Download 9.5 Technical paper on the importance of including oral cancer as a

Technical Working Group Meeting on Regional Action Plan
and Targets for Prevention and Control of
Noncommunicable Diseases
Bangkok, Thailand, 11-13 June 2013
NCDs AND ORAL CANCER
RATIONALE FOR INCLUSION IN
SEAR NCD ACTION PLAN AND VOLUNTARY TARGETS
Document prepared for WHO SEARO by:
Dr. Habib Benzian
The Health Bureau Ltd
Consultants for Global Health
The Little Barn, Haversham Manor
Haversham, MK19 7DZ
United Kingdom
Mobile: +49 179 7825 420
[email protected]
Updated version 31.5.2013
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1.
BACKGROUND & CONTEXT
The WHO Regional Office for South-East Asia (SEARO) convened a Regional Consultation to
Develop a Regional Strategic Action Plan with Indicators and Targets for Prevention and Control of
NCDs in SEA Region during 25–27 February 2013 in New Delhi, India. The participants provided
inputs for the draft Regional Action Plan (2013–2020) and discussed the regional indicators and
voluntary targets for prevention and control of noncommunicable diseases (NCDs). The proposed nine
global targets were confirmed for the region; in addition participants highlighted the need for
addressing common cancers such as cervical cancer and oral cancers, as well as indoor air pollution.
A small technical working group was tasked to revise the draft Regional Strategic Action Plan, the
indicators and targets for consideration of the Regional Committee in September 2013.
This document provides the rationale for inclusion of oral cancer in the Regional Strategic NCD Action
Plan as requested during the Regional Consultation. The document will be discussed in a meeting of
the technical working group in Bangkok in June 2013.
2.
WHY SHOULD ORAL CANCER BE INCLUDED IN THE VOLUNTARY
TARGETS FOR SEA REGION?
There are clearly defined arguments to support the inclusion of oral cancer in the voluntary targets of
the Regional Strategic Action Plan for the Prevention and Control of NCDs.
1. The SEA Region is facing a very specific oral cancer burden that differs from other world
regions, mainly due to culturally determined practices of tobacco use and habitual chewing of
carcinogenic substances. Oral cancer is a significant public health problem for a number of
countries in the SEA Region, ranking 2nd for men, 6th for women among all cancers. Oral
cancer is the most prevalent cancer for men in India.
2. Oral cancer shares risk factors and determinants that are common to other NCDs, such as
tobacco use, high alcohol consumption, nutritional deficits, viral infections, poor (oral) hygiene
and genetic dispositions (among other factors). The policy basis for including oral cancer in
the NCD context is solid with a number of WHO resolutions supporting a focus on oral cancer
among other oral diseases. Therefore, the inclusion of oral cancer is in coherence with major
NCD strategies.
3. There is ample scientific evidence related to different aspects of oral cancer, indicating good
to medium effectiveness and feasibility of prevention and screening, early detection and
referral, as well as guidelines for clinical care and rehabilitation.
4. Examples of successful public health strategies, both in high-, middle- and low-income
countries indicate feasibility of integrating oral cancer prevention and care into a primary
health care context.
5. Data on oral cancer is available through national, regional and global epidemiological
surveillance mechanisms, though oftentimes with limitations due to general weakness of
national disease surveillance and/or cancer registration systems in particular.
2.1.
PUBLIC HEALTH SIGNIFICANCE IN THE SEA REGION
Oral cancers, which are predominantly squamous cell carcinomas (>90%), are a significant public
health problem worldwide. Analysing the problem through a variety of indicators and statistical
methods reveals that the SEA Region carries the biggest burden of all world regions and comprises
some of the countries with highest rates for incidence, mortality and crude risk as well as absolute
case numbers globally, both for men and women. Similarly, the key risk factors for oral cancer are of
particular relevance in the region.
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EPIDEMIOLOGY
Some summary statistics (for full details see section 6. Tables and Figures):
Table 1: Summary statistical characteristics of oral cancer in the SEA Region (GLOBOCAN2008)
Indicator (per year) all SEAR countries Men
Women
Both
8.4
5.0
6.7
59,001
35,399
95,400
Incidence, percent of all cancers
7.9
4.0
5.8
Mortality, age-standardised (W) per 100.000 population
5.7
3.3
4.5
39,345
23,608
62,953
Mortality, percent of all cancers
6.9
4.2
5.6
Ranking (by case numbers)
nd
th
5th
Incidence, age-standardised (W) per 100.000 population
Incidence, cases numbers
Mortality, case numbers
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6
Other key epidemiological facts for oral cancer:

Worldwide 6th most common cancer, estimations of 400,000-700,000 new cases per year.

