Population-based cancer registry

The main objective of PBCR is to collect and classify information on all incident cancer cases occurring in a defined population, most specifically to a geographic area, in order to generate statistics on the occurrence of cancer in that population and to provide a framework for assessing and controlling the impact of cancer on the community (Jensen et al., 1991).

The earliest population based cancer registry was commissioned in Hamburg, Germany in 1929, with emphasis on medical, scientific, public health and economic aspects through active form of registration of cases from multiple sources and subsequent comparison with death certificates as a follow up activity on a voluntary basis. The continuous recording of cancer cases by patient name began in Mecklenburg in 1937 signifying a methodological progress of eliminating multiple registrations and determining individual outcomes.

Population-based cancer registry of New York State in USA was established in 1940 with compulsory notification of cancer cases. The Danish Cancer Registry, founded in 1942 is the oldest serving registry covering a national population (Jensen et al., 1991). Since then, this activity has gradually progressed and is currently well developed in high resource countries.

In most of the well-developed countries, cancer has been declared as a notifiable disease and hence registration of incident cases is predominantly done by passive method. However,

population-based cancer registration is still in variable levels of development in low or medium resource countries

Unlike in the well-developed countries, cancer is not a notifiable disease in most low or medium resource countries and hence registration of incident cancer cases had been carried out predominantly by active methods as per the guidelines advocated by the International Agency for Research on Cancer (IARC) and the International Association of Cancer Registries (IACR). The location of registry is usually in the major cancer hospital with research facility in the region. The cancer registrars of the PBCR regularly visit multiple sources of data including major hospitals in government or public and private sectors, nursing homes, consultants, radiation centres, pathology laboratories, imaging centres, screening programmes, insurance firms and hospices, for data collection from patients by direct interview and/or from medical records or case listings or computer print-outs. A standardized form is used for collection of data on personal identification, disease, treatment and outcome variables. The mandatory data collected are as follows: patient identity (patient name and/or personal identity number, area of residence with particular emphasis on duration of stay of one or more years to avoid registering cases from a floating population, age at diagnosis and/or date of birth, sex) and disease related (incidence date, most valid basis of cancer diagnosis, cancer site and morphology, tumour behaviour and grade). Other data pertaining to the patient (socio-demographic, elements of socio-economic status, etc.), disease (clinical extent of disease and/or tumour stage) and treatment (received or not and/or type or modality, etc.) are collected as optional data, depending on the resources and availability. Data collection on deaths due to cancer, occurring in the region, is independently carried out as part of PBCR operations from vital statistics division as well as hospital death registers. It included data on deceased identity (name and/or personal identity number, age at death, sex, etc.) and death (all or cancer causes, date, place, etc.). The mortality data thus collected were

matched against all incident cancer cases in PBCR database through visual inspection of probable lists of similar pairs of listings manually or by electronic linkages. Data on all deaths, irrespective of the stated cause of death, were also utilized for this linkage to optimize the availability of mortality information on registered cancer cases. Matched cases were updated with death information in registry database. In a majority of PBCRs, unmatched deaths were traced back to hospitals for availability of more details on disease factors and registered accordingly. If no additional information is forthcoming, these deaths are registered in PBCR as cases on the basis of a death certificate only (DCO). Since cases are registered from multiple sources, elimination of duplicate notifications is done with utmost care. This is directly related to the quality of person identity data at registration. With the knowledge of background population that is giving rise to the cases, reports on incidence rates are published routinely. Even in low or medium resource countries, PBCRs have been extensively utilized in evaluating cancer screening and early detection programmes in the region (Swaminathan et al., 2009).

PBCR operations have been carried out in a systematic manner for many decades now even in low or medium resource countries (Table 1). The scientific publication series from the IARC, Lyon, France, titled Cancer incidence in five continents (CI5C) from volumes I to IX, constitute a compendium of cancer incidence statistics based on good quality data from cancer registries worldwide (Parkin et al., 2005, Curado et al., 2007).

Table 1: Current status of cancer registration and survival studies in low or medium resource countries by continent or region

Conduct of population-based survival study

Conduct of survival study on hospital series Continent/

Region

Number of countries

Number of registries

Number of populations studied

Year of starting registration – Range

Countries Year of 1^st publication

Countries Year of 1^st publication

Africa 8 10 17 1953-1999 4 2003 1 1999

Asia 14 52 57 1960-2000 8 1995 6 1971

Caribbean 4 4 4 1958-1995 1 1996 0 -

Latin America

11 21 22 1958-2000 3 2006 3 1999

Table 1 shows the status of population based cancer registration in low or medium resource countries by continents or regions as included in volumes I to IX of CI5C series (Parkin et al., 2005, Curado et al., 2007). Cancer registration activity in Africa, Asia, the Caribbean and Latin America had commenced in late 1950s or early 1960s: Uganda, Kyadondo, in 1954; Israel in 1960; India, Mumbai (formerly Bombay) in 1962; Colombia, Cali, in 1967 (Parkin et al., 2005). New registries in low or medium resource countries have started their operations in mid or late 1990s and newer ones have been added to this list as recent as in early or mid-2000 (Curado et al., 2007). Collective or individual reports on cancer incidence and mortality have been published as a routine from many of the registries in low or medium resource countries continuously from time to time (Sierra et al., 1988, Laudico et al., 1989, National Cancer Registry Programme, 1992, Vatanasapt et al., 1993, Parkin et al., 2003, Shanta et al., 1994). Hospital and population based cancer registries, being the repositories of data on cancer cases collected in a systematic manner using standard methods, are generally regarded as important sources of information about cancer survival (Black et al., 1998c). Cancer registries could also serve as a novel alternative for long-term clinical trial follow up (Shi et al., 2010).