Technology Insight: combined external-beam radiation therapy and brachytherapy in the management of prostate cancer

There have been considerable advances in external-beam delivery and brachytherapy techniques for prostate cancer. Combined-modality therapy with external-beam radiotherapy and brachytherapy is an attractive treatment option for a selected group of patients with clinically localized prostate cancer. Hurwitz discusses the indications for use of combination therapy, choice of low-dose-rate versus high-dose-rate brachytherapy boost, and toxicity and quality of life issues. External-beam radiation therapy (EBRT) combined with brachytherapy is an attractive treatment option for selected patients with clinically localized prostate cancer. This therapeutic strategy offers dosimetric coverage if local-regional microscopic disease is present and provides a highly conformal boost of radiation to the prostate and immediate surrounding tissues. Either low-dose-rate (LDR) permanent brachytherapy or high-dose-rate (HDR) temporary brachytherapy can be combined with EBRT; such combined-modality therapy (CMT) is typically used to treat patients with intermediate-risk to high-risk, clinically localized disease. Controversy persists with regard to indications for CMT, choice of LDR or HDR boost, isotope selection for LDR, and integration of EBRT and brachytherapy. Initial findings from prospective, multicenter trials of CMT support the feasibility of this strategy. Updated results from these trials as well as those of ongoing and new phase III trials should help to define the role of CMT in the management of prostate cancer. In the meantime, long-term expectations for outcomes of CMT are based largely on the experience of single institutions, which demonstrate that CMT with EBRT and either LDR or HDR brachytherapy can provide freedom from disease recurrence with acceptable toxicity. Key Points Combined-modality therapy (CMT) offers patients with adverse-risk, clinically localized prostate cancer the advantages of both broad regional coverage derived from external-beam radiation therapy (EBRT) and a highly conformal boost with brachytherapy Controversies remain in relation to the use of CMT: appropriate patient selection, choice of low-dose-rate (LDR) versus high-dose-rate (HDR) brachytherapy boost, and how best to integrate EBRT and brachytherapy A growing number of retrospective series indicate that both LDR and HDR boost offer clinical outcomes and toxicity profiles that compare well with other treatment approaches for similar patient populations Phase II and III studies, a