May useful for Public Health Students

1. Cancer Prevalence and
Causative agents
Presentation By:
Birendra Prasad Bhatt
MPH 3rd Semester
Shalom Institute of Health and Allied Sciences,SHUATS

2. Introduction : Cancer
Cancer is a generic term for a
large group of diseases
characterized by the growth of
abnormal cells beyond their usual
boundaries that can then invade
adjoining parts of the body and/or
spread to other organs.

3.  Cancer can affect almost any part of the body and
has many anatomic and molecular subtypes that
each require specific management strategies.
All cancers derive from single cells that have
acquired the characteristics of continually
dividing in an unrestrained manner and invading
surrounding tissues.
Cancer cells behave in this abnormal manner
because of changes in the DNA sequence of key
genes, which are known as cancer genes.
Therefore all cancers are genetic diseases.

4.  Cancer is not a single disease but rather a name applied
to a great variety of malignant tumor that are formed by
the same basic process of uncontrolled growth.
 Cancer is one of the most common and severe problem
of clinical medicine.
 Cancer has emerged as a major public health problem in
developing countries for the first time, matching its effect
in industrialized nations. This is a global problem.

5.  Do not spread from their site of origin, but can crowd out (squash)
surrounding cells e.g. brain tumour, warts.
 Self-limited in their growth.
 Do not invade or metastasize (although some benign tumor types are
capable of becoming malignant).
 Can spread from the original site and cause secondary tumours. This is
called metastasis. They interfere with neighbouring cells and can block
blood vessels, the gut, glands, lungs etc.
 Excessive growth and division without respect to normal limit
 Invasive, invade and destroy adjacent tissues, and sometime distant
metastasis spread to other locations in the body.

6.  A “neoplasm” is defined as an abnormal
mass of tissue, the growth of which exceeds
and is uncoordinated with the normal tissues
and persists in the same excessive manner
even after cessation of the stimuli which
evoked the change.
1
A tumor grows
from a single
cancer cell.
2
Cancer cells invade
neighboring tissue. 3
Cancer cells spread
through lymph and
blood vessels to other
parts of the body.
Glandular
tissue
Tumor
Lymph
vessels
Metastasis
(spread to other locations in the body)

7. MAJOR TYPES OF CANCER
1. Carcinomas
2. Lymphomas
3. Sarcomas
1.) Carcinomas
 Around 85% carcinoma cases were diagnosed in world
wide. Carcinomas develop in epithelial cell and have four
sub types, they are:
• Aadeno carcinomas: example Lung Cancer
• Squamous cell carcinomas: example Oral Cancer
• Transitional cell carcinoma: example Bladder Cancer
• Basal cell carcinomas: example Skin Cancer
Source: A Short Note on Cancer, Journal of Carcinogenesis & Mutagenesis

8. MAJOR TYPES OF CANCER
2.) Lymphomas
It is cancer of lymph cell in immune system.
Lymph nodes are the small structures
presents along with blood vessels in human
body. Nearly 7% of lymphomas cancer seen in
worldwide
The person who has lymphomas cancer their
lymph nodes enlarges and forms lumps.
Source: A Short Note on Cancer, Journal of Carcinogenesis & Mutagenesis

9. MAJOR TYPES OF CANCER
3.) Sarcomas
The caner which was formed in the
mesoderm tissue is known as sarcomas
. Bone tumour, fat, muscle, tumour of
hematotopoietic tissue comes under
sarcomas.
Example for Sarcomas is soft tissue
sarcomas
Source: A Short Note on Cancer, Journal of Carcinogenesis & Mutagenesis

10. KEY FACTS ON CANCER
 Cancer is the second(2nd) leading cause of death globally.
 Responsible for 8.8 million deaths in 2015.
 Globally, nearly 1 in 6 deaths is due to cancer.
 Approximately 70% of deaths from cancer occur in low-
and middle-income countries
 Cancer causing infections, such as hepatitis and human
papilloma virus (HPV), are responsible for up to 25% of
cancer cases in low- and middle-income countries
Source: A synthetic analysis. Lancet Glob Health. 2016 WHO

