cancer epidemiology and program implementation in low and middle income (lmi) countries: a lesson to...

8/8/2019 Cancer Epidemiology and Program Implementation in Low and Middle Income (LMI) Countries: A Lesson to Learn

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Cancer Epidemiology and ProgramImplementation in Low and Middle

Income (LMI) Countries:

A Lesson to Learn

David B. Thomas, MD, DrPH


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Outline of Talk

Cancers of major concern in LMI countries

Setting priorities for cancer control activities inLMI countries

Estimating the magnitude of the cancer problemand identifying high risk groups in LMI

Cancer registration in LMI

The role of epidemiology in the planning andevaluation of cancer control programs in LMIcountries


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Cancers of Major concern in Low and

Middle Income (LMC) Countries


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As a country transitions from a less

developed to a more developed countrycancer will become a more important

problem for 2 reasons:

Rates of most cancers increase with age, so asmore people live longer, more people will

enter the high risk age groups

Rates of many cancers increase as a

population develops a more western life

style


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Age Specific Mortality Rates ofColon Cancer in Japan


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Incidence Rates ofBreast Cancer in 9 Asian

Populations over Time


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In addition to becoming a greater

problem in the future, cancer will

be come a greater problem in

relation to other health problemsas these other health problems

come under control.


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Causes of Death in Thailand, China, South

Korea, and Belgium

(WHO, 2002)


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What are the most common

cancers in LMI countries now, andwhat will be the most common

cancers in the future?


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The 12 Most Common Cancers in the

Developed and Developing Regions of the

World, 2002


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The 12 Most Common Cancers in the

Developed and Developing Regions of the

World, 2002


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The Most Frequent Cancers in LMI

CountriesMales

Now

Lung

Stomach

Liver

Esophagus

In the Future

Lung

Prostate

Colorectal

Bladder

Females

Now

Breast

Cervix

Stomach

Lung

In the Future

Breast

Colorectal

Lung

Corpus uteri


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Outline of Talk


Setting priorities for cancer control activities inLMI countries

Estimating the magnitude of the cancer problemand identifying high risk groups in LMI




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Setting Priorities for Cancer Control

Activities In planning for cancer control activities,

priorities must be set on the basis of:

The magnitude of the problem (What are the

most important cancer in the population?)

What can be done about the problem?

Primary prevention

Secondary prevention


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Primary Prevention:

Reduce the occurrence of the cancer by

reducing exposure to cancer causing agentsExamples:

Reduce smoking to prevent lung cancer

Reduce exposure to asbestos in the work place

to prevent mesothelioma

Vaccinate against human papilloma viruses to

prevent cervical cancer Vaccinate against hepatitis B virus to prevent

liver cancer


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Secondary Prevention:

Early detection of cancer followed by

attempts at curative treatment

Examples:

Mammographic screening for breast cancer

followed by effective treatment Pap smears for detection of cervical cancer

followed by effective treatment

Note: Before screening can begin, there must

be sufficient resources for diagnosticevaluation in those who screen positive, andtreatment of those found to have the cancer.


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Highest Priority for Cancer Control in

LMI Countries (Underlined)Males

Now

Lung

Stomach

Liver

Esophagus

In the Future

Lung

Prostate

Colorectal

Bladder

Females

Now

Breast

Cervix

Stomach

Lung

In the Future

Breast

Colorectal

Lung

Corpus uteri

Note: This is an example. The actual cancers of highest priority in Indonesia may

differ from these. If possible, priority for cancer control activities should be

established based on local data.


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Outline of Talk


Setting priorities for cancer control activitiesin LMI countries

Methods for assessing the cancer problemlocally




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Proportional Mortality ratios

Definition: The percentage of all deaths thatare due to various causes

Based on death certificates

Gives information on what the mostimportant causes of death are

Can be misleading due to:

under-reporting of deaths

misclassification of cause of death

the frequency of other causes of death


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Methods for Assessing the Cancer

Problem Locally

Proportional mortality ratios

Proportional incidence ratios

Mortality rates

Incidence rates


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Methods for Assessing the CancerProblem Locally



Mortality rates

Incidence rates


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What is needed in order to obtain accurate

mortality rates?

Accurate census of the population

Complete ascertainment of all deaths

Accurate information on cause of death

A statistical unit that can analyze the data

Note: Cancer mortality rates will show which cancers are the most

common causes of death. Cancers with the poorest prognosis will

be over-represented, and cancers with better prognosis will be

under-represented by mortality rates.


