Fiducial Marker Placement by Interventional Radiologists
Amy Deipolyi, MD
NEW ORLEANS—Transrectal ultrasound (TRUS)-guided prostate fiducial marker placement appears to be a safe and reliable technique that may be performed by an interventional radiologist for subsequent prostate localization during radiotherapy, according to a new study presented at the Society of Interventional Radiology's 38th Annual Scientific Meeting.
Lead investigator Amy Deipolyi, MD, PhD, a research fellow at Massachusetts General Hospital in Boston, noted that the procedure traditionally has been done in urologists' offices, “so we wanted to show that it could be safely done in interventional radiology.”
“The primary issue is that we see is a misplaced marker,” Dr. Deipolyi said. “Sometimes, one of the markers goes to a place we don't want it to.” This is always corrected easily on the day of the procedure, however, with placements of additional markers if necessary, she added.
Dr. Deipolyi and her colleagues conducted a study with 111 patients who underwent TRUS-guided prostate fiducial marker placement from January, 2011 to August, 2012. In this series of patients, three gold markers were placed, one each in the right and left prostate base as well as right apex. Post-procedure frontal and lateral radiographs confirmed placement. An additional marker was placed if malposition was noted.
The 111 men had a mean age of 69 years (range 52-90 years), a mean PSA level of 11 ng/mL (range 1-106 ng/mL), and mean prostate volume of 31.5 mL (range 2-130 mL). The mean Gleason score was 7 (range 6-9). Clinical stages ranged from T1c-T3b. Six patients (5.4%) previously had undergone transurethral resection of the prostate and one patient (0.9%) previously had received cryotherapy.
In 60 men (54%), 1% lidocaine was injected into the neurovascular bundle; the remaining 51 men (46%) received no lidocaine. Moderate sedation was used to allay anxiety on one patient and general anesthesia was used because of anal canal stenosis in another patient.
The researchers observed excellent primary placement in 105 patients (94.5%). Malposition of one marker was recognized on ultrasound in four cases (3.6%) and on radiograph in two cases (1.8%). These malpositions required additional fiducial placement. In all cases, the fiducials were still used during radiotherapy.
As a result of poor visualization of the fiducial markers, three patients (2.7%) required additional prostate localization using B-mode acquisition and targeting ultrasound at the time of radiotherapy. All the patients later underwent radiotherapy. Forty patients underwent proton beam radiotherapy and 71 underwent intensity-modulated radiation therapy.
All the patients received ciprofloxacin 500 mg twice a day for three days peri-procedurally and gentamycin 80 mg at the time of procedure. Post-procedure, a urinary tract infection requiring oral antibiotics occurred in one patient (0.9%) and urosepsis requiring hospital admission and intravenous antibiotics occurred in one patient (0.9%).
“It was overall very safe,” Dr. Deipolyi told Renal & Urology News. “We had a very low complication rate. There is always a risk of bleeding, but we did not see that in our series. So that was reassuring.”