The success of early detection and cancer treatment may be measured by improvements in survival from cancer. Long-term survival reflects cure and is a positive measure that can be used by planners and health professionals to discuss the outcome of cancer diagnosis and treatment. It is also the result of most interest to patients, their families and the general public.

Cancer survival estimated from hospitals and clinical trial settings at best reflects the selective experience of groups of patients in specific settings, and cannot be generalized as reflecting the overall efficiency of the cancer health services in a given region or country. On the other hand, estimates of population-based survival based on all cancer patients diagnosed by all means in a given geographical region or country incorporate the influence of different socio-economic factors, natural histories, health-seeking behaviours, awareness, early detection practices and treatment availability and accessibility. Therefore, such estimates reflect the general efficiency of cancer health services and provide a key indicator of progress in cancer control in a given region. Such estimates can be derived from studying the survival experience of cancer patients registered in population-based cancer registries.

Comparative data on cancer survival from different regions could serve as the baseline for future improvement, through adequate and determined investments in improving awareness, health services infrastructure and accessibility. Population-based survival studies that have systematically analysed the survival outcomes of cancer patients are readily available in Europe, North America and other more-developed regions. However, they are relatively rare from countries in Africa, Asia and Central America. This gap was offset to an extent by the appearance, in 1999, of the first volume of the International Agency for Research on Cancer (IARC) scientific publication on Cancer survival in Developing Countries.

The Agency presents here the second volume in the series, which includes survival data from 27 cancer registries in 14 countries from Africa, Asia, the Caribbean and Central America. This study would not have been possible without the availability of population-based cancer registries, thus underscoring the urgent need for organizing such information systems in sentinel populations in the least-represented areas of sub-Saharan Africa, central Asia and the Middle East.

For this volume, the response from registries has been overwhelming: the geographic coverage has a wider representation, the number of registries participating increased nearly threefold, and the number of cancer sites and incident cases analysed has increased manifold compared to the first volume. This provides a unique example of cooperation at the international level for improvement in cancer control, and the Agency is proud to play its part in this collaborative effort.

Considerable emphasis has been placed on improving follow-up for vital status of cancer patients by instituting a variety of innovative active and passive follow-up methods and on improving overall data quality by appropriate validation studies, although some level of overestimation of survival cannot be ruled out. The understanding and applicability of cancer survival estimates can be further improved by better collection of data for clinical stage and treatment of cancer as well as for vital status by the population-based cancer registries.

The striking inequalities in cancer survival between countries and within countries described in this volume are largely related to the differences in general awareness, availability of early detection practices, trained human resources, diagnosis and treatment and the development and accessibility to cancer services, as well as, to a lesser extent, to issues of data quality and reliability. The findings described in this scientific publication emphasize the need for urgent and adequate investments in comprehensive cancer control, including improving public and professional awareness, early detection, prompt treatment using locally feasible yet effective regimens, health services infrastructure and human resources development, as well as ensuring referral pathways and improved and equitable accessibility to health services.

The differences in cancer survival reported in populations observed between and within countries studied in this volume provide valuable insights for future planning and investment by governments in primary prevention activities, early detection initiatives and tertiary care to achieve meaningful cancer control. They should also prove a stimulus to those involved in cancer prevention and control to redouble their efforts to ensure that all cancer patients have the best possible chance to survive their own experience of this disease.

Christopher P. Wild