ABSTRACT
Permanent prostate brachytherapy (PPB) is an acceptable curative treatment modality for men with localized prostate cancer.1-6 However, as currently performed, it is used either as monotherapy or in conjunction with a short course of external beam radiotherapy (RTPPB). The reasons for combining therapy are multifactorial (Table 38.1). Without prospective data, it is difficult to ascertain which is the best indication. The most frequently used indication is based on the ‘statistical’ risk of extracapsular disease associated with Gleason score, prostate-specific antigen (PSA), and stage.1 An implant only provides dose to the prostate with a 3-5 mm margin and may extend to include just the base of the seminal vesicles.2 The ‘field’ effect of external radiation to encompass the seminal vesicles and a larger prostatic margin potentially are at risk for extracapsular disease not treated by the implant. This approach has continued without much change since originally suggested by Blasko et al during the initiation of the modern era of prostate brachytherapy. Doses of 45 Gy with 75% of the prescribed implant dose are considered standard when using combined therapy.
