Intraoperative Neurovascular Bundle Preservation with Hyaluronic Acid during Radical Brachytherapy for Localized Prostate Cancer: Technique and MicroMosfet In Vivo Dosimetry.

PURPOSE: To evaluate the reduction in the absorbed dose delivered to the neurovascular bundle (NB) in patients with localized prostate cancer treated with only HDR brachytherapy and NB protection with hyaluronic acid (HA) on the side of the prostate to increase the distance from NB to the radioactive sources. METHODS: This is the first published report in the medical literature that studies a new approach to decrease neurovascular bundle toxicity and improve quality of life for patients with prostate cancer treated with radical brachytherapy as monotherapy. Transperineal HA injection on the side of the prostate into the lateral aspect of the prostate fat was used to consistently displace several autonomic fibers and vessels on the lateral wall of the prostate away from radiation sources. RESULTS: When a protection in the form of an HA layer is placed, the reduction effect at the maximum dose is between 46% and 54% (calculated values), which means that the method for protection is highly recommended. The values of the absorbed dose calculated in this project have been compared with the ones given by the treatment planning system. CONCLUSIONS: This newly created space decreases absorbed dose in the NB, calculated with the TPS and measured by microMOSFET due to the thickness of HA.

A radiobiological study of the schemes with a low number of fractions in high-dose-rate brachytherapy as monotherapy for prostate cancer.

PURPOSE: Schemes with high doses per fraction and small number of fractions are commonly used in high-dose-rate brachytherapy (HDR-BT) for prostate cancer. Our aim was to analyze the differences between published clinical results and the predictions of radiobiological models for absorbed dose required in a single fraction monotherapy HDR-BT. MATERIAL AND METHODS: Published HDR-BT clinical results for low- and intermediate-risk patients with prostate cancer were revised. For 13 clinical studies with 16 fractionation schedules between 1 and 9 fractions, a dose-response relation in terms of the biochemical control probability (BC) was established using Monte Carlo-based statistical methods. RESULTS: We obtained a value of α/ß = 22.8 Gy (15.1-60.2 Gy) (95% CI) much larger than the values in the range 1.5-3.0 Gy that are usually considered to compare the results of different fractionation schemes in prostate cancer radiotherapy using doses per fraction below 6 Gy. The doses in a single fraction producing BC = 90% and 95% were 22.3 Gy (21.5-24.2 Gy) and 24.3 Gy (23.0-27.9 Gy), respectively. CONCLUSIONS: The α/ß obtained in our analysis of 22.8 Gy for a range of dose per fraction between 6 and 20.5 Gy was much greater than the one currently estimated for prostate cancer using low doses per fraction. This high value of α/ß explains reasonably well the data available in the region of high doses per fraction considered.

Characterization of microMOSFET detectors for in vivo dosimetry in high-dose-rate brachytherapy with 192 Ir.

PURPOSE: The objective of this study was to characterize the Best Medical Canada microMOSFET detectors for their application in in vivo dosimetry for high-dose-rate brachytherapy (HDRBT) with 192 Ir. We also developed a mathematical model to correct dependencies under the measurement conditions of these detectors. METHODS: We analyzed the linearity, reproducibility, and interdetector variability and studied the microMOSFET response dependence on temperature, source-detector distance, and angular orientation of the receptor with respect to the source. The correction model was applied to 19 measurements corresponding to five simulated treatments in a custom phantom specifically designed for this purpose. RESULTS: The detectors (high bias applied in all measurements) showed excellent linearity up to 160 Gy. The response dependence on source-detector distance varied by (8.65 ± 0.06)% (k = 1) for distances between 1 and 7 cm, and the variation with temperature was (2.24 ± 0.05)% (k = 1) between 294 and 310 K. The response difference due to angular dependence can reach (10.3 ± 1.3)% (k = 1). For the set of measurements analyzed, regarding angular dependences, the mean difference between administered and measured doses was -4.17% (standard deviation of 3.4%); after application of the proposed correction model, the mean difference was -0.1% (standard deviation of 2.2%). For the treatments analyzed, the average difference between calculations and measures was 4.7% when only the calibration coefficient was used, but it is reduced to 0.9% when the correction model is applied. CONCLUSION: Important response dependencies of microMOSFET detectors used for in vivo dosimetry in HDRBT treatments, especially the angular dependence, can be adequately characterized by a correction model that increases the accuracy of this system in clinical applications.

