Understanding Cancer: Types, Risk Factors, Stages and Prevention
1.
2. At the end of the Teaching students should be able to :
- Define Cancer.
identify the prevalence of cancer.
list risk factors and etiology.
Enumerate the warning sign of cancer.
Describe types of cancer.
Lerarning Objectives
3. Cancer may regarded as a group of diseases characterized by an
Abnormal growth of cells
Ability to invade tissue and even distant organs
The eventually death of the affected patient if the tumor has progressed
beyond the stage when it can be successfully removed
Introduction
4. Cancer is among the leading causes of death worldwide. In 2012, there were 14
million new cases and 8.2 million cancer-related deaths worldwide.
The number of new cancer cases will rise to 22 million within the next two
decades.
More than 60 percent of the world’s new cancer cases occur in Africa, Asia, and
Central and South America; 70 percent of the world’s cancer deaths also occur in
these regions.
In 2016, an estimated 1,685,210 new cases of cancer will be diagnosed in the
United States and 595,690 people will die from the disease.
The number of new cases of cancer (cancer incidence) is 454.8 per 100,000 men
and women per year (based on 2008-2012 cases). The number of cancer deaths
(cancer mortality) is 171.2 per 100,000 men and women per year (based on 2008-
2012 deaths).
Prevalence
5. Cancer Services in Nepal
SN Male Female
1 Lung Cervix
2 Oral Breast
3 Stomach lung
Pradhanga et al, 2005
Oncology in Nepal was heralded in 1991 when
country’s 1st radiation therapy center started
with instillation of telecobalt at Bir Hospital,
Kathmandu along with the 1st and single
oncologist in the country, Prof. Tara
Manandhar.
6. The establishment of Bhaktapur Cancer Care Center in 1992, which was later
converted to Bhaktapur Cancer Hospital (BCH) by Nepal Cancer Relief Society
(NCRS) with the support from Rotary Clubs, local people of Bhaktapur and the
Government of Nepal.
NCRS has now established its branches in 43 districts of Nepal and has been
mobilizing over 10,000 volunteers nationwide.
Considering treatment of cancer in Nepal, at present, there are only 4 centers in
the country treating cancer patients with the radiation therapy facilities, thus
providing a huge load of radiation services every day.
-BPKMCH, Manipal Teaching Hospital, Bir Hospital & Bhaktapur Cancer Hospital
National Cancer Hospital, Jawlakhel(2009PrivateComprehensivecare)
Cancer Services in Nepal
7. In United States:(American Cancer Society,2016)
- Bladder Cancer
- Breast Cancer
- Colon & Rectal Cancer
- Endometrial Cancer
- Kidney Cancer
- Leukemia
- Lung Cancer
- Non Hodgkin’s Lymphoma
Common Cancer
8. In Nepal:(NCRS)
- Cervical Cancer 13.03% death rate
- Lung Cancer 11.92%
- Breast Cancer 8.13%
- Oral Cancer 6.225
- Stomach Cancer 5.60%
- Ovary Cancer 5.13%
- Lymphomas 3.97%
Common Cancer
9. Risk Factors & Etiology
Non Modifiable
- Age
- Sex
- Genetic factor
Modifiable
- Tobacco
- Chronic infection
- Alcohol drinking
- Occupational exposure
- Dietary factors
- Obesity and physical exercise
- Radiation
- Medical drugs and procdures
- Lifestyle
10. Tobacco Consumption
- Main single cause of human cancer worldwide
- Accounts for 30% approx of all human cancer in developed
countries.
- Responsible for 13 types of cancer: lung, oral cavity, nasal cavity
and nasal sinuses, pharynx, larynx, oesophagus, stomach,
pancreas, liver, urinary bladder, kidney, uterine cervix and myeloid
leukaemia.
- Any form of tobacco are risk( smoking, SHS, chewing)
- Benefit of quitting tobacco in adulthood for all kind of major
cancer.
worldl cancer report, 2008 IARC
11. Chronic infection
- Approx 15- 20% of cancer worldwide: 26% in developing
countries, 8% in developed countries.
- Common cancer associated with chronic infection: HCC- HBV
HCV,Cervical cancer and other malignancy- HPV, Lymphoma-
EBV, Leukemia- HTLV, Kaposi sarcoma- HHV8, Gastric cancer- H.
