Cancer Survivorship Worldwide

Just what is the descriptive epidemiology of cancer survivorship in the world today? While there is no single source for this information yet I will attempt to provide a worldwide perspective. The main source of international cancer statistics is the IARC. In 1975, this agency began estimating the burden of incident cancer cases for 12 common forms of cancer throughout the 24 different countries where the United Nations collected data.3 These forms of cancer included mouth/pharynx, esophagus, stomach, colon/rectum, liver, bronchus/lung, breast, cervix, prostate, bladder, lymphatic tissue, and leukemia. Since the 1960s, individual countries had collected registries on their populations, but until recently this was done without coordination or collaboration among or between the nations. In 1989, the EUROCARE project was established by the European Community under Health Service Research to determine and assess international variation in cancer survivorship. The EUROCARE-1 reported on the survival of 800,000 cancer patients who were diagnosed during 1978-1985 and followed up to the end of 1990. These individuals were in 30 population-based cancer registries from12 European countries that included Denmark, England, Estonia, Finland, France, Germany, Italy, The Netherlands, Poland, Scotland, Spain, and Switzerland. This study represented the first population-based collection and analysis of survival data on cancer patients using a common methodology.5 This endeavor was a significant step forward in addressing and quantifying cancer survivorship globally.

The EUROCARE-2 study followed individuals from 1985-1989 through 1994,5 building upon the EUROCARE-1 data to look at trends in survivorship and to examine what the trends meant in both time and geographic region. Results from EUROCARE-3 were reported in 2003. This phase of the study examined 1,815,584 adults and children from 22 countries with 67 participating registries from the period 1990-1994 and followed up to the end of 1999.6 The goal of this phase was to better understand the survival differences seen overtime and the various populations to examine how earlier diagnosis, differences in types and benefits of treatments, and the interaction of these two impact survival rates.3 Results of EUROCARE-3 are presented in Figure 1 showing that the average survival rates range from less than 4% for those with pancreatic cancer to a high of 94% for those with lip cancer. Survival rates in this study, for all tumors considered together, were found to be higher for women than men, and higher in the younger versus the older patients.2 Figure 1 depicts this pattern, showing in 30 of the 35 cancers that the cancer rate was higher in women than men for cancers that occur in both sexes.6

Broadening the EUROCARE focus by including other counties, the IARC obtains its data from cancer registries maintained by individual countries, combining them into a single dataset entitled GLOBOCAN. GLOBOCAN is a combination of EUROCARE, the Surveillance, Epidemiology, and End Results (SEER) program of the United States, and the Cancer Survival in Developing Countries project conducted by IARC.3,7 The focus of GLOBOCAN is on measuring incidence, mortality, and prevalence of cancer on a worldwide basis.

Most of the European nations maintain cancer registries, but not all contribute to the EUROCARE project. Other nations maintain and report on their own registries, such as the Australian health care system which is able to report that the 5-year survival rate for individuals diagnosed with cancer at nearly 50%,8 with about 270,000 Australians living with cancer,9

Some countries have not been able to establish registries; most developing nations find creating and maintaining a registry difficult because medical records and other vital information is not uniformly or consistently recorded, and population denominators are not always known. For example, researchers at the Institute of Pasteur in Madagascar did attempt to review the epidemiology of cancer in Madagascar, but found their review not to be representative because of an extremely low rate of health care coverage across the nation, particularly in the rural areas, and that some types of cancers are hard to quantify as there is not diagnostic equipment available.10

Quantifying the number of survivors is a difficult task, as discussed above, because such data are not readily and comprehensively collected on an international basis. However, it seems to be agreed upon in the scientific community that survival means the individual is at least 5 years post-cancer treatment, and in some communities, the individual is considered cured."7 Many researchers have begun to reconceptualize cancer as a chronic illness as more people are living longer after treatment,11 yet as the chapters in this book indicate there is no universal agreement on the definition of cancer survivor, with some considering any time since

No. of

Five-year

No. of

Five-year

MALIGNANCY

patients

survival

patients

survival

Salivary glands

1.612

68.7

1.926

51.0

Tongue

2.302

52.2

5.555

34.9

Oral cavity

3,431

56.9

7,315

40.6

Oropharynx

1,170

43.5

5,015

28.7

Thyroid

9,953

81.4

3,203

71.8

Melanoma of skin

26,793

84.3

20,625

74.8

Nasopharynx

573

49.3

1,299

39.9

Hypopharynx

868

32.3

4,029

23.2

Choroid (melanoma)

