Group 3 To Screen or Not to Screen: Who, Why, When and Where? Paul - - PowerPoint PPT Presentation

March 4th/5th 2016

Group 3 To Screen or Not to Screen: Who, Why, When and Where?

Paul Speight (Chair), Omar Kujan, Toru Nagao, Kannan Ranganathan, Pablo Vargas Joel Epstein (Moderator) ,

Paul Speight PhD, BDS, FDSRCPS, FDSRCS (Eng), FDSRCS (Edin.), FRCPath Professor, School of Clinical Dentistry, University of Sheffield Chair, Group 3 p.speight@sheffield.ac.uk Omar Kujan DDS DipOPath MSc PhD Assistant Professor, Al-Farabi College for Dentistry and Nursing

• mar.kujan@gmail.com

Kannan Ranganathan BDS, MDS, MS (oral path), PhD, FIAOMP Professor, Ragas Dental College and Hospital ranjay22@gmail.com Toru Nagao PhD, DMSc, DDS Professor, Fujita Health Science University tnagao@dpc.aichi-gakuin.ac.jp Pablo Vargas, DDS, MSc, PhD, FRCPath Professor, Piracicaba Dental School-UNICAMP pavargas@fop.unicamp.br

Joel Epstein, DDS, MSD Samuel Oschin Comprehensive Cancer Institute, Cedars-Sinai Health System, Los Angeles jepstein@coh.org

Moderator

Screening

“……the application of a test or tests to

people who are apparently free from the disease in question in order to sort out those who probably have the disease from those who probably do not.” “A screening test is not intended to be diagnostic”

Wilson JMG, Jungner G. Principles and practice of screening for disease. Geneva: WHO; 1968: http://www.who.int/bulletin/volumes/86/4/07- 050112BP.pdf

The purpose of screening is to interrupt the natural history of a disease at its asymptomatic stage when it is treatable and progression can be halted

Screening

Case finding

The detection of lesions with the objective

• f bringing patients to treatment..

…or for epidemiological studies and surveys

not screening, but often called screening

• eg. Awareness weeks, free clinics,

epidemiological studies

Types of screening

Mass (population) screening

• large scale screening of population groups
• usually by invitation

Selective screening

• targeted screening of high-risk groups

Opportunistic screening

• examining individuals when they attend for

some other, often unrelated, purpose

Why screen for oral cancer and precancer?

Current detection of early lesions is inadequate:

• only 50% attend a dentist
• many lesions are missed
• over 60% of patients present with late lesions
• high mortality

Why screen for oral cancer and precancer?

Pattern of disease:

• Increasing incidence?
• No improvement in survival
• Patients still present late

Why screen for oral cancer and precancer?

Clinical features of the disease

• easy to detect
• identifiable precursor lesion
• effective treatment available for small lesions

Why screen for oral cancer and precancer?

Criteria for screening

• Disease must be common and serious
• Disease must have a known natural history
• A good screening test must be available
• Effective treatment must be available
• It must be cost-effective

From: Wilson and Jungner 1968

UK National screening committee 19 criteria

Oral Cancer Screening to screen or not to screen?

Is oral cancer a screenable disease? Is screening for oral cancer feasible? Is screening for oral cancer cost-effective?

Criteria for screening

• Disease must be common and serious
• Disease must have a known natural history
• A good screening test must be available
• Effective treatment must be available
• It must be cost-effective

From: Wilson and Jungner 1968

keratosis dysplasia carcinoma

Leukoplakia Erythroplakia Oral premalignant lesions

Leukoplakia

A predominantly white lesion of the oral mucosa that cannot be characterised as any other definable disease, and which has a significantly increased risk of oral cancer.

Leukoplakia:

• Overall about 5% become malignant within 5 years
• About 1.5% /year transformation

Leukoplakia and malignancy

Oral Cancer Screening to screen or not to screen?

Is oral cancer a screenable disease?

Oral Cancer Screening to screen or not to screen?

Is oral cancer a screenable disease?

