Deborah A. Kuban, MD

Although high-level evidence is lacking, the existing literature indicates that select men with lymph node–positive prostate cancer benefit from local therapy.

So here we go again with one more round in the battle of treatment options for localized prostate cancer. While more than 3 decades of such sparring has gotten us no closer to evidence-based conclusions, one might say that these matches do serve the purpose of bringing out the best and the worst of the therapeutic contenders.

In the article entitled "Interstitial Brachytherapy Should Be Standard of Care for Treatment of High-Risk Prostate Cancer," Merrick, Wallner, and Butler once again make the case for interstitial brachytherapy as a primary treatment for prostate cancer (see their earlier article, "Permanent Prostate Brachytherapy: Is Supplemental External-Beam Radiation Therapy Necessary?" in ONCOLOGY, April 2006).[1] This time Nathan Bittner has joined as the lead author.

Permanent prostate brachytherapy with or without supplemental therapies is a highly effective treatment for clinically localized prostate cancer, with biochemical outcomes and morbidity profiles comparing favorably with competing local modalities. However, the absence of prospective randomized brachytherapy trials evaluating the role of supplemental external-beam radiation therapy (XRT) has precluded the development of evidence-based treatment algorithms for the appropriate inclusion of such treatment. Some groups advocate supplemental XRT for all patients, but the usefulness of this technology remains largely unproven and has been questioned by recent reports of favorable biochemical outcomes following brachytherapy used alone in patients at higher risk. Given that brachytherapy can be used at high intraprostatic doses and can obtain generous periprostatic treatment margins, the use of supplemental XRT may be relegated to patients with a high risk of seminal vesicle and/or pelvic lymph node involvement. Although morbidity following brachytherapy has been acceptable, supplemental XRT has shown an adverse impact on long-term quality of life. The completion of ongoing prospective randomized trials will help define the role of XRT as a supplement to permanent prostate brachytherapy.

The introduction of prostate-specific antigen (PSA) as a reliabletumor marker for prostate cancer brought significant changes in theend points used for outcome reporting after therapy. With regard to adefinition of failure after radiation, a consensus was reached in 1996that took into account the particular issues of an intact prostate aftertherapy. Over the next several years, the consensus definition issued bythe American Society for Therapeutic Radiology and Oncology(ASTRO) was used and studied. Concerns and criticisms were raised.The sensitivity and specificity of this definition vs other proposals hasbeen investigated, and differences in outcome analyzed and compared.Although the ASTRO definition came from analysis of datasets on external-beam radiation and most of the work on this topic has been withthis modality, failure definitions for brachytherapy must be exploredas well. The concept of a universal definition of failure that might beapplied to multiple modalities, including surgery, should also be investigated,at least for comparative study and research purposes.

Clinical applications of image-based radiation therapy for the study of prostate cancer have expanded significantly over the past years. The results of recent studies of magnetic resonance imaging (MRI) combined with magnetic