India: Oral cancer ranks 2nd for men, 4th for women and 3rd for both; over 100,000 new cases
every year; highest incidence (40-50/100,0000) in men (60+ age group); most prevalent
cancer for men; doubling incidence rate between 1985 and 2006.

Sri Lanka: highest overall incidence for males in the region (16.5); as high as 100/100,000 for
age group 60+.

5-yr survival rates are generally low (around 40% in India, generally below 50% compared to
50-70% in high-income countries) and have remained largely unchanged over the last
decade.

Low early detection rates, late presentation of cases and delayed referral rates contribute to
low survival rates, together with inadequate oncology care.

Clear gradients for all indicators along socio-economic status with higher rates, later diagnosis
in more advanced tumour stages and lower survival rates among poor and disadvantaged
population groups.

Significant inequalities between men and women in terms of disease burden (due to
differential exposure to key risk factors), though indicators among women are generally high
and increasing; specific inequalities for several ethnic groups and minorities due to cultural
practices and risk exposure (i.e. reverse smoking).

Predictions for the region: doubling of rates by 2030 based on long latency time after risk
exposure, persisting high rates for various risk factors and projected demographic
developments.
In some statistics oral cancers are grouped together with naso-pharyngeal, other pharyngeal and lip
cancer under the term “head and neck cancer” (usually excluding skin cancer). Separation of these
statistics would result in even higher oral cancer morbidity and mortality rates.
RISK FACTORS
Oral cancer shares key risk factors and determinants common to other major NCDs:

Tobacco
Tobacco use in all forms (including bidis, smokeless tobacco and water pipes) is the single
most important risk factor for oral cancer with a clear causal dose-response relationship.
There is a belief that tobacco products are beneficial to oral health and several toothpastes
and other oral care products are produced on this basis containing tobacco.

Other carcinogenic substances (areca nut, betel quid, pan masala, gutka etc)
Specific risks arise from the use of other carcinogenic substances: “Betel quid with or without
chewing tobacco is common in South Asia. It contains leaves of the Piper betel vine, smeared
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with lime paste (aqueous calcium hydroxide), chopped nuts of the Areca catechu palm
(chrysalidocarpus lutescens) tree, and condiments including astringent catechu bark extract
(acacia catechu), cardamom, clove, and sweeteners. In South/Southeast Asia, it is mainly
consumed with tobacco; in China and Taiwan, it is mainly chewed by itself, though most users
smoke cigarettes. In South Asia, there has been a recent, major increase in pan masala and
gutka consumption. These recent, commercialized, dry-packaged versions of betel quid do not
include betel leaves. They are mainly produced in India and exported to over 30 countries.
Areca nut alone is formally recognized by the IARC as carcinogenic; the dangers are much
enhanced if tobacco is included. It is highly addictive. Betel quid is the major risk factor for
OPMD and oral cancer in Sri Lanka, a fact of which the population is largely unaware.”
(Johnson et al 2011)

Alcohol
Harmful use of alcohol is a major risk factor for oral cancer, particularly when combined with
smoking, which results in a multiplication of risk. A clear dose-response relationship is
established. Like for smoking, alcohol use as a risk factor is closely linked to socio-economic
deprivation.

HPV Infection
Emerging evidence suggests that infection with HPV16 and 18 are independent or co-factors
for certain oral cancers (oropharynx and posterior tongue), particularly in younger Western
populations without other risk factors. HPV-positive oral cancers have been reported at
varying rates (20-70%) and no clear conclusions are possible to date with regard to public
health consequences for SEAR countries. Studies investigating the impact of HPV
vaccinations against cervical cancer are under way.

Poor oral hygiene
The long-held belief that poor oral hygiene contributes to an increased risk for developing oral
cancer has not been confirmed; yet a general neglect of hygiene (including oral) may be
symptom of general socio-economic deprivation and related risk factors. Specific issues
related to oral health and hygiene (such as sharp edges from a decayed tooth or broken
denture) can cause malignancy through chronic mechanical irritation.

