The role of fine-needle aspiration biopsy of the prostate in staging adenocarcinoma.

Stage A prostate cancer is defined as the incidental finding of cancer in specimens obtained by transurethral resection of the prostate (TURP) in a clinically benign gland. A low-to-moderate grade tumor involving less than 5% of the TURP specimen has been termed Stage A1; a high-grade tumor or tumor involving more than 5% of the TURP specimen is termed Stage A2. Most investigators agree that Stage A1 disease has a significantly better prognosis than Stage A2 disease and may not warrant radical prostatectomy. However, the problem of correctly differentiating A1 and A2 disease remains. The authors prospectively studied 100 consecutive patients undergoing TURP for outlet obstruction without clinical suspicion of prostate cancer by digital examination. Each patient underwent fine-needle aspiration biopsy (FNAB) of each side of the prostate immediately before TURP. These data show that the addition of preprostatectomy FNAB increased the incidence of finding adenocarcinoma of the prostate from 10% to 14%. An additional 3% had FNAB results that were highly suspicious. A positive correlation between cytologic and histologic findings was seen in 83% of patients. Of three patients with Stage A2 prostate cancer, none had malignant cytologic findings. Of seven patients with Stage A1 disease, five (71%) had suspicious or malignant cytologic findings. Seven patients (7%) had suspicious or malignant cytologic findings with no histologic evidence of tumor. In conclusion, preprostatectomy FNAB cannot differentiate Stage A1 from Stage A2 prostate cancer. However, the procedure does increase the yield of finding incidental prostate cancer. The therapy of patients with either (1) malignant cytologic findings alone (Stage A0 disease), or (2) Stage A1 histologic and malignant cytologic findings (Stage A1+) is unclear at present.