Diagnostic ultrasound ( PDFDrive )

CHAPTER 10 The Prostate and Transrectal Ultrasound 401
A
B
D
C
FIG. 10.13 Ultrasound-Guided Radiotherapy. Fiducial marker seeds inserted with transrectal ultrasound (TRUS) guidance and used to guide
escalated-dose external beam radiotherapy. (A) Transverse image shows basal seed (arrow) with characteristic comet-tail reverberation artifact.
(B) Rectal surface seed (arrow). (C) Fiducial (marker or reference) gold seed, which is inserted into the prostate to precisely guide escalated-dose
conformal radiotherapy (arrow). The smaller seed is a bone wax plug used to keep the seed in the needle before placement. (D) Pelvic x-ray ilm
shows the three marker seeds in place.
(conformed) to the prostate to lessen collateral damage to adjacent
organs (Fig. 10.13). Five-year freedom from biochemical recurrence
(no PSA rise) is 70% to 85%. Erectile function is preserved
in about 50% and continence in 80% of patients, but long-standing
rectal irritation may occur. 61,66,121
Brachytherapy involves intraoperative placement of radioactive
seeds, usually iodine-125, into the prostate using TRUS guidance
and a perineal template (Fig. 10.14). Direct radioactive seed
placement into the prostate allows higher local radiation doses.
he technique is restricted to low-risk patients with PSA less
than 10 ng/mL, Gleason score of 6 or less, and gland volume
less than 50 mL. Erectile function is preserved in about 50% and
continence in about 80% of patients, although urinary stricture
and bowel irritation are common. 66
Two new treatment strategies, watchful waiting and active
surveillance, are being introduced to delay invasive therapy and
its side efects and avoid possible overtreatment. Watchful waiting
is used in men who have asymptomatic cancer but are unlikely
to beneit from therapy because of comorbid conditions. hey
are monitored until they become symptomatic and then receive
symptomatic palliative care, usually with hormones.
Active surveillance (active monitoring with curative intent)
is an increasingly popular “PSA era phenomenon” that is almost
unique to prostate cancer and seeks to avoid overtreatment. It
recognizes that many men with low-risk cancer will never sufer
from the cancer and are 10 times more likely to die from other
causes such as cardiovascular disease. It also takes into consideration
the apparent indolent behavior of Gleason grade 3 lesions (Gleason
score 3 + 3 = 6), which do not appear to metastasize or cause
death. here is no general consensus on optimal protocols and
there are very many published guidelines for inclusion criteria,
monitoring, and criteria for triggering of deinitive therapy. It is
suggested that pure Gleason 3 + 3 = 6 disease and tumor volumes
of up to 1.3 mL (diameter about 1.4 cm) may behave in a benign
manner, and patients could be ofered surveillance. 115,116,123
Strict criteria are suggested to deine suitable low-risk patients,
typically including PSA below 10 ng/mL, Gleason score of 6 or
lower, stage T1c or T2a, less than 50% of length of any biopsy