Diagnostic ultrasound ( PDFDrive )

402 PART II Abdominal and Pelvic Sonography
U
A
B
C
D
FIG. 10.14 Ultrasound-Guided Brachytherapy. Transrectal ultrasound (TRUS) used to plane and guide brachytherapy (radioactive seed implantation)
using a special stepping device and perineal needle template. This same template can be used to guide transperineal saturation biopsy.
(A) One of multiple transverse prostate images used to plan seed sites (dots) and determine radiation isodose dose curves (colored lines).
Urethral dose is avoided (white central area inside the green triangle). Note the grid markers at the bottom (A, a, b … G) and on the left side (1.0,
1.5, 2.0 … 4.5) and the grid dots superimposed on the ield. (B) TRUS-guided seed placement in the operating room; U, urethra. Transverse image
shows the guiding grid dots and the tip of one inserting needle as a hamburger-like echo (arrow). (C) Sagittal image shows brachytherapy needle
inserted to base of prost ate (arrow) to insert a row of seeds. (D) Postprocedural CT reconstruction shows the position of the seeds (green) and
that the entire prostate is receiving a high (white) radiation dose. (Courtesy of Dr. Juanita Crook, Radiation Oncology, Princess Margaret Hospital,
Toronto.)
core, fewer than three positive biopsy cores, and life expectancy
of over 10 years. In general, ater initial diagnosis of low-risk
disease and a conirming biopsy and if patients agree, they are
actively monitored with combinations of PSA, PSA kinetics,
PSA density, DRE, TRUS, repeat biopsy, and the new biomarkers
to detect signs of progression resulting in reclassiication,
which triggers therapy. Use of mpMRI to speciically allow
targeting of high-risk areas at repeat biopsy is emerging, but
currently the efectiveness of the mpMRI approach has not been
established. 125
Signiicant progression and reclassiication that triggers
treatment is variably deined by a rapid rise in PSA (doubling
time < 2 years) and increase in tumor grade or volume. Using
this approach and with 14-year follow-up, Klotz has reported
that 1.5% of men showed progression and 30% of men requested
active therapy; cancer-speciic mortality was only 5%, and in
the interval 10 times as many men died of unrelated causes and
were never symptomatic and avoided prostate cancer treatment
and attendant complications. Other groups have shorter follow-up
but have reported similar results. 115,116,123
Progression of known or treated disease is monitored with
PSA because it provides an easier and more objective indicator
of total tumor burden and neoplastic activity than TRUS
or mpMRI. 2,4,89