A surveillance study of cancer incidence and mortality among young adults in Costa Rica

Background: There has been an increase in certain cancers among young adults (YA) aged 20-39, particularly in Latin America. This is the first study to examine cancer incidence and mortality in YA in Costa Rica, focusing on sex-specific patterns.

Methods: Invasive cancer cases (excluding non-melanoma skin cancer) in YA from 2006 to 2015 were obtained from the Costa Rican National Registry of Tumors. Utilising SEER∗Stat software, age-standardized incidence rates (IRs) and incidence rate ratios (IRRs) were calculated. Trends and annual percent changes (APCs) in IRs were estimated using the Joinpoint regression analysis program. Cancer deaths from 2000 to 2021 were obtained from the Costa Rican National Institute of Statistics and Census. Age-standardised mortality rates were calculated using STATA®17.

Findings: YA comprised 10.7% of all invasive cancer cases diagnosed from 2006 to 2015. The age-standardized incidence rate (ASIR) of invasive cancer in YA was 50.9/100,000 person-years. The ASIR was twofold higher for females compared to males (IRR = 2.03, 95% CI:1.94, 2.13). This difference increased with age, peaking in the 35-39-year age group (IRR = 2.84, 95% CI:2.62, 3.10). Thyroid, breast, and cervical cancer were the most common in females. Testicular cancer was the most common in males. Leading causes of cancer-related deaths included cervical and breast cancer in females and stomach and brain/nervous system cancer in males.

Interpretation: The study highlights sex-specific patterns in cancer incidence and mortality among YA in Costa Rica to increase understanding and improve cancer outcomes in this age group.

Funding: This study was funded by the Intramural Research Program of the National Cancer Institute.