Permanent Interstitial Brachytherapy Research Articles

Sunday, June 19, 202210:00 AM - 10:15 AMPO47 Presentation Time: 10:00 AM: Dose Distribution of Permanent Interstitial Brachytherapy (Iodine-125) in Comparison to Temporary Interstitial Brachytherapy (Iridium-192) with a Hydrogel Spacer for Prostate Cancer

<h3>Purpose</h3> Brachytherapy (BT) for prostate cancer can be applied as permanent interstitial brachytherapy BT (LDR, low dose rate) and temporary interstitial brachytherapy BT (HDR, high dose rate), applied also alternatively in many centers. The aim of the study was to analyze the dose distribution in- and outside the prostate. <h3>Methods</h3> The intraoperative dose distribution of 102 LDR-BT patients was compared with the dose distribution of 109 HDR-BT patients (232 HDR-BT fractions). A hydrogel spacer (HS) (10ml) was only applied before HDR-BT. For the analysis of the dose coverage outside the prostate, a 5mm margin was added to prostate volume (PV+). Prostate V100 and V150 denote the PV covered by 100% and 150% of the prescription dose, while prostate D90 and urethra D30 denote the minimum dose in 90% of the PV and 30% of the urethral volume. <h3>Results</h3> The comparison of volume and dose values is shown in the table. HDR-BT patients had on average a slightly larger PV, but considerably larger PV+. The only not significantly different value comparing both methods was prostate V100. LDR-BT was characterized by a considerably more inhomogeneous dose distribution and higher doses to the urethra. However, the minimum dose in 90% of PV+ was lower. As a consequence of the HA in HDR-BT patients, the dose to the rectum was considerably lower. <h3>Conclusion</h3> In comparison to HDR-BT, LDR-BT is characterized by a more inhomogeneous dose inside the prostate, a higher dose to the urethra and a slightly less steep dose drop-off around the prostate. The dose to the rectal wall can be considerably reduced applying the HS.

Permanent interstitial brachytherapy for prostate cancer implementing neoadjuvant prostatic artery embolization

Indication for permanent interstitial brachytherapy (PIB) can be limited by prostate volume, commonly decreased using neoadjuvant hormonal therapy. Volume changes and initial clinical results focusing on patients treated with prostatic artery embolization (PAE) were evaluated in this study. A group of 102 consecutive patients were treated with permanent interstitial brachytherapy (PIB), 13 patients received a neoadjuvant PAE (median 12 weeks before PIB) in case of large prostate volume >60 cm³, and moderate to severe urinary problems. Patients after PAE were treated with significantly larger prostate volumes (52 ± 11 cm³ vs. 39 ± 11 cm³; p < 0.01; 66 ± 17 cm³ before PAE), but larger volume reductions to 44 ± 10 cm³ versus 35 ± 10 cm³ was found at day 30 (p < 0.05). International Prostate Symptom Score (IPSS) decreased significantly from 13 ± 5 before PAE to 7 ± 4 after PAE; p < 0.01. Initial PSA and first PSA after PIB were similar for patients with versus without PAE (5.9 ± 2.9 ng/mL vs. 6.2 ± 2.8 ng/mL and 1.5 ± 0.8 ng/mL vs. 1.9 ± 1.5 ng/mL). However, PSA 12 months after PIB was significantly lower after PAE (0.4 ± 0.3 ng/mL vs. 0.8 ± 0.6 ng/mL; p = 0.03). Four patients without prior PAE needed an intervention after urinary retention - transurethral resection of the prostate (TURP) in three cases and PAE in a single case. Urinary incontinence resulted in two cases after TURP. PAE could be successfully applied to decrease prostate volume and reduce urinary symptoms before PIB or as a treatment for urinary retention after PIB. A significantly lower PSA is promising for improved long-term cancer control.

Radioactive Iodine-125 in Tumor Therapy: Advances and Future Directions.

