Abstracts Category : Other

Implications of MRI/ultrasound fusion guided targeted biopsies on the diagnostics of prostate cancer

by Hannes Cash

PCa presents the most common cancer in men of the western world. In the past two decades, the diagnostics of PCa was defined by the PSA test and the TRUS guided systematic prostate biopsy. The primary TRUS guided biopsy reveals PCa in only about half the men. Men with a negative biopsy and further elevated PSA levels often undergo subsequent TRUS guided biopsies with further declining PCa detection rates. Historically, imaging of the prostate with MRI played no role in the diagnostics of PCa, but recently the paradigm has started to shift. Visualizing the cancer suspicious lesions within the prostate on the mpMRI allowed for MRI/US fusion guided targeted biopsies rather than systematic sampling. The mpMRI and targeted biopsy therefore presented an option to improve on the standard of care. The first study therefore analyzed the cancer detection rates for men undergoing a MRI/US fusion guided targeted biopsy in combination with a 10-core systematic biopsy. The analysis included 310 men with a suspicious lesion according to PI-RADS. The detection rate of the whole cohort was 51% and 62% of cancers were GS 7. In patients undergoing a primary biopsy cancer was detected in 75% and a GS 7 was diagnosed in 75% of the cases. In the repeat biopsy setting, the detection of PCa ranged from 44% for men with 3 negative to 54% for men with one negative systematic biopsy. The PI-RADS score of the target lesion was a significant predictor for GS 7 detection. We concluded that the combination of targeted biopsies with a systematic biopsy seem to advance the performance of the standard biopsy regimen. Furthermore, we established a need to evaluate the impact of the PI-RADS score on targeted biopsies. The second publication focused on correlating each single PI-RADS score with the cancers detected by of MRI/US fusion biopsy. The PI-RADS classification for the standardized reporting of mpMRI was published in 2012. Data on the actual value of the PI-RADS score at the time our study was scarce and with 408 included men, our study presented the largest PI-RADS based analysis. In 56% of men PCa was found and the detection rates regarding the number of previous prostate biopsy were further improved compared to the first analysis. Further, the analysis showed again that the detection of significant PCa stayed constant independent of the number of prior biopsies (76-79%). Whereas men with PI-RADS 3 lesions had cancer in 26% of cases, men with PI-RADS 5 lesions were diagnosed with PCa in 89%. The study showed the strong correlation of the PI-RADS score to the detection of clinically relevant PCa. Nonetheless, we also recommend combining targeted biopsies with systematic biopsies for increased diagnostic accuracy. The data of the cancers missed by targeted biopsy and detected by the systematic biopsy raised the question of the underlying reasons. The retrospective analysis included 61 men in which a blinded re-evaluation of each PI-RADS score was performed. This was followed by an unblinded correlation of the mpMRI targets and the