Researchers Highlight the Increase of Cancer in Young Adults

Granada has become, de facto, the main Andalusian 'thermometer' for tracking the evolution of cancer, as it is the only province with an active and consolidated population registry. Using its data, a team from ibs.GRANADA and the Andalusian School of Public Health has analyzed over 30 years of diagnoses, between 1985 and 2019, and 18,601 cases in individuals aged 20 to 49 years. The outcome is a landscape that clearly reflects that early-onset cancer has been steadily increasing, with a particularly marked pattern in women.

The overall figures show the gap. Including non-melanoma skin cancer, the incidence increases by 2.4% annually in young women compared to 0.8% in men. And when excluding this tumor, heavily influenced by solar exposure and prevention factors, the increase remains in women (2.0% annually), while in men the trend becomes non-significant. The analysis, recently published in BMC Public Health, is the result of the work of Alejandro Sánchez-Martín from the University of Granada, supervised by María José Sánchez and José-Juan Jiménez-Moleón, and signed by a multidisciplinary team led by Dafina Petrova.

The increase is not uniform; it is driven by specific locations. In young men, notable increases are seen in thyroid cancer (almost +10% annually) and testicular cancer (around +8%), as well as melanoma. In young women, the rise is concentrated in tumors of the central nervous system, thyroid, melanoma, breast, and uterine body, among others. Compared to those over 50 years old, the study detects tumors that grow relatively more in the young (such as rectum, thyroid, and testicle in men, and rectum, CNS, or uterine body in women), a finding that raises questions about early exposures and lifestyle.

The hypotheses, the authors warn, are multiple and may overlap. On one hand, the role of overweight, sedentarism, diet, alcohol, or environmental factors is being investigated. On the other, there are tumors where the health system might be influencing, as more tests lead to more findings and, in some cases, the risk of overdiagnosis (especially noted for thyroid).

Amidst the general uptick, there is a signal pointing to prevention. Lung cancer in young men changes direction and declines from the 1990s, in parallel with the reduction in smoking among young males. The work reinforces the need to investigate the causes of early-onset cancer, review prevention and early diagnosis strategies, and anticipate the impact on a generation facing the disease at working and family life ages. And it issues a warning for Andalusia: without more population registries, it will be difficult to accurately size up the phenomenon and direct resources where they are most needed.

Beyond the rates, the study reminds us that we are talking about a life stage deeply intertwined with decisions about fertility, employment, motherhood or fatherhood, and mental health. An increase in cases at these ages implies a greater demand for rapid diagnosis, agile care pathways, and long-term follow-up, especially in cancers with high survival rates.

The value of a local population registry with international reach

Beyond "what" tumors are increasing, the study provides a very valuable "how," as it relies on a quality population registry with stable and internationally comparable criteria, being part of the Cancer Incidence in Five Continents of the International Agency for Research on Cancer (IARC). This reduces biases typical of hospital series and allows detecting real changes in incidence over time. Additionally, the analysis uses trend models (joinpoint) to identify inflection points and estimate annual changes, key for ongoing surveillance in the field of public health.