2. WHAT IS CANCER?
• Cancer (medical term: malignant neoplasm) is a class of diseases in which a
group of cell display uncontrolled growth through division beyond normal limits,
invasion that intrudes upon and destroys adjacent tissues, and sometimes
metastasis, which spreads the cells to other locations in the body via lymph or
blood. These three malignant properties of cancers differentiate them from
benign tumors, which are self-limited, and do not invade or metastasize.
• Cancers are primarily an environmental disease with 90-95% of cases due to
lifestyle and environmental factors and 5-10% due to heredity.1. Common
environmental factors leading to cancer death include:
• tobacco:- (25-30%),diet and obesity:- (30-35%),infections:- (15-20%),
radiation, stress, lack of physical activity, and environmental pollutants.[1]These
environmental factors cause abnormalities in the genetic material of cells.
[2]Genetic abnormalities found in cancer typically affect two general classes of
genes oncogene sand tumor suppressor genes.
• Definitive diagnosis requires the examination of a biopsy specimen, although
the initial indication of malignancy can be symptomatic or radiographic. Most
cancers can be treated and this may include chemotherapy and radiotherapy
and/or surgery. The prognosis is most influenced by the type of cancer and the
extent of disease. While cancer can affect people of all ages the risk typically
increasing with age.[3] In 2004 cancer caused about 13% of all human deaths
[4] (7.6 million).[5]
4. CLASSIFICATION
Cancers are classified by the type of cell that resembles the
tumor and, therefore, the tissue presumed to be the origin of the
tumor. These are the histology and the location, respectively.
Examples of general categories include:
• Carcinoma: Malignant tumors derived from epithelial cells. This group
represents the most common cancers, including the common forms of
breast, prostate, lung and colon cancer.
• Sarcoma: Malignant tumors derived from connective tissue, or
mesenchymal cells.
• Lymphoma and leukemia: Malignancies derived from hematopoietic
(blood-forming) cells
• Germ cell tumor: Tumors derived from totipotent cells. In adults most
often found in the testicle and ovary; in fetuses, babies, and young
children most often found on the body midline, particularly at the tip of the
tailbone; in horses most often found at the poll (base of the skull).
• Blasti tumor or blastoma: A tumor (usually malignant) which resembles
an immature or embryonic tissue. Many of these tumors are most
common in children.
6. Signs and symptoms
Roughly, cancer symptoms can be divided into three groups:
• Local symptoms: unusual lumps or swelling (tumor), hemorrhage
(bleeding), pain and/or ulceration. Compression of surrounding tissues
may cause symptoms such as jaundice (yellowing the eyes and skin).
• Symptoms of metastasis (spreading): enlarged lymph nodes, cough and
hemoptysis, hepatomegaly (enlarged liver), bone pain, fracture of
affected bones and neurological symptoms. Although advanced cancer
may cause pain, it is often not the first symptom.
• Systemic symptoms: weight loss, poor appetite, fatigue and cachexia
(wasting), excessive sweating (night sweats), anemia and specific
paraneoplastic phenomena, i.e. specific conditions that are due to an
active cancer, such as thrombosis or hormonal changes.
7.
8. Causes
• Cancers are primarily an environmental disease with 90-
95% of cases due to environmental factors and 5-10% due
to genetics.[1] "Environmental", as used by cancer
researchers, means any cause that is not genetic, and
includes everything from natural sunlight to industrial
pollution to viruses to behavioral choices to old age. Most
environmental causes, such as naturally occurring
background radiation, are not modifiable or controllable.
Common environmental factors that lead to cancer death
include: tobacco (25-30% of deaths), diet and obesity (30-
35%), infections (15-20%), radiation, stress, lack of
physical activity, and environmental pollutants.[1]
10. Causes:- CHEMICALS
• Cancer pathogenesis is traceable back to DNA mutations that impact cell growth and
metastasis. Substances that cause DNA mutations are known as mutagens, and
mutagens that cause cancers are known as carcinogens. Particular substances have
been linked to specific types of cancer. Tobacco smoking is associated with many forms
of cancer, and causes 90% of lung cancer. Prolonged exposure to asbestos fibers is
associated with mesothelioma.
• Many mutagens are also carcinogens, but some carcinogens are not mutagens. Alcohol
is an example of a chemical carcinogen that is not a mutagen.[10] Such chemicals may
promote cancers through stimulating the rate of cell division. Faster rates of replication
leaves less time for repair enzymes to repair damaged DNA during DNA replication,
increasing the likelihood of a mutation.
