Cancer incidence and mortality among young adults aged 20–39 years worldwide in 2012: a population-based study

Cancer incidence and mortality among young adults aged 20–39 years worldwide in 2012: a population-based study
Population based study with the aim of quantifying the global burden of cancer in young adult patients (20-39y). Young adult cancers have not received the same amount of study as cancer in children or adults.
Authors gathered data on cancer diagnosis and cancer mortality in patients aged 20-39 years from 184 different countries using the International Agency for Research on Cancer's GLOBOCAN 2012 database. They calculated age-standardised incidence and mortality rates at the global and country level. Case fatality rates were approximated by dividing the age standardized mortality rate by the age standardized incidence rate. Results are also presented by geographic region and regional development level (Human development index, HDI).
975 396 cancer cases and 358 392 cancer-related deaths were estimated to have occurred worldwide in 2012. Cancer and cancer-related death was more common among women (male:female ratio of 0.5 and 0.8 for incidence and mortality respectively). There was a higher risk of cancer in young adults than in adolescents (four fold increase) but lower than in middle-aged adults.
Breast cancer was the most common cancer type in young adults world wide (19.6% of total estimated new cases). Cervical cancer was the second most common cancer type (11.4%). Thyroid cancer was the most common cancer type in young adults in Canada. The largest contributors to cancer-related deaths worldwide were breast (13.6%), leukemia (10.1%), and liver cancer (10.1%).
Breast cancer and cervical cancer were the most common cancers in the low, medium, and high-HDI levels. At very high-HDI levels, breast cancer was most common and cervical cancer was fifth most common. Thyroid cancer, melanoma and testicular cancer were more frequent in very high-HDI regions. Cancers linked to infectious agents were more common in lower HDI settings. Mortality decreased with increasing HDI.
Data are based on estimates from GLOBOCAN database and rely on quality of source information. There is a lack of uncertainty intervals provided, which is addressed by the authors. Bone and soft tissue sarcomas were not addressed.
Globally, the most common cancers in young adults (20-39y) are breast cancer, cervical cancer and thyroid cancer. Cancer and cancer-related death is more common among women than men. Cancer risk is increased for young adults relative to adolescents.
Young adults with cancer represent an underserved population with cancer. Future research should address the questions of prevention, surveillance and treatment.