Nutrition
There is clear evidence for a link between under- and malnutrition and cancer, including oral
cancer. Food rich in antioxidants from fruit and vegetables, a balanced vitamin intake together
with a diet low in animal fat contribute to lower (oral) cancer rates. Nutrition, like other risk
factors, is closely linked to socio-economic status and other determinants of health.

Industrial and indoor pollution
Both industrial and indoor air pollution contribute to head and neck cancer development. For
those working or living near certain industries with contact to hydrocarbons and cement and
those affected by indoor pollution have higher risks of to be contracted with chronic
inflammation of the upper aero-digestive tract and malignancy.
However, there also remains an influence of genetic disposition for the development of oral cancer
that is difficult to fully quantify across different populations.
2.2.
COHERENCE WITH MAJOR STRATEGIES
The inclusion of oral cancer in the NCD context builds on a sound global and regional policy basis,
which recognizes the specific challenges related to oral cancer prevention and control. In May 2013
the World Health Assembly adopted the Global Action Plan for the Prevention and Control of
Noncommunicable Diseases 2013-2020, which explicitly addresses oral diseases and oral cancer in
particular. The table in Appendix 3/Objective 4/p.50 lists various cancer control policy options for
Member States. Among the options listed the document states:

“Oral cancer screening in high-risk groups (e.g. tobacco users, betel-nut chewers) linked with
timely treatment (FOOTNOTE: Screening is meaningful only if associated with capacity for
diagnosis, referral and treatment)” (A66/A/CONF./1.rev1 p.50)
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Furthermore, the document states that, “increasingly cancers, including some with global impact such
as cancer of the cervix, liver, oral cavity and stomach, have been shown to have an infectious
aetiology. In developing countries, infections are known to be the cause of about one fifth of cancers
[…]. Strong population-based services to control infectious diseases through prevention, including
immunization (e.g. vaccines against hepatitis B, human papillomavirus, measles, rubella, influenza,
pertussis, and poliomyelitis), diagnosis, treatment and control strategies will reduce both the burden
and the impact of noncommunicable diseases.” (A66/A/CONF./1.rev1 p.41).
Key examples of other WHO resolutions and major international conference consensus documents
related to oral cancer are:
WHA58.R22 2005 Cancer Prevention and Control


…Urges Member States to…give “priority to tumours, such as cervical and oral cancer, that
have a high incidence in low-resource settings and are amenable to cost-effective
interventions”.
…Recommendations for outcome-oriented objectives…“National health authorities may wish
to consider the following outcome-oriented objectives for their cancer control programmes,
according to type of cancer: “Cancers amenable to early detection and treatment (such as
oral, cervical, breast and prostate cancers): to reduce late presentation and ensure
appropriate treatment, in order to increase survival, reduce mortality and improve quality of
life”
WHA60.R17 2007 Oral Health: Action Plan for promotion and integrated disease prevention

…Urges Member States to…”take steps to ensure that prevention of oral cancer is an integral
part of national cancer-control programmes, and to involve oral health professionals or
primary health care personnel with relevant training in oral health in detection, early diagnosis
and treatment”.
Political Declaration of the UN High-level Summit on Prevention and Control of Non-communicable
Diseases 2011

Article 19: ….Member States recognise ...”that renal, oral and eye diseases pose a major
health burden for many countries and that these diseases share common risk factors and can
benefit from common responses to non-communicable diseases”.
Crete Declaration on Oral Cancer Prevention 2005 (co-sponsored by WHO, International Congress on
Oral Cancer, Hellenic Cancer Association, Hellenic Association for the Treatment of Maxillofacial
Cancer)

