European Collaborative Group on Prostate Brachytherapy: Preliminary Report in 1175 Patients

Feasibility and early outcome of high-dose-rate Ir-192 brachytherapy as monotherapy in two fractions within 1 day for high-/very high-risk prostate cancer

The aim of the present study was to evaluate the feasibility and preliminary outcomes of high-dose-rate (HDR)-brachytherapy as a monotherapy in two fractions within 1 day for localized prostate cancer, including high-/very high-risk cases. Among the 68 patients treated with HDR monotherapy between July 2011 and December 2014, 65 had a minimal follow-up of 12 months without adjuvant androgen deprivation therapy and were enrolled in the present study [42/65 (64.6%) exhibited high-/very high-risk diseases]. HDR monotherapy was performed in two fractions with a minimal interval of 6 h and the prescribed dose was 13.5 Gy (×2). Adverse events (AEs) were assessed using Common Terminology Criteria for Adverse Events (version 4; http://ctep.cancer.gov/protocolDevelopment/electronic_applications/ctc.htm#ctc_40), and biochemical failure was assessed by the Phoenix definition. The median follow-up time was 30.1 months. The majority of patients had Grade 0-1 acute AEs. Four patients (6.2%) exhibited urinary retention, requiring a Foley catheter. Grade 3 acute AEs occurred at a frequency of 3.1% and hematuria at 1.5%. The majority of patients also exhibited Grade 0-1 chronic AEs. Grade 3 chronic AEs occurred at a frequency of 1.5% and urethral stricture at 1.5%, for which endoscopic treatment was indicated. Acute and chronic gastrointestinal AEs were uncommon, and no Grade 3 or above AEs developed. Biochemical failure occurred in 4 patients who all exhibited high-/very high-risk diseases. Kaplan-Meier estimated that 3 year biochemical failure-free survival was 91.6% overall and 88.0% in high-/very high-risk cases. The present two-fraction 1 day HDR monotherapy is feasible with minimal AEs and achieved acceptable biochemical control of localized prostate cancer, including high-/very high-risk cases, although long-term follow-up is required.

Dynamic dose-feedback prostate brachytherapy in patients with large prostates and/or planned transurethral surgery before implantation

OBJECTIVE

To compare the quality of permanent prostate brachytherapy (PPB) implants, dosimetric outcomes and urinary morbidity between patients with large (>50 mL) and those with smaller prostates, treated with a dynamic dose-feedback technique as monotherapy for localized prostate cancer.

PATIENTS AND METHODS

The series included patients with pre-existing bladder outlet obstruction managed with planned transurethral resection or incision of the prostate; 155 consecutive men had PPB implants as monotherapy for localized prostate cancer using a dynamic dose-feedback approach. Dosimetric variables assessed included the implant volume, the minimum dose to 90% of the prostate (D90), and the volumes of prostate receiving 100% and 150% of the prescribed dose as a percentage of the total volume (V100 and V150), during and after implantation. Urinary morbidity was recorded in terms of acute urinary retention (AUR), the need for surgical intervention after implantation and the American Urologic Association (AUA) symptom score at baseline, 1.5, 3, 6, 9, 12 and 18 months.

RESULTS

In all, 38 patients had prostate volumes of >or=50 mL; prostate volume had no influence on any dosimetric variable assessed. Two patients with large prostates (>or=50 mL) had AUR and required delayed surgery. Three patients with small prostates (<50 mL) had transient retention; the differences were not statistically significant (Fisher's exact test). AUA symptom scores peaked at 6 weeks and returned to baseline within a year; there were no statistically significant differences between the groups. Eight patients had planned transurethral surgery at >or=4 months before implantation; they all had D90s of >130 Gy and had no incontinence.

CONCLUSION

Using the dynamic feedback technique, there was no adverse dosimetric and urinary morbidity in men having PPB and with prostates of >50 mL. Likewise, there were no impediments, e.g. pubic arch interference, which precluded a favourable dosimetric implant in men with a large prostate. Large prostates should not be a contraindication to PPB and require no hormonal cytoreduction. Patients with obstructive lower urinary tract symptoms can be managed with planned transurethral prostatic surgery before implantation, without compromising implant quality or morbidity.

Techniques, indications et résultats de la curiethérapie interstitielle par implants permanents dans le cancer localisé de la prostate

Permanent seed brachytherapy as a monotherapy is an appropriate treatment in patients with low risk localized prostate cancer such as intraprostatic cancer, T1-2 stage, PSA less than 10 ng/mL, low tumour volume, well differentiated cancer (Gleason score less than 7), gland size less than 50 mL, no micturition symptoms that could decompensate after implantation. A brachytherapy program needs a specialized multidisciplinary team with the collaboration of urologists, radiotherapists (authorized person to manipulate radioactive elements), and physicists. The 10-year oncologic and morbidity results have been published in the literature and are comparable to those of other standard treatments of localized prostate cancer such as radical prostatectomy and external beam radiation therapy.

Early biochemical outcomes following permanent interstitial brachytherapy as monotherapy in 1050 patients with clinical T1–T2 prostate cancer

BACKGROUND AND PURPOSE

Five European centres (France, Finland, Italy, Spain and the UK) have pooled data to generate a large patient series involving 1175 patients treated with prostate brachytherapy. This paper reports preliminary data on PSA outcome up to 4 years.

PATIENTS AND METHODS

Out of 1175 in the database, 1050 patients with localised prostate cancer who had received transperineal seed implantation as monotherapy between May 1998 and August 2003 were stage T1-T2. A total of 668 (63.6%) patients met the low-risk group definition, 297 (28.3%) as intermediate-risk definition and 66 (6.3%) the high-risk group definition. The majority of patients were Gleason score 6 or less (n=951) and disease stage was T1c in 557 patients.

RESULTS

Of the 1050 patients, PSA data up to 4 years were available for 210 patients, while 364 patients with PSA values up to 36 months were evaluable by the Kaplan-Meier method for freedom from biochemical failure. The biochemical progression-free rate at 3 years was estimated to be 91%, with a 93% and 88% rate for low- and intermediate-risk groups, respectively, versus 80% for the high-risk group. PSA kinetics provide encouraging evidence of treatment efficacy.

CONCLUSION

These data on 4-year PSA follow-up on patients treated with prostate brachytherapy reflect those previously reported in the literature. This patient series will be followed to provide long-term outcome in the future.

Using combined x-ray and MR imaging for prostate I-125 post-implant dosimetry: phantom validation and preliminary patient work

Post-implantation dosimetry is an important element of permanent prostate brachytherapy. This process relies on accurate localization of implanted seeds relative to the surrounding organs. Localization is commonly achieved using CT images, which provide suboptimal prostate delineation. On MR images, conversely, prostate visualization is excellent but seed localization is imprecise due to distortion and susceptibility artefacts. This paper presents a method based on fused MR and x-ray images acquired consecutively in a combined x-ray and MRI interventional suite. The method does not rely on any explicit registration step but on a combination of system calibration and tracking. A purpose-built phantom was imaged using MRI and x-rays, and the images were successfully registered. The same protocol was applied to three patients where combining soft tissue information from MRI with stereoscopic seed identification from x-ray imaging facilitated post-implant dosimetry. This technique has the potential to improve on dosimetry using either CT or MR alone.