Radioactive iodine-125 (I-125) is the most widely used radioactive sealed source for interstitial permanent brachytherapy (BT). BT has the exceptional ability to deliver extremely high doses that external beam radiotherapy (EBRT) could never achieve within treated lesions, with the added benefit that doses drop off rapidly outside the target lesion by minimizing the exposure of uninvolved surrounding normal tissue. Spurred by multiple biological and technological advances, BT application has experienced substantial alteration over the past few decades. The procedure of I-125 radioactive seed implantation evolved from ultrasound guidance to computed tomography guidance. Compellingly, the creative introduction of 3D-printed individual templates, BT treatment planning systems, and artificial intelligence navigator systems remarkably increased the accuracy of I-125 BT and individualized I-125 ablative radiotherapy. Of note, utilizing I-125 to treat carcinoma in hollow cavity organs was enabled by the utility of self-expandable metal stents (SEMSs). Initially, I-125 BT was only used in the treatment of rare tumors. However, an increasing number of clinical trials upheld the efficacy and safety of I-125 BT in almost all tumors. Therefore, this study aims to summarize the recent advances of I-125 BT in cancer therapy, which cover experimental research to clinical investigations, including the development of novel techniques. This review also raises unanswered questions that may prompt future clinical trials and experimental work.

PRSOR05 Presentation Time: 12:20 PM: Permanent Interstitial LDR-Brachytherapy for Prostate Cancer Implementing Prostatic Artery Embolization

Background and Purpose: Permanent interstitial brachytherapy (PIB) is a well established treatment for prostate cancer. Treatment indication can be limited by prostate volume, usually decreased using neoadjuvant hormonal therapy. The aim of the study was to evaluated volume changes and initial clinical results with focus on patients after neoadjuvant prostatic artery embolization (PAE).

Permanent Interstitial Cesium-131 Brachytherapy in Treating High-Risk Recurrent Head and Neck Cancer: A Prospective Pilot Study.

Purpose/ObjectivesTo establish the feasibility and safety of intraoperative placement of cesium-131 (Cs-131) seeds for re-irradiation in recurrent head and neck cancer (HNC).MethodsPatients with resectable recurrent HNC who were deemed to have a high risk of second recurrence were eligible. Immediately after tumor extirpation, seeds were implanted in the surgical bed based on the preoperative treatment plan with intraoperative adjustment. The surgical bed and the seeds were covered with a regional flap or microvascular free flap. A CT of the neck was obtained on postoperative day 1 for evaluation of the postoperative dose distribution. Patients were followed 1 and 3 months after surgery, then every 3 months in the first 2 years.ResultsFrom November 2016 to September 2018, 15 patients were recruited and 12 patients received treatment per protocol. For the patients who had implants, the sites of initial recurrence included 10 neck alone, 1 neck and larynx, and 1 neck/peristomal. The median follow-up was 21.4 months. After surgery, patients remained hospitalized for a median of 6 days. There were no high-grade toxicities except two patients with wound complications requiring wound care. Eight patients had recurrences, three locoregional alone, three distant alone, and two with both locoregional and distant recurrences. Only one patient had an in-field failure. Five patients died, with 1- and 2-year overall survival of 75 and 58%.ConclusionsCs-131 implant after surgical resection in recurrent HNC is feasible and safe. There were no unexpected severe toxicities. Most failures were out-of-field or distant.Clinical Trial Registration ClinicalTrials.gov, identifier NCT02794675.

Isotope selection and PSA failure in prostate seed implant: Experience with CS-131 in a community hospital system.