…The following areas of work should be strengthened:
(a) Provision of systematic epidemiological information on prevalences of oral cancer and
cancer risks in countries, particularly in the developing world.
(b) Promotion of research into understanding biological, behavioural and psychosocial
factors in oral cancer, emphasizing the inter-relationship between oral health and general
health.
(c) Integration of oral cancer information into national health surveillance systems which
record chronic diseases and common risk factors.
(d) Dissemination of information on oral cancer, prevention and care through every possible
means of communication.
(e) Active involvement of oral health professionals in oral cancer prevention through control
of risk factors such as tobacco, alcohol and diet.
(f) Training of primary health workers in screening and provision of first-level care in oral
cancer
(g) Access to health facilities and provision of systems for early detection and intervention,
oral health care and promotion for the improvement of quality of life of people affected by
oral cancer.
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2.3.
AVAILABILITY OF EVIDENCE-BASED, EFFECTIVE AND FEASIBLE
PUBLIC HEALTH STRATEGIES
Major implementation strategies in the NCD context include the reduction of common risk factors, the
integration of determinants of health, the focus on prevention as well as addressing NCDs in a primary
health care context. The main strategies related to oral cancer are fully aligned with these approaches,
though tertiary prevention (clinical care/surgery) requires a rather specific skill-set and appropriate
facilities, which on the other hand are not much different to other oncology treatment requirements.
PRIMARY PREVENTION
Primary prevention remains the key approach to oral cancer control – reducing exposure to risk
factors and promoting healthy behaviour are the cornerstones of oral cancer prevention. Focussing on
enacting effective tobacco control policies, building capacity among (oral) health professionals for
effective behaviour change interventions and promoting healthy lifestyles through an inclusive and
appropriate population approach will show positive results across a number of NCDs, including oral
cancer.
SECONDARY PREVENTION
Secondary prevention for oral cancer mainly consists of screening for premalignant lesions and early
stages of oral cancer, identifying them correctly, and in providing emergency care (if required) and
rapid referral to specialist care if a suspicious condition has been diagnosed. The basic principle is,
like with screening for other diseases, that early intervention improves patient outcomes and reduces
subsequent treatment cost.
Screening can include self-examination, oral visual inspection, adjunctive tests to visual inspection
(such as toluidin staining and fluorescence), salivary testing and exfoliative cytology. Evidence
suggests that offering visual screening to populations at risk (smokers, users of alcohol or other
carcinogenic substances such as areca nut) is an efficient and cost-effective measure that reduces
mortality. The costs of screening in a large-scale programme in Trivandrum in India were 0.62US$,
while in the US costs were 84US$ per year (both programmes were considered cost-effective in terms
of disability-adjusted life years (DALYs) and disease cost averted). There is no justification for
adjunctive tests in addition to visual examination since they only increase cost and may not be feasible
in a large-scale context as concluded in a recent Cochrane review. The advantage of simple visual
examination is that trained non-specialist health personnel can perform it with sufficient reliability in
terms of sensitivity and specificity, thus further reducing the costs of screening. The International
Agency for Research on Cancer (IARC), a WHO agency based in Lyon (France), has conducted and
evaluated screening programmes for oral and cervical cancer and has produced a number of manuals
and documentation supporting the training and implementation of visual oral cancer screening.
TERTIARY PREVENTION
The survival and quality of life after oral cancer diagnosis largely depend on the availability and
appropriateness of clinical care and rehabilitation. Despite advances in cancer diagnostics, staging,
surgical intervention, multi-disciplinary care as well as chemo- and radiotherapy, survival rates for oral
cancer have remained virtually unchanged.
“Delay in presentation is attributed to lack of awareness of early symptoms and access to health
systems. Professional delay is related to failure of primary care professionals to recognize signs and
symptoms indicative of cancer. The main factors associated with late presentation and diagnosis are
gender, dental status, alcohol consumption, SES, and tumour location, especially at less visible
surfaces of the oral cavity. Treatment of oral cancer should be initiated quickly, but access to centers
providing multidisciplinary treatment is limited in developing countries. Facilities for sophisticated
reconstruction, advanced radiotherapy, and medical oncology are rare. The high cost of modern
