CHICAGOThree-dimensional, CT-guided transischiorectal biopsy of
the seminal vesicles in patients with biopsy-proven prostate cancer
resulted in upstaging of 10% of patients, according to a report at
the Radiological Society of North America (RSNA) annual meeting.
Standard ultrasound-guided biopsy of the seminal vesicles is not
considered to be practical by some clinicians because it requires six
needles to be placed through the bowel. However, the 3D CT-guided
transischiorectal biopsy procedure can be performed in 3 to 5 minutes
with a minimum of discomfort to patients and little danger to the
rectum, coccyx, and bowel, said Panos G. Koutrouvelis, MD, of the
Uro-Radiology Prostate Institute (URPI), Vienna, Virginia.
The study included 303 men with localized prostate cancer who
underwent 3D CT-guided biopsy of the seminal vesicles (before or
during brachytherapy) between June 1995 and January 1999. The biopsy
disclosed that prostate cancer had invaded one or both seminal
vesicles in 30 men, which changed pathologic staging of their disease
from T1 or T2 to T3c.
The biopsy was performed at the beginning of brachytherapy so that
anesthesia was administered only once. The stereotactic template for
the 3D system was placed on the ischiorectal area with the patient in
the prone position. To ensure that the biopsy needle would not
penetrate the rectum, the stereotactic system was adjusted to
correspond with the angle of the gantry, which usually is kept at
negative 26 degrees.
The biopsy needle was passed through the pararectal fat to avoid the
rectum and coccyx, and three biopsies were taken of the seminal
vesicles. One was obtained near the base of the prostate, one in the
midportion of the gland, and one in the distal region.
Twenty-four of the 30 men with a positive seminal vesicle biopsy were
not considered to be at high risk for seminal vesicle involvement
because they had a Gleason score of 7 or less. Thirteen had PSA
levels of 10 ng/mL or below, which is not consistent with spread of
prostate cancer to the seminal vesicles.
Based on these findings, Dr. Koutrouvelis concluded that after
a positive diagnosis of prostate cancer and prior to implementation
of any treatment optionradical prostatectomy, brachytherapy, or
external beam radiationbiopsy of the seminal vesicles, whether
it is guided by CT or ultrasound, is recommended in all patients to
rule out seminal vesicle invasion.