• Decades of research has demonstrated the link between tobacco use and cancer in the
lung, larynx, head, neck, stomach, bladder, kidney, oesophagus and pancreas. Tobacco
smoke contains over fifty known carcinogens, including nitrosamines and polycyclic
aromatic hydrocarbons. Tobacco is responsible for about one in three of all cancer deaths
in the developed world,[6] and about one in five worldwide.[12] Indeed, lung cancer death
rates in the United States have mirrored smoking patterns, with increases in smoking
followed by dramatic increases in lung cancer death rates and, more recently when?],
decreases in smoking followed by decreases in lung cancer death rates in men. However,
the numbers of smokers worldwide is still rising, leading to what some organizations have
described as the tobacco epidemic.
• Cancer related to ones occupation is believed to represent between 2-20% of all cases.
Every year, at least 200,000 people die worldwide from cancer related to their workplace.
Millions of workers run the risk of developing cancers such as lung cancer and
mesothelioma from inhaling asbestos fibers and tobacco smoke, or leukemia from
exposure to benzene at their workplaces. Currently, most cancer deaths caused by
occupational risk factors occur in the developed world.[15] It is estimated that
approximately 20,000 cancer deaths and 40,000 new cases of cancer each year in the
U.S. are attributable to occupation.
12. Causes:-RADIATION
• Sources of ionizing radiation, such as radon gas, can
cause cancer. Prolonged exposure to ultraviolet radiation
from the sun can lead to melanoma and other skin
malignancies. One report estimates that approximately 29
000 future cancers could be related to the approximately
70 million CT scans performed in the US in 2007. It is
estimated that 0.4% of current cancers in the United States
are due to CTs performed in the past and that this may
increase to as high as 1.5-2% with 2007 rates of CT usage.
• Non-ionizing radio frequency radiation from mobile phones
and other similar RF sources has also been proposed as a
cause of cancer, but there is currently little established
evidence of such a link.
13. Causes:-INFECTION
• Some cancers can be caused by infection. This is especially true in animals such as birds,
but also in humans, with viruses responsible for up to 20% of human cancers worldwide.]
These include human papillomavirus (cervical carcinoma), human polyomaviruses
(mesothelioma, brain tumors), Epstein-Barr virus (B-cell lymphoproliferative disease and
nasopharyngeal carcinoma), Kaposi's sarcoma herpes virus (Kaposi's Sarcoma and
primary effusion lymphomas), hepatitis B and hepatitis C viruses (hepatocellular
carcinoma), and Human T-cell leukemia virus-1 (T-cell leukemia's). Bacterial infection may
also increase the risk of cancer, as seen in Helicobacter pylori induced gastric carcinoma.
• Experimental and epidemiological data imply a causative role for viruses and they appear to
be the second most important risk factor for cancer development in humans, exceeded only
by tobacco usage. The mode of virally induced tumors can be divided into two, acutely
transforming or slowly transforming. In acutely transforming viruses, the virus carries an
overactive oncogene called viral-oncogene (v-onc), and the infected cell is transformed as
soon as v-onc is expressed. In contrast, in slowly transforming viruses, the virus genome is
inserted near a proto-oncogene in the host genome. The viral promoter or other
transcription regulation elements then cause over expression of that proto-oncogene. This
induces uncontrolled cell division. Because the site of insertion is not specific to proto-
oncogene and the chance of insertion near any proto-oncogene is low, slowly transforming
viruses will cause tumors much longer after infection than the acutely transforming viruses.
• Hepatitis viruses, including hepatitis B and hepatitis C, can induce a chronic viral infection
that leads to liver cancer in 0.47% of hepatitis B patients per year (especially in Asia, less
so in North America), and in 1.4% of hepatitis C carriers per year. Liver cirrhosis, whether
from chronic viral hepatitis infection or alcoholism, is associated with the development of
liver cancer, and the combination of cirrhosis and viral hepatitis presents the highest risk of
liver cancer development. Worldwide, liver cancer is one of the most common, and most
deadly, cancers due to a huge burden of viral hepatitis transmission and disease.
