Objective: To evaluate the usefulness of the combination of serum prostate-specific antigen (PSA) and cancer volume in biopsy specimens as markers to predict the extent of prostate cancer.
Patients and methods: Of patients presenting at our hospital with urinary symptoms suggesting prostatic disease, 311 (median age 70 years, range 42-88) with either nodules in the prostate detected by digital rectal examination or with elevated serum PSA levels (> 2.0 ng/mL) underwent systematic biopsy; 69 had prostate cancer. The cancer volume in the biopsy specimens was examined pathologically by measuring the percentage of the biopsy core involved with cancer, the length of cancer tissue per biopsy core and the percentage of cancer in the biopsy specimen. The relationship of serum PSA level, cancer volume in the biopsy specimen and the extent of disease was examined.
Results: The volume of cancer in the biopsy specimens increased with increasing serum PSA concentration and the incidence of skeletal metastasis. The number of patients with extraprostatic disease or bony metastasis was significantly higher for these Japanese patients with a serum PSA of < 10 ng/mL. All six patients with a positive bone scan and who had a serum PSA level of < 10 ng/mL had a larger volume of cancer in their biopsy specimens. Among patients who underwent radical prostatectomy and pelvic lymphadenectomy, the incidence of extraprostatic disease increased with the value of each biopsy variable. Among patients with similar serum PSA levels, those showing higher values for the biopsy variables also showed extraprostatic disease. Among those with extraprostatic disease, seminal vesicles were involved by cancer in four of six patients with > 40% positivity in the biopsy cores, > 1.5 mm of cancer per biopsy core or > 20% cancer in the biopsy specimens. Lymph node metastasis was found in four of five patients with serum PSA levels of > 20 ng/mL and a large cancer volume in the biopsy specimen.
Conclusions: These results indicate that a combination of serum PSA level and cancer volume in the biopsy specimen could be useful markers for predicting the extent of prostate cancer.