Global cancer statistics.

The global burden of cancer continues to increase largely because of the aging and growth of the world population alongside an increasing adoption of cancer-causing behaviors, particularly smoking, in economically developing countries. Based on the GLOBOCAN 2008 estimates, about 12.7 million cancer cases and 7.6 million cancer deaths are estimated to have occurred in 2008; of these, 56% of the cases and 64% of the deaths occurred in the economically developing world. Breast cancer is the most frequently diagnosed cancer and the leading cause of cancer death among females, accounting for 23% of the total cancer cases and 14% of the cancer deaths. Lung cancer is the leading cancer site in males, comprising 17% of the total new cancer cases and 23% of the total cancer deaths. Breast cancer is now also the leading cause of cancer death among females in economically developing countries, a shift from the previous decade during which the most common cause of cancer death was cervical cancer. Further, the mortality burden for lung cancer among females in developing countries is as high as the burden for cervical cancer, with each accounting for 11% of the total female cancer deaths. Although overall cancer incidence rates in the developing world are half those seen in the developed world in both sexes, the overall cancer mortality rates are generally similar. Cancer survival tends to be poorer in developing countries, most likely because of a combination of a late stage at diagnosis and limited access to timely and standard treatment. A substantial proportion of the worldwide burden of cancer could be prevented through the application of existing cancer control knowledge and by implementing programs for tobacco control, vaccination (for liver and cervical cancers), and early detection and treatment, as well as public health campaigns promoting physical activity and a healthier dietary intake. Clinicians, public health professionals, and policy makers can play an active role in accelerating the application of such interventions globally.

Worldwide variations in colorectal cancer.

Previous studies have documented significant international variations in colorectal cancer rates. However, these studies were limited because they were based on old data or examined only incidence or mortality data. In this article, the colorectal cancer burden and patterns worldwide are described using the most recently updated cancer incidence and mortality data available from the International Agency for Research on Cancer (IARC). The authors provide 5-year (1998-2002), age-standardized colorectal cancer incidence rates for select cancer registries in IARC's Cancer Incidence in Five Continents, and trends in age-standardized death rates by single calendar year for select countries in the World Health Organization mortality database. In addition, available information regarding worldwide colorectal cancer screening initiatives are presented. The highest colorectal cancer incidence rates in 1998-2002 were observed in registries from North America, Oceania, and Europe, including Eastern European countries. These high rates are most likely the result of increases in risk factors associated with "Westernization," such as obesity and physical inactivity. In contrast, the lowest colorectal cancer incidence rates were observed from registries in Asia, Africa, and South America. Colorectal cancer mortality rates have declined in many longstanding as well as newly economically developed countries; however, they continue to increase in some low-resource countries of South America and Eastern Europe. Various screening options for colorectal cancer are available and further international consideration of targeted screening programs and/or recommendations could help alleviate the burden of colorectal cancer worldwide.

Cancer burden in Africa and opportunities for prevention.

Cancer is an emerging public health problem in Africa. About 715,000 new cancer cases and 542,000 cancer deaths occurred in 2008 on the continent, with these numbers expected to double in the next 20 years simply because of the aging and growth of the population. Furthermore, cancers such as lung, female breast, and prostate cancers are diagnosed at much higher frequencies than in the past because of changes in lifestyle factors and detection practices associated with urbanization and economic development. Breast cancer in women and prostate cancer in men have now become the most commonly diagnosed cancers in many Sub-Saharan African countries, replacing cervical and liver cancers. In most African countries, cancer control programs and the provision of early detection and treatment services are limited despite this increasing burden. This paper reviews the current patterns of cancer in Africa and the opportunities for reducing the burden through the application of resource level interventions, including implementation of vaccinations for liver and cervical cancers, tobacco control policies for smoking-related cancers, and low-tech early detection methods for cervical cancer, as well as pain relief at the palliative stage of cancer.

Changes in smoking prevalence among U.S. adults by state and region: Estimates from the Tobacco Use Supplement to the Current Population Survey, 1992-2007.

BACKGROUND: Tobacco control policies at the state level have been a critical impetus for reduction in smoking prevalence. We examine the association between recent changes in smoking prevalence and state-specific tobacco control policies and activities in the entire U.S. METHODS: We analyzed the 1992-93, 1998-99, and 2006-07 Tobacco Use Supplement to the Current Population Survey (TUS-CPS) by state and two indices of state tobacco control policies or activities [initial outcome index (IOI) and the strength of tobacco control (SOTC) index] measured in 1998-1999. The IOI reflects cigarette excise taxes and indoor air legislation, whereas the SOTC reflects tobacco control program resources and capacity. Pearson Correlation coefficient between the proportionate change in smoking prevalence from 1992-93 to 2006-07 and indices of tobacco control activities or programs was the main outcome measure. RESULTS: Smoking prevalence decreased from 1992-93 to 2006-07 in both men and women in all states except Wyoming, where no reduction was observed among men, and only a 6.9% relative reduction among women. The percentage reductions in smoking in men and women respectively were the largest in the West (average decrease of 28.5% and 33.3%) and the smallest in the Midwest (18.6% and 20.3%), although there were notable exceptions to this pattern. The decline in smoking prevalence by state was correlated with the state's IOI in both women and men (r = -0.49, p < 0.001; r = -0.31, p = 0.03; respectively) and with state's SOTC index in women(r = -0.30, p = 0.03 0), but not men (r = -0.21, p = 0.14). CONCLUSION: State level policies on cigarette excise taxes and indoor air legislation correlate strongly with reductions in smoking prevalence since 1992. Strengthening and systematically implementing these policies could greatly accelerate further reductions in smoking.

