Rate Brachytherapy For Prostate Cancer Research Articles

High dose rate brachytherapy for prostate cancer

High dose rate (HDR) afterloading brachytherapy in the management of localised prostate cancer has practical, physical and biological advantages over low dose rate seed brachytherapy. There are no free live sources used, no risk of source loss and since the implant is a temporary procedure following discharge no issues with regard to radioprotection use of existing facilities. Adequate coverage of extracapsular and seminal vesicle tumour is possible for advanced cases and HDR brachytherapy is the most efficient means of obtaining dose escalation in terms of biological dose based on a low α/β ratio. Selection for HDR brachytherapy includes patients with any prostate specific antigen (PSA) level provided there is no demonstrable metastasis, any Gleason score and stages T1B to T3B. The results of a randomised trial show that HDR brachytherapy is an effective means of dose escalation with a favourable therapeutic ratio when compared with standard external beam radiotherapy. Current studies are evaluating HDR brachytherapy as monotherapy delivering a radical dose in two to four fractions. The acute toxicity with HDR brachytherapy is short-lived and far less severe than seen with low dose rate brachytherapy and late toxicity rates are low.

Low Morbidity Following High Dose Rate Brachytherapy in the Setting of Prior Transurethral Prostate Resection

We reviewed our single institution experience with high dose rate brachytherapy in patients who underwent prior transurethral prostate resection. A total of 28 patients treated with high dose rate brachytherapy for prostate cancer at our institution between 2001 and 2006 were identified as having undergone prior transurethral prostate resection. All patients received high dose rate brachytherapy as a boost before or after conformal external beam radiation therapy to 4,500 cGy. Boost brachytherapy doses ranged from 1,600 to 1,900 cGy, given in 2 or 3 fractions. Changes in American Urological Association symptom scores were assessed. Dosimetric goals were adequately achieved in all patients with a median minimal dose to 90% of the prostate of 109% of the prescription dose (range 100% to 117%). The median volume receiving 100% of the prescribed dose was 95% (range 87.9% to 100%) Three patients (11%) required temporary urinary catheter placement for acute obstructive symptoms after brachytherapy. At a median followup of 2.5 years there was 1 case each of grade 1 rectal proctitis, grade 1 hemorrhage and grade 2 cystitis. Two patients had worsening of existing grade 1 urge incontinence to grade 2. No patient had a bulbourethral stricture requiring dilation or new onset incontinence. Patients with a higher baseline American Urological Association score demonstrated significantly improved scores over those with lower baseline scores (less than 15) at least 1 year after treatment. High dose rate brachytherapy with careful attention to dosimetry is a reasonable treatment option for patients who have undergone prior transurethral prostate resection with the expectation of low morbidity.

High Dose Rate Brachytherapy as a Boost for the Treatment of Localized Prostate Cancer

We report the outcome and toxicities of high dose rate brachytherapy as a boost for localized prostate cancer. Between 1996 and 2003, 309 patients with prostate carcinoma were treated with external beam radiation therapy and high dose rate brachytherapy. Furthermore, 36% of the patients received neoadjuvant/concurrent or adjuvant androgen deprivation therapy. Patients were stratified into 3 groups. Group 1 of 67 patients had Gleason score 6 or less, pretreatment prostate specific antigen 10 ng/ml or less and clinical stage T2a or less. Group 2 of 109 patients had Gleason score 7 or greater, pretreatment prostate specific antigen greater than 10 ng/ml and clinical stage T2b or greater. Group 3 of 133 patients had 2 or more of these higher risk factors. At a median followup of 59 months the 5-year biochemical control rate, as defined by the American Society for Therapeutic Radiation and Oncology, was 86%, cause specific survival was 98% and overall survival was 91%. Biochemical control in stratified groups 1 to 3 was 98%, 90% and 78%, respectively. On univariate analysis risk group, pretreatment prostate specific antigen and Gleason score were significant predictors of biochemical control. However, on multivariate analysis only risk group and pretreatment prostate specific antigen were significant. Using the Common Toxicity Criteria scale there were 2 cases of grade 3 acute urinary toxicity. Regarding late side effects 4% of patients had grade 3 genitourinary toxicity and 1 had a grade 4 rectal complication. External beam radiation therapy and high dose rate brachytherapy for prostate cancer resulted in excellent biochemical control, cause specific survival and overall survival with minimal severe acute or late complications.

