Transcript Cancer and Infectious Diseases: Prevention as a Pathway to Control

CANCER AND INFECTIOUS
DISEASES: PREVENTION AS
A PATHWAY TO CONTROL
Dr. Rasha Salama
M.SC, PhD in Public Health
Suez Canal University
CANCER - GLOBAL BURDEN
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A major public health concern
Recognized globally as one of the leading chronic noncommunicable diseases, imposing strain on the public
and on existing health systems.
The impacts of cancer are multiple and far reaching,
affecting people of both gender, all ages, and
nationalities
13% of annual global mortality
Contribute to over 7.9 million deaths each year and
this figure may projected to nearly 10 million unless
the problem is addressed urgently.
CANCERS AND INFECTIOUS AGENTS
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The most important advance in oncology ever is
the understanding that most cancers have
specific causes, and that these causes may be
identified, leading potentially to control.
The causes of some cancers are infectious agents.
The proposal that cancers are caused by
infectious agents has had a very up and down
history: today we can be certain that many
cancers have aetiologies with infectious agents as
necessary factors.
WORLDWIDE, AN ESTIMATED 17.8% OF
NEOPLASMS ARE ASSOCIATED WITH
INFECTIONS; THIS PERCENTAGE RANGES FROM
10% IN HIGH-INCOME COUNTRIES
TO 25% IN AFRICAN COUNTRIES.
LESS THAN
GLOBAL BURDEN: NEOPLASMS -ASSOCIATED
WITH INFECTIONS
Global burden of cancers attributable to infections in 2008: a review and synthetic
analysis – lancet 2008
GLOBAL BURDEN: NEOPLASMS -ASSOCIATED
WITH INFECTIONS GENDER DISTRIBUTION
INFECTIONS: THE PERCENTAGE CONTRIBUTION
INFECTIONS: THE PERCENTAGE CONTRIBUTION
…..
www.thelancet.com/oncology Published online May 9, 2012 DOI:10.1016/S1470-2045(12)70137-7
MECHANISM
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Viruses may contribute to
the development of human
tumors by different
mechanisms:
indirectly by inducing
immunosuppression or by
modifying the host cell
genome without persistence of
viral DNA;
 directly by inducing
oncoproteins or by altering
the expression of host cell
proteins at the site of viral
DNA integration.
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INFECTION & CANCER …….
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Cancer of the cervix and hepatocellular carcinoma account
for about 80 percent of virus-linked cancers.
www.thelancet.com/oncology Published online May 9, 2012 DOI:10.1016/S1470-2045(12)70137-7
THE INTERNATIONAL AGENCY
FOR
RESEARCH
ON
CANCER
HAS CLASSIFIED THE
FOLLOWING INFECTIOUS AGENTS AS CARCINOGENIC OR PROBABLY CARCINOGENIC—THAT IS,
AS CAUSING OR CONTRIBUTING TO CANCER DEVELOPMENT—IN HUMANS
Infectious Agent
Associated Cancers
viruses
Epstein-Barr virus (EBV)
Burkitt lymphoma- Hodgkin lymphoma
Non-Hodgkin lymphoma - Nasopharyngeal carcinoma
NK/T-cell lymphoma
Hepatitis B virus (HBV)
Hepatocellular carcinoma (a type of liver cancer)
Hepatitis C virus (HCV)
Hepatocellular carcinoma - Non-Hodgkin lymphoma
Human papillomavirus types 16, 18, and others
(HPV)
Anal cancer - Cervical cancer - Oral cancer - Penile cancer
Oropharyngeal cancer (cancer of the base of the tongue,
tonsils, or upper throat)
Vaginal cancer - Vulvar cancer
Human immunodeficiency virus 1 (HIV 1)
A variety of immunosuppression-related cancers
Anal cancer - Cervical cancer
Conjunctiva cancer - Hodgkin lymphoma
Kaposi sarcoma - Non-Hodgkin lymphoma
Human T-cell lymphotropic virus 1 (HTLV 1)
Adult T-cell leukemia/lymphoma
Kaposi sarcoma herpesvirus/ human herpesvirus 8
(KSHV/HHV 8)
Kaposi sarcoma
Primary effusion lymphoma
Other infectious agents
Helicobacter pylori (bacterium)
Gastric cancer
Liver flukes (parasite)
Cholangiocarcinoma
Schistosomes (parasite)
Bladder cancer
CHRONIC BACTERIAL INFECTIONS AND CANCER
MAIN INFECTIOUS AGENTS INVOLVED IN
CANCER
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Looking world wide we can now
point at the main infectious
agents involved in cancer:
Human papillomavirus (HPV),
recognized as the primary cause
of cervical carcinoma;
 Hepatitis B and C viruses (HBV
and HCV), certainly contribute to
hepatocellular carcinoma; and
 Helicobacter pylori, which most
certainly contributes to gastric
carcinoma.