14. INFECTION
• Advances in cancer research have made a vaccine designed to prevent cancers
available. In 2006, the U.S. Food and Drug Administration approved a human papilloma
virus vaccine, called Gardasil. The vaccine protects against 6,11,16,18 strains of HPV,
which together cause 70% of cervical cancers and 90% of genital warts. It also lists
vaginal and vulvar cancers as being protected. In March 2007, the US Centers for
Disease Control and Prevention (CDC) Advisory Committee on Immunization Practices
(ACIP) officially recommended that females aged 11–12 receive the vaccine, and
indicated that females as young as age 9 and as old as age 26 are also candidates for
immunization. There is a second vaccine from Cervarix which protects against the more
dangerous HPV 16,18 strains only. In 2009, Gardasil was approved for protection
against genital warts. In 2010, the Gardasil vaccine was approved for protection against
anal cancer for males and reviewers stated there was no anatomical, histological or
physiological anal differences between the genders so females would also be protected.
• In addition to viruses, researchers have noted a connection between bacteria and certain
cancers. The most prominent example is the link between chronic infection of the wall of
the stomach with Helicobacter pylori and gastric cancer. Although only a minority of
those infected with Helicobacter go on to develop cancer, since this pathogen is quite
common it is probably responsible for most of these cancers.
• HIV is associated with a number of malignancies, including Kaposi's sarcoma, non-
Hodgkin's lymphoma, and HPV-associated malignancies such as anal cancer and
cervical cancer. AIDS-defining illnesses have long included these diagnoses. The
increased incidence of malignancies in HIV patients points to the breakdown of immune
surveillance as a possible etiology of cancer. Certain other immune deficiency states
(e.g. common variable immunodeficiency and IgA deficiency) are also associated with
increased risk of malignancy.
16. HEREDITY
• Most forms of cancer are sporadic, meaning that there is no inherited cause of the
cancer. There are, however, a number of recognized syndromes where there is an
inherited predisposition to cancer, often due to a defect in a gene that protects against
tumor formation. Famous examples are:
• certain inherited mutations in the genes BRCA1 and BRCA2 are associated with
an elevated risk of breast cancer and ovarian cancer
• tumors of various endocrine organs in multiple endocrine neoplasia (MEN types 1,
2a, 2b)
• Li - Fraumeni syndrome (various tumors such as osteosarcoma, breast cancer,
soft tissue sarcoma, brain tumors) due to mutations of p53
• Turcot syndrome (brain tumors and colonic polyposis)
• Familial adenomatous polyposis an inherited mutation of the APC gene that leads
to early onset of colon carcinoma.
• Hereditary nonpolyposis colorectal cancer (HNPCC, also known as Lynch
syndrome) can include familial cases of colon cancer, uterine cancer, gastric
cancer, and ovarian cancer, without a preponderance of colon polyps.
• Retinoblastoma, when occurring in young children, is due to a hereditary mutation
in the retinoblastoma gene.
• Down syndrome patients, who have an extra chromosome 21, are known to
develop malignancies such as leukemia and testicular cancer, though the reasons
for this difference are not well understood.
17.
18. PREVENTION
• Cancer prevention is defined as active measures to decrease the
incidence of cancer. The vast majority of cancer risk factors are
environmental or lifestyle-related, thus cancer is largely a preventable
disease. Greater than 30% of cancer is preventable via avoiding risk
factors including: tobacco, overweight or obesity, low fruit and vegetable
intake, physical inactivity, alcohol, sexually transmitted infection, air
pollution.
• Examples of modifiable cancer risk factors include alcohol consumption
(associated with increased risk of oral, esophageal, breast, and other
cancers), smoking (80% of women with lung cancer have smoked in the
past, and 90% of men), physical inactivity (associated with increased risk
of colon, breast, and possibly other cancers), and being overweight /
obese (associated with colon, breast, endometrial, and possibly other
cancers). Based on epidemiologic evidence, it is now thought that
avoiding excessive alcohol consumption may contribute to reductions in
risk of certain cancers; however, compared with tobacco exposure, the
magnitude of effect is modest or small and the strength of evidence is
often weaker. Other lifestyle and environmental factors known to affect
cancer risk (either beneficially or detrimentally) include certain sexually
transmitted diseases (such as those conveyed by the human
papillomavirus), the use of exogenous hormones, exposure to ionizing
radiation and ultraviolet radiation from the sun or from tanning beds, and
certain occupational and chemical exposures.
19.
