Cancer Surveillance

Reliable cancer data are essential for planning and monitoring the effectiveness of cancer control programs, for examining cancer care delivery patterns, and other types of research. Population-based cancer registries (PBCRs) fulfill this requirement by systematically collecting cancer incidence data for defined populations. This includes information on patient and tumor characteristics at diagnosis, as well as additional information including receipt of treatment and vital status where resources permit.

Cancer registry data are primarily used to describe the scale and profile of the cancer burden and changes in cancer patterns across time and geographic areas. A PBCR may cover an entire country, but most cover smaller regions within a country, particularly in large or resource-constrained countries. Registry quality varies widely by geographic region. (Map 1)

Although there are significant disparities in the status, population coverage, and quality of cancer registries worldwide, the number of high-quality cancer registries is increasing. (Figure 1) Volume I of the Cancer Incidence in Five Continents series, covering the early 1960s, included datasets from 31 cancer registries in 28 countries. The most recent volume (Volume XI), covering 2008–2012, has data from 343 registries in 68 countries. The Global Initiative for Cancer Registry Development (http://gicr.iarc.fr) was established by the International Agency for Research on Cancer (IARC) in 2011 in partnership with international and national organizations aiming to improve the availability of high-quality cancer registry data via support for within-country capacity building. Six IARC Regional Hubs and accompanying IARC Collaborating Centres work with local and regional partners to provide direct support to registries, deliver training, conduct research, and develop networks.

Cancer mortality data, predominantly collected through vital registration systems, are also important for planning and monitoring cancer control programs as well as for research. As with cancer registry data, the availability and quality of death certificate information varies widely, with many low- and middle-income countries having either poor quality data or a complete absence of vital registration. (Map 2)

In many countries, mortality data complements the cancer registry database as a means to identify a patient’s status (alive or dead) to estimate cancer survival. Survival studies remain sparse in many transitioning countries, in part due to the absence or low quality of national mortality information systems. Cancer survival is nevertheless a key indicator of the effectiveness of cancer services in a country or region, and a positive measure of prognosis that can reflect the prospects of clinical cure.

CANCER INCIDENCE IN FIVE CONTINENTS

Population-based cancer registries are represented throughout the world by the International Association of Cancer Registries (IACR) (http://www.iacr.com.fr/), an organization founded in 1966 that establishes standards and provides opportunities for cancer registry professionals to meet, exchange information, and receive training. High-quality cancer incidence data from registries worldwide are published by the International Agency for Research on Cancer and IACR in Cancer Incidence in Five Continents (CI5) (http://ci5.iarc.fr), now in its 11th volume, to enable the international comparison of cancer incidence rates across populations and time.