Objective: To compare a series of 121 sextant needle biopsy sets with their corresponding radical prostatectomy specimens in screened participants in the European Randomized study of Screening for Prostate Cancer (ERSPC), investigating the effect of screening for prostate cancer on disease-specific mortality and quality of life, as the clinical significance of a small focus of well-differentiated prostate cancer on biopsy is unclear.
Patients and methods: The expected clinical significance of the discovered tumours was estimated using an arbitrary model combining volume, grade, and stage characteristics.
Results: Of 34 patients who had a small focus (< 3 mm on a single biopsy core) of well-differentiated carcinoma on biopsy, only 18 (53%) were found to have minimal carcinoma (a small focus of well-differentiated carcinoma) at radical prostatectomy, while 16 (47%) had moderately advanced or advanced carcinoma at radical prostatectomy. The preoperative prediction of minimal carcinoma improved when the amount of cancer in the sextant biopsy set was combined with the preoperative serum prostate specific antigen (PSA) level. Of 12 patients with a small focus of well-differentiated carcinoma on biopsy and a serum PSA of < 4 ng/mL, 11 had minimal carcinoma at radical prostatectomy, while there was minimal carcinoma in only seven of 22 (32%) patients with a small focus of well-differentiated carcinoma on biopsy and a serum PSA of > or = 4 ng/mL.
Conclusions: The predictive value of a small focus of well-differentiated cancer on systematic sextant biopsy for a small well-differentiated tumour in the prostate is limited. The predictive value improves when serum PSA levels are considered concurrently, but is still considered insufficient to support a base for selecting therapy for the individual patient.