20. TREATMENT:- MEDICATION
• The concept that medications could be used to prevent cancer is an attractive
one, and many high-quality clinical trials support the use of such
chemoprevention in defined circumstances.
• Daily use of tamoxifen, a selective estrogen receptor modulator (SERM), typically
for 5 years, has been demonstrated to reduce the risk of developing breast
cancer in high-risk women by about 50%. A recent when?] study reported that the
selective estrogen receptor modulator raloxifene has similar benefits to tamoxifen
in preventing breast cancer in high-risk women, with a more favorable side effect
profile.
• Raloxifene is a SERM like tamoxifen; it has been shown (in the STAR trial) to
reduce the risk of breast cancer in high-risk women equally as well as tamoxifen.
In this trial, which studied almost 20,000 women, raloxifene had fewer side
effects than tamoxifen, though it did permit more DCIS to form.
• Finasteride, a 5-alpha-reductase inhibitor, has been shown to lower the risk of
prostate cancer, though it seems to mostly prevent low-grade tumors. The effect
of COX-2 inhibitors such as rofecoxib and celecoxib upon the risk of colon polyps
have been studied in familial adenomatous polyposis patients and in the general
population. In both groups, there were significant reductions in colon polyp
incidence, but this came at the price of increased cardiovascular toxicity.
• As of 2010 vitamins have not been found to be effective at preventing cancer,
while low levels of vitamin D is correlated with increased cancer risk. Whether
this relationship is causal and vitamin D supplementation is protective is yet to be
determined. Beta-carotene supplementation has been found to increase slightly,
but not significantly risks of lung cance.Folic acid supplementation has not been
found effective in preventing colon cancer and may increase colon polyps.
22. VACCINATION
• Vaccines have been developed to prevent
oncogenic infectious agents and therapeutic
vaccines are in development to stimulate an
immune response against cancer-specific
epitopes.
• Human papillomavirus vaccine (Gardasil and
Cervarix) decreases the risk of developing
cervical cancer. The hepatitis B vaccine
prevents infection with hepatitis B virus and
thus decreases the risk of liver cancer
24. RESEARCH
• Main article: Cancer research
• Cancer research is the intense scientific effort to understand disease
processes and discover possible therapies. The improved understanding
of molecular biology and cellular biology due to cancer research has led
to a number of new, effective treatments for cancer since President Nixon
declared "War on Cancer" in 1971. Since 1971 the United States has
invested over $200 billion on cancer research; that total includes money
invested by public and private sectors and foundations. Despite this
substantial investment, the country has seen a five percent decrease in
the cancer death rate (adjusting for size and age of the population)
between 1950 and 2005.
• Leading cancer research organizations and projects include the American
Association for Cancer Research, the American Cancer Society (ACS),
the American Society of Clinical Oncology, the European Organization for
Research and Treatment of Cancer, the National Cancer Institute, the
National Comprehensive Cancer Network, and The Cancer Genome
Atlas project at the NCI.
25. SO CANCER IS THREATNING
DISEASE OF LIFE.
THANK YOU VERY MUCH
![WHAT IS CANCER?
• Cancer (medical term: malignant neoplasm) is a class of diseases in which a
group of cell display uncontrolled growth through division beyond normal limits,
invasion that intrudes upon and destroys adjacent tissues, and sometimes
metastasis, which spreads the cells to other locations in the body via lymph or
blood. These three malignant properties of cancers differentiate them from
benign tumors, which are self-limited, and do not invade or metastasize.
• Cancers are primarily an environmental disease with 90-95% of cases due to
lifestyle and environmental factors and 5-10% due to heredity.1. Common
environmental factors leading to cancer death include:
• tobacco:- (25-30%),diet and obesity:- (30-35%),infections:- (15-20%),
radiation, stress, lack of physical activity, and environmental pollutants.[1]These
environmental factors cause abnormalities in the genetic material of cells.
[2]Genetic abnormalities found in cancer typically affect two general classes of
genes oncogene sand tumor suppressor genes.
• Definitive diagnosis requires the examination of a biopsy specimen, although
the initial indication of malignancy can be symptomatic or radiographic. Most
cancers can be treated and this may include chemotherapy and radiotherapy
and/or surgery. The prognosis is most influenced by the type of cancer and the
extent of disease. While cancer can affect people of all ages the risk typically
increasing with age.[3] In 2004 cancer caused about 13% of all human deaths
[4] (7.6 million).[5]](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)