Interfractional fluctuation of rectal dose in high dose rate brachytherapy for prostate cancer

The aim of the study was to explore the cause of the difference in the maximal rectal dose between the first and second high dose rate (HDR) brachytherapy applications by comparing the thickness of the anterior rectal wall. The rectal dose and the thickness of the anterior rectal wall were analyzed in 26 patients with prostate cancer. After undergoing external beam radiation treatment with a total isocenter dose of 50 Gy, they were treated with HDR brachytherapy of 7.5 Gy/fraction, two fractions daily. The interval between the first HDR brachytherapy session and the second was 5 h. The rectal doses were directly surveyed during irradiation of the HDR brachytherapy. Thickening of the anterior rectal wall was measured at the same level by axial computed tomography scans obtained before the first and second HDR brachytherapy applications. The maximal surveyed rectal doses during the first and second HDR brachytherapy applications were 188 +/- 51 cGy and 220 +/- 35 cGy, respectively (P < 0.01). The fluctuation ratio exceeded 1 in each case. The thickness of the anterior rectal wall before the first and second HDR brachytherapy applications was 18.78 +/- 4.34 mm and 14.95 +/- 4.09 mm (P < 0.01), respectively. The fluctuation difference exceeded 0 in each case. The different rectal dose is attributable to thinning of the anterior rectal wall. The total rectal dose is within the range of doses at risk of exerting a toxic effect on the rectum.

Interstitial Low Dose Rate Brachytherapy for Prostate Cancer — A Focus on Intermediate- and High-risk Disease

Aims To investigate the role of brachytherapy in intermediate- and high-risk prostate cancer. We report our results and a review of published studies. Materials and methods Between March 1999 and April 2003, 300 patients were treated with low dose rate I-125 interstitial prostate brachytherapy and followed prospectively. The patients were stratified into low-, intermediate- and high-risk groups and received brachytherapy alone or in combination with external beam radiotherapy (EBRT) and/or neoadjuvant androgen deprivation (NAAD). One hundred and forty-six patients were classified as low risk, 111 as intermediate risk and 43 as high risk. Biochemical freedom from disease and prostate-specific antigen (PSA) nadirs were analysed for risk groups and for treatment received in each risk group. Results The median follow-up was 45 months (range 33–82 months) with a mean age of 63 years. Actuarial 5-year biochemical relapse-free survival for the low-risk group was 96%, 89% for the intermediate-risk group and 93% for the high-risk group. When stratified by treatment group, low-risk patients had a 5-year actuarial biochemical relapse-free survival of 94% for brachytherapy alone ( n = 77), 92% for NAAD and brachytherapy ( n = 66) and 100% for NAAD, EBRT and brachytherapy ( n = 3). In the intermediate-risk patients, biochemical relapse-free survival was 93% for brachytherapy alone ( n = 15), 94% for NAAD and brachytherapy ( n = 67), 75% for EBRT and brachytherapy ( n = 4) and 92% for NAAD, EBRT and brachytherapy ( n = 25). In the high-risk group, biochemical relapse-free survival was 100% for brachytherapy alone ( n = 2), 88% for NAAD and brachytherapy ( n = 7), 80% for EBRT and brachytherapy ( n = 5) and 96% for NAAD, EBRT and brachytherapy ( n = 29). Overall 3- and 4-year PSA = 0.5 ng/ml were achieved by 71 and 86%, respectively, and a 4-year PSA = 0.2 ng/ml was achieved by 63%. Conclusion Although the role of combination treatment with pelvic EBRT and androgen therapy is not clear, our early results show that many patients with intermediate- and high-risk disease have excellent results with brachytherapy.

835 POSTER Similar effect on rectal dose reduction despite different displacement kits during high dose rate brachytherapy for prostate cancer

In preparation to change treatment planning systems for gynecological intracavitary insertion dosimetry, 3 patients were planned on 3 systems. The GE Target II, BrachyVision, and ADAC Pinnacle were the systems used. The dose distributions to several points of interest were calculated and compared. We analyzed the data sets to assess the differences and found that they were insignificant, mostly due to human error during digitization and calculation rounding.

