Role of interstitial radiotherapy in the management of clinically organ-confined prostate cancer: the jury is still out

Abstract

Purpose and design: To discuss the evolution of the use of brachytherapy in the treatment of clinically organ-confined prostate cancer and to review modern techniques, results of therapy, and optimal patient selection criteria.

Results: Using modern localization and immobilization techniques, interstitial prostate radiotherapy for patients with a prostate-specific antigen (PSA) level less than 10 ng/mL yields an at least 87% rate of freedom from biochemical relapse at 3 years, which is numerically equivalent to results achieved with external-beam radiotherapy or radical prostatectomy. With a minimum median follow-up time of 24 months, 81% to 85% (2-year actuarial and 3-year crude) potency rates have been reported concomitant with 2-year actuarial rates of 12% for grade > or = 2 rectal complications and 10% for grade > or = 3 urethral complications.

Conclusion: The combination of clinical stage, PSA level, and biopsy Gleason sum allows for selection of patients with the highest probability of having all of the prostate cancer encompassed by the high-dose implant volume, while simultaneously respecting the normal-tissue tolerance doses of the juxtaposed normal tissues (rectum and bladder). In particular, patients with nonpalpable (T1c) lesions, a biopsy Gleason sum < or = 6 (ideally < or = 4), and a PSA level less than 10 ng/mL represent the optimal implant candidates. Differential loading of the implant away from the geometric center and not accepting patients with large prostate glands (> or = 60 cm3) or history of a transurethral resection of the prostate (TURP) as implant candidates, may reduce urethral toxicity. Further follow-up evaluation of prostate cancer patients treated with interstitial radiotherapy will verify if favorable potency preservation rates and rates of freedom from biochemical failure equivalent to those achieved with radical prostatectomy or external-beam radiation therapy are maintained.