Improving Predictions of Pathologic Extracapsular Extension

Illustration of cancer of the prostate.
Use of a specialized reader to interpret multiparametric magnetic resonance imaging (MRI) of early prostate cancer tumors may benefit men who are candidates for nerve-sparing procedures, according to a study published in the August 2016 issue of European Urology.

The increase in the incidence of prostate cancer in recent years has spurred the development of gland-sparing treatment options to help preserve potency and continence in patients with low-risk and low-volume, intermediate-risk cancers.

Accurate staging of the disease is therefore important for determining a patient’s treatment options. However, although multiparametric MRI—the relatively new technology touted as a “game changer” for diagnosing prostate cancer—can stage prostate cancer more accurately than traditional biopsy, it is expensive, and its accuracy depends on the reader’s experience.

“There is a need to define the quantum of benefit multiparametric MRI confers so that patients and providers better understand when to obtain one and when a further specialized read is necessary,” says the study’s first author, Kae Jack Tay, MD, urologic oncology fellow at Duke.

The researchers retrospectively analyzed data from 120 men who underwent multiparametric MRI and prostatectomy for localized prostate cancer.

Given the cost and increased community adoption of multiparametric MRI, investigators sought to determine whether, compared with using clinical parameters alone, there was added benefit with regard to predicting pathologic extracapsular extension of having multiparametric MRI read in a standard radiologic setting vs by an additional dedicated, specialized reader.

Study results suggest that adding a standard read does not significantly improve classification of pathologic extracapsular extension compared with using clinical parameters alone. By contrast, adding a specialized read moderately increased specificity, with 81% specificity in the specialized read group compared with 44% in the standard read group. Sensitivity rates between the standard read and specialized groups were comparable.

The authors conclude from their findings that the improved rates of specificity of the specialized read are particularly beneficial to men interested in nerve-sparing, potency-preserving procedures where the absence of extracapsular extension is critical to success. Men who have already opted for broad resection of the erectile nerves may not see an additional benefit of having a specialized reader interpret their multiparametric MRI.

“This study is significant for 2 important reasons,” says senior author Thomas Polascik, MD, a prostate cancer surgeon at Duke who specializes in nerve-sparing techniques. “First, it demonstrates that the expertise of the radiologist reading the films is critical for an accurate assessment of cancer involving the capsule or erectile nerves. Second, I want to have all available information beforehand that informs where the cancer is located and if it is reasonable to spare the erectile nerves in a given situation.”