BRAC Cancer Screening FINAL March 2013

7/27/2019 BRAC Cancer Screening FINAL March 2013

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Cancer Screening

Developed by Dr. Alanna Fitzgerald-

Husek and Dr. Hamidah Meghani


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Objectives

To provide an introduction to basic concepts incancer screening

To understand the criteria for cancer screening

programs (WHO) To understand the role of screening in

prevention and control of cancer

Through the example of cervical cancer, toprovide students with an overview of effectivecancer screening programs


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Readings

Denny L, Quinn M, Sankaranarayanan R. 2006.

Chapter 8: Screening for cervical cancer in

developing countries. Vaccine 24S3: S3/71-S3/77.

World Health Organization. 2007. Early detection.Cancer control: Knowledge into action, WHO guide

for effective programmes. Available:

http://www.who.int/cancer/publications/cancer_contr

ol_detection/en/index.html


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Outline

Definitions

Rationale for Cancer Screening

WHO Screening Program Criteria

Biases in the interpretation of Screening tests Cervical Cancer

Disease facts

Screening options

Diagnosis and treatment

Barriers/challenges to screening

Current state of screening in Bangladesh


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Early Detection Programs

Aim: detect (pre-)cancer at an earlier stage (e.g.

when still localized, before any spread)

Rationale: earlier diagnosis and treatment

This can decrease incidence, mortality, increase

survival

Early detection should only be promoted and funded

within a public health system if certain conditionsare met(e.g. accurate pathological diagnosis and

effective, affordable treatment options available and

accessible


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Early Detection of Cancer

Two major components to early detection:

1.Education to promote early diagnosis andtreatment e.g. Cancer Awareness

campaigns

2.Screening


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Cancer Awareness

Early diagnosis can occur when seeking medical

attention for early signs or symptoms of disease

Health promotion aimed at increased awareness

is not recommended when there is no evidence of

improvement in survival


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Early detection: screening

Screening can be defined as the application of

diagnostic tests or procedures to asymptomatic

people for the purpose of dividing them into two

groups: those who have a condition that would

benefit from early intervention and those who do

not.

Wallace RB, ed. Public health and preventive medicine. 14th ed. Norwalk:

Appleton & Lange, 1998:907-8


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The ultimate purpose of screening is to reduce

morbidity and mortality.

If improved outcomes cannot be demonstrated, the

rationale for screening is lost.Early diagnosis by itself

does not justify a screening program. The only

justification for a screening program is early diagnosis

that leads to a measurable improvement in outcome.

Wallace RB, ed. Public health and preventive medicine. 14th ed. Norwalk:

Appleton & Lange, 1998:907-8


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Butwho or how

do I screen?!?


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Types of screening programs

Systematic/organized screening

Opportunistic screening


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Organized Screening

The systematic application of a screening test

to an asymptomatic population

An organized program is used to attempt to

invite all members of a target, at-risk

population (can include automatic recall)

Advantages & disadvantages e.g.

comprehensive but costly, false +


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Opportunistic Screening

The unsystematic application of screening testsused in routine health services e.g. primarycare visit

Individuals are offered screening when anappropriate opportunity presents itself

less expensive* from a programmatic view,but will miss many at-risk people


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Importance of cancer screening

Good quality, evidence-based cancer screening

programs can lead to:

incidence of invasive cancer (cervix, colorectal)

mortality (cervix, colon/rectum, breast)

survival *

cost/resource savings reduced treatment costs) andindirectly (e.g. sick leave from work)


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What makes a

good screeningtest?


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Criteria for a good screening test


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Disease factors

Relatively common disease

Associated with high morbidity and mortality

Natural history of the disease is understood

Better outcomes with early detection andtreatment

Treatment is available

Treatment benefits outweigh disadvantages (e.g.complications, side effects)

Must have asymptomatic phase detectable by test


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Screening for a disease

http://www.aafp.org/afp/2001/0201/p513.html


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Test factors

Good at catching all cases without missingany, and ensuring those that screenpositive for the test actually do have the

condition e.g. sensitivity and specificity

Safe, cost-effective/affordable, relativelyrapid and easy screening test

Acceptable and accessible to targetpopulation and those providing the test


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Health care system factors

Adequate capacity for diagnosis, treatment and

follow-up procedures for those that screen

positive

Clear policy guidelines and political will to

support a cost-effective, sustainable screening

program for the population


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The REAL impact of screening