375 Background: A recent large single institutional study reported excellent long-term biochemical control and survival for Cs-131 prostate implant. This isotope has short half-life (9.7 days) with clinical advantages including shorter duration of symptoms. We previously showed Cs-131 dosimetry to be quantitatively similar to I-125 with improved homogeneity (mean percent V150 36% for I-125 versus 27% for Cs-131 (p &lt; 0.0001). Our objective was to evaluate PSA failure rates and dosimetric outcomes in a multi-institutional community based setting. Methods: Within an IRB approved retrospective study, we compared outcomes for three groups of permanent prostate implant patients treated at Ascension Macomb Oakland, Ascension Saint John, and Ascension Providence Rochester Hospitals over a 10 year time interval. The comparison groups included isotopes Cs-131 (n = 66; t1/2 9.7 days), I-125 (n = 60; t1/2 60 days), and Pd-103 (n = 60; t1/2 17 days). Kaplan Meier estimates of PSA failure used the nadir plus 2 (Phoenix) definition. Results: Standard permanent implant doses employed were 145 Gy for I-125 monotherapy or 109 Gy for combination therapy. The dose for Cs-131 was 115 Gy for monotherapy and 85 Gy for combination therapy. For Pd-103, the doses employed were 125 Gy and 90 Gy for mono- and combination therapy, respectively. Median age at diagnosis was Cs-131; 69 (range 49-80), I-125; 71 (49-78), and Pd-103; 70 (60-82). Mean pretreatment PSA values were Cs-131 5.73 ng/ml, I-125 6.62 ng/ml, and for Pd-103 8.87 ng/ml. Median PSA follow up was 30 months and the median PSA value at 60 months was 0.11 ng/ml. There was excellent PSA control for all three groups of cases (p = NS), however with fewer failures using Cs-131. Conclusions: Permanent interstitial brachytherapy continues to be an attractive option for treatment early stage prostate cancer. Only a few large single institutional studies have examined PSA failure rates or dosimetric aspects of shorter half-life Cs-131 seed implants. This series confirms wide applicability of Cs-131 permanent prostate seed implant in the community hospital setting.

The 100 most cited articles in prostate cancer brachytherapy: systematic review and bibliometric analysis.

PurposeThe aim of this study was to identify the 100 most cited research articles in prostate cancer brachytherapy (PCB) and to review the characteristics of these citation.Material and methodsThe Web of Science Core Collection was used to identify the 100 most cited articles in PCB as of December 31st, 2019. The following important information was extracted: year and month of publication, title, journal, country of origin, authors, type of article, treatment modality, and topics.ResultsThe 100 most cited articles in PCB were published between 1999 and 2018, and the number of citations ranged from 455 to 54; these articles had collectively been cited 10,331 times at the time of search. These articles were from 11 countries, with most publications being from the United States (n = 61), followed by Canada (n = 10), the United Kingdom (n = 8), and Germany (n = 5). The “International Journal of Radiation Oncology, Biology, Physics” published the most articles (n = 47), followed by the “Journal of Urology” (n = 11), “Radiotherapy and Oncology” (n = 10), “Cancer” (n = 7), and “Urology” (n = 6). Permanent interstitial brachytherapy (n = 52) was the most widely used treatment modality, followed by temporary brachytherapy (n = 45). Disease control (n = 51) was the most common topic, followed by side effects (n = 44) and quality of life (n = 27).ConclusionsThe bibliometric analysis presents a detailed list of the 100 most cited articles in prostate cancer brachytherapy. There are clear recommendations for treatment with prostate cancer brachytherapy. The goal of prostate cancer brachytherapy is to improve long-term outcomes and quality of life.

A Pilot Study Using Intraoperative Placement of Cesium-131 Permanent Interstitial Brachytherapy in Resectable High Risk Recurrent Head and Neck Cancer

To determine the feasibility and safety of Cesium-131 implant in the management of recurrent head and neck cancer (HNC). This is a prospective trial approved by institutional IRB. Eligibility includes patients with resectable, recurrent failures who had a prior history of radiation to the head and neck deemed high risk for a second failure by our multidisciplinary tumor board. The strength and numbers of the Cesium 131 seeds were estimated based on a preoperative treatment plan with diagnostic CT images. Immediately after tumor extirpation, the seeds were implanted in the surgical bed based on the preoperative treatment plan with intraoperative adjustment. The surgical bed and the seeds were covered with a regional flap or microvascular free flap. A CT of neck was obtained on postoperative day 1 to confirm the dose distribution of the implant. The patient followed up at 1 month and 3 months after surgery, then every 3 months in the first two years. PET/CT scans or CT neck and chest with contrast was obtained at 3 months and one year after surgery. From November 2016 to September 2018, 15 patients were recruited, and 12 patients received protocol treatment. Of the three patients who did not receive protocol treatment, one had disease progression before surgery and went hospice, and two were determined to be low risk intraoperatively. Ninety-two percent (n=11) of the patients were male with a median age of 74.5 years old (range: 52-86). Primary sites included 5 oropharynx, 3 larynx, 3 skin, and 1 oral cavity. Recurrent sites included 10 neck alone, 1 neck and larynx, and 1 neck/peristomal. The interval between recurrence and previous radiation ranged from 3.7 – 103.8 months. Cesium implant dose ranged from 60 to 70 Gy. After surgery, patients remained in the hospital 3 to 9 days (median 6 days). There were no significant toxicities, and only one patient developed superficial wound breakdown requiring local wound care. The median follow-up was 10.1 months (range: 2.6 to 23.9) after implant. At last follow up, 5 patients had recurrence: 1 local, 2 distant, and 2 with both local and distant recurrences. Of the 3 local recurrences, only 1 had in-field failure. One patient failed in the contralateral neck and one in ipsilateral neck distant from the implant. Three patients had died, 2 with recurrences and 1 died of other cause with no recurrence. Intraoperative Cesium 131 implantation after surgical resection in recurrent HNC is feasible and safe. There were no unexpected severe toxicities. Most failures were out-of-field and distant failures. Future clinical trial with combination of cesium 131 implant and immunotherapy is under development.