Focal high-dose-rate brachytherapy for localized prostate cancer: toxicity and preliminary biochemical results.

BACKGROUND: This study aimed to evaluate the outcomes and the toxicity of focal high-dose-rate (HDR) brachytherapy in selected localized prostate cancer patients. METHODS: Fifty patients were treated with focal high-dose-rate brachytherapy between March 2013 and November 2017, representing 5% of the cases treated by our group during this period. Only patients with very limited and localized tumors, according to strict criteria, were selected for the procedure. The prescribed dose for the focal volume was 24 Gy. RESULTS: The treated volume corresponded to a mean value of 32% of the total prostatic volume. The mean focal D90 in our series was 23 Gy (range 16-26 Gy). The mean initial IPSS was 8.2 (range 0-26), at 6 months 7.5 (range 0-23), and at 24 months 6.7 (range 0-18). No acute or late urinary retention was seen. When the ICIQ-SF score was 0 at the end of treatment, it remained nil thereafter at 1 and 2 years for all patients. No intraoperative or perioperative complications occurred. No rectal toxicity was reported after treatment. Of the total patients identified as potent, only three patients had a very slight decrease of the mean IIEF5. The mean initial PSA was 6.9 ng/mL (range 1.9-13.4). At the last follow-up visit, the mean PSA was 3 ng/ml (range 0.48-8.11). CONCLUSION: HDR focal brachytherapy in selected patients with low intermediate-risk prostate cancer could achieve the same satisfactory results in terms of relapse-free survival as conventional whole prostate brachytherapy with less toxicity.

High-dose-rate interstitial brachytherapy as monotherapy in one fraction of 20.5 Gy for the treatment of localized prostate cancer: Toxicity and 6-year biochemical results.

PURPOSE: To evaluate acute and late genitourinary toxicity, the gastrointestinal toxicity, and the long-term biochemical control after high-dose-rate (HDR) monotherapy in one fraction (20.5 Gy). MATERIALS AND METHODS: Between May 2011 and October 2014, 60 consecutive patients with low- and intermediate-risk prostate cancer were treated; the median followup was 51 months (range 30-79). All patients received one implant and one fraction of 20.5 Gy HDR real-time U/S planned with transperineal hyaluronic acid injection into the perirectal. Toxicity was reported according to the Common Toxicity Criteria for Adverse Event, Version 4.0 (CTAE v4.03) by the National Cancer Institute. Biochemical failure was defined according to the "Phoenix definition". RESULTS: Our experience in a single fraction of 20.5 Gy HDR brachytherapy is well-tolerated. No intraoperative or perioperative complications occurred. Grade 1 acute genitourinary toxicity occurred in 36% of patients, Grade 2 or more was not observed, only 1 patient requiring the use of a catheter for 7 days in the immediate postoperative period. No gastrointestinal toxicity was observed. No chronic toxicity has been observed after treatment. Morbidity is practically the same as that obtained with 19 Gy in our previously published article but the actuarial biochemical control was better, 82% (±3%) at 6 years. CONCLUSIONS: A single dose of 20.5 Gy resulted in a low genitourinary morbidity and no gastrointestinal toxicity and achieves good levels of biochemical disease control.

Accelerated partial breast irradiation in a single 18 Gy fraction with high-dose-rate brachytherapy: preliminary results.

PURPOSE: To evaluate the feasibility of acute and chronic toxicity in patients suitable for accelerated partial breast irradiation (APBI) in a single 18 Gy fraction with multicatheter high-dose-rate (HDR) brachytherapy, as well as cosmetic and oncological outcomes. MATERIAL AND METHODS: Between September 2014 and March 2016, twenty consecutive patients with low-risk invasive and ductal carcinoma in situ were treated with interstitial multicatheter HDR brachytherapy in a single 18 Gy fraction. RESULTS: Median age was 63.5 years (range, 51-79). Acute toxicity was observed in seven patients, while the pain during following days and hematoma were seen in four patients. With a median follow-up of 24 months, late toxicity was found in one patient with fat necrosis g2 and fibrosis g2 in another patient. The overall survival (OS) and locoregional control (LC) was 100%. Disease-free survival (DFS) and distant control was 95%. Good to excellent cosmetic outcomes were noted in 80% of patients and fair in 4 patients (20%). CONCLUSIONS: This is the first report in the medical literature that focuses on feasibility and acute and chronic toxicity, with a median follow-up of 24 months (range, 20-40). The protocol is viable and convenient. However, a longer follow-up is needed to know chronic toxicity and oncologic outcomes.

