Objectives: To reveal the possible contribution of histological inflammation within the prostate to the abnormal elevation of serum prostate-specific antigen (PSA) levels in patients with needle biopsy negative for prostate cancer.
Methods: We reviewed negative needle biopsy specimens obtained in 93 patients. The degree of acute and chronic inflammation as evaluated histologically was compared with serum PSA levels in conjunction with age and prostate volume.
Results: Both age (P <0.01) and prostate volume (P <0.0001) correlated significantly with serum PSA levels and were significantly greater in patients with abnormal serum PSA levels (greater than 4.0 ng/mL) than in those with normal serum PSA levels (4.0 ng/mL or less) (P <0.01). The presence of histological inflammation within the prostate also correlated significantly with serum PSA levels. Multiple regression analysis demonstrated prostate volume to be the only independent determinant of serum PSA levels (P <0.01). In patients with a prostate volume larger than 25 mL, only prostate volume correlated significantly with serum PSA levels (P <0. 05). On the other hand, the degree of acute inflammation as represented by polymorphonuclear leukocyte infiltration was the only parameter correlating significantly with serum PSA levels (P <0.05) in patients with a prostate volume smaller than 25 mL.
Conclusions: Histologically defined acute inflammation within the prostate is a significant contributor to elevated serum PSA levels, especially in patients with small prostates. In the assessment of needle biopsy results negative for prostate cancer, it might be helpful to evaluate the degree of histological inflammation, especially in terms of the necessity of subsequent repeated biopsies.