3 The variation in the occurrence of cancer types between different parts of the world gives some indication of the proportion of cancers that could be prevented by modifying specific harmful lifestyle or environmental factors. Removal of HPV infection would substantially reduce the burden of cervical cancer; smoking and indoor and outdoor air pollution explain over two-thirds of lung cancer incidence. 4 Yet, for many cancers, the causes remain largely unknown. Only 5–20% of all prostate, colorectal and breast cancers could be prevented by better diet, increased physical activity, or reduced alcohol consumption.

Across the globe there are striking geographical differences in cancer occurrence, mortality and survival. 1 The relatively high rates of liver, stomach, and cervical cancer in some countries in Asia, South America, and Sub-Saharan Africa are partly due to the high prevalence of chronic infection of hepatitis, Helicobacter pylori and human papillomavirus (HPV), respectively. In Sub-Saharan Africa, there is a staggeringly high rate of Kaposi sarcoma due to the high prevalence of HIV infection. 2 In contrast, rates of infec-tion-related cancers are very low in Europe and North America, where cancers linked to lifestyle “westernization” such as colorectal and breast dominate the regional profile. These populations are further distinguished by their large burden of prostate and lung cancer, as well as the notably high rate of skin melanoma.

“‟Cancer varies between different populations, and every type is rare in some part of the world.

Many specific causes are now known (to explain these differences), but a large proportion of global variation for

common cancers remains unexplained.”

— Peto J. Nature, 2001.

OVERVIEW OF GEOGRAPHICAL DIVERSITYThe cancer incidence and mortality profile of a given country or region is the product of a mix of risk factors, screening and early detection efforts, and access to adequate treatment.

In addition to differences in risk factors, higher awareness in the population combined with more widespread early detection practices also explain the national and regional variation for some cancers. Finally, regional differences in incidence will be reflected in mortality. Yet death from cancer is also influenced by early detection and access to adequate treatment. 5 For example, less access to diagnosis and treatment facilities for prostate cancer is partly responsible for the higher mortality observed in low-income settings. On the other hand, for cancers for which treatment does not greatly affect survival, e.g. liver cancer, the regional mortality profile mimics that of incidence.

Canceratlas.cancer.org Copyright © 2014 The American Cancer Society, Inc.

Canceratlas.cancer.org Copyright © 2014 The American Cancer Society, Inc.

15 THE BURDEN

38%Esophagus

456,000 CASES

26%Lung

1,825,000 CASES

79%Breast

1,677,000 CASES

87%Colorectum

1,361,000 CASES

0%Cervix

528,000 CASES

95%Prostate

1,112,000 CASES

34%Stomach

952,000 CASES

23%Liver

782,000 CASES

The causes of a large portion of commonly diagnosed cancers in

Western populations remains unknown.

ESTIMATED NUMBER OF NEW CANCER CASES (2012) AND PERCENT ATTRIBUTABLE TO UNKNOWN

RISK FACTORS BY CANCER SITE

4

Unknown causes

ESTIMATED INCIDENCE OF CERVICAL CANCER (AGE-STANDARDIZED RATE [WORLD] PER 100,000) IN FEMALES IN 2012

| | | | | | |20 0 20 40 60 80 100

| | | | | | | | |10 0 10 20 30 40 50 60 70

Liver and cervical cancers are more common in regions where infection-related causes are more prevalent.

ESTIMATED INCIDENCE OF LIVER CANCER (AGE-STANDARDIZED RATE [WORLD] PER 100,000) IN MALES IN 2012

1

Colorectal cancer dominates in “westernized” cultures.

ESTIMATED INCIDENCE OF COLORECTAL CANCER (AGE-STANDARDIZED RATE [WORLD] PER 100,000) IN BOTH SEXES IN 2012

2

5

Higher mortality from prostate cancer generally reflects lower access to diagnosis and treatment facilities.

ESTIMATED MORTALITY FROM PROSTATE CANCER (AGE-STANDARDIZED RATE [WORLD] PER 100,000) IN MALES IN 2012

Variations in incidence rates of some cancers largely reflect differences in distribution of risk factors.

HIGHEST AND LOWEST INCIDENCE RATES (AGE-STANDARDIZED RATE [WORLD] PER 100,000) BY CANCER SITE AND SEX, 2003–2007Example cancer registries with markedly high and low rates are labeled.

3

6.8 or less 6.9–13.8 13.9–25.8 25.9–40.2 40.3 or more No Data

10.0 or less 10.1–18.0 18.1–27.6 27.7–41.8 41.9 or more No Data

6.1 or less 6.2–12.1 12.2–20.5 20.6–30.2 30.3 or more No Data

7.4 or less 7.5–14.2 14.3–22.8 22.9–36.6 36.7 or more No Data

China, Yanting County China, Yangcheng County

Australia, Queensland

Canada, Northwest TerritoriesTurkey, Edirne

Thailand, Khon Kaen

USA, Ohio Italy, Nuoro

Rural India

Singapore

Rural India

The Netherlands, Eindhoven

Esophagus0.7 2.1

1.9

0.1

3.3

1.5 60.9

86.8

102.5 65.1

45.4

35.4

Cervix

Colorectum

Melanoma

Lung

Liver

LOWEST MALES HIGHEST LOWEST FEMALES HIGHEST