YES?

OPMD exist and may progress to cancer

• Disease must have a known natural history

Criteria for screening

• Disease must have a known natural history

Criteria for screening

?

OPMD exist and may progress to cancer

• Disease must have a known natural history

Criteria for screening

?

OPMD exist and may progress to cancer

BUT

Only about 5% overall become malignant 95% do not progress

Leukoplakia and malignancy

We do not know how to identify this 5%?

Criteria for screening

• Disease must be common and serious
• Disease must have a known natural history
• A good screening test must be available
• Effective treatment must be available
• It must be cost-effective

From: Wilson and Jungner 1968

Possible screening methods

Oral examination

With or without adjunctive methods Toluidine blue Cytology Illumination and light-based methods

Evaluation of a screening test

• Systematic visual examination of the oral

mucosa

• ‘Positive’ screen:
• A white patch
• A red patch
• An ulcer of longer than 2 weeks duration

2013

Test accuracy of oral examination

• Identified 10 studies that evaluated conventional
• ral examination (COE)
• Criteria included available data on specificity AND

sensitivity (reference standard applied to those screened negative)

Test accuracy of oral examination

Test accuracy of oral examination

From: Walsh et al, Cochrane Systematic review 2013

“…….. there is limited evidence of performance in each of the different settings ….. which means that the current evidence base is limited …. though COE has been shown to have good estimates of both sensitivity and specificity in some studies. …… there is some evidence that implementing COE as a component

• f a population screening programme can reduce mortality and produce

stage-shift in a high risk population.

Test accuracy of oral examination

“…….. there is limited evidence of performance in each of the different settings ….. which means that the current evidence base is limited …. though COE has been shown to have good estimates of both sensitivity and specificity in some studies. …… there is some evidence that implementing COE as a component of a population screening programme can reduce mortality and produce stage-shift in a high risk population.

Test accuracy of oral examination Kerala study

A systematic review of test performance in screening for oral cancer and precancer.

Downer MC, Moles DR, Palmer S, Speight PM. Oral Oncology 2004, 40. 264-273

Evaluation of screening tests

Evaluation of screening tests

A systematic review of test performance in screening for oral cancer and precancer. Oral Oncology 2004, 40. 264-273 Downer MC, Moles DR, Palmer S, Speight PM

Warn’ 1990 Mehta,1986 Mathew,1997 Downer, 1995 Ikeda,1995 Jullien, 1995 0.98 0.99 0.99 0.98 0.96 0.99 NPV 0.58 0.81 0.95 21.6 1872 0.31 0.98 0.59 1.4 1921 0.87 0.98 0.94 10.3 2069 0.86 0.99 0.71 5.5 309 0.50 0.94 0.60 9.7 154 0.67 0.99 0.74 2.7 2027 PPV Specificity Sensitivity % +ive n Monteiro, 2015 0.98 0.96 0.98 0.96 3.4 727 Nagao, 2000 0.86 0.78 0.64 0.92 (68) 137

Meta-analysis of all screening studies

Sensitivity - 0.85 Specificity - 0.97 PPV

• 0.70

NPV

• 0.98

85% of lesions correctly identified 15% false negatives 3% false positives 70% likelihood of being right 1% likelihood of being wrong

Sensitivity and specificity of screening tests

Sensitivity Specificity Oral examination 0.85 0.97 Mammography* 0.80 0.97 Cervical smear* 0.80 0.99

*estimates from UK National Screening Programmes: http://www.cancerscreening.nhs.uk

Evaluation of screening tests

A systematic review of test performance in screening for oral cancer and precancer. Oral Oncology 2004, 40. 264-273 Downer MC, Moles DR, Palmer S, Speight PM

