Clinical outcomes of low-dose-rate brachytherapy based radiotherapy for intermediate risk prostate cancer

Abstract

Purpose: To monitor the outcomes for intermediate-risk prostate cancer patients treated with biologically effective dose (BED) ≥ 200 Gy radiotherapy using low-dose-rate (LDR) brachytherapy. Material and methods: Between 2005 and 2016, a total of 397 patients with intermediate-risk prostate cancer were treated by LDR-based radiotherapy with a BED ≥ 200 Gy. Treatments consisted of LDR brachytherapy alone (177 cases) or LDR and external beam radiotherapy (EBRT) (220 cases). Short-term androgen deprivation therapy (ADT) was used in 186 patients (46.9%). The median follow-up period was 72 months (range 29-165 months). Dosimetric parameters and BED were studied in each case. The numbers of intermediate-risk features were: 163 patients with 1 intermediate-risk feature (41%), 169 patients with 2 intermediate-risk features (43%), and 65 patients with 3 intermediate-risk features (16%). A total of 145 cases were diagnosed as having primary Gleason pattern 4: Gleason score 4 + 3 (36.5%). Results: Three patients developed biochemical failure, thus providing a 7-year actual biochemical failure-free survival (BFFS) rate of 99.1%. Biochemical failure was observed exclusively in cases with distant metastasis: two cases with lymph node metastasis and one case with bone metastasis, thus yielding a 7-year freedom from clinical failure (FFCF) rate of 99.1%. We observed eight deaths, but there was no death from prostate cancer, thus yielding a 7-year cause-specific survival (CSS) rate of 100%, and an overall survival (OS) rate of 98.4%. Conclusions: This study highlights excellent outcomes for intermediate-risk prostate cancer patients, including unfavorable intermediate-risk cases, treated with BED ≥ 200 Gy radiotherapy using LDR brachytherapy. LDR alone with a BED of 200 Gy may be an optimal treatment for both favorable and unfavorable intermediate-risk prostate cancer patients, although a longer follow-up is mandatory to confirm the present findings.

Focal low-dose-rate prostate brachytherapy for low- and intermediate-risk prostate cancer

“…Radical whole-gland therapies provide excellent oncological outcomes for these patients. Low-dose-rate (LDR) whole-gland prostate brachytherapy provides excellent oncological outcomes [ 2 ]; however, excessive treatment may influence quality-of-life. Although prostate cancer is mostly a multi-focal disease [ 3 ], recent evidence indicates that focal therapy delivered to the index lesion, the largest tumor focus within the prostate, may effectively control disease.…”

Low-/high-dose-rate brachytherapy boost in patients with intermediate-risk prostate cancer treated with radiotherapy: long-term results from a single institution team experience

“…The published literature of combined treatment (EBRT plus LDR or HDR-BT) including IR patients exclusively is scarce [ 35 - 38 ]. In contrast to these data, our series reflects great homogeneity, both in the performance of the treatments and in the follow-up of these patients over time.…”

Ten‐step method of high‐dose LDR 125I brachytherapy for intermediate‐risk prostate cancer

“…The prescription dose of seed implantation was set at 144 Gy for LDR 125 I monotherapy: we set D90 at 190 Gy. For this method, we commonly used 125 I seed activity at 0.361 (U) as described in our previous report 6 …”

“…Postimplant dosimetry was carried out at 1 month after seed implantation by using CT and MRI fusion guidance 6,11 . The biologically effective dose (BED) was calculated using an α/β ratio of 2 9 …”

“…For brachytherapists, including physicists, LDR alone with a BED of ≧ 200 Gy requires a highly skilled brachytherapy technique to safely deliver a high radiation dose. In the previous publication, 6 we declared that the detailed method of the high‐dose implantation technique would be presented separately. Thus, in the present technical report, our LDR 125 I implant monotherapy method with a BED of 200 Gy is described in detail.…”