Advanced Diagnostics and Treatment for Prostate Cancer
Diagnostic Innovation: MRI/Ultrasound Fusion-Guided Biopsy
To help identify a prostate malignancy and determine if and how it should be treated, there are a number of options, from the well-known prostate-specific antigen (PSA) screening test to various genetic tests, followed by a biopsy if the earlier tests warrant. As with other cancers, early detection and treatment can save lives. Yet traditional biopsies may yield inconclusive or inaccurate results, possibly missing some aggressive tumors and finding some indolent ones, potentially leading to under- or over-treatment.
Now physicians at Stony Brook University Cancer Center are employing an innovative diagnostic modality that provides more selectivity and accuracy than the traditional biopsy method.
Targeted biopsies yield better results
A new magnetic resonance imaging (MRI)/ ultrasound fusion-guided biopsy procedure lets doctors take advantage of the best of two technologies — MRI and ultrasound — simultaneously during a prostate biopsy.
Using a special device that “fuses” a stored MRI image with a real-time ultrasound image, urologists can see the prostate in 3D, which allows greater clarity and more precise targeting of lesions suspicious for tumors.
Stony Brook is the only hospital in Suffolk County that is currently using the fusion-guided biopsy method to benefit patients whose previous testing has indicated a strong possibility for prostate cancer.
How fusion-guided biopsy works
With the traditional biopsy method, doctors take ultrasound-guided tissue cores without being able to differentiate between cancerous and normal tissue. In contrast, with the MRI/ ultrasound-fusion method, the urologist can target specific lesions that have previously been identified as potentially significant cancers on an MRI scan.
First, the patient gets an MRI. A specially trained radiologist then analyzes the MRI, marks specific lesions, and grades them with a score from one to five, with five being most suspicious for prostate cancer. The patient then has an ultrasound during which the urologist, who has been trained in using the sophisticated fusion software, synchs the marked-up MRI image with the real-time ultrasound image. The fusion of the two images allows the urologist to more clearly visualize suspicious areas in the prostate and, with ultrasound guidance, target those specific areas for biopsy.
“Research has shown that these targeted biopsies are better at detecting more clinically significant cancers,” said Wayne Waltzer, MD, Chair, Department of Urology. “These high-risk cancers need to be treated, as opposed to low-risk tumors that often don’t need treatment at the time of detection.”
Dr. Waltzer cautions that an MRI/ultrasound fusion-guided biopsy doesn’t guarantee to find all lesions, but finding more of the ones that are high risk can help reduce the need for repeat biopsies. The fusion-guided biopsy may also be more accurate in detecting suspected malignancies in men who have elevated PSAs but had previous negative biopsies. And just as important, it may help reduce further procedures for tumors that don’t need intervention.
In cases where a prostate biopsy is negative, but there is reason to pursue further testing, Stony Brook physicians have other advanced diagnostic options to help determine an appropriate course of action:
ConfirmMDx® examines the tissue around the biopsied areas and the results can indicate a high probability of malignant cells near, or adjacent, to the area that was biopsied. The hypermethylationof promotor regions GSTP1, APC and RASSF1 is assessed in core-biopsy tissue samples. The testis able to detect abnormal changes to the DNA associated with the presence of prostate cancer and can help determine if a repeat biopsy is needed. This has a negative predictive value of approximately 90 percent to confirm the absence of cancer in a histopathologically negative biopsy.
Post-biopsy diagnostics for genetic abnormalities
Additionally, there are other specialized diagnostics that look for genetic abnormalities in the tissue:
The Oncotype DX® test uses small (1mm) paraffin-embedded tissue samples obtained by a needle biopsy for patients who have undergone radical prostatectomy. Assay by reverse transcription polymerase chain reaction (RT-PCR) measures 12 cancer-related genes, which represents four different biologic pathways to a Genomic Prostate Score (GPS). The GPS is used to determine whether men with newly diagnosed low-risk prostate cancer are appropriate candidates for watchful waiting or harbor a more aggressive disease.
Prolaris® testing uses RT-PCR on RNA and measures the level of 31 genes involved in cell cycle progression (CCP). This test stratifies cancer aggressiveness based on a score and plots a curve of 10-year prostate cancer specific mortality.
The Decipher® test predicts the risk of five-year metastasis after radical prostatectomy. Those with low risk can be observed, but high-risk patients may benefit from early radiation.
“The objective is for doctors to have all the relevant information they need to create a treatment plan that will best serve the patient,” said Dr. Waltzer.
For the full issue: Cancer Today • Fall 2015