Pylori, Bladder cancer- schistosomiasis
oxford text book of public health, 5th edition
12. Alcohol Drinking
- Global burden of cancer attributed to alcohol -3.6%
- A causal association has been established between alcohol
drinking and cancers of the oral cavity, pharynx, larynx,
esophagus, liver, colon, rectum and, in women, breast
- For all cancer sites, risk if the function of amount of alcohol
consumption
oxford text book of public health, 5th edition
13. Dietary Factors, Obesity and Physical
activities
- Responsible for 25% of human cancers in high income countries but
exact role of dietary factors for causing cancer remains largely
obscure.
- Increased weight gain is associated with cancer of colon, gall
bladder, postmenopausal breast, endometrium, kidney and
esophagus.
- Increasing physical activities decrease the risk of the breast and
colon cancer
oxford text book of public health, 5th edition
14. Smoked fish is related to stomach cancer
Dietary fiber to intestinal cancer
Beef consumption to bowel cancer
High fat diet to breast cancer
Food additives and contaminants have fallen under
suspicion as causative agents
Dietary factor
15. These includes exposure to benzene, cadmium, arsenic,
chromium, vinyl chloride, asbestos, polycyclic
hydrocarbons, etc.
The risk of occupational exposure is said to be increased
if the individual also smokes cigarette
Occupational exposure is usually reported 1-5% of human
cancer
Occupational exposures
16. Hepatitis B & C - hepatocarcinoma
HIV infection – kaposi’s carcinoma
AIDS – non Hodgkin’s lymphoma
Epstein – bar virus – Burkitts lymphoma and naso –
pharyngial carcinoma
Cytomegalovirus – Kaposi’s Sa
Pappiloma virus – cervix cancer
Human T cell leukemia virus – T cell leukemia
Virus
17. Parasite
May be a cause of cancer
Schistosomiasis can produce Ca of bladder
Customs, habits and life style
May be associated with an increased risk of cancer
Smoking and lung cancer
Tobacco and beetle chewing and oral cancer
Contd…
18. Others
Sunlight, radiation, water and air pollution, medication
and pesticides
These are related to cancer as environmental factors
Contd….
19. Reproductive factor and exogenous
hormone
- Reproductive factors(Age at menarch, age at first child, number of
pregancy, age at last child, and age at menopause) strongly
associated with cancer of breast, ovaries and endometrium.
- Exogenous estrogens and progestin's in combination as HRT in
menopause and in steroid contraceptives increase the risk of breast
and ovarian cancers.
- OCP exert long term protection for ovarian and endometrial cancer
but increase risk for cervical and liver cancer.
oxford text book of public health, 5th edition
20. Genetic Factor
Cancer susceptical genes may be oncogenes, tumor suppressor
gene, risk modifier genes.
oncogenes are genes where either over-expression or gain of
function mutations contribute to tumorigenesis.
Tumour suppressor gene: genes where either under-expression or
loss of function mutations contribute to tumorigenesis. melanoma
predisposition gene CDKN2A (p16), BRCA1, TP53
World cancer Report 2008 IARC
21. Others
Ionizing and non ionizing radiation
Medical procedures and drugs
Sunlight
22. Warning Signs
- WeightChanges(Loss): Oesophagus ,Lung ,Pancrease Stomach
- Fever or Blood Loss : Leukemia Lymphoma or stomach
- Pain & Tiredness: Colon Prostate, Ovaries Rectum
- Persistent Cough; Lung Cancer & Thyroid
- Skin Changes;
Remember CAUTION for Warning signs
C= Change in Bowel or bladder habits
A=A sore that does not healing in given normal time
U= Unusual bleeding or discharge
T=Thickening of mass or lump
I= Indigestion, difficulty in swallowing
O= Obvious change to moles or wart
N=Nagging cough
23. Major categories of cancer are
Carcinoma
Arises from the epithelial cells lining the internal surface of various organs
(e.g. mouth, oesophagus, uterus)
Sarcoma
Arises from the mesodermal cells constituting the various connective
tissues (e.g. fibrous tissue, bone)
Lymphoma, myeloma and leukemia
Arising from the cells of the bone marrow and immune system
Categories of Cancer
26. Characteristics of Benign Tumour
• Cells tend not to spread
• Most grow slowly
• Do not invade nearby tissue
• Do not metastasize (spread) to other parts of
the body
• Tend to have clear boundaries
27. • Under a pathologist's microscope,shape,chromosomes, and
DNA of cells appear normal.
