Diagnostic ultrasound ( PDFDrive )

396 PART II Abdominal and Pelvic Sonography
tissue and tries to allow for elevated PSA in men with enlarged
glands due to BPH. Cut points range from 0.12 to 0.15. his test
is less oten used to determine need for biopsy but commonly
used as one of the risk criteria for entering men into active
surveillance programs. 10,75,79,80
PSA velocity evaluates rate of increase of PSA over time. It
assumes that PSA rises faster with cancer and requires at least
three PSA determinations over 18 months showing a rise over
0.75 ng/mL per year. 81 his test is less oten used currently but
may have a role in active surveillance. 10,82
Role of Prostate-Speciic Antigen (PSA)
PSA and digital rectal examination today are the standard
of care for initial prostate cancer screening
PSA level is associated directly with the tumor burden of
prostate cancer
Not all cancers produce PSA
20% to 40% of men with clinically signiicant cancer will
have a “normal” PSA level
PSA may be elevated by nonmalignant conditions
PSA variants are used to improve screening accuracy
PSA density
PSA velocity
Free/total PSA ratio
Used during active surveillance, to evaluate for progression
and reclassiication
Used after active therapy, to follow patients for recurrence
Can be combined with other biomarkers to improve
sensitivity and speciicity
Alternate Prostate Cancer Biomarkers
PSA remains the most commonly used biomarker, but numerous
other biomarkers are being developed to overcome the limitations
of PSA to indicate need for initial and repeat biopsy, to help
distinguish between indolent and aggressive tumors, to help select
appropriate therapy, and to follow patients ater therapy. Biomarkers
can be evaluated in blood, other body luids, urine, or tissues.
Some have been approved for use and others remain investigational.
In general, their role is supportive to clinical acumen and
initial PSA use. In many instances their incremental value has
not yet been established. Also, multiparametric risk nomograms
and mpMRI are increasingly being used. 74,75,77,83
PCA3 score uses noncoding RNA in urine and is approved
for use. PCA3 is not found in normal prostate tissue but is
expressed in 95% of prostate cancers. It is recommended as a
test to help determine need for repeat biopsy with elevated PSA.
A cut point of 35 has been recommended, which would yield
optimal balance between sensitivity (47%) and speciicity (72%)
while missing 21% of high-grade tumors. 74,75,77,83-85
Prostate Health Index (PHI) is approved for men 50 years
or older in the PSA 4- to 10-ng/mL range and negative DRE
indings. It combines several isoforms of PSA. It is used to help
support need for biopsy in the PSA 4 to 10 range. 74,75,77,84,85
4Kscore is currently not a US Food and Drug Administration
(FDA)–approved test. It uses four diferent PSA forms and an
algorithm including age, DRE indings, and prior biopsy status
to predict a risk score for inding aggressive cancer in a future
biopsy. 74,75,77
TMPRSS2:ERG is currently not an FDA-approved test. It is
a urine test for pathologic fusion of TMPRSS2 and ERG genes
that is found in 50% of prostate cancer specimens. It has a low
sensitivity but high speciicity for predicting prostate cancer at
biopsy. 74,75,77
On biopsy samples, tissues near cancer show altered ield or
“halo” efects that can be evaluated on biopsy samples and can
manifest as changes in genes (Oncotype DX test) or tissue
methylation (ConirmMDx test). A negative biopsy result in a
patient with positive tissue markers suggests that a nearby cancer
was missed and can help determine need for repeat biopsy. 74,75,77
Increasingly the concept of combining these tests and other
tests including mpMRI and clinical parameters in the form of
“risk calculators” is proving useful. he more popular risk calculators
in current use are the ERSPC-RC, PCTP-RC, and UCSF-
CAPRA calculators, which can be found online or downloaded
to smartphones (http://www.prostatecancer-riskcalculator.com/
seven-prostate-cancer-risk-calculators; http://deb.uthscsa.edu/
URORiskCalc/Pages/uroriskcalc.jsp; https://urology.ucsf.edu/
research/cancer/prostate-cancer-risk-assessment-and-the-ucsf
-capra-score). 86,87
Screening
Early stage prostate cancer is curable but rarely symptomatic.
he presence of symptoms suggests advanced disease with little
likelihood of cure. his would suggest that screening is reasonable
to detect asymptomatic disease while it is still curable. he goal
of any cancer screening, including prostate, is the early identiication
of cancer or precancerous lesions before symptoms develop
and at a point when treatment improves outcomes. he World
Health Organization (WHO) has proposed criteria that should
be met before population screening is ofered. he condition
should be an important health problem with a known natural
history; have agreed-on treatment that is acceptable, available,
and efective; have a recognizable latent stage to allow time for
screening; and have a screening test that is acceptable and efective
and has a reasonable cost. 88 Many of these conditions are met
for prostate cancer, but issues remain that have introduced
controversy into screening. 60
TRUS is not used as a primary screening modality in screening
for prostate cancer. TRUS has sensitivity of 30% to 67% and
speciicity of 52% to 61%, compared with mpMRI sensitivity of
72% to 90% and speciicity of 55% to 79%. 89 It is hoped that
CEUS and ultrasound elastography will improve ultrasound
accuracy. here is increasing discussion of use of hybrid or
multiparametric imaging to improve detection and characterization.
4,6,90-92 Most techniques are qualitative and not quantitative,
and operator skills remain paramount. his results in variabilities
in accuracy and performance characteristics that are apparent
in the literature for cancer detection.
he current recommended screening tests are PSA and DRE
followed by conirmatory diagnostic transrectal biopsy. 7 he
added value of TRUS for cancer detection at screening over PSA
plus DRE is about 5%. 93 Diagnosis requires tissue to be obtained
by biopsy. Currently this is most eiciently and efectively done