Why Are Younger Adults Getting More Cancers?

5 min read  |  January 09, 2024  | 
Disponible en Español |

A government study of cancer registries shows younger adults – and especially young women — are diagnosed with certain kinds of cancers at a higher rate than in previous years, a worrisome trend for oncologists trying to figure out the underlying reasons for the increase. 

The increase is a national trend 

Published in August 2023 in JAMA Network Open, the study examined more than 500,000 early-onset cancers between 2010 and 2019 — cancers diagnosed in people under age 50 — at 17 National Cancer Institute registries around the country. The incidence of cancers increased overall by 0.28% annually.

Early cancers in women, however, increased by 0.67% a year, with breast cancer leading the way. In contrast, overall rates decreased for men by 0.37% a year. Meanwhile, the rate of cancers in people 50 and older decreased. 

“Unfortunately, we see a lot of young women with breast cancer at Sylvester,” says Alejandra Perez, M.D., a breast medical oncologist with Sylvester Comprehensive Cancer Center, part of the University of Miami Miller School of Medicine. “Breast cancer is now the most common type of cancer in women younger than 40.” 

In fact, the youngest patient Dr. Perez treated was 18 years old. 

The national study on early-onset cancers shows:  

  • Early onset cases in women increased by 4.35% in the decade studied. Among men, cases fell 4.91%. 
  • Cancer rates were going up fastest among Native Americans, Alaska Natives, Asians and Hispanics. It remained stable among whites and decreased among Blacks. 
  • While breast cancer had the highest number of cases, gastrointestinal cancers had the fastest-growing incidence rates among all early-onset cancers, spiking almost 15%.  
  • The most significant increases were in cancers of the appendix (up 252%) and cancers of the bile duct (up 142%). 
  • Breast cancer claimed the highest number of cases in 2019, with 12,649 cases. That was followed by thyroid, with 5,869 cases, and colorectal cancers, with 4,097. 

Mammograms are important for young women 

At Sylvester, the figures don’t appear to totally reflect the trend, at least not in an analysis of more current years. For instance, between 2020 and 2021, the incidence rates of breast cancer as part of the total number of cancer diagnoses in women decreased from 32% of the total number of cases in 2021 to 27% in 2022. (This small drop was true in stages 1 through 4 of clinical cancer staging.) 

Dr. Perez, however, remains concerned about early-onset breast cancer, mainly because “young women with breast cancer are more likely to be diagnosed at a later stage, have more aggressive cancers, and be African American. Young women also have to manage unique issues to them like fertility, body image, sexual health, financial toxicity, and others.” 

Younger women do not undergo mammograms routinely (screening usually begins at age 40), so they might be diagnosed at a later stage when they present with large palpable tumors. 

Genetic testing can help determine your risk

“Young women are more likely to have a genetic mutation than older women,” Dr. Perez says. In addition, they’re also more likely to have triple-negative breast cancer, an aggressive type of tumor.  

It’s essential for women to know their risk factors, she adds. “Having a first-degree relative (mother or sister), a male relative with breast cancer, prior history of radiation to the chest or hormonal factors like an early menarche (start to menstruation), can increase the risk.”  

Seeing an uptick of gastrointestinal cancer in women

As for GI cancers, an analysis of Sylvester cases that overlap the years of the national study shows the incidence rate held steady between 2015 and 2022 for men. For women, though, there was an uptick in GI cases as part of the total number of cancers. This was true at all clinical stages. 

With colon cancer, early-onset cases among men also stayed the same between that period. Still, it increased for women between 2021 and 2022, making up 19% of the total number of cancers in females compared to 22% in 2022.  

Merce Jorda, M.D., Ph.D., M.B.A., professor and chair of the Department of Pathology and Laboratory Medicine, says this may be due to the demographics of patients in South Florida, some of whom come from Latin America with a more advanced stage of the disease. She points to the increase in stage 3 and stage 4 colon cancers for both men and women. Also, colon cancer screening as part of routine healthcare doesn’t start until 45. “It is possible that with [early] colon cancer screening, we might see different [staging],” she says. 

Regular checkups are a must

Shria Kumar, M.D., a gastrointestinal cancer risk mitigation researcher at Sylvester and clinical epidemiologist and gastroenterologist at the Miller School, says she has seen an uptick in early-onset colorectal cancers, even as the incidence rate inches down in the older demographic. The reason? “There are numerous risk factors that we think [are causing this], but there’s really nothing clear-cut. There are likely multiple components, including genetic predisposition, lifestyle, and environment,” she says. 

The guidelines for colorectal cancer initiation have recently expanded so that instead of starting colon cancer screening at age 50, most societies now recommend doing so at age 45. It’s an important initiative that could help with early diagnosis and interventions.  

“The best thing you can do is get regular checkups,” she says. “Maintain a healthy lifestyle. Eat right. Exercise.” 

Headshot of Ana Veciana, author (2023)

Ana Veciana-Suarez is a regular contributor to the University of Miami Health System. She is a renowned journalist and author who has worked at The Miami Herald, The Miami News, and The Palm Beach Post. Visit her website at or follow @AnaVeciana on Twitter.

Tags: Adolescent and Young Adult Cancer Program, cancer care in Miami, cancer prevention, cancer prevention efforts, cancer screening, high risk cancer

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