We’ve seen many advances in the diagnosis and treatment of prostate cancer over the last decade. One stellar example is the MRI-guided fusion biopsy of the prostate. It represents a quantum leap forward in identifying who would benefit from a prostate biopsy, as well as increasing the accuracy of the biopsy itself. These advantages allow for a better assessment of the presence, grade, and extent of prostate cancer, and MRI-guided fusion biopsy of the prostate has become essential in the diagnosis of certain prostate cancers.
Over the years, studies have shown that many men who have random biopsies of the prostate and are tested for an elevated PSA blood level are frequently deemed negative for cancer. But these random biopsies, at times, can miss a smaller cancerous lesion.
While ultrasound-based prostate biopsy continues to be appropriate for many men, others may require a unique approach. This may include men in whom cancer is suspected despite a prior normal prostate biopsy, as well as men with larger prostate glands in which small cancers may not have been detected in their first biopsy.
Conversely, MRI fusion biopsies radiologically image the prostate and identify small lesions if they are present. These MRI images are fused with the ultrasound image so that physicians can be more precise and have much higher accuracy in their diagnosis, thereby decreasing false negative results.
Patients who undergo fusion biopsies usually have had one biopsy before their insurance company will allow for an MRI of the prostate. In these patients, if there is an increasing PSA or a palpable abnormality, an MRI is frequently ordered.
How MRI Fusion Biopsies Work
Georgia Urology urologists, with assistance from our skilled radiology partners, utilize the KOELIS Trinity® biopsy system, which employs state-of-the-art real-time 3D MRI-ultrasound fusion technology.
This MRI is performed on an outpatient basis, using brief anesthesia and with contrast dye, which creates images that the radiologist then uses to look for specific lesions based on the contrast diffusing into the prostate gland and a lesion, if present. The suspicious lesions are detected, defined, and outlined with millimetric precision. (note: patients who have an allergy to the contrast (rare) or who have MRI incompatible implants are not candidates for this test).
The MRI and live ultrasound images are then fused, matching anatomical points and improving the accuracy of sampling the lesions of interest.
Results, Grading, and the Gleason Score
A negative result means that the radiologist found no signs of cancer. There is a small possibility of a false negative, so if your PSA remains elevated for other prostate cancer signs still exist, we may suggest a follow-up biopsy in a few months.
A suspicious result indicates that the biopsy results did not seem normal, and therefore, we cannot safely exclude cancer.
A positive result means that cancer was found, and you were urologist will discuss treatment options based on the aggressiveness of the cancer found.
Lesions are graded from levels one to five. Grades four and five are much more likely to indicate the presence of cancer, whereas grades one and two are very unlikely to be cancerous. Grade three is indeterminate.
Your doctor may also give you a Gleason score between 6 and 10. The lower the number, the lower the grade of the cancer and the lower the likelihood of spread (metastasis).
The Bottom Line
A fusion biopsy can help minimize unnecessary biopsies and is a technique that provides more accuracy than random 12 or 14-core biopsies, especially on patients who have had negative random biopsies in the past but are experiencing increasing PSA levels.
It is important to note that no single imaging or blood test should be relied upon to make a definitive diagnosis. If a patient has a normal prostate MRI but there is some suspicion based on blood test results or physical examinations, a biopsy of the prostate is still recommended.
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