cancer care is unaffordable in health systems with low resources, and high demand on facilities leads
to delay, contributing to upstaging of disease and decreased survival” (Johnson et al. 2011).
Furthermore, in most low- and middle-income countries there are no comprehensive treatment
guidelines for oral cancer, a lack of training opportunities for surgeons, specialists and teams.
“Treatment will never represent the route to reduced incidence” (Gupta et al. 2013).
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2.4.
EVIDENCE OF ACHIEVABILITY AT THE COUNTRY LEVEL
PRIMARY PREVENTION
There is good evidence for achievability of policies and legislation related to curbing key NCD risk
factors, in particular tobacco use and alcohol regulations.
SECONDARY PREVENTION
Screening programmes for oral cancer have been successfully implemented in India, Sri Lanka,
Bangladesh, Thailand and other low-income countries outside of the region. These programmes
showed that screening of high-risk populations is possible, leads to reduced mortality, and results in
increased awareness and training in health professionals. The large-scale programme in
Trivandrum/Kerala involved more than 200,000 patients observed over a nine-year period and
concluded that even under a resource-constrained developing country context visual screening for oral
cancer is a cost-effective public health measure if targeted at high-risk populations. Similar findings
are reported from the US. However, screening is only useful if appropriate care is available to patients
identified with oral cancer or precancerous lesions.
TERTIARY PREVENTION
The capacity of health systems in the SEA Region with regard to cancer care, and more specifically
oral cancer care, varies considerably. Oral cancers are often taken care of by general or plastic
surgeons, although the speciality of maxillo-facial surgery is recognized in most countries of the
region. The numbers of the oral health professional workforce are generally low, and updated statistics
about practicing maxillo-facial specialists for each country are not available. The same applies to other
oncology specialists, and to advanced diagnostic capabilities and availability of dedicated treatment
centres for tertiary care. While India reports 1500 specialised oncologists, Bhutan reports just two in
the country.
2.5.
AVAILABILITY OF DATA COLLECTION INSTRUMENTS AND BASELINE
Functioning and reliable cancer registration is key to sound epidemiological data on all cancers,
including oral cancers. The IARC is promoting the establishment and the strengthening of existing
national cancer registration systems and has opened a regional hub in New Delhi last year to
coordinate efforts in the SEA Region. While some countries have relatively well functioning cancer
registries (India, Sri Lanka, Thailand) others have weak or no systems at all (Bangladesh, East Timor),
resulting in poor data on (oral) cancer so that policy decisions must be based on extrapolations.
Baseline data is available from IARC GLOBOCAN 2008, however, for some countries of the region the
data are based projections (i.e. East Timor). With regard to oral cancer risk factors the situation is
much better thanks a number of surveillance instruments related to NCDs and common risk factors.
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3.
POSSIBLE VOLUNTARY TARGET AND INDICATORS
VOLUNTARY REGIONAL TARGET
25% REDUCTION OF PREMATURE MORTALITY FROM ORAL CANCER BY 2025
The formulation of this target is in line with the approach and wording chosen in the Global NCD
Action Plan and reflects overall changes in mortality, which can result from both, changes in incidence
through reduction of risks as well as from improved health system performance. Given the predicted
increases of oral cancer cases by 2030 it seems ambitious, but with the relatively high incidence rates
and huge population numbers already small improvements may result in significant changes in
mortality rates. Furthermore, oral cancer benefits from all approaches to reducing risk factors in the
context of the other NCDs so that a considerable spill-over effect from these interventions can be
expected.
For discussion and decision of the technical expert group a set of indicator options are proposed as
follows (modified from Hobdell et al. 2003 – Global Goals for Oral Health by 2020):
INDICATOR OPTION 1
35% RELATIVE REDUCTION OF AGE-STANDARDISED OVERALL ORAL CANCER INCIDENCE
The formulation of this indicator is in line with the approach and wording chosen in the Global NCD
Action Plan. Reduction of incidence can result from decreased exposure to risk factors, either through
changes in the environment and protective legislation or through individual behaviour and lifestyle.
Age-standardised weighted incidence of oral cancer is routinely collected at regular intervals and
collated on the national, regional and global level. A relative reduction of 35% compared to baseline
(GLOBOCAN 2008) takes into account that incidence needs to be reduced more in order to achieve a