Long-term outcomes in patients younger than 60 years of age treated with brachytherapy for prostate cancer.

PURPOSE: The purpose of the study was to report the outcomes and late toxicities in patients younger than 60 years of age with long-term follow-up treated with low dose rate (LDR) brachytherapy for localized prostate cancer. METHODS: Between January 2000 and December 2009, 270 consecutive patients were treated with favourable localized prostate cancer; the median follow-up was 111 months (range 21-206). All patients received one implant of LDR brachytherapy. Toxicity was reported according to the Common Toxicity Criteria for Adverse Events, Version 4.0 (CTAE v4.02) by the National Cancer Institute. RESULTS: The overall survival according to Kaplan-Meier estimates was 99 (±1%) at 17 years. The 17-year rate for failure in tumour-free survival (TFS) was 97% (±1%), whereas for biochemical control it was 95% (±1%) at 17 years, 97% (±1%) of patients being free of local recurrence. No intraoperative or perioperative complications occurred. Acute genitourinary (GU) grade II toxicity was 4% at 12 months. No other chronic toxicity was observed after treatment. At 6 months, 94% of patients reported no change in bowel function. CONCLUSIONS: LDR brachytherapy provides patients younger than 60 years of age with low and intermediate-risk prostate cancer excellent outcomes and has a low risk of significant long-term GU or gastrointestinal morbidity.

Low-dose-rate brachytherapy for patients with transurethral resection before implantation in prostate cancer. Longterm results.

OBJECTIVES: We analyzed the long-term oncologic outcome for patients with prostate cancer and transurethral resection who were treated using low-dose-rate (LDR) prostate brachytherapy. METHODS AND MATERIALS: From January 2001 to December 2005, 57 consecutive patients were treated with clinically localized prostate cancer. No patients received external beam radiation. All of them underwent LDR prostate brachytherapy. Biochemical failure was defined according to the "Phoenix consensus". Patients were stratified as low and intermediate risk based on The Memorial Sloan Kettering group definition. RESULTS: The median follow-up time for these 57 patients was 104 months. The overall survival according to Kaplan-Meier estimates was 88% (±6%) at 5 years and 77% (±6%) at 12 years. The 5 and 10 years for failure in tumour-free survival (TFS) was 96% and respectively (±2%), whereas for biochemical control was 94% and respectively (±3%) at 5 and 10 years, 98% (±1%) of patients being free of local recurrence. A patient reported incontinence after treatment (1.7%). The chronic genitourinary complains grade I were 7% and grade II, 10%. At six months 94% of patients reported no change in bowel function. CONCLUSIONS: The excellent long-term results and low morbidity presented, as well as the many advantages of prostate brachytherapy over other treatments, demonstrates that brachytherapy is an effective treatment for patients with transurethral resection and clinical organ-confined prostate cancer.

High-dose-rate interstitial brachytherapy as monotherapy in one fraction for the treatment of favorable stage prostate cancer: Toxicity and long-term biochemical results.

BACKGROUND: To evaluate acute and late genitourinary, the gastrointestinal toxicity and the long-term biochemical control after HDR monotherapy in one fraction (19Gy). PATIENTS AND METHODS: Between April 2008 and October 2010, 60 consecutive patients were treated with favorable clinically localized prostate cancer; the median follow-up was 72months (range 32-91). All patients received one implant and one fraction of HDR. Fraction dose was 19Gy. Toxicity was reported according to the Common Toxicity Criteria for Adverse Event, Version 4.0 (CTAE v4.02) by the National Cancer Institute. RESULTS: No intraoperative or perioperative complications occurred. Acute toxicity grade 2 or more was not observed in any patients. No chronic toxicity, such as incontinence, late urinary retention, urethral narrowing, rectal bleeding, anal ulcer and/or rectourethral fistula has been observed after treatment. The overall survival and failure in tumor-free survival (TFS) according to Kaplan-Meier estimates was 90% (±5%) and 88% (±5%) respectively at 6years. The actuarial biochemical control was 66% (±6%) at 6years. CONCLUSIONS: This protocol is feasible and very well tolerated with low genitourinary morbidity, no gastrointestinal toxicity but no the same level of LDR biochemical control at 6years.