• Do not secrete hormones or other substances
(an exception: pheochromocytomas of the adrenal
gland)
• May not require treatment if not health threatening
• Unlikely to recure if removed or require further treatment
such as radiation or chemotherapy
28. Characteristics of Malignant Tumor
• Cells can spread
• Usually grow fairly rapidly
• Often invade basal membrane that surrounds
healthy tissue.
• Can spread via bloodstream or lymphatic system.
29. • May recur after removal, sometimes in areas other the original
site.
• Cells have abnormal chromosomes and DNA
characterized by large, dark nuclei; may have abnormal shape.
• Can secrete substances that cause fatigue and weight
loss (paraneoplastic syndrome).
• May require aggressive treatment, including surgery, radiation,
chemotherapy, and immunotherapy medications.
35. Staging is the process of finding out how much cancer is in a
person’s body and where it’s located. It’s how the doctor
determines the stage of a person’s cancer.
to know the amount of cancer and where it is in the body to be
able to choose the best treatment options.
Staging is done on the basis of location, physical exam & etc
Overall stages grouping (Roman Staging):
-Stage I: cancers are small localized cancers that are usually curable.
Stage II & III: usually locally advanced and/or with involvement of
local lymph nodes.
Stage IV: represents inoperable or metastatic cancer.
Stages of Cancer
36. TNM Staging System
T= T Classifies the extent of the primary tumor, and is normally given
as T0 through T4.
- T0 represents a tumor that has not even started to invade the local
tissues. This is called "In Situ".
- T4 on the other hand represents a large primary tumor that has
probably invaded other organs by direct extension, and which is
usually inoperable.
Stages of Cancer
37. TNM Staging System
- TX means the tumor can’t be measured.
- T0 means there is no evidence of a primary tumor (it cannot be
found).
- Tis means that the cancer cells are only growing in the most
superficial layer of tissue, without growing into deeper tissues. This
may also be called in situ cancer or pre-cancer.
- Numbers after the T (such as T1, T2, T3, and T4) might describe the
tumor size and/or amount of spread into nearby structures.
-
- The higher the T number, the larger the tumor and/or the more it
has grown into nearby tissues.
Stages of Cancer
38. TNM Staging System
N= N classifies the amount of regional lymph node involvement.
- Involvement of distant lymph nodes is considered to be metastatic
disease.
- N0 means no lymph node involvement while N4 means extensive
involvement.
Stages of Cancer
39. TNM Staging System:
NX means the nearby lymph nodes cannot be evaluated.
N0 means nearby lymph nodes do not contain cancer.
Numbers after the N (such as N1, N2, and N3) might describe the
size, location, and/or the number of nearby lymph nodes affected
by cancer.
The higher the N number, the greater the cancer spread to nearby
lymph nodes.
Stages of Cancer
40. TNM Staging System
M= M is either M0 if there are no metastases or M1 if there are
metastases.
- M0 means that no distant cancer spread was found.
- M1 means that the cancer has spread to distant organs or tissues
(distant metastases were found).
Stages of Cancer
41. Tumor Grading:
- Tumor grade refers to a measure of how abnormal cells from your
tumor appear under the microscope.
- This can refer to the appearance of the cells or to the percentage
that appear to be dividing.
- The higher the grade, the more aggressive and fast growing the
cancer.
- Tumors are typically classified from least to most aggressive as
grade I through IV.
