Donald Maxwell Parkin

Estimates of worldwide burden of cancer in 2008: GLOBOCAN 2008.

Estimates of the worldwide incidence and mortality from 27 cancers in 2008 have been prepared for 182 countries as part of the GLOBOCAN series published by the International Agency for Research on Cancer. In this article, we present the results for 20 world regions, summarizing the global patterns for the eight most common cancers. Overall, an estimated 12.7 million new cancer cases and 7.6 million cancer deaths occur in 2008, with 56% of new cancer cases and 63% of the cancer deaths occurring in the less developed regions of the world. The most commonly diagnosed cancers worldwide are lung (1.61 million, 12.7% of the total), breast (1.38 million, 10.9%) and colorectal cancers (1.23 million, 9.7%). The most common causes of cancer death are lung cancer (1.38 million, 18.2% of the total), stomach cancer (738,000 deaths, 9.7%) and liver cancer (696,000 deaths, 9.2%). Cancer is neither rare anywhere in the world, nor mainly confined to high‐resource countries. Striking differences in the patterns of cancer from region to region are observed.

Cancer incidence and mortality worldwide: Sources, methods and major patterns in GLOBOCAN 2012

Estimates of the worldwide incidence and mortality from 27 major cancers and for all cancers combined for 2012 are now available in the GLOBOCAN series of the International Agency for Research on Cancer. We review the sources and methods used in compiling the national cancer incidence and mortality estimates, and briefly describe the key results by cancer site and in 20 large “areas” of the world. Overall, there were 14.1 million new cases and 8.2 million deaths in 2012. The most commonly diagnosed cancers were lung (1.82 million), breast (1.67 million), and colorectal (1.36 million); the most common causes of cancer death were lung cancer (1.6 million deaths), liver cancer (745,000 deaths), and stomach cancer (723,000 deaths).

Estimates of cancer incidence and mortality in Europe in 2008

Up-to-date statistics on cancer occurrence and outcome are essential for the planning and evaluation of programmes for cancer control. Since the relevant information for 2008 is not generally available as yet, we used statistical models to estimate incidence and mortality data for 25 cancers in 40 European countries (grouped and individually) in 2008. The calculations are based on published data. If not collected, national rates were estimated from national mortality data and incidence and mortality data provided by local cancer registries of the same or neighbouring country. The estimated 2008 rates were applied to the corresponding country population estimates for 2008 to obtain an estimate of the numbers of cancer cases and deaths in Europe in 2008. There were an estimated 3.2 million new cases of cancer and 1.7 million deaths from cancer in 2008. The most common cancers were colorectal cancers (436,000 cases, 13.6% of the total), breast cancer (421,000, 13.1%), lung cancer (391,000, 12.2%) and prostate cancer (382,000, 11.9%). The most common causes of death from cancer were lung cancer (342,000 deaths, 19.9% of the total), colorectal cancer (212,000 deaths, 12.3%), breast cancer (129,000, 7.5%) and stomach cancer (117,000, 6.8%).

THE GLOBAL HEALTH BURDEN OF INFECTION-ASSOCIATED CANCERS IN THE YEAR 2002

Several infectious agents are considered to be causes of cancer in humans. The fraction of the different types of cancer, and of all cancers worldwide and in different regions, has been estimated using several methods; primarily by reviewing the evidence for the strength of the association (relative risk) and the prevalence of infection in different world areas. The estimated total of infection‐attributable cancer in the year 2002 is 1.9 million cases, or 17.8% of the global cancer burden. The principal agents are the bacterium Helicobacter pylori (5.5% of all cancer), the human papilloma viruses (5.2%), the hepatitis B and C viruses (4.9%), Epstein‐Barr virus (1%), human immunodeficiency virus (HIV) together with the human herpes virus 8 (0.9%). Relatively less important causes of cancer are the schistosomes (0.1%), human T‐cell lymphotropic virus type I (0.03%) and the liver flukes (0.02%). There would be 26.3% fewer cancers in developing countries (1.5 million cases per year) and 7.7% in developed countries (390,000 cases) if these infectious diseases were prevented. The attributable fraction at the specific sites varies from 100% of cervix cancers attributable to the papilloma viruses to a tiny proportion (0.4%) of liver cancers (worldwide) caused by liver flukes.

