Journal of Geriatric Oncology – 2021 Dec 2;S1879-4068(21)00257-5. doi: 10.1016/j.jgo.2021.11.01
Author : Sophie Pilleron, Nuffield Department of Population Health, Big Data Institute, University of Oxford, Oxford, UK.
Editor : Janine Capobiango Martins, Prevent Senior Brazil

The description of cancer burden in older people at international level is quite recent. For a long time, cancer incidence and mortality have been described for all ages combined masking differences across age groups. Recently, trends in cancer incidence were described in children and young adults was published but not in older people, that we defined as people aged 65+. Monitoring incidence rates over time is, however, important to assess the impact of cancer control measures and to ensure sufficient and appropriate resources to manage cancer in older people.

The authors aimed to describe trends in the incidence of all cancers combined (excluding non-melanoma skin cancer) in adults aged 50–64, 65–74 and 75+ years in 44 countries between 1998 and 2012. They analysed trends in incidence for most common cancers in older adults, namely lung, colorectal, prostate, and breast cancers.They were able to do this work thanks to the availability of the Cancer Incidence in Five Continents (CI5) series held at the International Agency for Research on Cancer (IARC). CI5 includes only population-based cancer registry data assessed as of good quality. The main objective wished to compare trends in incidence observed in older adults with that observed in middle-aged people, ie. the 50-64 age group, as a reference group.

Overall, the paper showed that the incidence of all cancers combined was increasing in older adults similarly to middle-aged patients. About lung cancer, they observed a decrease in the incidence in males aged under 75, but the decrease was not that marked in older males because of the long latency between exposure and lung cancer diagnosis. However, the incidence has increased in females of all age groups, reflecting the increasing number of females smokers. In high-income countries, such as the US, Canada or Australia, the incidence of lung cancer is levelling off thanks to the adoption of preventing measures.

Concerning colorectal cancer, its incidence has increased in all age groups in most countries, especially in those in epidemiological transition because of the change in risk factors related to westernized lifestyle. In some high-income countries, they observed a decrease in the incidence of colorectal cancer though.

This decrease may be partially explained by colorectal cancer screening at least in adults aged less than 75 years but also by change in risk factors. Indeed, in New Zealand there is no colorectal cancer screening program, and the incidence of colorectal cancer has decreased over the study period. Besides, a decrease in the incidence in adults aged 75+ not usually targeted by organized screening program also indicates a potential change in risk factors profiles.

Regarding prostate cancer, its incidence has increased in men aged less than 75 years old in most countries, and in those 75 years old mainly in Asia. It is hypothesized that the increase in Asia is explained by the westernization of lifestyle and prostate cancer screening.

The incidence of breast cancer was increasing in most countries but more importantly in Asian countries. In Northern American countries, European countries, and Australia, breast cancer incidence decreased in the 50-64 age group, reflecting the reduced use of hormonal replacement therapy since early 2000s.

Since 2012, a lot has changed in terms of prevention and cancer screening (i.e., PSA-based cancer screening), we hope that CI5 data will be soon updated so we can have an updated picture of the incidence trends. We will continue describing the cancer burden specifically in older adults, not only in terms of incidence but also in terms of number of years lost and survival. Stay tuned.