Clinical Investigation
High-Dose-Rate Brachytherapy and External-Beam Radiotherapy for Hormone-Naïve Low- and Intermediate-Risk Prostate Cancer: A 7-Year Experience

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Purpose

To report clinical outcomes and early and late complications in 264 hormone-naïve patients with low- and intermediate-risk prostate cancer treated with high-dose-rate brachytherapy (HDR-BT) in combination with external-beam radiotherapy (EBRT).

Methods and Materials

Between February 2000 and July 2007, 264 patients underwent HDR-BT in combination with EBRT as a treatment for their low- to intermediate-risk prostate cancer. The HDR-BT was performed using ultrasound-based implantation. The total HDR-BT dose was 18 Gy in 3 fractions within 24 h, with a 6-h minimum interval. The EBRT started 2 weeks after HDR-BT and was delivered in 25 fractions of 1.8 Gy to 45 Gy within 5 weeks.

Results

After a mean follow-up of 74.5 months, 4 patients (1.5%) showed prostate-specific antigen progression according to the American Society for Radiation Oncology definition and 8 patients (3%) according to the Phoenix definition. A biopsy-proven local recurrence was registered in 1 patient (0.4%), and clinical progression (bone metastases) was documented in 2 patients (0.7%). Seven-year actuarial freedom from biochemical failure was 97%, and 7-year disease-specific survival and overall survival were 100% and 91%, respectively. Toxicities were comparable to other series.

Conclusions

Treatment with interstitial HDR-BT plus EBRT shows a low incidence of late complications and a favorable oncologic outcome after 7 years follow-up.

Introduction

External-beam radiotherapy (EBRT) is one of the most used options for the treatment of localized prostate cancer (PC). High doses >70 Gy have to be used to achieve good local control, but may increase complications (1). High-dose conformal radiotherapy can also be achieved with brachytherapy. The use of high-dose-rate brachytherapy (HDR-BT) as a boost combined with EBRT is advocated. Martinez et al. (2) reported good results using two to three implants with fractions of 5.5–11.5 Gy. With a median follow-up of 8.2 years, the overall survival (OS) at 8 years in the series of Galalae et al. (3) was 70% after 40 Gy EBRT and 2 × 15 Gy HDR-BT, with a local recurrence rate of 6% for intermediate- and high-risk PC patients. This combined radiotherapy approach may enhance local control and decrease complications because HDR-BT creates a highly conformal dose of radiation within the prostate, with a rapid dose fall-off outside. The HDR boost also has a radiobiologic advantage gained by hypofractionation (4). Starting in 2000 we treated hormone-naïve patients with low- and intermediate-risk PC with HDR-BT as a boost in combination with EBRT to shorten the overall treatment time and to reduce toxicity. We report here our long-term results and toxicity.

Section snippets

Patients

Between February 2000 and July 2007, 264 patients with low- and intermediate-risk PC were treated with EBRT in combination with an HDR-BT boost. These patients had Stage T1a–T2c histologically proven PC, an initial prostate-specific antigen (PSA) level <15 ng/mL, and a Gleason score (GS) ≤7. Pretreatment evaluations included a clinical history, physical examination, and blood laboratory findings. A bone scan and pelvic computed tomography (CT) were recommended on demand. Tumor-node-metastases

Results

The median age of patients was 66 years (range, 45–79 years). Median follow-up was 74.5 months (range, 2.0–133.0 months). All but 13 patients (95.1%) contributed a minimum of one toxicity assessment to these results, and all but 2 patients (99.3%) contributed with a minimum of one PSA analysis. The T stages of the patients were as follows: T1a (1.5%), T1b (0.4%), T1c (60.2%), T2a (32.2%), T2c (1.1%), T2b (3.4%), T2c (1.1%), and unknown T (1.1%). The GS was 7 in 6% of the patients, and 94% had

Discussion

High-dose-rate brachytherapy in combination with EBRT was given for localized low- and intermediate-risk PC. This group of patients can be treated with radical prostatectomy, with a freedom from biochemical failure (FFBF) ranging from 70% to 80% (6); the same long-term results are reported with laparoscopic prostatectomy (7). External-beam RT in this risk group has a good oncologic outcome, but toxicity is a major concern 1, 8. The majority of our patients were low-risk patients with a

Conclusions

We reported our long-term follow-up results of EBRT plus HDR-BT for low- and intermediate-risk PC patients, in terms of oncologic outcome and toxicity, and we compared our results with the available literature. We confirm the excellent results for low- and intermediate-risk PC patients using EBRT plus HDR-BT. We suggest the use of less intensive treatment for this group, using monotherapy HDR-BT. We also suggest the treatment of higher (intermediate)-risk patients with this regimen (EBRT plus

Acknowledgment

The authors thank Renee Rijnsdorp, Connie de Pan, and Dick Sipkema for their skilled technical assistance.

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Conflict of interest: none.

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