Genomic prognostic signatures are used on prostate biopsy tissue for cancer risk assessment, but tumor heterogeneity and multi-focality may be an issue. We evaluated the variability in genomic risk assessment from different biopsy cores within the prostate using three prognostic signatures (Decipher, CCP, GPS).
Materials and Methods
Men in this study came from two prospective prostate cancer trials of patients undergoing mpMRI and MRI targeted biopsy with genomic profiling of positive biopsy cores. We explored the relationship between tumor grade, MRI risk, and genomic risk for each signature. We evaluated the variability in genomic risk assessment between different biopsy cores, and assessed how often MRI targeted biopsy or the current standard of care (profiling the core with the highest grade) resulted in the highest genomic risk level.
224 positive biopsy cores from 78 men with prostate cancer were profiled. For each signature, higher biopsy grade (p <0.001) and MRI risk level (p <0.001) were associated with higher genomic scores. Genomic scores from different biopsy cores varied with risk categories changing by 21-62% depending on which core or signature was used. MRI targeted biopsy and profiling the core with the highest grade resulted in the highest genomic risk level in 72-84% and 75-87% of cases, respectively, depending on the signature used.
There is variation in genomic risk assessment from different biopsy cores regardless of the signature used. MRI directed biopsy or profiling the highest grade core resulted in the highest genomic risk level in most cases.