Saturation / MRI Fusion Prostate Biopsy
Two types of prostate biopsies are widely considered more accurate than a standard office transrectal biopsy: Saturation biopsy and MRI fusion biopsy. Dr. Engel is currently the only Urologist regularly performing Saturation biopsies on his patients; MRI fusion biopsy is a widely performed biopsy. Dr. Engel performs both, usually at the same time.
Saturation biopsy stemmed from the development and popularity of radioactive seed implantation (brachytherapy) as a treatment for prostate cancer and used much of the same equipment. As seed implantation lost its popularity over time, the availability of this equipment waned, and thus, fewer and fewer sites offered Saturation biopsy. However, in nearly every contemporary report that has studied the various forms of prostate biopsy, Saturation biopsy nearly always shows superiority over all others, including MRI fusion, in terms of providing superior sensitivity and specificity of prostate biopsy. Other factors beyond equipment availability have also limited the use of saturation biopsy, including low physician reimbursement and the typical need for sedation to perform it. However, Dr. Engel has never stopped performing this biopsy as his “put up or shut up” biopsy. In cases where a patient’s prostate cancer is being followed as part of an active surveillance program or in patients where the PSA continues to climb despite a normal standard office biopsy, Dr. Engel always turns to the modality of Saturation biopsy to be definitive.
The MRI fusion biopsy is performed on a patient who has already had a normal office biopsy or is on an active surveillance program for low-grade prostate cancer, and a screening MRI shows a suspicious lesion. However, even the most suspicious MRI lesion correlates to significant cancer only approximately 50% of the time, so this biopsy is far from definitive. However, Dr. Engel still does this biopsy at the time of Saturation biopsy in the hopes of performing the most comprehensive combined biopsy possible for the patient to avoid future biopsies. However, the most important component of a combined procedure is the Saturation biopsy. In fact, Dr. Engel will soon be publishing a study of hundreds of patients asking the questions: Has there ever been a time that a significant prostate cancer was found on MRI fusion biopsy but missed on Saturation biopsy? (No). Has there ever been a time that the Saturation biopsy showed significant cancer that was missed by the MRI fusion biopsy (Several times)? Have there been times that the MRI was normal, but significant cancer was found by Saturation biopsy? (Several times).
In Dr. Engel’s hands, the Saturation biopsy and MRI fusion biopsy will be performed under sedation in a surgery center setting. Preoperative antibiotics will be given, but since this is a transperineal biopsy (needles don’t go through the rectum but through the skin under the scrotum), the infection risk is almost zero- far safer than an office biopsy. Patients can still expect blood in their urine, stool, and semen, and there will be scrotal bruising from the needles. Patients who struggle with enlarged prostate symptoms are usually sent home with a urinary catheter that they remove the next day to avoid the inability to urinate that can happen after this biopsy, given the extra needles and anesthesia. Results are given three days later, and patients will finish their antibiotic prescriptions. There is still little recovery from this type of prostate biopsy.