Tumor Grading
42. Staging:
Stage 0: carcinoma in situ, derived from the Latin
phrase meaning “in its place”
Stage I: Tumor limited to the tissue of origin, localized
tumor growth
Stage II: Limited tissue spread
Stage III: extensive local and regional spread
Stage IV: Metastasis
43. Grading:
Grade I: cells differ slightly from normal cells and are
well differentiated (mild dysplasia)
Grade II: cells are more abnormal and are moderately
differentiated (moderate dysplasia)
Grade III: cells are very abnormal and are poorly
differentiated (severe dysplasia)
Grade IV: cells are immature (anaplasia) and
undifferentiated; cells of origin is difficult to determine
44. TNM classification:
T describes the size of the tumor and whether
it has invaded nearby tissue
N describes regional lymph nodes that are
involved
M describes distant metastasis
45. Mandatory parameters
T (a, CIS,(0),1–4): size or direct extent of the primary tumor
N (0–3): degree of spread to regional lymph nodes
N0: tumor cells absent from regional lymph nodes
N1: regional lymph node metastasis present; (at some sites: tumor
spread to closest or small number of regional lymph nodes)
N2: tumor spread to an extent between N1 and N3
N3: tumor spread to more distant or numerous regional lymph
nodes
M (0/1): presence of metastasis
M0: no distant metastasis
M1: metastasis to distant organs (beyond regional lymph nodes)
46. A lowercase ‘c’ or ‘p’ is used in the TNM system to denote
whether a cancer is in the clinical or pathologic stage.
Clinical Stage: Clinical stage cancers are identified using all of
the information that isprocured before the surgical removal of the
tumor. This information may include the results of a physical
examination and certain imaging tests.
Pathologic Stage: The identity of pathologic stage cancers has
been embellished by the addition of information gained through
histological (microscopic) evaluation of tissue samples.
Using the TNM system, a patient with a ‘cT1N0M0’ cancer would
have a clinical stage T1 tumor with no lymph node involvement
and no metastasis.
47. IMAGING TESTS USED TO
DETECT CANCER
• TEST : Tumor marker identification
• DESCRIPTION : Analysis of substances found in the blood
or other body fluids that are made by the tumor or by the
body in response to the tumor
• DIAGNOSTIC USES : Breast, colon, lungs, ovaries, testes,
protest
48. • TEST : Magnetic resonance imaging (MRI)
• DESCRIPTION : Use of magnetic fields and radiofrequency
signals to create sectioned images of various body structures
• DIAGNOSTIC USES : Neurologic, pelvic, abdominal,
thoracic cancers
49.
50. • TEST : Computed tomography (CT scan)
• DESCRIPTION : Use of narrow beam x-ray to
scan successive layers of tissue for a cross-
sectional view
• DIAGNOSTIC USES : Neurologic, pelvic, skeletal,
abdominal, thoracic cancers
51.
52. • TEST : Fluoroscopy
• DESCRIPTION : Use of x-rays that identify contrasts in body
tissue densities; may involve the use of contrast agents.
• DIAGNOSTIC USES : Skeletal, lung, gastrointestinal cancers
53.
54. • TEST : Ultrasonography (ultrasound)
• DESCRIPTION : High-frequency sound waves echoing off
body tissues are converted electronically into images; used to
assess tissues deep within the body.
• DIAGNOSTIC USES : Abdominal and pelvic cancers
55. • TEST : Endoscopy
• DESCRIPTION : Direct visualization of a body cavity or
passageway by insertion of an endoscope into a body cavity or
opening; allows tissue biopsy, fluid aspiration and excision of
small tumors; both diagnostic and therapeutic.
• DIAGNOSTIC USES : Bronchial, gastrointestinal cancers
56.
57. • TEST : Nuclear medicine imaging
• DESCRIPTION : Uses intravenous injection or ingestion of
radioisotope substances followed by imaging of tissues that
have concentrated the radioisotopes.
• DIAGNOSTIC USES : Bone, liver, kidney, spleen, brain,
thyroid cancers.
58.
59. • TEST : Positron emission tomography (PET scan)
• DESCRIPTION : Computed cross-sectional images of
increased concentration of radioisotopes in malignant cells
provide information about biologic activity of malignant
cells; help distinguish between benign and malignant
processes and responses to treatment.
• DIAGNOSTIC USES : Lung, colon, liver, pancreatic, breast,
esophagus cancers; Hodgkin’s and non-Hodgkin’s lymphoma
and melanoma.
60.