11. KEY FACTS ON CANCER
 Cancer is one of the most common diseases in the
developed world
 1 in 17 deaths are due to lung cancer
 Lung cancer is the most common cancer in men
 Breast cancer is the most common cancer in women
 There are over 100 different forms of cancer
Source: A synthetic analysis. Lancet Glob Health. 2016 WHO

12. Cancer Prevalence

13. Cancer Prevalence ?
 Cancer prevalence is defined as the number of living people
who have ever been diagnosed with cancer. It includes people
diagnosed with cancer in the past as well those who were
recently diagnosed.
 Cancer prevalence is determined by how often a cancer occurs
(incidence) and by how long people normally live after
diagnosis (survival). This means prevalence counts are highest
for the most common cancers with the longest survival. And, a
common cancer with shorter survival may have a lower
prevalence count than a less common cancer with longer
survival.
American Cancer Society’s Cancer Treatment & Survivorship

14. Cancer Prevalence: Global
 Cancer may affect people at all ages, even fetuses but risk for
the more common varieties tends to increase with age.
 Growing and aging population in developing countries are
disproportionately affected by increasing number of cancers.
 The pattern of cancer incidence seen high in high HDI settings.
 Lack of early detection and access to treatment made worse the
situation of prevalence and mortality.
Source: WHO(2018) world cancer statistics

15. Cancer Prevalence: Global
Variations in the distribution of cancer :Global
 Stomach cancer is very common in Japan
 Stomach cancer is less common in United states
 The cervical cancer is high in Columbia and has low incidence in Japan
 The WHO SEARO region has great majority of oral , cervix and uterine cancer.
Variations in site of cancer :Global
 organ site most commonly involved
i. Uterine cervix – in women
ii. Oropharynx – in both sexes
These two sites represent approximately 50 Per cent of all cancer cases.
Source: K.Parks text book of preventive and social medicine 24th edition

16. Cancer Prevalence: Global
 The global cancer burden is estimated to have risen to 18.1 million new
cases and 9.6 million deaths in 2018.
 One in 5 men and one in 6 women worldwide develop cancer during
their lifetime, and one in 8 men and one in 11 women die from the
disease.
 Worldwide, the total number of people who are alive within 5 years of a
cancer diagnosis, called the 5-year prevalence, is estimated to be 43.8
million
 Global patterns show that for men and women combined, nearly half of
the new cases and more than half of the cancer deaths worldwide in
2018 are estimated to occur in Asia, in part because the region has
nearly 60% of the global population.
Source: The International Agency for Research on Cancer (IARC) GLOBOCAN Press release 2018 September 12

17. Top ten Cancer Prevalence : More and less developed region
Lung
cervix
uterus and
stomach
cancer -
more
common

18. Estimated number of new cases (Both sexes,all ages) 2018 : Continents
ASIA- 48.4%
Europe- 23.4%
North America- 13.2%
Latin America &
caribbean- 7.8%
Africa- 5.8%
Oceania- 1.4%

19. Top ten estimated number of cancer cases world wise (Both sexes,all ages) in 2018
 Lung cancer
 Breast
 Colorectum
 Prostate
 Stomach
 Liver
 Oesophagus
 Cervix uteri
 Thyroid
 bladder

20. Estimated number of deaths (Both sexes, all ages) in 2018 : Cancer types
Lung cancer is responsible for the
largest number of deaths (1.8 million
deaths, 18.4% of the total) because
of the poor prognosis for this
cancer worldwide, followed by
colorectal cancer (881 000 deaths,
9.2%), stomach cancer (783 000
deaths, 8.2%), and liver cancer
(782000 deaths, 8.2%).
Female breast cancer ranks as the
fifth leading cause of death (627 000
deaths, 6.6%) because the
prognosis is relatively favorable, at
least in more developed countries.

