Presentation Authors: Ayesha Butt*, Rahul Pandya, Ahmed Ibrahim, Iqbal Miakhil, Peterborough, United Kingdom
Introduction: Prostate specific antigen (PSA) has been a useful screening tool in identifying prostate cancer since its discovery. However relying on PSA alone has shown poor performance in prostate cancer detection. It is envisaged that measuring PSA density can possibly enhance its predictive value in detecting cancers, however it is not standard practice or recommended in national guidelines. Previous studies have shown that PSA density is most useful when the PSA is in the range of 4-10ng/ml due to diagnostic uncertainty within that range. _x000D_
We aim to study the effectiveness of PSA density at detecting prostate cancer within that range as well as outside that range.
Methods: Retrospective single centre study at North West Anglia NHS Trust including 500 patients who had a mp-MRI prior to prostate biopsy between July 2017 to July 2018. Patients undergoing repeat biopsy already on a cancer pathway were excluded. PSA density was calculated by dividing PSA over the prostate volume as recorded on the mp-MRI.
Results: Data was collected from 500 patients with a mean age of 65 and mean PSA of 10.7ng/ml. A total of 321 (64.2%) patients had a PSA between 4-10 ng/ml. The mean PSA density within that range was calculated for each Gleason score and found to be 0.11 ng/ml/cm3 for benign, 0.13 for Gleason 6, 0.16 for Gleason 7, 0.18 for Gleason 8 and 0.21 for Gleason 9. Overall the mean PSA density in prostate cancer was found to be 0.15 and 0.17 in clinically significant prostate cancer defined as Gleason score â‰¥ 7. _x000D_
There is a statistically significant difference between the mean PSA density values of cancer positive biopsies vs benign (T test p < 0.001)._x000D_
A cut off value of PSA density was chosen at 0.15 and 0.10. Sensitivity of 0.10 at detecting all prostate cancer with PSA 4-10 was 76% and 88% for clinically significant prostate cancer. The negative predictive value was 94% for clinically significant prostate cancer. _x000D_
With PSA of < 4 or >10 and PSA density of 0.10 the sensitivity was 93% (all cancer) and 96.6% (Gleason â‰¥ 7) with a negative predictive value of 93.7% for clinically significant prostate cancer. _x000D_
At a cut off PSA density of 0.15 sensitivity and negative predictive value was 39% and 65% (all prostate cancer) and 50% and 87% (Gleason 7 and above) respectively with PSA of 4-10.
Conclusions: PSA density usage can help improve the accuracy of detecting prostate cancer and thus reduce the number of unnecessary prostate biopsies. A cut off value of 0.10 ng/ml/cm3 has a higher sensitivity and negative predictive value, especially when compared against clinically significant cancer.