MR-ultrasound Fusion May Improve Prostate Biopsy Results
Wednesday, Dec. 02, 2015
Prostate biopsies could become significantly more accurate if guided by MR-ultrasound fusion, according to a retrospective analysis of more than 600 patients conducted at the Hospital Israelita Albert Einstein in Sao Paulo, Brazil, and presented on Tuesday.
The study showed that targeted prostate biopsies using MR-ultrasound fusion can detect more clinically significant lesions than random sextant biopsy, the current standard of care, and can increase the accuracy of the procedure, particularly in cases where clinical or laboratory findings establish a high suspicion of cancer.
Random sextant biopsies are performed about a million times a year in the U.S., and detect between 27 and 40 percent of Cancers, said presenter Guilherme Mariotti, M.D. The procedure misses about 35 percent of cancers, and also detects a large number of low-risk cancers.
"Prostate cancer demands better tools to prevent over-detection of low-risk cancers and to improve identification of high-risk patients, and that's where targeted prostate biopsy using MRI-ultrasound fusion can play a role," he said.
The research team conducted a retrospective analysis of 286 patients who underwent targeted prostate biopsies using MR-ultrasound fusion from August 2013 to January 2015. The analysis included all patients with suspected prostatic cancer based on clinical or laboratory findings (for example, positive digital rectal examination or high PSA) who underwent multiparametric MRI and US-MRI fusion prostate biopsy. Their mean age was 61.8 years and their prostate weight was 53.4 grams.
Results for the study group were compared with 331 patients in the same period who underwent ultrasound-guided random biopsies with an average of 14 fragments. The comparison group had a mean age of 62.2 and prostate weight of 53.3 grams.
In the test group, the targeted biopsy with MRI-ultrasound fusion found significant cancer, requiring surgery, in 47 percent of patients, and low-risk cancer in another 11 percent, with one stromal tumor of uncertain malignant potential. In the subgroup with the highest risk (142 patients with Likert scores of 4 or 5), the technique detected cancer requiring surgery in 69 percent of cases in the test group. An additional 7 percent of the biopsies detected low-risk cancers.
In comparison, random ultrasound-guided prostate biopsies performed on a sextant basis in a comparison group had only a 40 percent incidence of true positives requiring surgery. An additional 12 percent of the studies detected low-risk cancers.
The patients in the study will be followed for a number of years to determine whether there are differences in death rate or metastases, Mariotti said. The researchers also plan a prospective study that will compare the two techniques used in the same patient.