21. Estimated number of deaths all cases (Both sexes, all ages) : World areas

22. Number of prevalent cases (5-Year) all cancer, both sexes, all ages

23. Number of prevalent cases (5-Year) all cancer, : female and male

24. Cancer Prevalence in India
“Cancer hits more women in India than men, but more men die of it.”
- The Times of India (New Delhi edition) 10 Jan2018
Source: WHO(2012) GLOBOCAN
Five most frequent
cancer in men
1- Lung Cancer
2- Lip & oral cavity
3- Stomach
4- Colorectum
5- Pharynx
Five most frequent
cancer in women
1- Breast Cancer
2- Cervix uterus
3- Colorectum
4- Ovary
5- Lip and oral cavity

25. Cancer Prevalence in India
According to world Cancer report 2014
 5.37 lakh Indian women got cancer in 2012 as against 4.77 lakh men
 But 75% of the men affected with cancer have low life expectancy, while the
mortality rate of cancer in women is 60%.
 In 2012, 3.56 lakh men died of the disease in comparison to 3.26 lakh women.
 Among all cancers in both sexes, the incidence of breast cancer is highest at
1,44,937, while the cervix uteri is the second most frequently occurring cancer
with an incidence of 1,22,844.
 The third most common cancer is of the lip and oral cavity with 53,842 men
affected.
Source: WHO(2014) GLOBOCAN

26. Cancer Incidence & 5-year prevalence of Cancer in India: 2018
Source: WHO(2018) GLOBOCAN

27. Estimated number of cancer cases all ages in India
Source: WHO(2018) GLOBOCAN

28. Cancer Incidence & 5-year prevalence : Comparison with China
Source: WHO(2018) GLOBOCAN

29. CANCER CAUSES &
CAUSATIVE AGENTS

30. CANCER CAUSES
 Cancer are still not really
understood
 Carcinogens are chemicals that
cause cancer by causing
mutations (change in structure of
gene)
 Lifestyle habits (diet ,tanning,
tobacco,alcohol,radiation,occup
ational hazards)
 Environmental triggers
 Family history

31. CANCER CAUSES
 Cancer arises from the transformation of normal cells into tumour
cells in a multistage process that generally progresses from a pre-
cancerous lesion to a malignant tumour.
 These changes are the result of the interaction between a person's
genetic factors and 3 categories of external agents, including
1) Physical carcinogens : Ultraviolet and ionizing radiation
2) Chemical carcinogens : asbestos, components of tobacco smoke, aflatoxin (a
food contaminant), and arsenic (a drinking water contaminant)
3) Biological carcinogens : infections from certain viruses, bacteria, or parasites.

32. CANCER CAUSES
Cancer arises from the mutation of a normal gene.
Mutated genes that cause cancer are called oncogenes (a
gene which in certain circumstances can transform a cell in to a tumour cell)
It is thought that several mutations need to occur to give
rise to cancer
Cells that are old or not functioning properly normally self
destruct and are replaced by new cells.
Cancerous cells do not self destruct and continue to
divide rapidly producing millions of new cancerous cells.

33. CANCER CAUSES
 A factor which brings about a mutation is called a mutagen.
 A mutagen is mutagenic.
 Any agent that causes cancer is called a carcinogen and is
described as carcinogenic.
 So some mutagens are carcinogenic.

34. CANCER CAUSES

35. CANCER CAUSES

36. CANCER CAUSES
1.Environmental Factors :
Responsible for 80-90% 0f all human cancer.
Environmental factor Affected organ :Cancer Deaths
TOBACCO LUNG ,Larynx , Mouth, Pharynx,
Oesophagus, Bladder, Pancreas
More than 1 million
premature death
ALCOHOL Liver and Esophageal 3% of all cancer death
DIETARY FACTORS Stomach,I ntestinal, Bowel , Breast

37. CANCER CAUSES
Environmental factor Factor responsible for Cancer Deaths
Occupational exposure 1-5% of all human cancer
Viruses Hepatitis B&C- Hepatocellular Carcinoma
HIV Infection- Kaposi’s sarcoma
AIDS- Non Hodking’s Lymphoma
EBV(Epstain barr Virus)- Burkitt’s lymphoma,
nasopharyngeal carcinoma
CMV( Cytomegalo virus)- Kaposi’s Sarcoma
HPV( Human Papiloma virus)- Cervix
Parasites Schistosomiasis - Bladder cancer
Custom Habits & Lifestyles Lung cancer ,oral cancer etc
Others( Sunlight, radiation, air
and water pollution,
medication pesticides)
Different type of cancers