Radical prostatectomy versus high‐dose rate brachytherapy for prostate cancer: effects on health‐related quality of life

To examine the effects of different treatments on the health-related quality of life (HRQoL) of men with localized prostate cancer. Between October 1997 and August 2002, 182 men diagnosed with prostate cancer (T1c to T3bN0M0) had radical prostatectomy (RP, 89) or (192)iridium high-dose rate brachytherapy (HDR-BT, 93) with external beam radiotherapy, and were followed for > or = 6 months. A postal survey was sent in which HRQoL was assessed using the 36-item Short-Form Health Survey (SF-36) QoL questionnaire, and disease-specific QoL using the University of California Los Angeles Prostate Cancer Index (UCLA-PCI). Questionnaire responses were obtained from 151 of 182 patients; there was no significant difference in SF-36 scale scores between men treated with RP or HDR-BT. In the UCLA-PCI, the HDR-BT group had better urinary function (P < 0.001) and sexual function scores (P= 0.043). Men treated with RP had better bowel bother scores (P = 0.027). In patients with > or = 2 years of follow-up, urinary function (P < 0.001) and sexual bother (P = 0.029) were better for men treated with HDR-BT than for men treated with RP. Men treated with HDR-BT had significantly better urinary function (P = 0.009) and sexual bother (P = 0.013) even than 30 men treated with unilateral nerve-sparing RP. In terms of HRQoL, RP and HDR-BT did not differ, but HDR-BT resulted in better urinary and sexual function than RP. When planning treatment, QoL concerns, including mental health issues associated with prostate cancer, need to be addressed with the patients, as do the potential side-effects.

211 poster workshop Multi-institutional results of 1493 patients treated with an hypofractionated regime combining external beam irradiation and high dose rate brachytherapy for prostate cancer

211 poster workshop Multi-institutional results of 1493 patients treated with an hypofractionated regime combining external beam irradiation and high dose rate brachytherapy for prostate cancer

1.5T MRI for cathether placement and treatment planning in high dose rate brachytherapy for prostate cancer

MRI provides superior visualization of the prostate and surrounding anatomy making it the modality of choice for imaging the prostate gland. This study was performed to determine the feasibility and dosimetric quality achieved when placing high dose rate (HDR) prostate brachytherapy catheters under MR image guidance in a standard 1.5T scanner. In a secondary objective, catheter encroachment and dose delivered to the path of the neurovascular bundles (NVB) was determined. Patients with intermediate and high-risk localized prostate cancer received MRI-guided HDR brachytherapy boosts (1050cGy each) before and after a course of external beam radiotherapy (4600cGy). Preliminary MRI evaluations and procedures were performed in a standard 1.5T MRI scanner with a 60cm diameter bore. Patients were placed under general endotracheal anesthesia for the entire procedure. An endorectal coil was modified with immobilization hardware and rigidly affixed perpendicular to a custom designed perineal template. The coil was inserted and placed against the anterior rectal wall adjacent to the prostate gland, centered on the urethra. Upon satisfactory device positioning, a 3D-SSFP image volume which comprises the template, pubic arch, and prostate gland was acquired. These images were sent to an adjacent PC workstation with a custom written image-visualization and targeting program. Needle paths potentially encroaching on the pubic arch and urethra were identified and marked, and a peripheral brachytherapy catheter arrangement was designed with the assistance of the pre-plan. Fast-spin-echo images of the prostate gland (scan time = 28sec) were then acquired for improved tumor definition and to confirm the adequacy of the brachytherapy catheter placements. These images were projected within the MR room to allow the operator more timely feedback of catheter position. HDR brachytherapy inverse treatment planning (IPSA-PLATO, Nucletron Inc.) was performed using an axial T2-weighted FSE image corrected for spatial distortion obtained at the end of the procedure. The PTV consisted of the prostate gland as well as any visualized extracapsular extension of disease. Dose constraints were applied to the urethra and rectum. Dose-volume histograms were generated for the PTV, urethra, rectum, and path of the NVB on contrast-enhanced MRI. Catheter encroachment on the path of the NVB was documented. Fourteen MRI-guided transperineal brachytherapy and biopsy procedures have been performed in 7 patients. Prostate gland sizes ranged from 21.6 to 81.8 cc (mean 40.6cc). The median PTV V100 was 94%, with a mean of 92% (CI 90%-94%). Urethral V125 ranged from 0 to 18% (median 5%), and rectal V75 ranged from 0 to 5.8 % (median 0.3%). In all cases, lesions highly suspicious for malignancy could be visualized on the procedural MR images, and extracapsular disease was identified in two patients and included in the PTV. On average, 21% of the left and 12% of the right NVB paths received the prescription dose, with a V150 of 3% bilaterally. In 8 of 14 cases, catheters directly encroached on the path of the NVB below the apex of the gland. HDR prostate brachytherapy in a standard 1.5T MRI scanner is feasible and achieves favorable dosimetry with high-quality image guidance. This procedure may offer a therapeutic advantage for those patients with extracapsular extension of disease visualized on MR images, whereby extracapsular disease may be included in the high dose region. MRI also permits the evaluation of catheter trauma and radiation dose to the NVB. This system establishes a procedural platform ideally suited to the evaluation and integration of anatomic, functional, and molecular imaging techniques in cancer radiotherapy