Single institution implementation of permanent 131Cs interstitial brachytherapy for previously irradiated patients with resectable recurrent head and neck carcinoma.

PurposePermanent interstitial brachytherapy is an appealing treatment modality for patients with locoregional recurrent, resectable head and neck carcinoma (HNC), having previously received radiation. Cesium-131 (131Cs) is a permanent implant brachytherapy isotope, with a low average photon energy of 30 keV and a short half-life of 9.7 days. Exposure to medical staff and family members is low; patient isolation and patient room shielding are not required. This work presents a single institution’s implementation process of utilizing an intraoperative, permanent 131Cs implant for patients with completely resected recurrent HNC.Material and methodsFifteen patients receiving 131Cs permanent seed brachytherapy were included in this analysis. The process of pre-planning, selecting the dose prescription, seed ordering, intraoperative procedures, post-implant planning, and radiation safety protocols are described.ResultsTumor volumes were contoured on the available preoperative PET/CT scans and a pre-implant treatment plan was created using uniform source strength and uniform 1 cm seed spacing. Implants were performed intraoperatively, following tumor resection. In five of the fifteen cases, intraoperative findings necessitated a change from the planned number of seeds and recalculation of the pre-implant plan. The average prescription dose was 56.1 ±6.6 Gy (range, 40-60 Gy). The average seed strength used was 2.2 ±0.2 U (3.5 ±0.3 mCi). Patients returned to a recovery room on a standard surgical floor and remained inpatients, without radiation safety restrictions, based on standard surgical recovery protocols. A post-implant treatment plan was generated based on immediate post-operative CT imaging to verify the seed distribution and confirm delivery of the prescription dose. Patients were provided educational information regarding radiation safety recommendations.ConclusionsCesium-131 interstitial brachytherapy is feasible and does not pose major radiation safety concerns; it should be considered as a treatment option for previously irradiated patients with recurrent, resectable HNC.

Patient Reported Outcomes of NRG Oncology/RTOG 0232: A Phase III Study Comparing Combined External Beam Radiation and Transperineal Interstitial Permanent Brachytherapy with Brachytherapy Alone in Intermediate Risk Prostate Cancer

Patient Reported Outcomes of NRG Oncology/RTOG 0232: A Phase III Study Comparing Combined External Beam Radiation and Transperineal Interstitial Permanent Brachytherapy with Brachytherapy Alone in Intermediate Risk Prostate Cancer

Replacing the Syed: Initial Safety Results of a New Interstitial Template Technique using Cesium-131 Permanent Interstitial Brachytherapy (PIB) for Advanced Gynecologic Cancers

Replacing the Syed: Initial Safety Results of a New Interstitial Template Technique using Cesium-131 Permanent Interstitial Brachytherapy (PIB) for Advanced Gynecologic Cancers

Permanent Interstitial Brachytherapy for Previously Irradiated Head and Neck Cancer.