38. CANCER CAUSES
2. Genetic Factors :
Genetic factors are less noticeable and more difficult to
identify. There is complex interrelationship between
hereditary susceptibility and environmental carcinogenic
stimuli in the causation of number of cancers.
 Retinoblastoma occurs in children of same parents.
 Mangols are more likely to develop cancer than normal children.

39. CANCER CAUSES
The etiology of cancer is multifactorial, with
genetic, environmental, medical, and lifestyle
factors interacting to produce a given malignancy.
Most cancer is caused by genetic mutations often,
by a series of mutations.

40. CANCER CAUSES
Abnormalities in the genetic mutation due to:
 Error in DNA replication (randomly
acquired).
 Effects of carcinogens, such as tobacco
smoke, radiation, chemicals, or
infectious agents.
 Inheritance, and thus present in all cells
from birth.

41. CANCER CAUSES
RISK FACTORS :CANCER
 A risk factor is anything that increases a person's chance
of getting a disease. Some risk factors can be changed, and
others cannot. Different cancers have different risk factors
 Old age
 Unhealthy lifestyle (Western lifestyle), Poor diet, lack of physical activity,
or being overweight.
 Environmental factors, defined broadly to include tobacco use, diet,
sunlight and infectious diseases.
 Occupational carcinogens
 Radiation
 Family history of cancer (Genetic susceptibility)
 Alcohol
 Chemicals and other substance

42. CANCER CAUSES
RISK FACTORS /CANCER TYPE
Cancer Type Risk Factor
Lung Cancer Tobacco smoke
Radon( a radioactive gas)
Asbestos and other substances
Air pollution
Breast Radiation
Genetic changes (Inherited mutation)
Colorectal Cancer polyp
Genetic alteration
Diet
Cigarette smoking
Ulcerative colitis or chon's disease
Prostate Diet
Certain prostate changes
Race Africans Americans

43. CANCER CAUSES
RISK FACTORS /CANCER TYPE
Cancer Type Risk Factor
Liver Hepatitis viruses (HCV.HBV)
Pancreas Smoking
Diabetes
Being male
Chronic pancreatitis
Kidney Tobacco smoking
High blood pressure
Von-Hippel-Lindau syndrome (VHL)
Leukemia Radiation
Chemotherapy
Certain disease (Down syndrome)
Human T cell leukemia virus
Myelodysplatic syndrome

44. CANCER CAUSES
RISK FACTORS /CANCER TYPE
Cancer Type Risk Factor
Bladder Occupation
Certain infection
Tobacco smoking
Treatment with cyclophosphamide or arsenic
Uterine Endometrial hyperplasia
Race Africans Americans
Hormonal replacement therapy
Obesity
Melanoma Dysplastic nevi
Fai skin
Weakened immune system
Sever blistering/Sunburn
UV irradiation
Source:http://ishwaryatechnosolutions.com/cancer.aspx

45. CANCER CAUSES
Certain viruses or bacteria may increase the risk of developing cancer
Microorganism Cancer
Human papilloma virus Cervical cancer
Helicobacter pylori Stomach cancer
Hepatitis B and hepatitis C viruses Liver cancer
Human T-cell leukemia/lymphoma virus Lymphoma and leukemia
Human immunodeficiency virus Lymphoma and a rare cancer called
Kaposi's sarcoma
Epstein-Barr virus Lymphoma
Human herpes virus 8 Kaposi's sarcoma

46. CANCER CAUSES

47. CANCER CAUSES
 Around one third of deaths from cancer are due to the 5 leading
behavioral and dietary risks:
1. High body mass index,
2. Low fruit and vegetable intake,
3. lack of physical activity,
4. tobacco use, and
5. alcohol use.
 Tobacco use is the most important risk factor for cancer and is
responsible for approximately 22% of cancer deaths.
Source: A synthetic analysis. Lancet Glob Health. 2016 WHO