Low-dose-rate brachytherapy for patients with transurethral resection before implantation in prostate cancer. Long-term results

ABSTRACT We analyzed the long-term oncologic outcome for patients with prostate cancer and transurethral resection who were treated using low-dose-rate (LDR) prostate brachytherapy. Methods and Materials: From January 2001 to December 2005, 57 consecutive patients were treated with clinically localized prostate cancer. No patients received external beam radiation. All of them underwent LDR prostate brachytherapy. Biochemical failure was defined according to the "Phoenix consensus". Patients were stratified as low and intermediate risk based on The Memorial Sloan Kettering group definition. Results: The median follow-up time for these 57 patients was 104 months. The overall survival according to Kaplan-Meier estimates was 88% (±6%) at 5 years and 77% (±6%) at 12 years. The 5 and 10 years for failure in tumour-free survival (TFS) was 96% and respectively (±2%), whereas for biochemical control was 94% and respectively (±3%) at 5 and 10 years, 98% (±1%) of patients being free of local recurrence. A patient reported incontinence after treatment (1.7%). The chronic genitourinary complains grade I were 7% and grade II, 10%. At six months 94% of patients reported no change in bowel function.Conclusions: The excellent long-term results and low morbidity presented, as well as the many advantages of prostate brachytherapy over other treatments, demonstrates that brachytherapy is an effective treatment for patients with transurethral resection and clinical organ-confined prostate cancer

Adaptation and validation of the Spanish version of the Patient-Oriented Prostate Utility Scale (PORPUS).

OBJECTIVE: The Patient-Oriented Prostate Utility Scale (PORPUS) is a combined profile and utility-based quality of life measure for prostate cancer patients. Our objectives were to adapt the PORPUS into Spanish and to assess its acceptability, reliability, and validity. METHODS: The PORPUS was adapted into Spanish using forward and back translations and cognitive debriefing. PORPUS was administered jointly with the SF-36 and the Expanded Prostate Index Composite (EPIC) to 480 Spanish prostate cancer patients treated with radical prostatectomy or radiotherapy. The Spanish PORPUS scores' distribution and reliability were examined and compared with the original instrument. To evaluate construct validity, relationships were assessed between PORPUS and other instruments (testing hypotheses of the original PORPUS study), and among known groups defined by side effect severity. RESULTS: Reliability coefficient was 0.76 (similar to the original PORPUS' 0.81). Spanish PORPUS items presented correlations ranging 0.57-0.88 with the corresponding EPIC domains, as in the original PORPUS study (0.60-0.83). Both PORPUS-P and PORPUS-U showed significant differences and large effect sizes (0.94-1.90) when comparing severe versus no problem groups on urinary, bowel, sexual and hormonal side effects defined by EPIC. CONCLUSIONS: A conceptually equivalent Spanish version was obtained, with high reliability and good construct validity, similar to the original Canadian PORPUS version. It can therefore be used to measure health-related quality of life and utilities in Spanish prostate cancer patients.

Long-term biochemical results after high-dose-rate intensity modulated brachytherapy with external beam radiotherapy for high risk prostate cancer.

BACKGROUND: Biochemical control from series in which radical prostatectomy is performed for patients with unfavorable prostate cancer and/or low dose external beam radiation therapy are given remains suboptimal.The treatment regimen of HDR brachytherapy and external beam radiotherapy is a safe and very effective treatment for patients with high risk localized prostate cancer with excellent biochemical control and low toxicity.

Biochemical outcome after high-dose-rate intensity modulated brachytherapy with external beam radiotherapy: 12 years of experience.

