By Charlie Schmidt
Two early warning signs of possible prostate cancer are high levels of prostate-specific antigen (PSA) within the blood and an abnormal digital rectal exam. When either occurs, a prostate biopsy is frequently done to see if those warning signs are being brought on by prostate cancer. A brand new study suggests that images from MRI scans might help improve biopsy results.
A typical biopsy is completed like this: A health care provider inserts an ultrasound probe into the person's rectum. The probe uses high-frequency sound waves to create images of the prostate gland. These images help the doctor guide several small, hole needles into the gland. These needles capture samples of prostate tissue which are later analyzed to see if prostate cancer cells are present.
A drawback to this method is that ultrasound cannot easily distinguish cancerous tissue from healthy tissue. This means the needles can miss a piece of prostate tissue harboring potentially aggressive cancer cells. In fact, ultrasound-guided biopsy misses such high-grade tumors about 40% of the time.
A study in gave Journal of the American Medical Association reports promising results with a more targeted approach to prostate biopsy. The researchers call it “fusion-guided biopsy” since it fuses ultrasound images with high-resolution images of the prostate made by a brand new technology called multiparametric magnetic resonance imaging (MP-MRI). Prostate tumors appear as dark spots on MP-MRI. By adding pre-taken MP-MRI images to real-time ultrasound images, doctors can goal suspicious areas of the gland while clearing out healthy tissue.
Preliminary tests suggested that fusion-guided biopsy and standard biopsy together are higher at detecting potentially malignant tumors than standard biopsy alone.
gave Jama The study is designed to independently compare the 2 methods. Mohammad Minhaj Siddiqui, assistant professor of urologic surgery on the University of Maryland, and colleagues recruited 1,003 men with either a really high PSA level or an abnormal digital rectal exam and not less than one suspicious site of prostate cancer. was identified by MP-MRI.. All men underwent two biopsies through the same session: a fusion-guided biopsy by one physician, followed by a typical biopsy by a special physician who was not shown the MP-MRI images.
Prostate cancer Evaluates The two methods were almost similar: fusion-guided biopsy detected 461 cases, compared with 469 cases detected by standard biopsy. However, fusion-guided biopsies detected 30% more high-grade cancers, that are potentially more dangerous, and 17% fewer slow-growing, low-risk cancers than standard biopsies.
“The fusion-guided method allowed us to reliably detect more advanced prostate tumors,” said Siddiqui, who conducted the study while he was a fellow on the National Institutes of Health. “And it also reduced the diagnosis of indolent tumors that are unlikely to harm the patient.”
The combination of fusion-guided and standard biopsies detected 103 additional cancers, or 22 percent greater than either method alone. But nearly all of these additional cancers were slow-growing, low-risk tumors. “This suggests that fusion-guided biopsy by itself is sufficient,” Siddiqui said. “Combining two biopsies causes more discomfort to the patient and even increases the risk of complications such as infection and bleeding with limited clinical benefit.”
In a companion editorialLawrence H. Schwartz, Columbia University College of Physicians and Surgeons, and Ethan Bash, a medical oncologist and associate editor on the University of North Carolina. Jamawrote that fusion-guided biopsy “promises more appropriate treatment recommendations, such as more intensive treatment for high-risk disease and active surveillance for men with low-grade tumors.”
Yet Schwartz and Bash emphasize that additional studies are needed to find out whether fusion-guided biopsy has any effect on long-term survival, some extent Siddiqui agrees with.