61. • TEST : Radioimmunoconjugates (Radio-immuno-conjugates)
• DESCRIPTION : Monoclonal antibodies are labeled with a
radioisotope and injected intravenously into the patient; the
antibodies that aggregate at the tumor site are visualized with
scanners
• DIAGNOSTIC USES : Colorectal, breast, ovarian, head and
neck cancers; lymphoma and melanoma
62. Cancer Prevention and control
Four Strategies: WHO
- Primary Prevention
- Early Detection and Secondary Prevention
- Diagnosis and Treatment
- Palliative Care
Gobal cancer facts and figures 2007 ACS
63. Primary Prevention
Goal: to reduce or eliminate exposure to cancer-causing factors
Approaches :
- Immunization against, or treatment of, infectious agents that
cause certain cancers- HBV and HPV vaccine, eradication
treatment of H. pylori
- application of effective tobacco control measures
- reduction of excessive alcohol consumption
- maintenance of healthy body weight and physically active
lifestyles
- reduction in occupational exposure to carcinogens
- pharmacological intervention
Gobal cancer facts and figures 2007 ACS
64. Secondary Prevention
Cancer Registration
- Provide base for assessing the magnitude of the
problem and for planning necessary services
- Two types: Hospital based Registries and Population
based Registries
Cancer Epidemiology: Principle and Methods IARC
65. Early Detection of Cases
Objective: to detect pre-cancerous changes or early stage cancer
when they can be treated most effectively
Two strategies of cancer screening
- Opportunistic Screening: Physician or individual
- Organized screening: Mass screening or selective screening
Cancers that have proven early detection methods include cervix,
colon and rectum, and breast
Global cancer facts and figures 2007 ACS
66. Diagnosis and Treatment
Cancer diagnosis first step in cancer management
Cancer staging
Treatment- surgery, Radiotherapy, Chemotherapy ,
Hormonal therapy
Gobal cancer facts and figures 2007 ACS
67. Palliative care
70% of cases presented in hospital at advance stage-
Goal: To improve quality of life of the patients & relief
of sufferings
To decrease the problems faced by the
families psychologically
To prolong the life
Gobal cancer facts and figures 2007 ACS
68. It consists of prevention, detection, diagnosis,
treatment, after care and rehabilitation, reducing
incidence and prevalence
Primary control
Reducing the exposure to the risk factors
Control of Tabaco and alcohol consumption
Control of these two will reduce the total burden of cancer
by 1 million cases per year
Cancer control
69. Personal hygiene
Improvement in hygiene may decline the incidence of certain
types of cancers
Radiation
Effort should be made to reduce the amount of radiation
received by each individuals to a minimum without reducing
the benefits
Occupational Exposure
Should protect workers from exposure to industrial
carcinogens
Contd…..
70. Food, drugs, and cosmetics
Should be tested for carcinogens
Air pollutions
Control of air pollution is a preventive measure
Treatment of pre cancerous lesions
Early detection and prompt treatment of precanerous
lesions
Contd……
71. Cancer Education
Should be directed in high risk groups
To motivate people for early diagnosis and treatment
Remind early warning symptoms
A lump or hard area in the breast
A change in a wart or mole
A persistent change in digestive and bowel habits
A persistent cough or hoarseness
Excessive loss of blood at the monthly period or loss of blood
outside the usual dates
Blood loss from any natural orifice
A swelling or sore that does not get better
Unexplained loss of weight
Contd…..
Overall the most common site in males was the lung, followed by the oral cavity and stomach, while the first three in females were cervix uteri, breast and lung.
-burden of tobacco related cancer is lower given relatively recent start of the epidemics of smoking, however I will result in greater burden in future
-Approximately >> 15–20% of cancers worldwide have been attributed to infectious agents. However, this proportion is higher in low-resource countries (26%) than in the developed world (8%)
->>HPV, EBV, HTL V1 and HHV8 play a direct role in carcinogenesis encoding oncoprotein
->>Other infectious agents, e.g. HBV, HCV and H. pylori, appear to have an indirect role, inducing a chronic inflammation with tissue necrosis and regeneration
Only for alcohol and aflatoxin sufficient evidence has been established for increased risk for cancer. Though high fat diet or other nutrients in determing breast and colorectal cancer has showen associated however risk has not been confirmed. As well limited evidence for protective role of the vegetable and fruits.