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Methods for Assessing the CancerProblem Locally



Mortality rates

Incidence rates


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What is needed in order to obtain accurate

cancer incidence rates?

Accurate census of the population

Complete ascertainment of all cancer cases bya population-based cancer registry

Accurate information on type of cancer

A statistical unit that can analyze the data


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Outline of Talk


Setting priorities for cancer control activitiesin LMI countries

Methods for assessing the cancer problemlocally




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Some Comments on Establishing a

Population Based Cancer Registry-1 With limited resources it is far better to

establish one or more good registries in

carefully selected areas than to attempt toregister all cancers in a large population

such as Indonesia

Selected areas can then serve as resourcesfor conducting epidemiologic studies and

evaluating cancer control programs


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Some comments on Establishing a

Population Based Cancer Registry-2

Criteria for choosing a population for a cancerregistry:

An accurate census, or the facilities and resourcesneeded to obtain accurate census information Large enough population to generate enough cancer

cases to provide stable incidence rates (1-2 million ) Small enough to be able to obtain information on all

of the cancer cases with the available resources. All cancers are treated in a single hospital, or just a

small number of hospitals People should not go out of the area for care

(although people may come into the area for care)


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Population Based Cancer-3 The level of cooperation of local offices of

vital statistics, health departments, hospitalsand pathology laboratories in the area mustbe considered

Consider populations of special interest:For example, different ethnic groups of

interest (e.g. in Indonesia, Javanese,Sundanese, Malays, Madurese, Chinese)

For example, populations with unusualexposures of interest (e.g. in areas withexposures to mines or petroleum refineries)


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Population Based Cancer-4

Establish a population based registry only if:

There are trained epidemiologist who willutilize the registry to answer relevantquestions

The important questions cannot be answeredby other means (such as hospital-based caseseries, or mortality statistics)

A population-based registry should only be

established if there is a stable source of

funding to ensure that the registry can be

maintained over a long period of time


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Some Comments on Establishing a

Population Based Cancer-5

A population-based registry is best

established in association with a healthdepartment, university, or research

institution so that the data can be

appropriately used for studies of cancer

etiology and cancer care, that provide

answers to questions that need to be

answered to inform decision makers.


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The Role of Epidemiology in The Planning

and Evaluation of Cancer Control Activities

Assess the magnitude of the problem and

identify the most important cancers (already

discussed) Identify high risk groups of people

Assist in designing programs so that they can

be rigorously evaluated

Evaluate success of cancer control programs

Primary prevention programs (prevention of disease)

Secondary prevention programs (reduction in deaths dueto the disease)


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Identification of High Risk Groups of people

People at high risk of disease (for primary prevention)

Identification of groups of people at high risk of getting thedisease (as discussed)

Identification of people at high risk of exposure to knowncarcinogenic agents

E.g. smokers (tobacco smoke), women with sexuallytransmitted diseases (HPV), certain industrial workers(asbestos miners, dye workers)

People at high risk of advanced disease (for secondaryprevention)

Identification of people without access to screeningfacilities

Identification of people who present with advanceddisease


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The Role of Epidemiology in The Planning

and Evaluation of Cancer Control Activities

Assess the magnitude of the problem and

identify the most important cancers (already

discussed)

Identify high risk groups of people

Assist in planning programs so that they can be

rigorously evaluated

Evaluate success of cancer control programs Primary prevention programs (prevention of disease)

Secondary prevention programs (reduction in deaths dueto the disease)


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Measurements of success of Primary and

Secondary Prevention Programs

Primary prevention programs Intermediate endpoint: reduction in exposure to a

carcinogen (e.g. smoking)

Ultimate goal: a reduction in the incidence of the disease

(very long term) Secondary prevention programs

Intermediate endpoints:

Down staging of disease at diagnosis

Increase in survival

Ultimate goal: a reduction in mortality due to thedisease (long term)

Note: a reduction in stage and an increase in survival can occurwithout a reduction in mortality.


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Examples of Planning and Evaluation

of Cancer Control Programs


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Two methods of Implementation and

Evaluation of Secondary PreventionPrograms

Feasibility project to determine whether:

the methods proposed for use in a screening

program are likely to be efficacious, and whether

implementation of the program is likely to be

successful.