UNLABELLED: Study Type - Therapy (case series) Level of Evidence 4 What's known on the subject? and What does the study add? Biochemical control from series in which radical prostatectomy is performed for patients with unfavorable prostate cancer and/or low dose external beam radiation therapy are given remains suboptimal. The treatment regimen of HDR brachytherapy and external beam radiotherapy is a safe and very effective treatment for patients with high risk localized prostate cancer with excellent biochemical control and low toxicity. OBJECTIVE: • To investigate the long-term oncological outcome, during the PSA era, of patients with prostate cancer who were treated using high-dose-rate (HDR) brachy therapy (BT) combined with external beam radiation therapy (EBRT). PATIENTS AND METHODS: • From June 1998 to April 2007, 313 patients with localized prostate cancer were treated with 46 Gy of EBRT to the pelvis with a HDR-BT boost. • The mean (median) follow-up was 71 (68) months. • Toxicity was reported according to the Common Toxicity Criteria for Adverse Event, V.4. RESULTS: • The 10-year actuarial biochemical control was 100% for patients with no high-risk criteria, 88% for patients with two intermediate-risk criteria, 91% with one high-risk criterion and 79% for patients with two to three high-risk criteria (P= 0.004). • The 10-year cancer-specific survival was 97% (standard deviation ± 1%). • The multivariate Cox regression analyses identified, Gleason score and T stage as independent prognostic factors for biochemical failure. • Gleason score was the only factor to significantly affect distant metastases. • Grade ≥ 3 late toxicity was not detected. CONCLUSION: • The 10-year results confirm the feasibility and effectiveness of EBRT with conformal HDR-BT boost for patients with localised prostate cancer.

High-dose-rate interstitial brachytherapy as monotherapy in one fraction and transperineal hyaluronic acid injection into the perirectal fat for the treatment of favorable stage prostate cancer: treatment description and preliminary results.

PURPOSE: To evaluate the technical feasibility, acute and late genitourinary (GU) toxicity, and gastrointestinal toxicity after high-dose-rate (HDR) brachytherapy as monotherapy in one fraction with transperineal hyaluronic acid injection into the perirectal fat to displace the rectal wall away from the radiation sources to decrease rectal toxicity. METHODS AND MATERIALS: Between April 2008 and January 2010, 40 consecutive patients were treated with favorable clinically localized prostate cancer; the median followup was 19 months (range, 8-32). No patients received external beam radiation, and 35% received hormone therapy before brachytherapy. All patients received one implant and one fraction of HDR. Fraction dose was 19 Gy. Toxicity was reported according to the Common Toxicity Criteria for Adverse Event, Version 4.0. RESULTS: All patients tolerated the implantation procedure very well with minimal discomfort. No intraoperative or perioperative complications occurred. Acute toxicity Grade 2 or more was not observed in any patients. No chronic toxicity has been observed after treatment. Logistic regression showed that the late Grade 1 GU toxicity was associated with D(90) (p=0.050). The 32-month actuarial biochemical control was 100% and 88%, respectively (p=0.06) for low- and intermediate-risk groups. CONCLUSIONS: This is the first published report of the use of HDR brachytherapy as monotherapy in one fraction for patients with favorable-risk prostate cancer. This protocol is feasible and very well tolerated with low GU morbidity, no gastrointestinal toxicity, and the same level of low-dose-rate biochemical control at 32 months.

Prostate-specific antigen relapse-free survival and side-effects in 734 patients with up to 10 years of follow-up with localized prostate cancer treated by permanent iodine implants.

STUDY TYPE: Therapy (case series) Level of Evidence 4. OBJECTIVE: To report our analysis of the oncological outcome, side-effects and complications after (125)I-brachytherapy, based on 10 years of experience, as low dose-rate (LDR) prostate brachytherapy is an accepted, effective and safe therapy for localized prostate cancer. PATIENTS AND METHODS: Between April 1999 and December 2006, 734 consecutive patients were treated with clinically localized prostate cancer with a follow-up of >or=30 months. No patients received external beam radiotherapy and 43% received hormonal therapy before brachytherapy; this therapy was given for 3-4 months. All patients had LDR prostate brachytherapy administered by one radiation oncologist. Biochemical failure was defined according to the 'Phoenix consensus'. RESULTS: The median follow-up for the 734 patients was 55 months; 26 had a clinical relapse and 11 died from prostate cancer; 20 patients died from other illnesses. The 10-year actuarial biochemical control was 92%, 84% and 65%, respectively (P < 0.001) for the low-, intermediate- and high-risk groups. Multivariate Cox regression analyses identified Gleason score and prostate-specific antigen (PSA) level as independent prognostic factors for biochemical failure. The actuarial biochemical control with Gleason score was 88%, 76% and 67% for patients with a Gleason score of 7, respectively (P < 0.001). The biochemical control was 90%, 80% and 42% for patients with a PSA level of 20 ng/mL, respectively (P < 0.001). No patients reported incontinence after treatment. There was acute urinary retention in 22 (2.9%) patients. Logistic regression showed that the most significant factors correlating with the probability of catheterization were the pretreatment prostate volume and hormonal therapy. CONCLUSIONS: The excellent long-term results and low morbidity, and the many advantages of prostate brachytherapy over other treatments, show that brachytherapy is an effective treatment for clinically organ-confined prostate cancer.

