Cancer epidemiology in the freely associated U.S. Pacific Island jurisdictions: challenges and methodologic issues.

The health care systems of the U.S.-associated Pacific Island jurisdictions, especially the three freely associated states (Federated States of Micronesia, Republic of the Marshall Islands, and Republic of Belau), are faced with problems similar to developing countries such as malnutrition and infectious diseases, as well as diseases relating to westernization such as diabetes, heart disease, and cancer. Although cancer has emerged as an important cause of morbidity and mortality in the Pacific, little population-based data are currently available. This paper addresses some of the practical and methodological challenges to obtaining accurate and reliable cancer data in these jurisdictions. This paper discusses the use of annualized period prevalence to allow for some measurement of cancer burden when cancer incidence cannot be accurately calculated. This method, however, has its own limitations as cancer prevalence relates to both incidence and duration of illness, and numerous factors impact survival potential (i.e., preexisting diseases, lifestyle practices, and access to treatment). In addition, under-ascertainment and data quality issues will impact any cancer morbidity or mortality measurements. Thus, improvement in the health care systems, including the creation and ongoing support of active cancer registries would be the optimal approach to better delineating cancer occurrence and risk for the populations of these Pacific Island jurisdictions.