967

72.3

1,099

65.0

Chronic myeloid leukaemia

2,687

36.9

3,391

30.5

Hodgkin's disease

4,658

81.5

6,179

75.2

Non-Hodgkin lymphoma

27,068

53.7

30,702

47.7

Stomach

34,871

25.4

55,254

20.0

Rectum

40,463

49.6

52,504

45.1

Multiple myeloma

11,501

33.0

11,951

28.5

Nasal cavities

1,330

48.0

2,046

43.8

Chronic lymphatic leukaemia

6,411

66.4

8,973

62.2

Bone

1,241

56.3

1,515

53.0

Kidney

18,082

57.2

28,536

54.2

Brain

11,976

18.5

15,611

16.4

Oesophagus

11,491

10.5

21,702

8.5

Colon

78,258

51.0

72,234

49.2

Small Intestine

2,039

39.2

2,214

37.6

Pancreas

25,004

4.6

24,070

3.8

Acute myeloid leukaemia

5,555

13.4

6,220

12.7

Pleura

1,374

5.5

5,564

4.8

Breast

256,464

76.1

1,809

75.5

Liver

7,368

6.7

12,747

6.2

Soft tissues

4,612

54.2

5,675

54.2

Lung

68,463

9.6

183,514

9.7

Biliary tract

12,164

11.6

6,591

12.3

Larynx

2,590

59.4

19,669

60.7

Lip

1,231

90.3

4,964

92.5

Bladder

25,558

67.1

78,514

69.5

Acute lymphatic leukaemia

1,068

21.6

1,405

24.2

Total

711,196

713.620

All malignant neoplasms2

878.319

51.2

911,574

39.8

1 Absolute difference—e.g. for kidney, 57.2% - 54.2% = 3.0% (see text)

2 Excluding cancers that only arise In one sex

Figure 1. Source. Coleman et al.6

Difference in survival (%) between women and men': age-standardised five-year relative survival

diagnosis as survival time,12 while others have used this 5-year mark as the defining point because many physicians consider the risk of recurrent cancer being greatly reduced by the fifth year.13 GLOBOCAN uses the 5-year definition for their prevalence estimates; therefore, they are able to estimate a level of survivorship globally defining prevalent cases as those "alive with cancer" meaning that the individual is either receiving treatment or possibly being followed up with ongoing medical care. Individuals may have been diagnosed with cancer prior to the establishment of a registry, therefore, longer-term survivors may have been undercounted,14 or loss to follow-up over represent the numbers.

None-the-less, maintaining some form of a cancer registry is critical to the World Health Organization's (WHO) mission to promote early detection and treatment to try to control the spread of cancer, and in turn, enhancing chances of survival. The survival statistics collected by registries, including incidence and mortality, are a way of monitoring effectiveness of the WHO's mission on population levels.15 Table 1 presents the comparison of survival rates by country using SEER registries and the EUROCARE3 registries. The numbers in the table depict estimates of survival based on the ratio of age-adjusted mortality and incidence of 11 significant cancers in eight different countries, with the world divided into two areas: developed countries and developing countries. The table reveals that survivorship is more likely in the developed countries over the developing countries, with Eastern Europe being an exception where those rates are lower than South America for many types of cancer. The nations of Sub-Saharan Africa fair the worst overall. However, data related to cancer survivorship in Africa are scant, but because of the tremendous effort that has been placed on population-based cancer registries in this continent, more information on survivorship will be elucidated in the coming years. The principal factors contributing to the disease pattern seen in this table reflects countries where there are increasing numbers of the elderly (a population in which cancer is more prevalent), the increase in medical science's ability to manage cancer, and the increase in some types of cancer, particularly, lung cancer from tobacco use. Therefore, some nations will see an increase in survivors where others will not.

Distinct geographical variations in the incidence patterns by type of cancer are influenced by risk factors present in the different environments. Furthermore, it has been noted that the affluence of a country affects the overall cancer survival rates, with greater affluence resulting in higher survival rates, depending on how the reliability and accessibility of the screening, diagnostic, and treatment systems.2

The IARC has found that individuals are more likely to survive following cancers of the head and neck, large bowel, breast, melanoma, cervix, ovary, and urinary bladder. Early detection is the greatest factor to influence survival in those cancers.15 The differences between developing and the developed countries with respect to survival is that the greatest disparities are found in cancers where multiple modalities are needed for care, including access to a combination of crucial medications, chemotherapy, radiation treatment, and the trained personnel for care delivery. These cancers include those of the testis, leukemia, and lymphoma.15

Overall differences in survival rates have been attributed to variables such as stage of the cancer diagnosis, the availability and quality of health care services, the type of cancer treatment received, and the follow-up care received, if any.15 Additionally, there are individual level variables that also contribute to the variation in survival rate including socioeconomic status, attitudes and beliefs about treatment, and adherence to the treatment recommendations.15 Similar work at the population level has not been undertaken.

Table 1. Estimated Age-Adjusted Survival (%) from 11 Cancer Types, by Country/Area

Developed

areas

Developing areas

United

Eastern

Western

All developed

South

Sub-Saharan

All developing

States

Europe

Europe

Japan

areas

America

India

Thailand

Africa

areas

Esophagus (male)

14

6

18

25

15

7

13

13

4

17

Esophagus (female)

8

2

14

15

8

5

14

10

5

16

Stomach (male)

44

15

30

54

35

25

14

12

7

21

Stomach (female)

33

16

24

51

31

24

14

14

5

20

Colon/rectum (male)

66

35

56

65

56

50

28

37

13

39

Colon/rectum (female)

65

36

53

58

54

50

31

37

14

39

Liver (male)

20

r; 0

ss 0

9

6

ps 0

4

3

2

5

Liver (female)

0

r; 0

ps 0

12

0

ps 0

9

3

1

3

Lung (male)

21

9

9

15

13

8

12

5

4

12

Lung(female)

26

10

14

22

20

1

11

5

5

12

Kaposi sarcoma (male)

Kaposi sarcoma (female)

Breast

81

58

74

75

73

67

46

62

32

57

Cervix uteri

70

51

66

65

61

55

42

58

21

41

Corpus uteri

89

69

83

79

82

70

59

67

61

67

Prostate

87

44

72

55

76

62

35

36

21

45

Leukemia (male)

43

29

43

25

40

24

19

15

14

19

Leukemia (female)

45

29

45

29

39

24

19

15

17

19

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