Low serum neutrophil count predicts a positive prostate biopsy

BACKGROUND: Asymptomatic prostatic inflammation may cause increased PSA in some men, leading to unnecessary prostate biopsy. We investigated whether the differential white cell count could predict the result of prostate biopsy. METHODS: Prostate needle biopsy was carried out in 323 Japanese men with elevated PSA levels or abnormal digital rectal findings. White blood cell count (WBC), differential white cell count (neutrophils, lymphocytes, basophils, eosinophils, and monocytes), and serum C-reactive protein level were assessed for associations with biopsy findings. RESULTS: In all, 203 (62.1%) were positive for prostate cancer. WBC, neutrophil count, age, PSA, prostate volume, and PSA density (PSAD) were associated with the results of biopsy (P<0.05). Multivariate analysis showed that neutrophil count, age, PSA, prostate volume and PSAD were independent predictors. When the cut-off neutrophil count was set at 2900 mu l(-1), 78 of 104 men (75.0%) with a count below this value had a positive biopsy, while 125 of 219 (57.0%) men with a count above this value were positive. The area under the receiver-operator characteristics curve (AUC) for the predicted probability of a positive biopsy for prostate cancer according to the optimum logistic model was 0.83 (95% confidence interval (CI) 0.78-0.87), while the AUC for PSA was 0.70 (95% CI 0.64-0.76) and that for PSAD was 0.79 (95% CI 0.74-0.84). CONCLUSIONS: An elevated neutrophil count may be a good indicator of a benign prostate biopsy. Men with a low neutrophil count and an increase of serum PSA should strongly be considered for biopsy.