Warn’ 1990 Mehta,1986 Mathew,1997 Downer, 1995 Ikeda,1995 Jullien, 1995 0.98 0.99 0.99 0.98 0.96 0.99 NPV 0.58 0.81 0.95 21.6 1872 0.31 0.98 0.59 1.4 1921 0.87 0.98 0.94 10.3 2069 0.86 0.99 0.71 5.5 309 0.50 0.94 0.60 9.7 154 0.67 0.99 0.74 2.7 2027 PPV Specificity Sensitivity % +ive n Monteiro, 2015 0.98 0.96 0.98 0.96 3.4 727 Nagao, 2000 0.86 0.78 0.64 0.92 (68) 137

Three studies used non-medical health workers

Evaluation of screening tests

A systematic review of test performance in screening for oral cancer and precancer. Oral Oncology 2004, 40. 264-273 Downer MC, Moles DR, Palmer S, Speight PM

Warn’ 1990 Mehta,1986 Mathew,1997 Downer, 1995 Ikeda,1995 Jullien, 1995 0.98 0.99 0.99 0.98 0.96 0.99 NPV 0.58 0.81 0.95 21.6 1872 0.31 0.98 0.59 1.4 1921 0.87 0.98 0.94 10.3 2069 0.86 0.99 0.71 5.5 309 0.50 0.94 0.60 9.7 154 0.67 0.99 0.74 2.7 2027 PPV Specificity Sensitivity % +ive n Monteiro, 2015 0.98 0.96 0.98 0.96 3.4 727 Nagao, 2000 0.86 0.78 0.64 0.92 (68) 137

Similar sensitivity and specificity

Criteria for screening

• A good screening test must be available
• COE shows satisfactory sensitivity and

specificity

• Dentists and other trained health care

workers are able to detect lesions

Criteria for screening

• A good screening test must be available
• COE shows satisfactory sensitivity and

specificity

• Dentists and other trained health care

workers are able to detect lesions

BUT

criteria for a positive test (lesion) need to be established

Is screening for oral cancer feasible?

Yes

OPMD exist Dentists and health care workers are able to detect them

Do oral cancer screening programmes work?

India Japan

Only two significant studies of screening programmes

Oral cancer screening studies in Japan

Toru Nagao

Tokoname city

Population: 52,058 Over 40 yrs : 26,856 (52%)

Aichi prefecture

Tokoname study

Los Angeles County Museum of Art

Beckoning cat

Nagoya

Period: 1995 to 1998 Objectives: to elucidate efficacy of mouth examination Method: by invitation Strategy: Annual screening as part of general health screening Subjects: 40 yrs and older 9,536 (36%) (male:32%, female:68%)(age:61±11 yrs) Total number of examinations: 3,275 ( in 1995) 19,056 (in 1996-1998) (including repeat examinations) Examiners: Dentists (n=42) Calibration of screeners 1 week before

Study design

Programme processes in oral cancer screening in Tokoname study in Japan

Community Level Primary Level Secondary Level Tertiary Level

• Detection

(1st screening)

General health screening

Free shuttle bus available

Pathology lab

Treatment

+ Hospital units

250 examinations per day

Diagnosis

(2nd Exam)

OMS units

Sc posi

Specialist vs. Screening diagnosis

(67/70) 137 43 44 2 40 8 Total

(1/4) 5 1 2 2 Normal (27/26) 53 36 4 8 5 Other (9/31) 40 3 32 2 3 * Erythroplakia (28/9) 37 3 6 27 1 Leukoplakia (2/0) 2 2 Cancer

(M/F)

Total Others Leuko Cancer Specialist Diagnosis

Screening diagnosis

Erythro Lichen planus Lichen planus

Nagao et al. Oral Oncol. 2000;36(4):340-6. Detected lesions confirmed by specialists:

• 2 of 8 cancers (25%)
• 27 of 40 leukoplakias (68%)
• 32 of 44 lichen planus (80%)
• 36 of 43 benign lesions (84%)

Sensitivity :0.92 (95% CI 0.86-0.98) PPV: 0.78 (95% CI 0.70-0.86)

Compliance for secondary testing and detection rate in organized cancer screening

Colorectal cancer Screening

(Fecal occult blood test)

10,000

Colorectal cancer

17 (0.17%)

Referral for 2nd testing 620 (6%) Examinees for 2nd testing 419(68%)

In 2013, Japan Cancer Society Examinees as Breast cancer Screening

(Mammography)

10,000

Breast cancer

23 (0.23%)

Referral for 2nd testing 750 (8%) Examinees for 2nd testing 662(88%)

Examinees as Oral cancer screening

10,000

Oral cancer

1 (0.01%)

Referral for 2nd testing 105 (1%) Examinees for 2nd testing 72(69%)

Examinees

Nagao T et al. J Med Screen, 2000;7(4):203-8.