The global burden of cancer: priorities for prevention.

Despite decreases in the cancer death rates in high-resource countries, such as the USA, the number of cancer cases and deaths is projected to more than double worldwide over the next 20-40 years. Cancer is now the third leading cause of death, with >12 million new cases and 7.6 million cancer deaths estimated to have occurred globally in 2007. By 2030, it is projected that there will be approximately 26 million new cancer cases and 17 million cancer deaths per year. The projected increase will be driven largely by growth and aging of populations and will be largest in low- and medium-resource countries. Under current trends, increased longevity in developing countries will nearly triple the number of people who survive to age 65 by 2050. This demographic shift is compounded by the entrenchment of modifiable risk factors such as smoking and obesity in many low-and medium-resource countries and by the slower decline in cancers related to chronic infections (especially stomach, liver and uterine cervix) in economically developing than in industrialized countries. This paper identifies several preventive measures that offer the most feasible approach to mitigate the anticipated global increase in cancer in countries that can least afford it. Foremost among these are the need to strengthen efforts in international tobacco control and to increase the availability of vaccines against hepatitis B and human papilloma virus in countries where they are most needed.

Cancer occurrence.

In this chapter, we describe the variability of cancer occurrence by using measures of incidence, mortality, prevalence, and survival, according to demographic characteristics such as age, sex, socioeconomic status, and race/ethnicity, as well as geographic location and time period. We also discuss the variability of cancer occurrence in relation to changes in risk factors, screening rates, and improved treatments. The variation according to risk factors provides strong evidence that much of cancer is caused by environmental factors and is potentially avoidable.

International variation in prostate cancer incidence and mortality rates.

CONTEXT: Wide variation exists internationally for prostate cancer (PCa) rates due to differences in detection practices, treatment, and lifestyle and genetic factors. OBJECTIVE: We present contemporary variations in PCa incidence and mortality patterns across five continents using the most recent data from the International Agency for Research on Cancer. EVIDENCE ACQUISITION: PCa incidence and mortality estimates for 2008 from GLOBOCAN are presented. We also examine recent trends in PCa incidence rates for 40 countries and mortality rates for 53 countries from 1985 and onward via join-point analyses using an augmented version of Cancer Incidence in Five Continents and the World Health Organization mortality database. EVIDENCE SYNTHESIS: Estimated PCa incidence rates remain most elevated in the highest resource counties worldwide including North America, Oceania, and western and northern Europe. Mortality rates tend to be higher in less developed regions of the world including parts of South America, the Caribbean, and sub-Saharan Africa. Increasing PCa incidence rates during the most recent decade were observed in 32 of the 40 countries examined, whereas trends tended to stabilize in 8 countries. In contrast, PCa mortality rates decreased in 27 of the 53 countries under study, whereas rates increased in 16 and remained stable in 10 countries. CONCLUSIONS: PCa incidence rates increased in nearly all countries considered in this analysis except in a few high-income countries. In contrast, the increase in PCa mortality rates mainly occurred in lower resource settings, with declines largely confined to high-resource countries.

International trends in liver cancer incidence rates.

BACKGROUND: Several previous studies have documented region or country-specific liver cancer incidence trends around the world. However, no study has systematically examined the international pattern using the most recently updated incidence data from the International Agency for Research on Cancer. METHODS: We examined recent trends in liver cancer incidence rates from 1993 to 2002 by joinpoint analysis for 32 cancer registries worldwide, using Cancer Incidence in Five Continents. We also examined the male to female rate ratios for these and four additional registries, based on the 1998-2002 incidence data. RESULTS: Liver cancer incidence rates for both men and women statistically significantly increased from 1993 to 2002 for 8 of 32 cancer registries considered in the analysis. Increases were largely confined to economically developed countries of Western Europe, North America, and Oceania. In contrast, rates decreased in both men and women in 5 registries including 3 in Asia. Despite this, the incidence rates in Asian countries are twice as high as those in Africa and more than four times as high as rates in North America. Male to female rate ratios varied from 0.9 in sub-Saharan African and South American registries to 5.0 in France and Egypt. CONCLUSIONS: Liver cancer incidence rates continue to increase in some low-risk parts of the world whereas they are decreasing in some of the highest risk countries in Asia. Etiologic studies are required to further elucidate factors contributing to the divergent liver cancer incidence trends worldwide. IMPACT: Our description of international liver cancer incidence trends may stimulate further etiologic studies.

Global patterns of cancer incidence and mortality rates and trends.

