IRCCS Policlinico San Martino Hospital - University of Genova
Introduction: To evaluate the PCa detection rate in men with chronic use of Aspirin and to compare it with the detection rate of non-users. We suspect to find a significantly higher detection rate in Aspirin users, due to the reduction of the proportion of PSA that would have been raised due to inflammation.
Methods: After institutional review board approval, we retrospectively collected patients undergoing prostate biopsy over the last 10 years in five institutions. Patients with PSA levels higher than 100 ng/dL, with unknow pathology at prostate biopsy, with Aspirin dosages other than 100mg and with unknown duration of Aspirin therapy were excluded from the analyses. Patients were divided in two groups according to their exposure to Aspirin. Descriptive statistics tested differences in clino-pathological characteristics between the two groups. We relied on multivariable linear and logistic regression models to test whether Aspirin administration was associated with lower PSA values at prostate biopsy, higher prostate cancer diagnosis and higher Gleason Grade Grouping (GGG) at biopsy.
Results: We identified 1,059 patients, of whom 803 (76%) did not take Aspirin vs 256 (24%) were taking Aspirin. Patients taking Aspirin were significantly older (72 vs 67 years), were smokers (44 vs 15%), had lower PSA levels (8 vs 7 ng/dL), and had displayed prostatic inflammation at prostate biopsy (48 vs 34%) (all p<0.001). No statistically significant differences in prostate volume, histology (cancer vs non-cancer) and higher GGG (4-5 vs 1-2-3) were recorded. In multivariable loglinear regression analysis, Aspirin administration was associated with lower PSA levels (OR 0.83, 95% CI 0.71-0.97, p=0.01), after controlling for age, prostate volume, smoking history, associated inflammation at prostate biopsy, presence of PCa at biopsy, and GGG. In multivariable logistic regression analysis, Aspirin administration was not found to be a predictor of PCa at prostate biopsy (OR 1.40, 95% CI 0.82-2.40, p=0.21) after controlling for Age, PSA, smoking history, prostate volume, findings at digital rectal examination (DRE) and number of biopsy cores. After controlling for the same variables, in patients with PCa at prostate biopsy (n=516), Aspirin administration was found to predictor of higher GGG (OR 2.24, 95% CI 1.01-4.87, p=0.04).
Conclusions: Our study suggests that Aspirin administration is associated with lower levels of PSA in patients undergoing prostate biopsy. Aspirin administration does not seem to be associated with a higher probability of PCa at prostate biopsy. However, in patient with PCa at prostate biopsy, Aspirin administration was found to be a predictor of more aggressive Gleason Grade Grouping. These findings suggest that a lower PSA threshold should be considered in patients taking Aspirin, as, despite low PSA levels, they might harbour aggressive prostate cancer.