A new study published in JAMA Network Open found that the rate of cancer in adolescents and young adults increased by nearly 30% from 1973 to 2015.
Adolescents and young adults (AYA) are known to be a distinct population when it comes to cancer incidence and care, but long-term data on the trends and characteristics of those cancers is still lacking. A new study from the Penn State College of Medicine published in JAMA Network Open aiming to identify those trends found that the rate of cancer in AYAs increased by nearly 30% from 1973 to 2015.1
"Adolescents and young adults are a distinct cancer population," study author Nicholas Zaorsky, assistant professor of radiation oncology and public health sciences at Penn State, said in a statement.2 "But they are often grouped together with pediatric or adult patients in research studies. It is important to study how this group is distinct so that care guidelines can be developed to address the increase in cases."
Study authors wrote that although there has been a significant increase in AYA cancer-focused research recently, the fact that research has historically focused on childhood and adult cancers still leaves a knowledge gap regarding guidelines for diagnosis, treatment, and monitoring of AYA patients.
The main objectives of the study were to identify the patient demographic characteristics, frequencies of cancer types, and cancer incidence trends over time in AYAs aged 15 to 39. The retrospective, cross-sectional, population-based study included 497,452 AYAs diagnosed between 1973 and 2015, using data from the Surveillance, Epidemiology, and End Results (SEER) database. The population of the U.S.-based study was geographically diverse, 59.1% female, and 79.9% White, meant to represent the demographics of the country’s population.
Researchers found that overall, the rate of cancer in AYAs increased by 29.6% between 1973 and 2015. The mean annual percentage change (APC) in the rate of cancer in AYAs was 0.537 per 100,000 persons (95% CI, 0.426-0.648; P < .001), and kidney cancer incidence increased at the greatest rate in both males and females ([APC, 3.572; 95% CI, 3.049-4.097; P < .001] and [APC, 3.632; 95% CI, 3.105-4.162; P < .001], respectively.
Despite kidney cancer having the greatest incidence increase, the authors note that its relatively low absolute incidence rate means it may have minimal impact on the increased rate of cancer overall. Cancers with larger absolute incidence numbers—including gastrointestinal tract carcinoma, thyroid carcinoma, melanoma, non-Hodgkin lymphoma, and germ cell and trophoblastic neoplasms of the gonads—contributed more significantly to the overall increase in the AYA cancer rate.
In females, 24.7% were diagnosed with breast carcinoma, 16.6% with thyroid carcinoma, and 11.5% with cervix and uterus carcinoma. In males, 18.5% were diagnosed with testicular cancer, 10.2% with melanoma, and 9.6% with non-Hodgkin lymphoma. In general, the relative incidence of carcinomas increased while the relative incidence of leukemias, lymphomas, germ cell and trophoblastic neoplasms, and neoplasms of the central nervous system decreased as AYAs aged.
The data show that cancer in AYAs is a growing problem and that it has a distinct distribution, the study authors concluded. While more research is needed, the findings regarding the unique patterns in AYA cancers can also help inform diagnosis and treatment options in this age group.
"These cancers all have unique risk factors," Zaorsky said. "Now that there is a better understanding of the types of cancer that are prevalent and rising in this age group, prevention, screening, diagnosis and treatment protocols specifically targeted to this population should be developed.”
1. Scott AR, Stoltzfus KC, Tchelebi LT, et al. Trends in Cancer Incidence in US Adolescents and Young Adults, 1973-2015. JAMA Netw Open. 2020;3(12):e2027738. doi:10.1001/jamanetworkopen.2020.27738
2. Cancer cases are rising in adolescents and young adults. News release. Penn State College of Medicine; December 1, 2020. Accessed December 3, 2020. https://news.psu.edu/story/640279/2020/12/01/research/cancer-cases-are-rising-adolescents-and-young-adults