relative mortality reduction of 25%. This is not unrealistic given the multitude of interventions aiming at
reducing risk factor exposure, particularly tobacco control.
INDICATOR OPTION 2
50% INCREASE OF VISUAL SCREENING FOR INDIVIDUALS AT RISK FOR ORAL CANCER
This indicator focuses on the important role of early detection through screening of populations at risk
for oral cancer. The challenge is, however, the data collection and documentation, as well as the
absence of a reliable baseline. One way could be to establish sentinel sites for long-term evaluation to
follow-up on screening interventions.
INDICATOR OPTION 3
50% INCREASE OF HEALTH CARE PROVIDERS COMPETENT TO DIAGNOSE ORAL CANCER AND
ENSURE RAPID REFERRAL
This indicator supports the screening and early detection of oral cancer, as well as the effective
referral to appropriate care. Data collection could be done on the basis of attendance figures of
continuing professional education courses, or through the selection of sentinel sites for long-term
evaluation. Challenges with this indicator are that the competency of providers to screen effectively is
no guarantee that they are in fact screening as part of comprehensive screening interventions. Also,
screening is only appropriate if adequate care is available.
INDICATOR OPTION 4
30% INCREASE OF EARLY DETECTION OF ORAL CANCER
This indicator again supports screening and early detection, but the data collection can be done at the
facility where the patient presents for first diagnosis. It requires that the cancer registration system is
also documenting the staging of the neoplasm.
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4.
GENERAL REMARKS & CONCLUSIONS
Existing challenges and current shortcomings in terms of surveillance, prevention and control of (oral)
cancer should rather be seen as opportunities to improve and strengthen the respective health
system. By developing appropriate and pragmatic solutions aiming at inclusiveness and universal
coverage in a primary health care context these challenges can be addressed. This includes the
development of a dedicated research agenda to address the gaps in knowledge about oral cancer in
the SEA Region.
Though oral cancer care requires special training, particularly maxillo-facial surgery, the general
challenges related to primary, secondary and tertiary prevention are not very different from other types
of cancer. Given the complexity and cost-intensiveness of tertiary prevention a strong focus should be
on primary and secondary prevention, including reduction of common risk factors. Similarly to all other
cancers, a significant increase in absolute case numbers is to be expected over the next decades due
to demographic developments and the long lead-in time of oral cancer..
In conclusion, the analysis of the epidemiological evidence, the available public health approaches,
the policy basis, the feasibility of country implementation and continued monitoring through data
collection clearly shows that oral cancer is of great and unique relevance for the SEA Region,
particularly for India, Bangladesh, Sri Lanka, Nepal and Thailand. Including oral cancer would be
completely in line with the policy template of the Global Action Plan on Prevention and Control of
Noncommunicable Diseases 2013-2020. The inclusion of oral cancer in the Regional Strategic Action
Plan for Prevention and Control of NCDs as an additional voluntary regional target would be a signal
to Member States, but also to other countries and world regions, that oral diseases can and must be
integrated in the NCD context and that addressing them in this context contributes to reducing the
overall NCD burden.
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5.
GLOSSARY OF TERMS
Oral Cancer
The definition of oral cancer varies, WHO uses the definition proposed by the International Agency for
the Research on Cancer (IARC). This classification is the basis for the GLOBOCAN project, which
provides contemporary estimates of the incidence of, and mortality, prevalence and disability-adjusted
life years (DALYs) from major type of cancers, at national level, for 184 countries of the world.
Diagnoses are encoded according to the International Classification of Diseases (ICD10). The latest
data available is from GLOBOCAN 2008, released in 2011.
Table 2: ICD 10 Cancer localisations
ICD 10 Diagnosis
Cancer localisation
C00
Lip
C01-02
Tongue
C03-06
Mouth
C07-08
Salivary glands
C09-14
Pharynx
GLOBOCAN defines ICD C00-C08 as oral cancer, while other cancer statistics also include cancer of
the pharynx (ICD C09-14) under the term oro-pharyngeal or head-and-neck cancer, thus resulting in
different epidemiological figures and difficulties in comparison.
Incidence
Incidence is the number of new cases arising in a given period in a specified population. This
information is collected routinely by cancer registries. It can be expressed as an absolute number of
cases per year or as a rate per 100,000 persons per year (see Crude rate and ASR below). The rate
provides an approximation of the average risk of developing a cancer.
Mortality
Mortality is the number of deaths occurring in a given period in a specified population. It can be
