world cancer report - iarc

SCREENING FOR PROSTATE CANCER
SUMMARY
> Prostate-specific antigen (PSA) testing is
widely used for the early detection of
prostate cancer.
> Elevated levels of PSA are closely, but
not definitively, associated with prostate
cancer; false positive results may lead to
unnecessary treatment.
> Assessment of population-based PSA
screening suggests a reduction in mortality
in countries with access to urological
follow-up and treatment.
Secondary prevention of prostate cancer
is feasible, but is subject to controversy,
since the capacity to detect early disease
must inevitably result in overtreatment for
the individual patient, with substantial
costs to society, in exchange for
decreased mortality [1]. The lack of effective,
appropriate markers of disease and
any reasonable consensus on subsequent
treatment necessitates extensive patient
counselling as an important prerequisite,
with some degree of prudence until the
outcomes of the ongoing randomized trials
in Europe and North America have
been evaluated and audited [2].
Biological basis of secondary
prevention
Prostate-specific antigen (PSA), a glycoprotein,
is a proteinase that is responsible
for the liquefaction of semen. PSA analysis
has replaced prostatic acid phosphatase
as the preferred serum marker of
prostate cancer. The fact that PSA is highly
tissue-specific and the consideration
that few prostatic conditions result in a
sustained, elevated level of serum PSA
have made it the most efficacious marker
currently available for the detection of
prostate cancer. A serum “cut-off level” of
4 ng/ml for normality was used to demon-
160 Prevention and screening
Fig. 4.37 A physician in discussion with a patient:
informed consent is a prerequisite for PSA testing.
strate the efficacy of PSA as a diagnostic
tool [3]. Unfortunately, 25% of patients
diagnosed with prostate cancer have levels
of serum PSA that are less than 4
ng/ml. Of men with PSA levels between 4-
10 ng/ml, 25% have cancer, and 60% have
cancer when PSA levels are greater than
10 ng/ml.
PSA analysis should be combined with a
digital rectal examination, the latter providing
an assessment of the volume of the
gland, since PSA is also released into the
bloodstream of patients with benign
prostate hyperplasia and other prostatic
diseases. To improve the sensitivity of the
PSA analysis, a number of parameters
Advantages Disadvantages
may be assessed, most of which relate to
concomitant benign prostate hyperplasia
and also include age-specific reference
ranges [4], typical values being: 40-49
years,