1.5T MRI for cathether placement and treatment planning in high dose rate brachytherapy for prostate cancer

MRI provides superior visualization of the prostate and surrounding anatomy making it the modality of choice for imaging the prostate gland. This study was performed to determine the feasibility and dosimetric quality achieved when placing high dose rate (HDR) prostate brachytherapy catheters under MR image guidance in a standard 1.5T scanner. In a secondary objective, catheter encroachment and dose delivered to the path of the neurovascular bundles (NVB) was determined.

Image‐based high dose rate brachytherapy for prostate cancer

The passage from conventional radiographic film‐based to image‐based high dose rate (HDR) brachytherapy for prostate cancer has significantly improved our ability to define the targets and organs at risk (OAR). Three‐dimensional (3D) anatomical information are obtained from Computed Tomography (CT) or Magnetic Resonance Imaging (MRI), and cancer areas are validated using functional imaging with magnetic resonance spectroscopy imaging (MRSI). Together with inverse planning optimization, image‐based HDR brachytherapy can deliver a highly conformal dose distribution to the target while sparing OAR. However, uncertainties inherent to the use of the new imaging modalities may impact on the dose distribution. In this work, we have selected the major uncertainties and studied their impact within the context of the clinical procedures of ultrasound guided HDR prostate brachytherapy delivered in two fractions. The feasibility of using functional imaging to guide the delivery of higher dose to dominant intraprostatic lesions (DIL) within the prostate was also investigated. The average cranio‐caudal displacement of catheters between fractions was 2.7 mm and 5.4 mm for bony anatomy and gold seed marker measurement, respectively. Either increase or reduction of prostate volume was observed with an average of 7.8% and a maximum of 17% between fractions, resulting in minimal dose changes. The dose uncertainty due to the planning CT slice thickness showed a relative error of 1% on average for current 3 mm planning CT, independent of the transversal region of the prostate. A retrospective study taking advantage of MRI/MRSI for the dose escalation of the DIL demonstrated that high dose areas could be redistributed to boost the DIL by 120% without any additional dose delivered to OAR compared to a reference plan. On average, the rigid endorectal probe was shown to rotate the prostate anteriorly by to expand it in the antero–posterior direction by 1.2 mm, and compress it in lateral direction with 1.5 mm. Finally, MRI scans with and without the probe could be registered with a 2 mm precision using translation only. The use of 3D anatomical and functional information combined with inverse planned HDR brachytherapy is a precise procedure for the treatment of localized prostate cancer with potential for dose escalation.

102 poster Dose volume inhomogeneity corrected biological effective dose (DVIC-BED) and the use in high dose rate brachytherapy for prostate cancer

102 poster Dose volume inhomogeneity corrected biological effective dose (DVIC-BED) and the use in high dose rate brachytherapy for prostate cancer