Objective: To evaluate our institutional experience using brachytherapy for the re-irradiation of the head and neck.Study Design/Methods: We reviewed the records of patients who received brachytherapy for head and neck cancer in a previously irradiated field between 2007 and 2016.Results: Sixty-nine patients received brachytherapy-based re-irradiation. Forty-nine patients (71%) were treated for recurrent cancers, 15 patients (22%) had second primary cancers, and five patients (7%) were treated for persistent tumors. The median dose was 90 Gy (range 30-180). Median follow-up was 3.0 years for surviving patients and 0.6 years for all patients. Overall survival at one, three, and five years was 58%, 19%, and 12%, respectively. Local control at one, three, and five years was 55%, 38%, and 28%, respectively. A disease-free interval of less than one year was associated with significantly worse local control (p=.04). Patients who received brachytherapy for a neck disease had significantly worse locoregional control than those who received brachytherapy for mucosal disease (heart rate (HR) 2.14, 95% CI 1.00-4.56, p=.05). Patients who had an extranodal extension had significantly worse overall survival than those without an extranodal extension (HR 2.57, 95% CI 1.28-5.37, p=.008). Seventy-four percent of patients who had pain before brachytherapy (with or without surgery) had an improvement of symptoms. Acute and chronic toxicity of at least Common Terminology Criteria for Adverse Events Grade 3 was seen in 27% and 19% of the patients, respectively.Conclusions: Brachytherapy-based re-irradiation is an effective approach for patients undergoing re-irradiation for head and neck cancer. Brachytherapy may be more effective for mucosal recurrences than neck recurrences.

A cold spot compensation technique using a combination of trans-rectal ultrasonography and intraoperative computed tomography for interstitial permanent prostate brachytherapy: a single-arm prospective trial.

PurposeTo evaluate the efficacy of a cold spot compensation technique using a combination of trans-rectal ultrasonography (TRUS) and computed tomography (CT) for permanent interstitial prostate brachytherapy.Material and methodsSixty-five patients were treated with the cold spot compensation technique using TRUS-CT fusion. The prescribed dose was set at 145 Gy. The dose to 90% of prostate volume (D90) was planned to be within 195 Gy (134%) and 205 Gy (141%). After implantation using the conventional technique, additional seeds were implanted if cold spots were detected on TRUS-CT fusion images.ResultsCold spots were detected in 32 of 65 patients (49%) and were compensated by additional seeds. Median number of additional seeds was 3 (range, 1-5). A CT scan 1 month later revealed that the percentage of patients receiving an undesirably low D90 (160-180 Gy) was significantly reduced in the examination arm compared to historical controls. However, mean operation time was significantly longer in the examination arm (64 min) than in historical controls (49 min, p < 0.001). With median follow-up of 18 months (range, 9-24 months), no grade 3 or worse toxicity was encountered.ConclusionThe cold spot compensation technique using TRUS-CT fusion appears effective for patients receiving permanent interstitial prostate brachytherapy.

Manual vs. automated implantation of seeds in prostate brachytherapy: Oncologic results from a single-center study

PurposeThe objective of this study was to study survival and tolerance of prostate cancer patients treated with 125I permanent interstitial brachytherapy by automated vs. manual implantation of seeds. Methods and MaterialsBetween 2002 and 2010, 349 selected patients were treated with 125I brachytherapy by the same team: from 2002 to April 2005, 65 patients with linked seeds and then 284 patients treated using Nucletron First System automated implantation. We analyzed biochemical recurrence-free survival (bRFS) rates and toxicities (univariate and multivariate analyses). ResultsTwo hundred seventy-seven (79.4%) and 69 patients (19.8%) with low- and intermediate-risk disease were treated, respectively (median follow-up: 64 months). The 5-year bRFS rate was 93.1% (95% confidence interval 89.3–95.6) for the entire cohort. The 5-year bRFS rates were 93.4% and 91.7% for patients with low- and intermediate-risk disease, respectively (p = 0.42). In univariate and multivariate analyses, there was no statistically significant difference in the 5-year bRFS rate depending on the implantation technique (93.1% vs. 91.8%, respectively, for automated and linked seeds; p = 0.53). In univariate analysis, only D90 prostate (dose delivered to 90% of the prostate) <140 Gy (p = 0.01), lack of prostate-specific antigen bounce (p = 0.008), and nadir prostate-specific antigen >0.11 (p = 0.01) were predictive factors for bRFS. We observed Grade 3 urethritis in 7 patients (2%), urinary incontinence in 2 patients (0.7%), and Grade 4 proctitis in 2 patients (0.7%). ConclusionsIn this large single-center series, brachytherapy for selected localized prostate cancer achieved excellent rates of biochemical control at 5 years (93.1%) with an acceptable toxicity profile, irrespective of the implantation technique used.