While incidence and mortality rates for most cancers (including lung, colorectum, female breast, and prostate) are decreasing in the United States and many other western countries, they are increasing in several less developed and economically transitioning countries because of adoption of unhealthy western lifestyles such as smoking and physical inactivity and consumption of calorie-dense food. Indeed, the rates for lung and colon cancers in a few of these countries have already surpassed those in the United States and other western countries. Most developing countries also continue to be disproportionately affected by cancers related to infectious agents, such as cervix, liver, and stomach cancers. The proportion of new cancer cases diagnosed in less developed countries is projected to increase from about 56% of the world total in 2008 to more than 60% in 2030 because of the increasing trends in cancer rates and expected increases in life expectancy and growth of the population. In this review, we describe these changing global incidence and mortality patterns for select common cancers and the opportunities for cancer prevention in developing countries.

The convergence of lung cancer rates between blacks and whites under the age of 40, United States.

Lung cancer rates in the United States have been consistently higher in blacks than in whites at all ages in men and at younger ages in women. However, since the 1970s, smoking initiation decreased more rapidly among blacks than whites. We examined trends in lung cancer rates for white and black young adults (ages 20-39) from 1992 to 2006 using joinpoint models and black-to-white rate ratios by sex. Lung cancer death rates in 20- to 39-year-olds significantly decreased in all groups but was much steeper for blacks than for whites. From 1992 to 1994 and 2004 to 2006, the black-to-white mortality rate ratio (95% confidence interval) decreased from 2.16 (1.90-2.44) to 1.28 (1.05-1.55) for men and from 1.47 (1.25-1.71) to 0.97 (0.78-1.19) for women. A similar convergence was observed in the lung cancer incidence rates. These findings suggest that if current smoking trends in the young continue, racial differences in overall lung cancer rates in men will be eliminated in the next 40 to 50 years.

International trends in colorectal cancer incidence rates.

BACKGROUND: Previous studies have documented significant variations in colorectal cancer incidence rates and trends regionally and across countries. However, no study has examined the worldwide pattern using the most recently updated incidence data from the IARC. METHODS: We obtained sex-specific colorectal cancer incidence for 1953-57 through 1998-2002 by cancer registry from Cancer Incidence in Five Continents (CI5) databases. For 51 cancer registries with long-term incidence data, we assessed the change in the incidence rates over the past 20 years by calculating the ratio of the incidence rates in 1998-2002 to that in 1983-87. RESULTS: Colorectal cancer incidence rates for both males and females statistically significantly increased from 1983-87 to 1998-2002 for 27 of 51 cancer registries considered in the analysis, largely confined to economically transitioning countries including Eastern European countries, most parts of Asia, and select countries of South America. These increases were more prominent for men than for women. We also observed substantial variations in colorectal cancer incidence trends within countries such as Japan. Similarly, trends in Israel and Singapore varied significantly according to ethnicity. The United States is the only country where colorectal cancer incidence rates declined in both males and females. CONCLUSIONS: Colorectal cancer incidence rates continue to increase in economically transitioning countries, with incidence rates among men in the Czech Republic and Slovakia exceeding the peak incidence observed in the United States and other long-standing developed nations. Targeted prevention and early detection programs could help reverse the trend in these countries.

Annual report to the nation on the status of cancer, 1975-2005, featuring trends in lung cancer, tobacco use, and tobacco control.

BACKGROUND: The American Cancer Society, the Centers for Disease Control and Prevention (CDC), the National Cancer Institute (NCI), and the North American Association of Central Cancer Registries (NAACCR) collaborate annually to provide updated information on cancer occurrence and trends in the United States. This year's report includes trends in lung cancer incidence and death rates, tobacco use, and tobacco control by state of residence. METHODS: Information on invasive cancers was obtained from the NCI, CDC, and NAACCR and information on mortality from the CDC's National Center for Health Statistics. Annual percentage changes in the age-standardized incidence and death rates (2000 US population standard) for all cancers combined and for the top 15 cancers were estimated by joinpoint analysis of long-term (1975-2005) trends and by least squares linear regression of short-term (1996-2005) trends. All statistical tests were two-sided. RESULTS: Both incidence and death rates from all cancers combined decreased statistically significantly (P < .05) in men and women overall and in most racial and ethnic populations. These decreases were driven largely by declines in both incidence and death rates for the three most common cancers in men (lung, colorectum, and prostate) and for two of the three leading cancers in women (breast and colorectum), combined with a leveling off of lung cancer death rates in women. Although the national trend in female lung cancer death rates has stabilized since 2003, after increasing for several decades, there is prominent state and regional variation. Lung cancer incidence and/or death rates among women increased in 18 states, 16 of them in the South or Midwest, where, on average, the prevalence of smoking was higher and the annual percentage decrease in current smoking among adult women was lower than in the West and Northeast. California was the only state with decreasing lung cancer incidence and death rates in women. CONCLUSIONS: Although the decrease in overall cancer incidence and death rates is encouraging, large state and regional differences in lung cancer trends among women underscore the need to maintain and strengthen many state tobacco control programs.