Transperineal injection of hyaluronic acid in the anterior perirectal fat to decrease rectal toxicity from radiation delivered with low-dose-rate brachytherapy for prostate cancer patients.

PURPOSE: Monitored rectal late morbidity using proctoscopy and a modified radiation therapy oncology group rectal bleeding scoring scale, in patients treated with permanent implant of I-125 and submitted to rectal protection with hyaluronic acid (HA) injecting in the perirectal fat to increase the distance between the prostate and the anterior rectal wall to decrease rectal toxicity. This is the first article looking at such injections in low-dose-rate brachytherapy patients and subsequent rectal toxicity. METHODS AND MATERIALS: Between January 2005 and July 2006, a total of 69 consecutive outpatients with low- and intermediate-risk prostate cancer were enrolled in a clinical trial. First group received brachytherapy alone with I-125 and the second group received brachytherapy I-125 and protection of the rectal wall with HA. We injected 6-8cc of HA in the perirectal fat, to increase the distance between the prostate and the anterior rectal wall. Proctoscopic examinations with scoring of mucosal damage were performed according to a descriptive scale, described by Wachter et al. The median follow-up at time of endoscopy was 18 months. Toxicity measures included modified radiation therapy oncology group late bleeding toxicity grading. RESULTS: The hyaluronic and non-hyaluronic groups were similar for most patients, in tumor, treatment, and dosimetric characteristics. Patients treated with brachytherapy I-125 and rectal protection with HA had significantly smaller incidence of mucosal damage at the proctoscopic examinations (5% vs. 36%, p=0.002) and no macroscopic rectal bleeding (0% vs. 12%, p=0.047) than those treated with brachytherapy I-125 alone without HA. No toxicity was produced from the HA or its injection. CONCLUSIONS: The increased distance between the rectal wall and the prostate, as a result from the injection of HA in the perirectal fat, has significantly decreased the rectal dose from low-dose-rate brachytherapy. Patients treated with brachytherapy I-125 and protection rectal with HA had significantly smaller incidence of mucosal damage at the proctoscopic examinations and no macroscopic rectal bleeding than those treated with brachytherapy I-125 alone without HA.

Transperineal injection of hyaluronic acid in anterior perirectal fat to decrease rectal toxicity from radiation delivered with intensity modulated brachytherapy or EBRT for prostate cancer patients.

PURPOSE: Rectal toxicity remains a serious complication affecting quality of life for prostate cancer patients treated with radiotherapy. We began an investigational trial injecting hyaluronic acid (HA) in the perirectal fat to increase the distance between the prostate and the anterior rectal wall. This is the first report using HA injection in oncology. METHODS AND MATERIALS: This is a trial of external beam radiation therapy with HDR brachytherapy boosts in prostate cancer. During the two high-dose-rate (HDR) fractions, thermoluminescent dosimeter dosimeters were placed in the urethra and in the rectum. Before the second HDR fraction, 3-7 mL (mean, 6 mL) of HA was injected under transrectal ultrasound guidance in the perirectal fat to systematically create a 1.5-cm space. Urethral and rectal HDR doses were calculated and measured. Computed tomography and magnetic resonance imaging were used to assess the stability of the new space. RESULTS: Twenty-seven patients enrolled in the study. No toxicity was produced from the HA or the injection. In follow-up computed tomography and magnetic resonance imaging, the HA injection did not migrate or change in mass/shape for close to 1 year. The mean distance between rectum and prostate was 2.0 cm along the entire length of the prostate. The median measured rectal dose, when normalized to the median urethral dose, demonstrated a decrease in dose from 47.1% to 39.2% (p < 0.001) with or without injection. For an HDR boost dose of 1150 cGy, the rectum mean Dmax reduction was from 708 cGy to 507 cGy, p < 0.001, and the rectum mean Dmean drop was from 608 to 442 cGy, p < 0.001 post-HA injection. CONCLUSION: The new 2-cm distance derived from the HA injection significantly decreased rectal dose in HDR brachytherapy. Because of the several-month duration of stability, the same distance was maintained during the course of external beam radiation therapy.

Conformal prostate brachytherapy guided by realtime dynamic dose calculations using permanent 125iodine implants: technical description and preliminary experience.