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These four examples probably
account for a fifth or more of cancer
globally.
EVIDENCE:
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In 1997, the World Health Organization estimated
that up to 84% of cases of some cancers are
attributable to viruses, bacteria, and parasites and
that more than 1.5 million (15%) new cases each year
could be avoided by preventing the infectious disease
associated with them
In 1994, the International Agency for Research on
Cancer concluded that infection of humans with H.
pylori is causally associated with the risk of
developing adenocarcinoma of the stomach. H. pylori
is also associated with two less common forms of
cancer, non-Hodgkin lymphoma and mucosaassociated lymphoid tissue lymphomas of the stomach
EVIDENCE (CONT.)
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Another landmark study, published in June,
1997, shows that a 12-year nationwide
vaccination program against hepatitis B virus in
Taiwan resulted in a significant reduction in the
number of cases of childhood liver cancer.
The infectious origin of carcinoma of the cervix
has long been suspected, because known risk
factors for the disease are linked to sexual
activity (105). Recent evidence indicates that
human papillomavirus (HPV) types 16 and 18 are
definitely carcinogenic in humans, Types 31 and
33 are classified as probably carcinogenic
TRUE CANCER CONTROL
“aspires to prevent cancer, to detect cancer at an
early stage, and to treat and hopefully cure the
disease in those who are diagnosed, and to
increase the survival and the quality of life in
those who develop it.”
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Primary prevention is the most cost-effective form of
cancer control.
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Prevention means eliminating exposure to the
environmental causes of cancer
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Promotion of healthy lifestyles could reduce as many as
one third of cancers worldwide.
PREVENTION AND CONTROL EFFORTS
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Population-based education and awareness
campaigns are urgently required to increase
screening rates for at-risk individuals and to
facilitate early diagnosis and prompt treatment,
thereby reducing morbidity and improving
survival.
Note: What women think about Cervical cancer
APPROACHES TO CONTROLLING
INFECTION-RELATED CANCERS
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Attempts to reduce infection-related cancers
should involve efforts to prevent infection and
control ongoing disease processes.
Using knowledge of infectious disease processes
in cancer causation will further help in guiding
intervention, and the benefit must go beyond
individual cases to have impacts on the
population.
APPROACHES TO CONTROLLING
INFECTION-RELATED CANCERS - SOME EVIDENCE
VACCINE APPROACH
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There are two approaches to vaccination, one
aiming at prevention of infection (prophylactic)
and the other aiming at prevention of disease
development following infection (therapeutic).
ANTIBACTERIAL
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APPROACH
A prototype of an anti bacterial approach to
cancer prevention is treatment of helicobacter
pylori (H pylori). It is over two decades since the
discovery of H pylori as the cause of gastric ulcers
and cancer. Early H pylori eradication is known
to lead to decreased risk of gastric cancer in
patients with peptic ulcer diseases
Effective treatment with antibiotics in
combination with good hygiene could decrease
gastric cancers.
ANTIVIRAL APPROACH
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Currently several antiviral drugs are in use in
the treatment of chronic HBV infection
worldwide
Antiviral therapies have been shown to delay
progression of cirrhosis and lower the incidence
of HCC, thus improving long-term survival.
(another example: AIDS associated malignancies is a major complication
associated with AIDS patients upon immunosuppression who pose
markedly increased risk of developing cancers. Through antiretrovirals
therapy (ARV), the malignant complications due to HIV-1 infection have
decreased in developed countries.
CERVICAL CANCER BURDEN WORLDWIDE
Every minute a woman is diagnosed with cervical cancer.1
Every 2 minutes a woman dies of cervical cancer.1
Every one hour the Middle East loses a
woman for cervical cancer.2
NA + Europe
Asia
75,000
266,000
36,000
143,000
Africa
Latina
79,000
72,000
62,000
33,000
New cases per year: ~ 500,000
80% in developing countries = 2nd
cause of cancer death in women
Deaths per year: ~ 270,000
1-Ferlay J, et al. GLOBOCAN 2002 Cancer Incidence, Mortality and Prevalence Worldwide. IARC CancerBase; Lyon, 2004
2Parkin M, Bray F, Ferlay J, Pisani P. Global Cancer Statistics, 2002. CA Cancer J Clin 2005; 55:74–108.
