番茄社区

KISSIMMEE, Fla. -- MRI missed some clinically significant prostate cancer pathology, a researcher said here.

In a retrospective, 3-year study, preoperative MRI was performed on 156 men suspected of having prostate cancer, and in 33 cases (21%), MRI failed to detect that region of interest (ROI) that was later found on biopsies, reported Kanika Taneja, MD, of Henry Ford Hospital in Detroit.

The most frequently missed pattern was infiltrative growth with cancerous glands intermingling between benign glands, Taneja and colleagues found, adding that one of those "misses" was a 2.5-cm, grade 5 tumor.

"This is a tumor which should not have been missed by MRI, but it was," Taneja said at the College of American Pathologists annual meeting.

The cancer was detected after pathological examination of the biopsy specimen, she said, and about 10% of the mass was cancerous; 90% was benign.

"The association between [ROI] identified through [MRI] of the prostate and radical prostatectomy findings has been extensively studied," the authors stated. "However, the pathology of prostate cancer ... that does not produce visible changes on MRI is not well characterized."

The study population consisted of patients who underwent MRI from 2015 to 2018, and had ultrasound-guided biopsy-proven prostate cancer, but did not have any region of interest identified with MRI.

The mean patient age was 62.7, the mean prostate specific antigen (PSA) was 6.85 ng/mL, and the mean PSA density was 0.13 ng/mL/cm². More than 80% of the patients had prostate cancer classified as grade ≥2. Tumor size ranged from 0.8 cm to 4 cm.

When the MRI failed to show an ROI, patients was referred for biopsy."The decision to go to biopsy, in these cases, is based on clinical judgment," Taneja explained. "For example, a digital examination might determine abnormal prostate, and prompt the clinician to go ahead with a biopsy, even when the MRI is negative."

Ten of 33 patients (30%) had extraprostatic disease -- nine with pT3a, the other with pT3b, the authors reported.

"Our study outlines limitations of MRI, as some clinically significant prostate cancer may not be detected," they wrote. "Clinicians should be aware of this limitation and pay attention to other preoperative variables in their decision making and management of prostate cancer patients."

Rong Xia, MD, of the State University of New York Downstate Medical Center in New York City, told 番茄社区, "We often experience similar situations in which an MRI fails to find a prostate cancer. However, we usually would perform a biopsy if the patient has symptoms, which may appear clinically to be some sort of obstruction. The gold standard in these cases is, of course, biopsy."

"There is a lot of new developments in technology and imaging, but the best thing we can do to diagnose prostate cancer is to take a bit of tissue and examine it under the microscope," Xia said. "I believe there is a role in pathology for new techniques, and with artificial intelligence, but now the best method is to take a look at the tissue."

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