OPMDs 41 (0.4%) Colon polyp 157 (1.6%)

Summary of the outcomes

• Satisfactory participation can be obtained for annual oral

cancer screening when this is coupled to a general health screening: this allows detection of new lesions including oral cancer and precancer

• Those with risk habits (smoking and drinking) are likely not to

show-up in subsequent years.

• An attendance of 69% for re-examination by specialists

compares well with other reported studies measuring patient compliance

• The performance of the Japanese dentists employed in

screening was satisfactory

Kannan Ranganathan

India

Gold standard: Randomised controlled trial with mortality as the end point

KERALA STUDY

INDIA

TRIVANDRUM CITY Kerala

Indian Ocean Bay of Bengal Vakkom Kadakavoor Kizhuvilam Azhoor Mangalapura m Andoorkonam Pothencod e Kazhakutta m Sreekariyam Attipra Kadinamkula m Chirayinkil

Anjuthengu

Intervention Clusters Control Clusters

TRIVANDRUM CITY

Arabian Sea

Kannan Ranganathan

The Kerala screening studies

• 1. Sankaranarayanan R, Ramadas K, Thara S, Muwonge R, Thomas G, Anju G, Mathew B. Long term effect of visual

screening on oral cancer incidence and mortality in a randomized trial in Kerala, India. Oral Oncol. 2013 Apr;49(4):314- 21.

• 2. Sankaranarayanan R, Ramadas K, Thomas G, Muwonge R, Thara S, Mathew B, RajanB. Trivandrum Oral Cancer

Screening Study Group. Effect of screening on oral cancer mortality in Kerala, India: a cluster-randomised controlled

• trial. Lancet. 2005 Jun 4-10;365(9475):1927-33.
• 3. Ramadas K, Sankaranarayanan R, Jacob BJ, Thomas G, Somanathan T, Mahe C, Pandey M, Abraham E, Najeeb S,

Mathew B, Parkin DM, Nair MK. Interim results from a cluster randomized controlled oral cancer screening trial in Kerala, India. Oral Oncol. 2003 Sep;39(6):580-8.

• 4. Sankaranarayanan R, Mathew B, Jacob BJ, Thomas G, Somanathan T, Pisani P, Pandey M, Ramadas K, Najeeb K,

Abraham E. Early findings from a community-based, cluster-randomized, controlled oral cancer screening trial in Kerala, India. The Trivandrum Oral Cancer Screening Study Group. Cancer. 2000 Feb 1;88(3):664-73.

• 5. Subramanian S, Sankaranarayanan R, Bapat B, Somanathan T, Thomas G, Mathew B, Vinoda J, Ramadas K. Cost-

effectiveness of oral cancer screening: results from a cluster randomized controlled trial in India. Bull World Health

• Organ. 2009 Mar;87(3):200-6.
• 6. Pandey M, Thomas G, Somanathan T, Sankaranarayanan R, Abraham EK, Jacob BJ, Mathew B; Trivandrum Oral

Cancer Screening Study Group. Evaluation of surgical excision of non-homogeneous oral leukoplakia in a screening intervention trial, Kerala, India. Oral Oncol. 2001 Jan;37(1):103-9.

• 7. Mathew B, Sankaranarayanan R, Sunilkumar KB, Kuruvila B, Pisani P, Nair MK. Reproducibility and validity of oral

visual inspection by trained health workers in the detection of oral precancer and cancer. Br J Cancer. 1997;76(3):390- 4.