GOVERNMENT OF DUBAI- DUBAI HEALTH AUTHORITY
DUBAI CENTRAL CANCER REGISTRY
CERVICAL CANCER STATISTICAL REVIEW 2010-2011
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The total Number of Cervical Cancer cases registered during the
period 2010-2011 were 38 cases,
HPV cancers
Highest burden in cervical cancer
HPV related cancer in women
527,100 cases WW/year
492800
HPV related cancer in men
33,800 cases WW/year
5100
13000
5200
10500
1100
2900
14300
16000
90% of HPV cancer in women
are cervical cancers
Adapted from Parkin DM, Bray F. Vaccine. 2006;24 Suppl 3:S11-25
25
HPV and Cervical Cancer
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HPV infection is common – skin/skin contact in genital
mucosa
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50-80% of sexually active women will acquire an HPV
infection in their lifetime
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50% of the HPV infection will be oncogenic
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Natural infection does not reliably protect against
subsequent infection: ~50% of women develop no
measurable antibody response after HPV infection 1–
2 When detectable, serum antibody levels are
relatively low
Wallboomers JM et al. J. pathol 1999; 189:12-9
Ferlay J et al. Globocan 2002. IARC 2004;
Yang BH et al. Int J Cancer 2004; 109: 418–24;
Sankaranarayanan R et al. WHO Bulletin 2001; 79: 954–62;
Baseman JG et al. J Clin Virol 2005; 32 Suppl 1; S1624;
Brown DR et al. J Infect Dis 2005; 191: 182–92
Bosch FX et al. J Natl Cancer Inst Monogr 2003; 313;
CERVICAL CANCER INTERVENTIONS FOR
PREVENTION
HPV VACCINES
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HPV, is related to cervical cancer . HPV vaccines are
highly effective in preventing infection and
precancerous lesions in women, and the quadrivalent
vaccine has an extended efficacy to a number of
conditions such as genital warts in men and women
and precancerous anal lesions in men.
Other HPV-related cancers that potentially can
benefit from this vaccine include oropharyngeal
cancers and HPV-related penile cancers. The focus is
already turning to these other cancers in developed
countries, where cervical screening is effective,
causing re-evaluation of male HPV immunisation.
HBV VACCINES
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Vaccination against HBV, the cause of chronic
liver diseases such as liver cancer, is a prototype
of the former approach. It has already been
shown to be very successful and a leading
example of a new direction for controlling cancers
Since its introduction there has been a marked
reduction in chronic liver disease including
hepatocellular carcinoma.
HBV vaccination is already serving as a model
for the global control of another important viral
cause of cancer
EVEN BREAST CANCER
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The most common cancer worldwide among women is breast
cancer. The initiation, promotion, and progression of this
cancer result from both internal and external factors. The
International Agency for Research on Cancer stated that
members of the herpesvirus, polyomavirus, papillomavirus,
and retrovirus families definitely associate with breast cancer.
It is apparent that more effort needs to be devoted to assessing
the role of these viruses in carcinogenesis, by characterizing
additional confounding and synergistic effects of carcinogenic
factors.
It is proposed that preventing and treating infections may
eliminate certain types of cancers.
Review : Role of viruses in the development of breast cancer
Kenneth Alibek12, Ainur Kakpenova1*, Assel Mussabekova1, Marzhan Sypabekova1 and Nargis Karatayeva1
Infectious Agents and Cancer 2013, 8:32
CANCER CONTROL STRATEGY: THE
GOAL…..
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Reducing incidence of cancer
in the country
Detection of cancer at earliest
possible time
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Providing equitable access to care
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Enhancing patient quality of life
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Ensuring high quality of cancer control services
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International standards of best practice
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Stimulating high-quality research on all aspects of cancer control
Key to Reducing Cancer Burden
CANCER CONTROL STRATEGY
 The
development and implementation of a
cancer control strategy is the most effective
means of reducing the incidence and impact of
cancer, and improving the quality of life of
those living with cancer.
 Focus
on the entire cancer care continuum :
REFERENCES
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WHO, 2002, National cancer control programs, Policies and managerial
guidelines, 2nd edition
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National cancer forum: A Strategy for Cancer Control in Ireland, 2006.
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Cancer control policy in Australia: Australia and New Zealand Health
Policy 2006, 3:12
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Canadian Strategy for Cancer Control: A provincial cancer control policy
framework, 2010
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WHA57.17 2004, WHO global strategy on diet, Physical Activity and
Health.
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Review : Role of viruses in the development of breast cancer Kenneth
Alibek12, Ainur Kakpenova1*, Assel Mussabekova1, Marzhan
Sypabekova1 and Nargis Karatayeva1 - Infectious Agents and Cancer
2013, 8:32
An analysis of the health status of the United Arab Emirates: the ‘Big 4’
public health issues. Institute of Public Health, College of Medicine and
Health Sciences, United Arab Emirates University, School of Public
Health, Loma Linda University, California, Dubai Health Authority,
Dubai, United Arab Emirates – 5 Feb 2013
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