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Volume2 Issue6
S
upporting
Y
our
P
ractice
Screening forOral Potentially
MalignantEpithelialLesions and
SquamousCellCarcinoma
Current guidelinesdonot support population screening
forOPMDandOSCC.
4–6
However, opportunistic screening
hasbeen suggested inconjunctionwithoral examination
duringdental visits.
7,8
A single study supports screening inahigh-riskpopulation
in India.
9
In this study, clinical examination todetect early-
stageOSCCwas conductedannually for 3years for 96517
patients amongwhom205casesofOSCCwerediagnosed.
Of thesecases, 41%were stage I or II cancers and5-year
survival ratewas 50%. Among87655peoplenot evaluated
annually, 158caseswerediagnosed, 23%ofwhichwere
stage I or II cancers and the5-year survival ratewas 34%.
Thus, identificationof earlier stagecancers in the screened
population translated intoa21% reduction inoral cancer
mortality.
9
Screeninganddiagnostic testsmustbeevaluated in terms
of test characteristics andoutcomes (
Table2
). Riskof over-
diagnosis (falsepositive results) ofOSCCandOPCmay lead
toadditional and sometimes invasive testing (typicallya
minorbiopsywith short-liveddiscomfort andcost) and
thepotential for overtreatment.
9
The resultsof biopsy is
also subject tovariableaccuracy.
10
It is important tobe
aware thatmost studiesdonot address thevalueof correct
diagnosisof benignconditions that, of themselves, require
management, but in screening studies are frequently
referred toas “falsepositive” results. Falsenegative results
arepotentiallyof greatest concern, as theymaybe
reassuringandallowundetectedcancer toprogressbefore
diagnosis. Ingeneral,more sensitive tests areat riskof
producingahigher rateof falsepositiveoutcomes and lead
to increasedevaluationand testingwith inherent risks and
costs.
Discussion
AlthoughearlydetectionofOPMD, OSCCandOPC is a
desirablegoal, evidence supporting screening is limited. A
focusonhigh-riskpopulations (
Table3
)whereprevalence
isgreatermay increase thepotential valueof screening.
The issues surrounding screening for low-prevalence
diseases lead tochallenges indetectionandan increased
riskof falsepositiveand falsenegativeoutcomes and
higher costs. Thesewill continue tochallengeoral cancer
detection. Current best evidence is limited tohigh-risk
populations, suchas thosewithprior upper aerodigestive
tract cancer, exposure toheavy tobaccoandalcohol
use, exposure toHPVand immunosuppression. These
populationsmaybebest evaluated inhigh-risk clinics,
suchasmucosal diseaseclinics, cancer centres andclinics
for sexually transmitteddiseases. Theguidanceprovided
by theAmericanDental Association for better, available
Table1
Keyquestions and test characteristics that determine
theutilityof oral cancer screening
Keyquestions
➤
Is thereadetectableearlystageofdisease?
➤
Is therebenefit fromearlydetection?
➤
Is theprevalenceof thediseasehigh?
➤
Ifprevalence is low, is ituseful toassesshigh-riskgroups?*
Characteristicsof tests thataffectutility:
–Technical natureof test
–Amountof experienceor training required
– Invasiveversusnoninvasive
–Validation in the settingorpopulation inwhich the test is tobe
used
–Riskof falsepositiveor falsenegative results
–Frequencyof use
–Steps taken if resultsarepositiveornegative
–Costof testor equipment
*Seerisk factors listed in
Table3
.
Table2
Impact of screening test results
Truepositive
Falsepositive*
Earlydetection, early
diagnosis
Less complex treatment
Increased likelihoodof cure
with reducedmorbidity
Reducedcostof care
Anxiety
Additionalmedical/dental
visits
Increasedcost
Morbidity related to the test
Truenegative
Falsenegative
Reassurance, no further
testing
Delay in truediagnosis
Potential progressionof
disease
*Often increased intestswithhighsensitivity.
Whilemore predictable tools for
diagnosis andmeasures of lesion
behaviour are sought, current clinical
decisions are based onavailable evidence
and experience.
