Diagnostic ultrasound ( PDFDrive )

CHAPTER 10 The Prostate and Transrectal Ultrasound 397
with TRUS guidance. MRI in-bore biopsy and MRI-TRUS fusion
biopsies are being introduced but currently are less practical and
limited by access and costs. Cancer detection by mpMRI is
imperfect, and currently systematic biopsy cannot be avoided if
the MRI is negative.
Prostate cancer mortality has decreased since 1990 and there
has been a 75% reduction in the proportion of advanced disease
at diagnosis. his is attributed to opportunistic PSA screening
rather than new and improved therapies. 94 However, there are
concerns regarding generalized population screening. On one
hand, prostate cancer remains an important cause of morbidity
and mortality. On the other hand, prostate cancer afects older
men and typically has a 10-year course. Men of this age have
competing causes of mortality, so men with cancer oten die
with, and not from, their cancer. PSA screening has limited
sensitivity and speciicity. he diagnostic transrectal biopsy is
not infallible and has risks. here is a large background of lowvolume
low-grade (Gleason 6) cancer that is not likely to need
active therapy. his raises concerns regarding overdiagnosis and
overtreatment because therapy (surgery, radiation, hormones)
is not without risk and has signiicant side efects afecting quality
of life.
Several studies have evaluated the role of screening and therapy
for prostate cancer; some have shown beneit but others have
not, possibly because of study design limitations. 95,96 he major
quoted screening studies are the ERSPC (European Randomized
Study of Screening for Prostate Cancer) 97 and the US study PLCO
(Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial). 98
he ERSPC irst consented and then randomized men into a
screening arm ofered PSA testing every 4 years and a control
arm. Biopsy was ofered for PSA above 3 ng/mL. At 13 years,
the screened arm showed a 29% decrease in mortality. To prevent
one cancer death, the number needed to invite for screening
was 781 and number needed to detect was 27. he Göteborg
subset of this study used a more real-world approach that irst
randomized men to be invited to screening and then obtained
consents. Biopsy was recommended for PSA above 2.5 ng/mL.
At 14 years, the investigators reported that the relative risk for
dying from cancer decreased to 0.44, with number needed to
screen of 293 and number needed to treat of 12. 97,99
he PLCO randomized men to annual PSA and DRE or usual
care groups. Biopsy indication was PSA above 4 ng/mL or palpable
nodule. At 13 years there was no signiicant diference in mortality.
Subsequent analysis showed that about 90% of the control arm
had undergone PSA screening either before or during the study.
True comparison was not possible because both screen and control
arms in efect were screened with PSA. 58,95,98
Considering these and other studies, in 2012 the US Preventive
Services Task Force (USPSTF) issued a D recommendation against
prostate cancer screening (no net beneit or harms outweigh
beneits). 96 Notwithstanding decreasing prostate cancer mortality
since introduction of PSA screening, the USPSTF concluded
that any screening beneits were outweighed by the seeming lack
of overall beneit as shown especially in the PLCO study, the
risks of overdiagnosis and overtreatment, the risks of biopsy and
therapy, the large proportion of indolent disease that is unlikely
to be symptomatic, and competing mortality in older men. his
recommendation is strongly contested by many who believe that
it will decrease detection of prostate cancer while still treatable
and result in increasing morbidity and mortality; this appears
to be happening. 58,100,101 Also, urologic groups are promoting
“smart screening” that focuses screening on those most likely
to beneit and only ater shared decision making; to avoid harms
of active therapy, they recommend active surveillance of men
with seemingly indolent cancer (low-volume Gleason 6, also
called IDLE [indolent lesions of epithelial origin]). In general,
in men without risk factors, screening is recommended starting
at about age 50 years, is repeated at 1- to 4-year intervals, and
is stopped at about 70 years or with life expectancy below 10
years. A low (<1.0 ng/mL) baseline PSA between 40 and 49 years
of age is associated with low cancer risk and can be used to
further lengthen intervals between testing. Before biopsy, the
PSA should be repeated to allow normal luctuations from
producing a false-positive result. Antibiotics should not be given
to asymptomatic patients to lower PSA to test if there is an
asymptomatic infection causing the PSA elevation. In high-risk
groups such as those with a irst-degree relative with prostate
cancer or African-American men, screening should start at about
age 40. he new biomarkers, mpMRI, and risk calculators could
further be used to increase speciicity of screening tests and need
for biopsy or therapy. 58,73,88,95,102
Clinical Staging and Histologic Grading
Staging relates to extent of disease spread; grading relates to
histologic appearance of aggressiveness. Clinical staging of
prostate adenocarcinoma uses pretreatment parameters to estimate
extent of tumor, determine treatment options, and predict
prognosis by using DRE; PSA; biopsy characteristics; imaging
including TRUS, CT, isotope scan, and mpMRI; and nomograms
such as the Partin tables, which combine multiple characteristics
such as PSA, clinical stage, and Gleason score (Fig. 10.11, Table
10.1). 103 Pathologic staging requires histologic evaluation of
T1 (former A)
– not palpable
T3 (former C)
– local extension
capsule or SV
T2 (former B)
– palpable
– contained
T4 (former D)
– metatastic
FIG. 10.11 Contemporary prostate cancer staging using the tumornodes-metastasis
(TNM) classiication. SV, Seminal vesicle.