Cancer burden in the year 2000. The global picture

Although the general idea of ‘burden’ of a disease to a community seems fairly straightforward, there are multiple dimensions in which it may be expressed, either in terms of disease frequency (the ‘need’ for services) or the demand which it places upon them. In this review, we confine ourselves to three elementary measures of cancer frequency: incidence, mortality and prevalence. Incidence is the number of new cases occurring. It can be expressed as an absolute number of cases per year (the volume of new patients presenting for treatment) or as a rate per 100 000 persons per year. The latter provides an approximation to the average risk of developing a cancer, and is necessary if we wish to compare the risk of disease between populations (countries, ethnic groups, or different time periods within a country, for example). When considering the impact of primary prevention strategies, a reduction in incidence (occurrence of new cases) is the appropriate statistic to use. Mortality is the number of deaths occurring, and the mortality rate the number of deaths per 100 000 persons per year. The number of deaths provides one measure (and a rather unambiguous one) of the outcome or impact of cancer. It is the product of the incidence and the fatality of a given cancer. Fatality, the inverse of survival, is the proportion of cancer cases that die and this is generally assumed to be the most severe sequel of the disease. Mortality rates therefore measure the average risk to the population of dying from a specific cancer, while fatality (1-survival) represents the probability that an individual with cancer will die from it. Mortality rates are sometimes used as a convenient proxy measure of the risk of acquiring the disease (incidence) when comparing different groups, since they may be more generally available (as described below). However, when used in this way, an assumption of equal survival/fatality in the populations being compared is introduced. Since this is rarely correct—there are, for example, quite large differences between countries—it is safer to use mortality as a measure of outcome rather than occurrence. Prevalence: There is no agreed definition of ‘prevalence’ of cancer. Strictly speaking, it is the number of persons in a defined population alive at a given time who have had cancer diagnosed at some time in the past. However, the resource requirements for treating newly diagnosed patients are very different from those for supporting long-term survivors. Thus, overall prevalence is not particularly useful for healthcare planning purposes, especially as a large proportion of long-term survivors can be considered cured. Partial prevalence, which limits the number of patients to those diagnosed during a fixed time in the past, is therefore a more useful measure of cancer burden. Prevalence for cases diagnosed within 1, 3 and 5 years are likely to be of relevance to the different stages of cancer therapy, namely, initial treatment (1 year), clinical follow-up (3 years) and cure (5 years). Patients who are still alive 5 years after diagnosis are usually considered cured since the death rates of such patients are similar to those in the general population. There are some exceptions, primarily that of female breast cancer, for which the risk of death remains higher than the general population for many more years. Several other more complex statistics have been used to measure the impact of disease, particularly in health economics. They include person-years of life lost (how many years of normal lifespan are lost due to deaths from cancer). This measurement may be refined by giving different values to life-years at different ages, so that a year saved at, for example, age 20 years, is valued

Cancer incidence and mortality worldwide

Estimates of the worldwide incidence and mortality from 27 major cancers and for all cancers combined for 2012 are now available in the GLOBOCAN series of the International Agency for Research on Cancer. We review the sources and methods used in compiling the national cancer incidence and mortality estimates, and briefly describe the key results by cancer site and in 20 large “areas” of the world. Overall, there were 14.1 million new cases and 8.2 million deaths in 2012. The most commonly diagnosed cancers were lung (1.82 million), breast (1.67 million), and colorectal (1.36 million); the most common causes of cancer death were lung cancer (1.6 million deaths), liver cancer (745,000 deaths), and stomach cancer (723,000 deaths).

Data quality at the Cancer Registry of Norway: An overview of comparability, completeness, validity and timeliness

AIM To provide a comprehensive evaluation of the quality of the data collected on both solid and non-solid tumours at the Cancer Registry of Norway (CRN). METHODS Established quantitative and semi-quantitative methods were used to assess comparability, completeness, accuracy and timeliness of data for the period 1953-2005, with special attention to the registration period 2001-2005. RESULTS The CRN coding and classification system by and large follows international standards, with some further subdivisions of morphology groupings performed in-house. The overall completeness was estimated at 98.8% for the registration period 2001-2005. There remains a variable degree of under-reporting particularly for haematological malignancies (C90-95) and tumours of the central nervous system (C70-72). For the same period, 93.8% of the cases were morphologically verified (site-specific range: 60.0-99.8%). The under-reporting in 2005 due to timely publication is estimated at 2.2% overall, based on the number of cases received at the registry during the following year. CONCLUSION This review suggests the routines in place at the CRN yields comparable data that can be considered reasonably accurate, close-to-complete and timely, thereby justifying our policy of the reporting of annual incidence one year after the year of diagnosis.