Kerala study

• 13 districts randomised
• 7 intervention
• 6 control
• Subjects over 35 years
• Subjects screened by non-medical HWs
• Oral examination
• Positives referred to hospital
• Health, habits and socioeconomic data

recorded

77/205 died 37.6% Total cancers in population 205 (43.7 per 100,000) 3,218 attended for referral 131 cancers 2,252 precancers 5,145 positives 6.55% Intervention arm 87,655 (91.0%) screened 87/158 died 55% Total cancers in population 158 (37.6 per 100,000) Control arm 95,356 13 districts 114 601 population >35 years

Results at 9 years

96,517

13 clusters 114 601 population >35 years

Intervention Control Deaths 37.6 55.0 NS Survival (5yr) 50.0 34.0 P<0.01 Stage I & II 42.0 23.0 P<0.005 Mortality rate 16.4 20.7 NS

Kerala study – after 9 years

Intervention Control Males Tobacco & Alchol: Mortality rate 24.6 42.9 P<0.01 Females Tobacco & Alchol: Mortality rate 39.9 50.7 NS

Kerala study – after 9 years

Conclusions at nine years

• Oral visual screening can reduce mortality in

high-risk individuals

• This has the potential of preventing at least

37 000 oral cancer deaths worldwide

Sankaranarayanan et al (2005) Effect of screening on oral cancer mortality in Kerala, India: a cluster- randomised controlled trial. Lancet, 365, 1927–33

‘Our findings support the routine use of oral visual screening in the

reduction of oral cancer mortality in the high-risk group …...’

138/279 died 50% Total cancers in population 279 (37.1 per 100,000) 5,586 (6.3%) positive 188 cancers 2,336 precancers 88,822 screened 92% Intervention arm 96,517 154/244 died 63% Total cancers in population 244 (30.8 per 100,000) Control arm 95,356 13 clusters 191,872 population >35 years

Results at 15 years

1996 - 2010

All subjects

129/254 died 51% Total cancers in population 254 (57.3 per 100,000) Intervention arm 45,791 147/232 died 63% Total cancers in population 232 (58.5 per 100,000) Control arm 39,151 13 clusters 84,942 population >35 years

Results at 15 years

1996 - 2010

High Risk Group

5,246 screened positive

Intervention Control Deaths 50% 63% NS Survival (5yr) 55.5 43.4 P=0.003 Survival (10yr) 48.3 30.6 P=0.003 Stage I & II 47.4 34.8 P=0.002 Mortality rate 15.4 17.1 NS

Kerala study – after 15 years (1996 - 2010)

Sankaranarayanan et al, Oral Oncology, 2013. 49:314-321

Intervention Control Tobacco & Alchol: Deaths 51% 63% Mortality rate 30.0 39.0 P<0.05 Advanced cancers 54% 66% P<0.05 No Habits: Mortality rate 1.9 1.3 NS

Kerala study – after 15 years

Mortality (% reduction)

All n (%) Tob & Alc n (%)

3 Rounds 38%

22,008 (23%)

47%

10,373 (23%) P<0.05

4 Rounds 79%

19,228 (20%)

81%

8,163 (18%) P<0.05

Effect of compliance with screening

Sankaranarayanan et al, Oral Oncology, 2013. 49:314-321

Kerala study – after 15 years (1996 - 2010)

Sankaranarayanan et al, Oral Oncology, 2013. 49:314-321

Summary:

• “..a sustained reduction in oral cancer mortality …….. In high-risk

individuals….after 15 years”

• Overall 12.5% were screened positive
• 59% of those attended follow up
• Significant reduction in mortality in high-risk group (39% vs 30%)
• BUT significant reduction in mortality & incidence ONLY in high-risk individuals

attending 4 rounds

• NO significant reduction in the total population

Kerala study – after 15 years (1996 - 2010)