OBJECTIVE: Low dose rate (LDR) prostate brachytherapy (permanent 125I or 103Pd seeds) is an accepted treatment option for low risk prostate cancer patients. However, differences in prostate spatial location, volume and gland deformation between the images obtained during pre-planning and later on during the implant procedure prevent the pre-planned intended dose to be accurately delivered. We are reporting on a new technique based on interactive real-time dynamic intra-operative dose calculation with avoidance of postimplant CT for final dosimetry. The reasons leading us to implementing this new technique are discussed and preliminary results reported. 47-78 years). For the real time intra-operative dosimetric analysis the following values were obtained: a median of 98% (90%-100%) for V90, of 60% (22%-76%) for V150 and 24% (9%-34%) for V200. The median intro-operative D90 obtained was 16,817 cGy with a range of 13,743 to 19,553 cGy. The median dose point calculation to the rectum maximum was 12,936 cGy and for the maximum in urethra was 21,880 cGy. For the real-time dynamic planning, the acute GU grade 1&2 toxicity was reduced from 28% and 2 1% to 16% and 6% respectively. Acute urinary retention was seen in 2/63 or 3% requiring a temporary post-implant bladder catheter. In addition, a decrease in chronic GU grade 1-2 toxicity was also seen from 16% and 17% to 1 1% and 2% respectively. No change in GI toxicity pattern was noted. No severe grade 3-4 intra-operative complications were noted. CONCLUSION: Real-time intra-operative planning was successfully implemented in our center. It avoids the possible implant quality and dose delivery disadvantages of the standard post-implant CT-based dosimetry by improving the accuracy of seed placement on real time, which was translated in lower rates of acute and chronic GU morbidity. In addition, avoids the unnecessary time, effort and cost of post-implant CT-based dosimetry.

Conformal prostate brachytherapy guided by realtime dynamic dose calculations using permanent 125iodine implants: technical description and preliminary experience

OBJETIVO: El tratamiento con braquiterapia de baja tasa de dosis (LDR) con implantes permanentes de 125-I o 103Pb, constituyen en la actualidad una opción terapéutica en los pacientes con cáncer de próstata de bajo riesgo. La variación observada en el posicionamiento espacial de la próstata, así como en el volumen y contorno prostático entre las imágenes obtenidasdurante la planificación y posteriormente durantela intervención, hacen dudar de la exactitud de dosificación, en los pacientes tratados con la técnica de preplanificación. Analizamos la técnica basada en la planificación previa, la planificación intraoperatoria interactiva, así como nuestro proceder actual de planificación intraoperatoria por cálculo dinámico en tiempo real y los motivos que nos llevaron a realizar este cambio de técnica. MÉTODOS: Con el cálculo del volumen prostático preoperatorio por ecografía transrectal, determinamos la posibilidad de realizar el implante en base a las consideraciones anatómicas existentes y decidimos la actividad por semilla y la actividad total del implante. El día de la intervención comprobamos de nuevo la volumetría, obtenemos de nuevo las imágenes ecográficas de base a apex, ayudados por un stepper motorizado que va conectado con el ecógrafo y el planificador. Cada aguja que se coloca en la posición que deseamos y no en una coordenada obligada, se identifica en el planificador en la posición real, una vez colocadas todas las agujas y obtenidas unas primeras isodosis adecuadas, realizamos una cistoscopia flexible y a continuación sembramos, identificando todas y cada una de las semillas en la retirada de la aguja guía ecográficamente, con lo que nos permite obtener una postplanificación intraoperatoria en tiempo real y hacer las correcciones oportunas en el propio acto quirúrgico. Realizamos un implante periférico puro. RESULTADOS: Iniciamos los tratamientos con braquiterapiade baja tasa de dosis en 1.999. Superadas las 700 intervenciones, hemos evaluado a los primeros 63 pacientes tratados con la técnica de cálculo dinámico de dosis en tiempo real por presentar un seguimiento mínimo de 10 meses. El tiempo medio del proceso fue de 90 minutos. La media de seguimiento para los 63 pacientes estudiados fue 20 meses con un rango entre 10 y 36 meses. Un 55% de los pacientes fueron estadiados como T1c, 36% T2a y 9% T2b. En el 81% de los pacientes el Gleason fue < 7. La media de PSA al inicio de tratamiento fue de 9ng/ml (4.2-30 ng/ml). La media de edad fue de 64 años (47-79 años). La técnica de braquiterapia por cálculo dinámico de dosis en tiempo real obtuvo los valores que se especifican a continuación: media 98% (90%-100%) para V90, V150 de 60% (22%-76%), V200 de 24% (9%-34%). La D90 media fue de 16.817 cGy (13.743-19.553 cGy). La dosis media máxima a nivel rectal fue de 12.936 cGy y a nivel uretral de 19.553 cGy. Con la técnica de cálculodinámico de dosis en tiempo real, la toxicidad agudagenitourinaria de grado 1-2 fue reducida del 28% y 21% respectivamente a 21% y 16%. El porcentaje de retenciones fue del 3% y la toxicidad urológica crónica fue reducida del 16% y 17% al 11% y 2% respectivamente. No se observaron cambios gastrointestinales de grado 3-4.CONCLUSIONES: La técnica de cálculo dinámico de dosis en tiempo real es utilizada de forma habitual con éxito en nuestro centro. Evita las desventajas que presentan otras técnicas, mejorando la cobertura de la próstata por las dosis ideales de irradiación que se traduciránen un mejor control local de la enfermedad y una disminución de las complicaciones así como evitar la realización de la postplanificación postoperatoria

