takes a doctor really being educated on this to take that next step in terms of doing more testing to get to the bottom of what’s going on,” he says.