Sankaranarayanan et al, Oral Oncology, 2013. 49:314-321

Summary: “….our findings support the routine use of oral visual screening to reduce oral cancer mortality among the high-risk group ……….. …..We recommend that dentists and general practitioners perform a careful visual oral examination in tobacco or alcohol users during routine clinical interactions …”

Kerala study – after 15 years (1996 - 2010)

Sankaranarayanan et al, Oral Oncology, 2013. 49:314-321

Summary: “….our findings support the routine use of oral visual screening to reduce oral cancer mortality among the high-risk group ……….. …..We recommend that dentists and general practitioners perform a careful visual oral examination in tobacco or alcohol users during routine clinical interactions …”

Opportunistic screening in high-risk groups may work

Paul Speight

Oral Cancer Screening to screen or not to screen?

Is oral cancer a screenable disease? Is screening for oral cancer feasible? Is screening for oral cancer cost-effective?

Cost-effectiveness

• The Kerala study also calculated costs of screening.
• Compared to no screening

Cost-effectiveness

From: Brocklehurst et al. Cochrane Systematic Review 2013. * Incremental costs at 9 years

Costs

Cost-effectiveness

From: Brocklehurst et al. Cochrane Systematic Review 2013. * Incremental costs at 9 years

Costs

Cost-effectiveness

• The screening cost less than US$ 6 per case
• The incremental cost per life-year saved was

$835

• Fell to $156 if only high risk individuals were to

be targeted.

“ This is the first clinical prospective study to show that opportunistic screening for oral cancer may be cost-effective.”

Subramanian, S. , Sankaranarayanan, R., Bapat, B. et al (2009) Cost-effectiveness of oral cancer screening: results from a cluster randomized controlled trial in India. Bull World Health Organ, 87, 200–206

Is screening for oral cancer cost-effective in a developed, low prevalence, country?

The cost-effectiveness of screening for oral cancer in primary care. Speight PM, Palmer S, Moles DR, Downer MC, Smith DH, Henriksson M, etal. Health Technology Assessment 2006;10(14):1–144.

• Baysian simulation model
• The outcome was determined for 100,000 individuals

entered into a 1 year screening cycle

• And for 100,000 individuals not screened (control)
• Costs calculated from record review and published cost

data

• Outcome measured in QALYs
• Prevalence data and sensitivity and specificity taken from

previous pilot screening programmes

A hypothetical model of oral cancer screening

Complex model, including estimates of probabilities of transition between disease states

Computer simulation model of cost-effectiveness

• f screening for oral cancer & precancer

Result of screening high-risk group:

QALYs in unscreened population = 1992982 QALYs in screened population = 1993294 QALYs gained = 312

Equivalent to 15 lives saved

Incremental cost-effectiveness ratios

• No screen

£0

• Opportunistic high risk screen, GDP

£18,919

• Opportunistic high risk screen, GMP

£19,703

• Opportunistic population screen, GMP

£21,623

Results

What is a life worth?

In USA:

• $40,000 was the price agreed by legislation

for mammography In UK

• NIHCE has approved £20,000 - £30,000

These have become benchmarks for the worth of a health care intervention

Costs of screening programmes

£ per QALY Breast cancer 80,000 Cervical cancer 300,000 Colon cancer 6,500

Oral cancer 18,500

Roberts et al, 1985; Lancet i, 89-91; Gray & Briggs, NSC 1998

Is screening for oral cancer cost- effective?

Probably

For opportunistic screening of high risk individuals but more research is needed

Omar Kujan

Evidence base for Oral cancer screening

Systematic reviews

Omar Kujan

2006 2003 2010 2013

• Review of RCTs of screening programmes for oral cancer or

OPMD

• Mortality as primary outcome
• Secondary outcomes:

– incidence – stage – Adverse effects – costs

• No RCTs in any developed or low-prevalence countries
• Only one study met the inclusion criteria

Kerala study:

