People who survived cancer as teens and young adults are at increased risk of developing cancer later in their lives, according to research from the Canadian Medical Association Journal.
Approximately 16% of adolescent and young adult cancer survivors who stayed cancer-free for at least five years are at high risk, compared to about 12% of people in the same age group without cancer.
New cancers that develop after earlier cancers are known as subsequent primary neoplasms. Important risk factors for developing an additional cancer later on in life include the cancer treatment the person received (chemotherapy, radiology, and/or hormone therapy) and age of initial cancer diagnosis.
The Alberta Adolescent and Young Adult Cancer Survivor Study included all people in Alberta, Canada, who were diagnosed with their first cancer from the ages of 15 to 39 years between 1983 and 2017. In the 34-year study, 6% of the 24,459 people with a median follow-up of 7.4 years developed a second cancer.
People who had cancers of the mouth or throat faced the highest risk, with nearly 29% developing a new cancer later on, followed by about 27% for breast cancer survivors. Colon cancer and Hodgkin lymphoma survivors also saw elevated risk, with about 24% and 23% developing a new cancer over time, respectively.
One in 6 survivors of adolescent and young adult cancer, or AYA cancer, will develop a new cancer 30 years after their first diagnosis. The study authors said earlier screenings may be beneficial, as new cancers develop decades sooner for survivors, compared to the general population.
Where people lived and how much money their neighborhood had did not appear to affect the risk of developing a new cancer. The risk of getting a new cancer also looked about the same whether researchers focused on people who had already survived five years or looked at their risk over their entire lifetime.
Girls and women who were first diagnosed with breast cancer at a later age had the highest incidence of developing subsequent primary neoplasms by 30 years post-initial cancer diagnosis.
Cancer incidents are substantially higher in girls and women, according to the American Cancer Society (particularly in older AYAs, research published on the National Institutes of Health website shows).
Cancer rates are 30% higher in women aged 20-29 (55 versus 42 per 100,000) compared to males and nearly double in those aged 30-39 (161 versus 84 per 100,000), the American Cancer Society states.
Black AYA patients have a 47% higher mortality risk and Hispanic patients have a 3% higher risk compared to white patients, according to research presented at the 2025 American Society of Clinical Oncology Annual Meeting.
AYA cancer incidences have been increasing over time, according to a study published in CA: A Cancer Journal for Clinicians in 2020 and shared on the National Library of Medicine website.
In the U.S., overall rates increased in all AYA age groups between 2007 and 2016, largely driven by thyroid cancer (rising approximately 3% annually among those 20 to 39 years old and 4% annually among those aged 15 to 19) and obesity-related cancers including kidney (3% annually), uterine corpus (3% among those 20-39 years old) and colorectal cancer (0.9-1.5% among those 20-39 years old).
A major limitation to the Alberta study is its relatability to the U.S. population, since the Canadian health care system is different than U.S. health care system.
In addition, the paper itself notes that researchers had incomplete data on the type of treatment exposure and the genetic, racial, or ethnic makeup of the cohort, and they were unable to analyze the data by these categories.
ABC News' Sabina Ghebremedhin contributed to this report.