expressed as an absolute number of deaths per year or as a rate per 100,000 persons per year.
Prevalence
The prevalence of a particular cancer can be defined as the number of persons in a defined population
who have been diagnosed with that type of cancer, and who are still alive at the end of a given year.
Complete prevalence represents the number of persons alive at certain point in time who previously
had a diagnosis of the disease, regardless of how long ago the diagnosis was, or if the patient is still
under treatment or is considered cured. Partial prevalence, which limits the number of patients to
those diagnosed during a fixed time in the past, is a particularly useful measure of cancer burden.
Prevalence of cancers based on cases diagnosed within one, three and five years are presented as
they are likely to be of relevance to the different stages of cancer therapy, namely, initial treatment
(one year), clinical follow-up (three years) and cure (five years). Patients who are still alive five years
after diagnosis are usually considered cured since the death rates of such patients are similar to those
in the general population. There are exceptions, particularly with regard to breast cancer.
Prevalence is presented for the adult population only (ages 15 and over), and is available both as
numbers and as proportions per 100,000 persons.
Disability-adjusted life years (DALYs)
In establishing priorities for cancer control, information about both fatal and non-fatal cancer-related
outcomes is necessary. Disability-adjusted life years (DALYs) is a key measure for such purposes in
that it links the burden of cancer mortality in society with the degree of illness and disability among
11
cancer patients and long-term survivors.
DALYs and its two components,- years of life lost (YLLs) and years lived with disability (YLDs)-, are
presented within GLOBOCAN 2008 for all ages combined, and are available both as numbers and as
standardised rate per 100,000 persons.
Crude rate
Data on incidence or mortality are often presented as rates. For a specific tumour and population, a
crude rate is calculated simply by dividing the number of new cancers or cancer deaths observed
during a given time period by the corresponding number of person years in the population at risk. For
cancer, the result is usually expressed as an annual rate per 100,000 persons at risk.
Age-standardised rate (ASR)
An age-standardised rate (ASR) is a summary measure of the rate that a population would have if it
had a standard age structure. Standardization is necessary when comparing several populations that
differ with respect to age because age has a powerful influence on the risk of cancer. The ASR is a
weighted mean of the age-specific rates; the weights are taken from population distribution of the
standard population. The most frequently used standard population is the World Standard
Population. The calculated incidence or mortality rate is then called age-standardised incidence or
mortality rate (world). It is also expressed per 100,000. The world standard population used in
GLOBOCAN is as proposed by Segi [1] and modified by Doll et al. [2]. The age-standardised rate is
calculated using ten age-groups. The result may be slightly different from that computed using the
same data categorised using the traditional five-year age bands.
Cumulative risk
Cumulative incidence/mortality is the probability or risk of individuals getting/dying from the disease
during a specified period. For cancer, it is expressed as the number of new born children (out of 100,
or 1,000) who would be expected to develop/die from a particular cancer before the age of 75 if they
had the rates of cancer observed in the period in the absence of competing causes.
(Source: IARC/GLOBOCAN 2008 http://globocan.iarc.fr)
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6.
TABLES AND FIGURES
Table 3: Most common cancers according to world regions
Source: Are C, Rajaram S, Are M, Raj H, Anderson BO, Chaluvarya Swamy R, Vijayakumar M, Song T, Pandey
M, Edney JA, Cazap EL. A review of global cancer burden: trends, challenges, strategies, and a role for
surgeons. J Surg Oncol. 2013;107(2):221-226.
Figure 1: Age-standardised (W) incidence of cancers in the SEA Region
Incidence/100 000 population
–30
–20
–10
0
10
20
30
Lung
Breast
Cervix uteri
Lip/oral cavity
Oesophagus
Stomach
Colorectum
Liver
Non-Hodgkin lymph
Larynx
Ovary
Bladder
FEMALES
MALES
Brain/Nervous
Leukaemia
Thyroid
Hodgkin’s lymphoma
Kidney
Prostate
Corpus uteri
Testis
Gallbladder
Pancreas
Lung and oral
cancer in males
and breast and
cervical cancer in
females are most
common
Source: World Health Organization (WHO), Office for South-East Asia. Noncommunicable Diseases in the SouthEast Asia Region: Situation and Response 2011. New Delhi: WHO/SEARO; 2011
13
Figure 2: Estimated DALYs for oral cancer for different world regions
(Source: IARC/GLOBOCAN 2008 http://globocan.iarc.fr)
Figure 3: Estimated cumulative mortality (%) for oral cancer
(Source: IARC/GLOBOCAN 2008 http://globocan.iarc.fr)
14
7.
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