48. CANCER CAUSES

49. CANCER CAUSES

50. WARNING SIGNALS FOR CANCER
Change in Bowel / bladder habits
A sore that does not heal
Unusual bleeding or discharge
Thickening or lump in breast / elsewhere
Indigestion or difficulty to swallow
Obvious change in wart / mole
Nagging cough or Hoarseness of voice

51. Cancer Prevention
2/3 of all cancers may be prevented by
Avoiding tobacco
Avoiding/limiting alcohol Consumption
Eating adequate fruits and vegetables daily
Knowing family history of cancer
Limiting exposure sun/radiation
Choosing healthy food reduces cancer risk by 30 – 40%
Eating a low fat diet
Regular exercising
Maintaining healthy weight throughout life

52. Screening for cancer
Early detection provides the best opportunity for
successful treatment.
Cancer screening examinations are medical tests
performed in healthy person.
Reliable screening tests are available for certain cancers
Ex: Cervix, Breast, Colon etc.

53. Current issues and Challenges
 Excessive weight and obesity, resulting from excess calorie intake and physical
inactivity, have become a serious health issue in many developed and
developing countries as well.
 The higher incidences of colon, breast, and prostate cancers in developed
countries are attributed in part to a lifestyle of high-calorie diet and physical
inactivity.
 More developed regions such as North America had relatively low cancer
mortality despite having high cancer incidence. conversely, some less
developed regions had relatively high cancer mortality despite having low
cancer incidence.
 The higher incidences of stomach and liver cancers in developing countries are
largely due to the higher prevalence of related infections. Other infections
considered to be important in cancer include human papilloma virus, Epstein-
Barr virus, and human immunodeficiency virus.

54. Current issues and Challenges
 The prevalence of smoking has declined in many developed countries, it is
increasing in developing countries . Currently, approximately 5 million people are
killed annually by tobacco use; by 2030, estimates based on current trends
indicate that this number will increase to 10 million, with 70 percent of deaths
occurring in developing countries
 Many developing countries go through an economic transition from primarily
agricultural activities to more industrial development and manufacturing, there
may be concerns about the lack of resources in monitoring occupational
exposures and developing or reinforcing occupational standards . Occupational
exposures linked to the risk of cancer.
 Exposure to environmental contamination, such as indoor air pollution and
pesticides, is known to increase the risk of cancer.
 According to WHO report the economic impact of the cancer is significant and
increasing the total global annual economic cost of cancer in 2010 was estimated
at approximately US$ 1.16 trillion.

55. Conclusions
 The increasing cancer burden is due to several factors, including
population growth and ageing as well as the changing prevalence of
certain causes of cancer linked to social and economic development.
particularly in rapidly growing economies, where a shift is observed
from cancers related to poverty and infections to cancers associated
with lifestyles more typical of industrialized countries.
 Early diagnosis and early treatment are vital, and identification of
persons at increased risk of cancer before its development is an
important objective of cancer research.
 Efficient prevention and early detection policies must be
implemented urgently to complement treatments in order to control
this devastating disease across the world.

56. References
 INTERNATIONAL AGENCY FOR RESEARCH ON CANCER ( IARC )GLOBAL
CANCER DATA OBSERVATORY.
 K.PARKS PREVENTIVE AND SOCIAL MEDICINE 24TH EDITION TEXT BOOK.
 INTERNATIONAL AGENCY FOR RESEARCH ON CANCER PRESS RELEASE 12
SEPTEMBER 2018.
 CANCER EPIDEMIOLOGY GLOBAL BURDEN OF CANCER YALE JOURNAL OF BIOLOGY AND
MEDICINE 79 (2006)
 CANCER INCIDENCE ATTRIBUTABLE TO LIFESTYLE AND ENVIRONMENTAL FACTORS IN ALBERTA IN
2012: SUMMARY OF RESULTS
 www.googleimages.com
 www.iacr.com

57. T