Lead time bias:

A new test diagnoses the disease earlier but does

NOT affect disease outcome (e.g. death at 5 yrs)

Early diagnosis falsely appears to prolong survivaltime

Length time bias:

Slower-growing, less aggressive/deadly disease is

over-represented as screening is done intermittentlyand so can miss severe, rapidly progressing disease


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Lead-time bias

http://en.wikipedia.org/wiki/Lead_time_bias


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Length time bias

http://sph.bu.edu/otlt/lamorte/EP713/Web_Pages/EP713_Screening/EP713_Screening8.html


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Evaluation of screening programs:

biases and pitfalls

Voluntary nature:Individuals volunteering for screening may be

more health-conscious, more likely to seek

detection if symptoms develop, etc.

Literacy:Those that are more literate or educated about

health issues might be more likely to access andunderstand screening programs and theirimportance


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Evaluation of screening programs:

biases and pitfalls

Culture:Individuals or groups finding a screening test

more culturally appropriate or relative would be

more inclined to get tested

Socioeconomic status:More financial resources = more likely able to

afford and access screening, treatment, etc.May be more likely to attain and maintain better

health status


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Cervical Cancer Screening: a success story:


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Cervical Cancer Screening: a success story:

http://www.cancerresearchuk.org/cancer-

info/cancerstats/types/cervix/mortality/uk-cervical-cancer-mortality-

statistics#trends


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Cervical Cancer

In some regions still the most common cancer in women.

Risk factors: Infection with HPV

early onset of sexual activity

increasing age, low SES

multiple partners

Symptoms: None early on in disease

Advanced stages: abnormal vaginal discharge or bleeding


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Figure 1: Worldwide age-standardized annual incidence (per 100 000)

of cervical cancer (all ages). Reproduced with permission from

Elsevier (Vaccine 2006;24[Suppl 3]:1125).13


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Cervical Cancer

Prevention:

Primary prevention with HPV vaccine

Secondary prevention through regular screening

Diagnosis: Colposcopy, biopsy

Treatment:

Cryotherapy

LEEP

hysterectomy


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Screening tests available

Pap test (Cytology)

scrape cells from cervix, smear on a slide and

examine with microscope

HPV-DNA test

collect cells from cervix (like Pap) and test them

for HPV DNA for high risk strains

Done usually in combination with Pap test


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Screening tests available

Visual inspection with acetic acid (VIA)

application of 3-5% dilute acetic acid using a

cotton swab

examination of cervix after one minute

microscope not needed

VILI

Similar to VIA but using Lugols iodine


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Accuracy of tests

Test Sensitivity Specificity

Pap test 55-80% 86-100%

HPV-DNA 84-100% 90%

VIA 62-80%* 77-84%*

VILI 53-92%* 78-85%*


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Cost-effectiveness


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Screening Tests

Test Advantages Disadvantages

Cytology -Gets sample of cells, thus moreaccurate

-Screen & treat model not

applicable

-Requires high level of

training

-expensive

VIA -Immediate result: screen and treatmodel applicable better access

-Range of health workers can be

trained to use it (LIC)

-inexpensive

-wide range of specificity

and sensitivity

VILI -higher sensitivity than VIA-same as VIA for results and users

- Low specificity

HPV-DNA - Can be combined with cytology orVIA to increase sensitivity and

specificity

-Expensive

-Not same day results


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Diagnostic Tests

Colposcopy +/- biopsy

Requires training in use

Requires referral system for positive results

Requires more than one visit due to waiting for

biopsy results

Usually only available in tertiary care centres

(access issue)


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Treatment

Cryotherapy easy to use

Low cost

LEEP

Feasibility and safety of use by non-MD health workersproven

Requires working electricity

Better efficacy than cryotherapy among HIV positivewomen

HysterectomyNeed for tertiary care and referral

Requires coordination of care


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Barriers to Screening

Competing health needs

High burden of diseases other than cancer

Shrinking public health budgets

Limited human and financial resources

Poorly developed healthcare services

Limited and under-resourced primary care

facilities in developing countries


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Women are uninformed and

disempowered

Lack of education (and health literacy)

Status to men (subservient)

Minimal access to money in the family

War and civil strife

Widespread poverty

Cultural attitudes


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Nature of the screening test