Replacing the Syed: Initial Safety Results of a New Treatment Technique Using Cesium-131 Permanent Interstitial Brachytherapy (PIB) for Advanced Gynecologic Cancers

Replacing the Syed: Initial Safety Results of a New Treatment Technique Using Cesium-131 Permanent Interstitial Brachytherapy (PIB) for Advanced Gynecologic Cancers

Reirradiation Using Permanent Interstitial Brachytherapy: A Potentially Durable Technique for Salvaging Recurrent Pelvic Malignancies

Topresent a time-to-failure (TTF) analysis for all patients treated with permanent interstitial brachytherapy (PIB) at our institution, with additional analyses to correlate successful reirradiation and to identify the frequency of severe grade 3 to 4 toxicity. Forty-two previously irradiated patients received curative or palliative intent PIB for a recurrent pelvic malignancy between January 2009 and August 2016. Minimum follow-up was 6months after the PIB procedure. All patients had a biopsy-proven recurrence and were treated using PIB alone (n=32) or in combination with a short course of additional radiation therapy (n=10). Competing risk analyses were performed to assess the risk of failures in the presence of death without failure. Exploratory analyses were performed for factors related to failure using competing risk analyses and the Gray statistic. A total of 61 PIB implants were performed among 42 patients with a median follow-up of 16.3months. Fifty-two implants were performed as the first salvage reirradiation to a solitary recurrence (8 patients had more than 1 lesion); the success rate for initial reirradiation using PIB was 73% (38 cases out of 52), and the median TTF was not reached. Nine patients underwent a second repeat PIB to the same recurrence as a form of salvage; 3 (33%) remain without evidence of recurrence. The median TTF after second salvage was 7.7months. Even with the limited sample size, prolonged TTF was marginally associated with definitive intent (P=.07) and the extent of disease at the time of PIB (P=.08). Grade 3+toxicities were seen in 8 patients (16.7%). Permanent interstitial brachytherapy is a feasible and potentially durable treatment modality that can be used to curatively salvage selected recurrent pelvic malignancies in a previously irradiated field.

Outpatient template-guided permanent interstitial brachytherapy using 131Cs in gynecologic malignancies: Initial report

PurposeOptimal curative intent brachytherapy for certain gynecologic cancers requires interstitial brachytherapy, often using template-guided techniques such as a Syed–Neblett implant. Whether high or low dose rate (LDR), these procedures pose significant risks to patients, partly attributable to the prolonged period of bed rest. Published results of free-handed permanent interstitial brachytherapy (PIB) with 131Cs demonstrate it to be an effective modality for the management of small volume gynecologic cancers. This report is the first to describe a permanent template-guided interstitial technique using 131Cs for gynecologic cancers, performed as an LDR outpatient procedure. Methods and MaterialsFive sequential patients with recurrent or primary gynecologic malignancies underwent template-guided PIB using 131Cs. A posttreatment planning CT was obtained immediately after the procedure and again 3–4 weeks later. Both CT data sets were fused and the relative positions compared to assess for migration in the x, y, and z planes. Seed positions as well as dosimetric parameters including D90, D100, V100, and the dose to 2 cc of rectum and bladder were compared to quantify migration of sources and the resulting effect, if any, on the treatment. ResultsThe median age was 69 years (range 64–85). All patients received a template-guided 131Cs PIB implant to treat gross disease. All 5 patients had significant medical comorbidities that limited treatment options. Considering all 5 patients, a total of 40 interstitial needles were placed. Ten needles carried only Vicryl-stranded sources, and 30 needles carried a combination of stranded 131Cs seeds and free seeds. Needle count was between 6 and 10 needles per patient, with active lengths of 4–10 cm. The median dose was 30 Gy (range 25–55 Gy) to permanent decay, enabling a cumulative median biological effective dose 91.5 Gy (range 60.9–92.1 Gy) and equivalent dose at 2 Gy per fraction 75.9 Gy (range 50.7–76.8 Gy). All implants were performed as outpatient procedures with only the first patient admitted for 23-hour observation. All calculated median migration distances were less than 1 cm in the axial, sagittal, or coronal planes. In 69.2% cases, the individual seed migration was <5 mm. Strand migration appeared directly related to peripheral placement and the use of stranded sources. The median D90, D100, and V100 were compared between study sets, and no significant differences were identified. No Grade 3 or higher complications occurred. ConclusionsPermanent LDR template-guided PIB using 131Cs can be safely performed on an outpatient basis. Compared to currently used template-guided techniques, the use of 131Cs avoids prolonged bed rest and hospitalization, significantly lowers cost, and enables a higher cumulative dose. Seed migration is minimal with this technique. Early experience suggests that the technique is safe and merits further study.