OBJECTIVE: Low dose rate (LDR) prostate brachytherapy (permanent 125I or 103Pd seeds) is an accepted treatment option for low risk prostate cancer patients. However, differences in prostate spatial location, volume and gland deformation between the images obtained during pre-planning and later on during the implant procedure prevent the pre-planned intended dose to be accurately delivered. We are reporting on a new technique based on interactive real-time dynamic intra-operative dose calculation with avoidance of post-implant CT for final dosimetry. The reasons leading us to implementing this new technique are discussed and preliminary results reported. METHODS: A pre-planning TRUS for volumetric analysis is performed in all our patients prior to implantation. This TRUS accomplishes two objectives: 1) assessment of implantability of the gland, of organs at risk and anatomical considerations and 2) determination of seed activity and total number of seeds. On the day of the implant, new TRUS images from base to apex are obtained using a motorized stepper connected to the ultrasound and planning system. Each real time needle position placed on the target is identified and capture by the planning system in the true position. Once all real needle positions have been captured, dosimetry is performed intra-operatively and the physician approves the corresponding isodoses on real time. Flexible cystoscopy is then performed followed by seed placement. Each seed implanted is then identified upon withdrawing the needle using TRUS guidance. This allows real-time intra-operative dosimetric analysis, allowing for correction of under-dosed zones during implantation in an interactive dynamic manner. Peripheral loading is used.RESULTS: We began our LDR prostate brachytherapy program on 1999. While we have treated >700 patients with LDR, the last 63 patients were treated with our real time dynamic intra-operative planning system. The median time duration for the procedure was 90 minutes. The median follow up time for these 63 patients was 20 months with a range of 10-36 months. At presentation, Stage T1c was seen in 55%, T2a in 36% and 9% as T2b. The Gleason grade was <7 in 81% of the patients. The median PSA value was 9 ng/ml (range 4.2-30). The median age was 64 years (range 47-78 years). For the real time intra-operative dosimetric analysis the following values were obtained: a median of 98% (90%-100%) for V90, of 60% (22%-76%) for V150 and 24% (9%-34%) for V200. The median intra-operative D90 obtained was 16,817 cGy with a range of 13,743 to 19,553 cGy. The median dose point calculation to the rectum maximum was 12,936 cGy and for the maximum in urethra was 21,880 cGy. For the real-time dynamic planning, the acute GU grade 1&2 toxicity was reduced from 28% and 21% to 16% and 6% respectively. Acute urinary retention was seen in 2/63 or 3% requiring a temporary post-implant bladder catheter. In addition, a decrease in chronic GU grade 1-2 toxicity was also seen from16% and 17% to 11% and 2% respectively. No change in GI toxicity pattern was noted. No severe grade 3-4 intra-operative complications were noted. CONCLUSION: Real-time intra-operative planning was successfully implemented in our center. It avoids the possible implant quality and dose delivery disadvantages of the standard post-implant CT-based dosimetry by improving the accuracy of seed placement on real time, which was translated in lower rates of acute and chronic GU morbidity. In addition, avoids the unnecessary time, effort and cost of post-implant CT-based dosimetry