Ramadas K, Sankaranarayanan R, Jacob BJ, Thomas G,Somanathan T, Mahe C, et al. Interim results from a cluster randomized controlled oral cancer screening trial in Kerala, India. Oral Oncolgy 2003;39(6):580–8. Sankaranarayanan R, Mathew B, Jacob BJ, Thomas G, Somanathan T, Pisani P, et al. Early findings from a community-based, cluster randomized, controlled oral cancer screening trial in Kerala, India. Cancer 2000;88(3): 664–73. Sankaranarayanan R, Ramadas K, Thara S, Muwonge R, Thomas G, Anju G, et al. Long term effect of visual screening on oral cancer incidence and mortality in a randomized trial in Kerala, India. Oral Oncology 2013;49 (4):314–21 Sankaranarayanan R, Ramadas K, Thomas G, Muwonge R, Thara S, Mathew B, et al. Effect of screening on oral cancer mortality in Kerala, India: a cluster-randomised controlled trial. Lancet 2005;365(9475):1927–33.

The evidence from the Kerala trial is that visual screening can reduce the mortality rate in users of tobacco, alcohol or both and can produce a stage shift. ………visual examination could be effective at reducing mortality rates for oral cancer when used within a targeted screening programme. …..but the risk of bias in the included study means that further well- designed randomised controlled trials are necessary to establish the validity of this relationship.

Conclusions:

The results suggest that there is insufficient evidence to recommend a whole population screening programme for oral cancer. In the meantime, opportunistic visual screening by appropriately trained dentists and oral health practitioners is recommended for all patients and particularly for those who use tobacco, alcohol or both.

Conclusions:

Summary and Conclusions

Paul Speight

JADA: 2010;141: 509-520

“……..defines “screening” as the process by which a practitioner

evaluates an asymptomatic patient to determine if he or she is “likely”

• r “unlikely” to have a potentially malignant or malignant lesion.”

“……..defines “screening” as the process by which a practitioner

evaluates an asymptomatic patient to determine if he or she is “likely” or “unlikely” to have a potentially malignant or malignant lesion.”

Conclusions:

“……screening by means of visual and tactile examination in the general adult population intended to detect early and advanced oral cancers may not alter disease specific mortality.” “…….insufficient evidence to determine whether screening by means of visual and tactile examination to detect potentially malignant and malignant lesions alters disease-specific mortality.” “…..screening by means of visual and tactile examination may decrease

• ral cancer–specific mortality among people who use tobacco,

alcohol or both.”

National Cancer Institute, USA:

Benefits

There is inadequate evidence to establish whether screening would result in a decrease in mortality from oral cancer.

Magnitude of Effect: No evidence of benefit or harm.

Study Design: Evidence obtained from one randomized controlled trial. Internal Validity: Poor. Consistency: Not applicable (N/A). External Validity: Poor.

National Cancer Institute, USA:

US Preventive Services Task Force

The USPSTF….. …....found inadequate evidence that the oral screening examination accurately detects oral cancer. …….found inadequate evidence that screening for oral cancer and treatment of screen-detected oral cancer improves morbidity or mortality. …….concludes that the current evidence is insufficient to assess the balance of benefits and harms of screening for

• ral cancer in asymptomatic adults.

http://www.uspreventiveservicestaskforce.org/Page/Document/ UpdateSummaryFinal/oral-cancer-screening1

UK National Screening Committee

UK National Screening Committee. Criteria for appraising the viability, effectiveness and appropriateness of a screening programme. London, UK: National Screening Committee, 2003. Updated 2015: http://legacy.screening.nhs.uk/oralcancer

9 of 19

Oral Cancer Screening to screen or not to screen?

Is oral cancer a screenable disease?

Problems:

• The clinical appearance is not specific for a

potentially malignant lesion

• Criteria for relevant lesions not clearly established
• Only 5% - 30% of screen detected lesions may be

relevant to the natural history of the disease

• Does an oral examination work in a screening

programme?

• Is it cost-effective?

Oral Cancer Screening to screen or not to screen?

Only about 5% overall become malignant 95% do not progress

OPMD and malignancy

How do we identify this 5%?

Priorities for further research