Comparison of prostate contours between conventional stepping transverse imaging and Twister-based sagittal imaging in permanent interstitial prostate brachytherapy.

PurposeTo compare prostate contours on conventional stepping transverse image acquisitions with those on twister-based sagittal image acquisitions.Material and methodsTwenty prostate cancer patients who were planned to have permanent interstitial prostate brachytherapy were prospectively accrued. A transrectal ultrasonography probe was inserted, with the patient in lithotomy position. Transverse images were obtained with stepping movement of the transverse transducer. In the same patient, sagittal images were also obtained through rotation of the sagittal transducer using the “Twister” mode. The differences of prostate size among the two types of image acquisitions were compared. The relationships among the difference of the two types of image acquisitions, dose-volume histogram (DVH) parameters on the post-implant computed tomography (CT) analysis, as well as other factors were analyzed.ResultsThe sagittal image acquisitions showed a larger prostate size compared to the transverse image acquisitions especially in the anterior-posterior (AP) direction (p < 0.05). Interestingly, relative size of prostate apex in AP direction in sagittal image acquisitions compared to that in transverse image acquisitions was correlated to DVH parameters such as D90 (R = 0.518, p = 0.019), and V100 (R = 0.598, p = 0.005).ConclusionsThere were small but significant differences in the prostate contours between the transverse and the sagittal planning image acquisitions. Furthermore, our study suggested that the differences between the two types of image acquisitions might correlated to dosimetric results on CT analysis.

Initial Report of NRG Oncology/RTOG 0232: A Phase 3 Study Comparing Combined External Beam Radiation and Transperineal Interstitial Permanent Brachytherapy With Brachytherapy Alone for Selected Patients With Intermediate-Risk Prostatic Carcinoma

Initial Report of NRG Oncology/RTOG 0232: A Phase 3 Study Comparing Combined External Beam Radiation and Transperineal Interstitial Permanent Brachytherapy With Brachytherapy Alone for Selected Patients With Intermediate-Risk Prostatic Carcinoma

Urinary Incontinence Following Prostate Brachytherapy

To define the incidence, time course, and risk factors associated with the development of urinary incontinence (UI) following prostate brachytherapy. A total of 2461 men were identified who underwent permanent interstitial prostate brachytherapy with or without external beam radiation therapy. We examined the relationship between clinical- and treatment-related variables with the onset of UI, defined as leakage requiring pad usage, and further classified as stress (SUI) or urge (UUI) predominant, using univariate and Cox proportional hazards regression models. The changes in International Prostate Symptom Score and quality of life domains were assessed from baseline to last follow, and examined by UI status. Patients were followed for a median of 6.4 years (interquartile range 4.1-9.3). UI was reported in 108 individuals (4.4%), at a median of 1.8 years (interquartile range 5 months-4.4 years): 30 with SUI and 78 with UUI. Seventy-two men (66.7%) reported using 1, 24 (22.2%) using 2, and 12 (11%) using ≥3 pads per day. On multivariate analysis, post-implantation transurethral resection of the prostate, urinary retention, external beam radiation therapy, and higher pretreatment International Prostate Symptom Score were significantly associated with the development of SUI, although transurethral resection of the prostate was the only significant risk factor associated with SUI. Men experiencing UI reported greater declines in urinary quality of life; however, no significant difference was observed between SUI and UUI. UI occurred in 4.4% of patients following prostate brachytherapy and is more commonly urge-predominant in character. Distinct risk factors exist for the development of UUI vs SUI. Urinary leakage requiring pad usage was associated with declines in urinary QOL.