Phased implementation of a screening programto determine if the program is efficacious


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An Example of a Feasibility Project:

Early Breast Cancer Detection Through

Clinical Breast Examination Training for

Midwives in Rural Jakarta, Indonesia

[Dr. Kardinah and colleagues]

Purpose: To determine whether training

midwives to perform CBE, and to teach

women BSE, can result in breast cancers

being diagnosed at an earlier stage Location: Sub-District of Koja in Jakarta

Population: 284,000 women eligible for screening

6 primary health clinics


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Midwives in Rural Jakarta (Cont.)

Step 1-Methods:

Volunteers recruit women to come to clinics for

screening Midwives perform CBE and teach BSE

Women are then independently screened bymammography

Women with a positive screening by any method areclinically evaluated and receive further diagnosticprocedures if indicated

Women who are found to have breast cancer aretreated


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Clinical Breast Examination Training

for Midwives in Rural Jakarta (Cont.)

Step 1-Evaluation:

Comparison of CBE to mammography:

Detection rates of breast cancer by CBE and by

mammography alone, and by both methods

False positive rates by each method alone, and by both

methods combined

Size and stage of tumors detected by each methodalone and by both methods

These results will indicate whether the screening

method used in the program (CBE) is likely to be

efficacious if successfully implemented.


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Midwives in Rural Jakarta (Cont.) Step 2-Methods:

If the results in step 1 are encouraging, they may

then attempt to recruit all of the women in thetarget population

Step 2-Evaluation:

Determine the % of women in the targetpopulation that are screened

If the percentage is high, then it can be concludedthat a larger program using the same methodscould also be successfully implemented

Note: The next logical step would then be to

initiate phased implementation


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Two methods of Implementation and

Evaluation of Secondary Prevention

Programs

Feasibility project to determine whether:

the methods proposed for use in a screening

program are likely to be efficacious, and whether

implementation of the program is likely to be

successful.

Phased implementation of a screening programto determine if the program is efficacious


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An Example of Phased Implementation:

Breast Cancer Screening by Opportunistic

Mammography plus CBE in Colombia-1[Dr. Raul Murillo and colleagues]

Primary health care centers in Bogota were randomized to

either opportunistic screening centers or control centers

Women eligible for care in the centers that were

randomized to screening are offered mammography and CBE

when they come to the health center for their medical care.

Those who accept are screened.

Women eligible for care in the control centers are notoffered screening, but they are offered educational material

on breast cancer when they come to the health center for

their medical care. Those who receive the informational

material are pseudo-screened.


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Breast Cancer Screening by OpportunisticMammography plus CBE in Colombia-2

[Dr. Raul Murillo and colleagues]

A system has been developed to identify allbreast cancers that occur in women in both

groups

Special training is given to medical personnel so

breast cancers that develop in women in bothgroups are diagnosed, staged, and treated in

the same manner, and according to BHGI

guidelines


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Breast Cancer Screening by Opportunistic



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An Example of Phased Implementation: Breast

Cancer Screening by Opportunistic


Breast cancers detected by screening will be comparedto the cancers that occur in the pseudo-screened group

on TNM staging to determine the efficacy of thescreening method in down-staging at diagnosis.

The percentage of women in the intervention arm whoare screened will be calculated to estimate the

coverage of the target population All of the cancers in the intervention and control arms

of the study will be compared on TNM staging todetermine the impact of the program on the totalbreast cancers in the population of women targeted for

screenin


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Phased Implementation (cont.)

Note that phased implementation requiresno more resources for screening than doesopportunistic screening

It does require additional resources for

evaluation: Selection of the segments of the population for

implementation

Data collection in both the segments of the

population with the new screening program andin the segments in which the program has notbeen introduced

Data processing and analysis

The BHGI is assisting in the evaluation efforts


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Summary and Final Comments-1

As LMI countries develop economically, cancer will become

a more important public health problem

Population based cancer registration can be useful in

assessing the cancer problem, but other less expensive

methods also exist that should be considered before

establishing a registry. If population based registries are established, it is

preferable to do so in limited and carefully selected

populations than to attempt to establish a nation wide

registry.

Prioritize the development of cancer control activities on

the basis of the importance of the cancer, the known

effectiveness of the means that exist for primary or

secondary prevention, and the resources available to utilize

these means.


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Summary and Final Comments-2

Cancer control activities should be initiated in such a

manner that they can be rigorously evaluated

Epidemiologists can play an important role in settingpriorities for cancer control activities, in planning

these activities, and in the evaluation of their

effectiveness

The training of cancer epidemiologists is therefore animportant early step in developing cancer control

activities


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END

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