Early diagnosis of prostate cancer in the Western Cape

Early stage prostate cancer does not cause symptoms, and even metastatic disease may exist for years without causing symptoms or signs. Whereas early stage prostate cancer can be cured with radical prostatectomy or radiotherapy, the prognosis of patients with locally advanced or metastatic cancer is significantly poorer.

In view of the high incidence of advanced and therefore incurable prostate cancer seen at the oncology clinic of the Department of Urology, Tygerberg Hospital, we started a prostate clinic with the aim of detecting early stage prostate cancer which is potentially curable. A secondary objective was to investigate the question whether there is a higher incidence of prostate cancer among black African men.

Men aged 50-70 years were invited by means of media communications (newspaper and radio) to attend our prostate clinic for a free physical examination, including a digital rectal examination (DRE) and serum prostate specific antigen (PSA) assay. If the DRE was clinically suspicious of malignancy and/or the serum PSA was > 4 ng/ml, the patient was appropriately counselled and referred for transrectal ultrasound (TRUS)-guided sextant prostate biopsy.

In the period June 1997-September 1999 a total of 1,056 men attended the prostate clinic. Biopsies were indicated in 160 cases, and were obtained in 114 (71.3%, i.e. 10.8% of the entire cohort). Prostate cancer was detected on first biopsy in 3.5% of the entire group of men (in 35.9% of those with a clinically abnormal DRE, in 41.3% of those with a serum PSA > 4 ng/ml and in 88.6% of those with an abnormal DRE and serum PSA > 4 ng/ml. In the 37 men with prostate cancer, the clinical tumour stage was T1-2 in 83.8% and T3-4 in 16.2%. In the group of patients with clinical stage T1-2 tumours, the treatment was watchful waiting in 62.5% of cases, radiotherapy in 20.8% and radical prostatectomy in 16.7%. Analysis of the data according to race showed that in the group of 47 black men there was a higher percentage of clinically abnormal DRE, PSA > 4.0 ng/ml and biopsies showing malignancy, and a higher overall prostate cancer detection rate (8.5%).

Our prostate cancer detection rate of 3.5% is slightly lower than that reported in larger studies (4.7%), which may be due to the fact that prostate biopsy was performed in only 71% of those who had an indication for biopsy. In the men diagnosed with clinically localised prostate cancer, potentially curative treatment was given in only 37.5% of cases. This compares unfavourably with the historical cohort of men seen at our oncology clinic, where 53% received potentially curative treatment, and a large European study where potentially curative treatment was given in 89% of cases. Our finding that black men had a higher percentage of clinically abnormal DRE, PSA > 4.0 ng/ml and biopsies showing malignancy and a higher overall detection rate of prostate cancer should be interpreted with caution, since black men comprised only 4.5% of our overall study cohort.