Changing epidemiology of malignant cutaneous melanoma in Europe 1953–1997: Rising trends in incidence and mortality but recent stabilizations in Western Europe and decreases in Scandinavia

We analyzed time trends in incidence of and mortality from malignant cutaneous melanoma in European populations since 1953. Data were extracted from the EUROCIM database of incidence data from 165 cancer registries. Mortality data were derived from the WHO database. During the 1990s, incidence rates were by far highest in northern and western Europe, whereas mortality was higher in males in eastern and southern Europe. Melanoma rates have been rising steadily, albeit with substantial geographic variation. In northern Europe, a deceleration in these trends occurred recently in persons aged under 70. Joinpoint analyses indicated that changes in these trends took place in the early 1980s. In western Europe, mortality rates have also recently leveled off [estimated annual percentage change (EAPC) from −13.6% (n.s.) to 3.3%], whereas in eastern and southern Europe both incidence and mortality rates are still increasing [incidence EAPCs 2.3–8.9%, mortality EAPCs −1.8% (n.s.) to 7.2%]. Models including the effects of age, period and birth cohort were required to adequately describe the rising incidence trends in most European populations, with a few exceptions. Time trends in mortality were adequately summarized on fitting either an age‐cohort model (with the leveling off of rates starting in birth cohorts between 1930 and 1940) or an age‐period‐cohort model. The most plausible explanations for the deceleration or decline in the incidence and mortality trends in recent years in northern (and to a lesser extent western) Europe are earlier detection and more frequent excision of pigmented lesions and a growing public awareness of the dangers of excessive sunbathing.

Time trends in cancer mortality in China: 1987–1999

A first analysis of time trends in cancer mortality in China at the national level is presented. Using a joinpoint regression model, based on data from a national mortality routine reporting system in China (CHIS), time trends in mortality for 9 major cancers are analyzed. Between 1987 and 1999, the age‐standardized mortality rates for all cancers combined declined slightly in rural areas but have increased since 1996 in urban areas. The mortality rates for cancers in oesophagus, stomach, cervix uteri, leukaemia (except for urban males after 1996) and nasopharynx declined, while lung cancer and female breast cancer showed significant increasing trends in both urban and rural areas and for both sexes. Cancers of the colon‐rectum and liver had different trends in mortality in urban and rural populations. The trends in age‐specific mortality rates suggest some different trends in the younger population, which may presage future overall trends, for example, increasing mortality from cancer of the cervix. The observed trends primarily reflect the dramatic changes in socioeconomic circumstances and lifestyles in China in the last 2 decades. Tobacco smoking remains a major problem, with increases in mortality from lung cancer. The improvements in socioeconomic status, diet and nutrition may be responsible for the declining risk of some cancers (oesophagus, stomach and nasopharynx), while increasing the risk for others (breast and colon‐rectum). Screening programs (especially for cervix cancer), and more available and better facilities for cancer therapy, may have helped to reduce mortality for several cancers. The large increases in the absolute number of deaths that resulted from the increasing and aging population are much more important in determining the future cancer burden than any changes due to change in risk, emphasizing the increasing importance of cancer as a health problem in the 21st century in China.

The evolution of the population-based cancer registry

The idea of recording information on all cancer cases in defined communities dates from the first half of the twentieth century, and there has been a steady growth in the number of such cancer registries since. Originally, they were concerned primarily with describing cancer patterns and trends. Later, many were able to follow up the registered patients and calculate survival. In the last 20 years the role of registries has expanded further to embrace the planning and evaluation of cancer control activities, and the care of individual cancer patients. This Review looks at the current status of cancer registration practice and use from an international perspective, mindful that the registration of cancer has expanded into a global activity.