Systematic overview of the evidence for brachytherapy in clinically localized prostate cancer

Abstract

Background: Brachytherapy (permanent implantation of radioactive seeds) has emerged as an alternative to existing standard therapy with radical prostatectomy or external beam radiotherapy in the treatment of clinically localized (T1 and T2) prostate cancer. The Genitourinary Cancer Disease Site Group of the Cancer Care Ontario Practice Guidelines Initiative examined the role of brachytherapy in treating clinically localized prostate cancer.

Methods: A systematic review of articles published from 1988 to April 1999, retrieved through a search of MEDLINE and CANCERLIT databases, was combined with a consensus interpretation of the evidence in the context of conventional practice.

Results: Although there were no randomized trials comparing brachytherapy with standard treatment, evidence was available from 13 case series and 3 cohort studies. Rates of freedom from biochemical failure (biochemically no evidence of disease [bNED]) varied considerably from one series to another and were highly dependent on tumour stage, grade and pretreatment serum prostate-specific antigen (PSA) levels. Results in patients with favourable tumours (T1 or T2 tumour, Gleason score of 6 or lower, serum PSA level of 10 ng/mL [microgram/L] or less) were comparable to those in patients undergoing radical prostatectomy. Acute urinary retention was reported in 1%-14% of patients. Long-term sequelae occurred in less than 5% of patients and included urinary incontinence, cystitis, urethral strictures and proctitis. Sexual potency was maintained after implantation in 86%-96% of patients.

Interpretation: At present, there is insufficient evidence to recommend the use of brachytherapy over current standard therapy for localized prostate cancer. Brachytherapy using transrectal ultrasound guidance for seed implantation is promising in terms of freedom from biochemical failure in selected patients with early-stage prostate cancer. Brachytherapy is currently available outside of clinical trials, but whenever possible patients should be asked to participate in randomized trials comparing brachytherapy and current standard therapy. Brachytherapy should be available to selected patients (those with T1c or T2a tumours, a Gleason score of 6 or lower and a serum PSA level of 10 micrograms/L or less), after discussion of the available data and potential adverse effects.

Fig. 1: Anteroposterior radiograph, showing radioactive seeds implanted into prostate gland.