Infrastructure required to do the test and analyze it

Communication of results

Development of appropriate referral system for

positive test results

Cost

Training of HCWs to do screening, diagnosis andtreatment

S i i l i


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Screening in low-resource settings

requires:

Screening, diagnosis and treatment provision on-site

or good clinic access to all

Low cost, low technology screening test that can lead

to immediate treatment of abnormalities Wide coverage of at-risk women

Appropriate educational programmes for women and

HCWs to ensure high uptake

Built-in mechanism for evaluation of programme


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Screen and treat approach

One visit screen and treat approach studied

Use of VIA +/- HPV DNA, colposcopy and

biopsy, and cryotherapy when indicated

25% relative reduction in cervical cancer incidence

Safety and feasibility assessed in India and

Thailand


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WHO paper Aug 2012

Prevention of cervical cancer through screening

using visual inspection with acetic acid (VIA)

and treatment with cryotherapy. A demonstration

project in six African countries: Malawi,Madagascar, Nigeria, Uganda, the United

Republic of Tanzania, and Zambia


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Training took place at the Department of Obstetrics and Gynecology, University of Zimbabwe,

Harare. Technical support was provided for data management by the APHRC and IARC.

Between September 2005 and May 2009, nearly 20 000 women aged 30-50 were screened with

VIA, 10.1% of which were VIA positive. Almost 90% of VIA-positive cases were eligible for

cryotherapy. 63% received cryotherapy within 1 week of their screen, and the single-visit

approach was successful for 39.1%. The report highlights successes and limitations, both of

which inform their policy recommendations, including: that each MOH develop, update and

review their strategies for cervical cancer control based on national guidelines and WHO

standards; that implementation should include health education along with adequate funding at

all levels through to district healthcare facilities; and that the programs should be linked to sexual

and reproductive health as well as other NCD prevention and care.


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Cervical Cancer Screening in Bangladesh


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Pilot Program

August 2004 to December 2005

Purpose: assess feasibility of training healthworkers and using this method within existing

governmental infrastructure Partners:

Government of Bangladesh

UNFPA (United Nations Population Fund)Bangabandhu Sheikh Mujib Medical University


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Pilot Program

Location: 16 of 64 districts in 6 division of the

country randomly selected among districts

with Maternal and Child Welfare Centres

Trained:

Master trainers trained senior staff nurses,

paramedics and doctors

15 days at BSMMU learning VIA and colposcopyin small groups


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References

Ahmed T, Ashrafunnessa KS, Rahman J. 2008. Development of a visual inspection programmefor cervical cancer prevention in Bangladesh.Reproductive Health Matters, 16(32): 78-85.

Ansink AC, Tolhurst R, Haque R, Saha S, Datta S, van der Broek NR. 2008. Cervical cancer in

Bangladesh: community perception of cervical cancer and cervical cancer screening. Transactions of the

Royal Society of Tropical Medicine and Hygiene, 102: 499-505.

Denny L, Quinn M, Sankaranarayanan R. 2006. Chapter 8: Screening for cervical cancer in developing

countries. Vaccine 24S3: S3/71-S3/77.

Goldie, S.J., Gaffikin, L., Goldhaber-Fiebert, J.D., Gordillo-Tobar, A., Levin, C., Mahe, C., and Wright,

T.C. (2005). Cost-effectiveness of cervical cancer screening in five developing countries.N Engl J Med,

353(20):2158-68.

Huchko MJ, Maloba M, Bukusi EA. 2010. Safety of the loop electrosurgical excision procedure performed

by clinical officers in an HIV primary care setting.International Journal of Gynecology Obstetrics. 111(1);

89-90.

Sankaranarayanan R, Bhatla N, Gravitt PE, Basu P, Esmy PO, Ashrafunnessa KS, Ariyaratne Y, Shah A,

Nene BM. 2008. Human Papillomavirus Infection and Cervical Cancer Prevention in India, Bangladesh, SriLanka and Nepal. Vaccine 26S: M43-M52.

WHO/ICO Information Centre on HPV and Cervical Cancer (HPV Information Centre). Human

Papillomavirus and Related Cancers in Bangladesh. Summary Report 2010. [Date accessed]. Available at

www.who.int/hpvcentre.
http://www.who.int/hpvcentrehttp://www.who.int/hpvcentre

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BRAC Cancer Screening FINAL March 2013