Which is also indirect benefit thru prevention of obesity that is known risk factor
-at least 30 minutes per day of more than moderate level of physical activity might be needed to see the greatest effect in risk reduction-colon cancer
- risk reduction begins at levels of 30–60 minutes per day of moderate-intensity to vigorous activity in addition to the usual levels of occupational and household activity of most women”- breast
Long-term exposure to high levels of endogenous sex steroids has been considered as the risk of breast and endometrial cancers in post-menopausal women
With development of newer technologies and understanding about the genome of human being, the role of gene in carcinogenesis is growing
The unifying characteristic of oncogenes is that their normal function tends to drive a process required for tumour
initiation, progression, invasion, or metastasis forward.oncogenes are genes where either over-expression or gain of function mutations contribute to tumorigenesis eg:RAS and MYC families
Tumour suppressor genes are the opposite; their normal function tends to inhibit a process required for tumorigenesis. Thus, from a genetics point of view, tumour suppressors are genes where either under-expression or loss of function mutations contribute to tumorigenesis. Classic examples include the retinoblastoma predisposition gene RB and the melanoma predisposition gene CDKN2A (p16)
-Caretakers are involved in detection or repair of DNA damage, eg Li-Fraumeni susceptibility gene TP53 and the breast/ovarian cancer susceptibility gene BRCA1
-risk modifier genes are not main-effect oncogenes or tumour suppressors but rather genes whose normal function can modify the risk due to a carcinogenic exposure (either environmental or genetic). Examples include the alcohol dehydrogenases and acetaldehyde dehydrogenases (ADHs and ALDHs) that modify risk of head and neck cancer attributable to heavy alcohol consumption but have little effect on cancer risk in nondrinkers [1] and RAD51, which can modify the risk of breast cancer in BRCA2 carriers but has little effect on risk in non-carriers [2].
Genetic susceptibility focuses on inherited (constitutional or germline) genetic variation in cancer susceptibility genes, and the effects of that inherited variation on an individual’s lifetime cancer risk. In contrast, somatic cell genetics focuses on mutations that arise in an individual’s cells during their lifetime and the role that those mutations play during tumour initiation and progression.
Ionizing- ALL, CML, cancer of breast, lung, bone, brain, thyroid
Non Ionizing- UV radiation skin
Chemotherapy- leukaemia, NHL- immunosupressive drugs, Phenacetin- renal pelvis
Ionizing- ALL, CML, cancer of breast, lung, bone, brain, thyroid
Non Ionizing- UV radiation skin
Chemotherapy- leukaemia, NHL- immunosupressive drugs, Phenacetin- renal pelvis
-The goal of primary prevention is to reduce or eliminate exposure to cancer-causing factors, which include modifiable factors related to tobacco use, nutrition, physical inactivity, occupational exposures, and chronic infections
-two currently available HPV vaccines [9,10] include HPV16 and 18(account 70%) and are based on L1 virus-like particles (VLPs), i.e. empty viral capsids. aged 9–26 years. at least 90% effective in preventing persistent HPV infection and 95% effective in preventing type-specific precancerous lesions. Available vaccines did not, however, prevent development of CIN2 and 3 in women who had been infected by HPV16 and 18 before immunisation, or CIN2 and 3 caused by other HPV types in clinical trials.
-HBV vaccines are predominantly produced by recombinant DNA technology. The vaccine is administered in a three-dose series and has resulted in high immunogenicity and efficacy,
Advantages of population based registries
(1) They describe the extent and nature of the cancer burden in the community and assist in the establishment of public health priorities.
(2) They may be used as a source of material for etiological studies.
(3) They help in monitoring and assessing the effectiveness of cancer control activities.
-In Nepal, a system of collection of cancer incidence data from 7 major hospitals(BPKIHS, BPCMH, TUTH, KANTI, BIR, MANIPAL TH, BHARATPUR) around the country was introduced in 2005, with the support of WHO.
-Objective through screening to detect pre-cancerous changes or early stage cancers when they can be treated most effectively
-organized screening in which a defined population is contacted and invited to be screened at regular intervals
- Mass screening by comprehensive cancer detection examination or at the specific site
-Cancer diagnosis, including careful clinical and pathological assessments, is the first step to cancer management.
Once a diagnosis is confirmed, it is necessary to determine cancer stage, where the main goals are to aid in the choice of therapy, to determine prognosis, and to standardize the design of research treatment protocols
- primary modalities of cancer treatment are surgery, chemotherapy, and radiotherapy; these may be used alone or in combination
In our parts of the world, the majority of cancer patients present with advanced disease
For these patients, the only realistic treatment option is pain relief and palliative care
-To improve quality of life of the patients & relief of sufferings
- To decrease the problems faced by the families psychologically
- To prolong the life