Placement of an absorbable rectal hydrogel spacer in patients undergoing low-dose-rate brachytherapy with palladium-103

PurposeRates of rectal toxicity after low-dose-rate (LDR) brachytherapy for prostate cancer are dependent on rectal dose, which is associated with rectal distance from prostate and implanted seeds. Placement of a hydrogel spacer between the prostate and rectum has proven to reduce the volume of the rectum exposed to higher radiation dose levels in the setting of external beam radiotherapy. We present our findings with placing a rectal hydrogel spacer in patients following LDR brachytherapy, and we further assess the impact of this placement on dosimetry and acute rectal toxicity.Methods and MaterialsBetween January 2016 and April 2017, 74 patients had placement of a hydrogel spacer, immediately following a Pd-103 seed-implant procedure. Brachytherapy was delivered as follows: as a monotherapy to 26 (35%) patients; as part of planned combination therapy with external beam radiotherapy to 40 (54%) patients; or as a salvage monotherapy to eight (11%) patients. Postoperative MRI was used to assess separation achieved with rectal spacer. Acute toxicity was assessed retrospectively using Radiation Oncology Therapy Group radiation toxicity grading system. Rectal dosimetry was compared with a consecutive cohort of 136 patients treated with seed implantation at our institution without a spacer, using a 2-tailed paired Student's t test (p < 0.05 for statistical significance).ResultsOn average, 11.2-mm (SD 3.3) separation was achieved between the prostate and the rectum. The resultant mean rectal volume receiving 100% of prescribed dose (V_100%), dose to 1 cc of rectum (D_1cc), and dose to 2 cc of rectum (D_2cc) were 0 (SD 0.05 cc), 25.3% (SD 12.7), and 20.5% (SD 9.9), respectively. All rectal dosimetric parameters improved significantly for the cohort with spacer placement as compared with the nonspacer cohort. Mean prostate volume, prostate V₁₀₀ and dose to 90% of gland (D₉₀) were 29.3 cc (SD 12.4), 94.0% (SD 3.81), and 112.4% (SD 12.0), respectively. Urethral D₂₀, D_5cc, and D_1cc were 122.0% (SD 17.27), 133.8% (SD 22.8), and 144.0% (SD 25.4), respectively. After completing all treatments, at the time of first the followup, 7 patients reported acute rectal toxicity—6 experiencing Grade 1 rectal discomfort and 1 (with preexisting hemorrhoids) experiencing Grade 1 bleeding.ConclusionsInjection of rectal spacer is feasible in the post-LDR brachytherapy setting and reduces dose to the rectum with minimal toxicity. Prostate and urethral dosimetries do not appear to be affected by the placement of a spacer. Further studies with long-term followup are warranted to assess the impact on reduction of late rectal toxicity.     

The impact of a rectal hydrogel spacer on dosimetric and toxicity outcomes among patients undergoing combination therapy with external beam radiotherapy and low-dose-rate brachytherapy

PurposeRectal hydrogel spacers have been shown to decrease rectal radiation dose and toxicity. In this study, we compared prostate and rectal dosimetry and acute toxicity outcomes in patients who had and had not received a rectal hydrogel spacer prior to combination therapy with external beam radiotherapy and low-dose-rate brachytherapy.Materials and MethodsAll patients with intermediate-risk and high-risk prostate cancer who received combination therapy at our institution were identified between 2014 and 2019. Dosimetric outcomes of brachytherapy implants and quality of life (QOL) outcomes were compared between patients who had and had not received a hydrogel spacer.ResultsA Total of 168 patients meeting our inclusion criteria were identified. Twenty-two patients had received a rectal hydrogel spacer, among whom the mean separation between the rectum and prostate was 7.5 mm, and the V100_rectum was reduced by 47% (0.09 cc vs. 0.17 cc, p = 0.04). There was no difference in the percentage of patients achieving a D90 of ≥100 Gy between those who had and had not received a spacer. The mean rate of change in I-PSS and SHIM scores did not differ between the two groups at 2 months after PID.ConclusionLDR brachytherapy appears feasible after the placement of a rectal hydrogel spacer. While there was a significantly reduced V100_rectum among patients who had received a hydrogel spacer, there was no statistically significant difference in patients achieving a D90_prostate of ≥100 Gy. Although there was no difference appreciated in QOL scores, the length of follow-up was limited in the rectal-spacer group.     

Improved rectal dosimetry with the use of SpaceOAR during high-dose-rate brachytherapy

PurposeHydrogel spacers have been suggested to limit rectal radiation dose with improvements in clinical outcomes in patients undergoing external beam radiation treatment for prostate cancer. No studies to date have assessed the utility and dosimetric effect of SpaceOAR (Augmenix, Inc, Waltham, MA), the only Food and Drug Administration–approved hydrogel rectal spacer, for high-dose-rate (HDR) brachytherapy.MethodsEighteen consecutive patients scheduled for HDR brachytherapy in the treatment of prostate cancer underwent transperineal ultrasound-guided placement of 10 cc of SpaceOAR hydrogel following catheter implantation. Treatment plans were generated using an inverse planning simulated annealing algorithm. Rectal dosimetry for these 18 patients was compared with the 36 preceding patients treated with HDR brachytherapy without SpaceOAR.ResultsFifty-four plans were analyzed. There was no difference in age, pretreatment prostate-specific antigen, Gleason score, clinical stage, prostate volume, or contoured rectal volume between those who received SpaceOAR and those who did not. Patients who received SpaceOAR hydrogel had significantly lower dose to the rectum as measured by percent of contoured organ at risk (median, V₈₀ < 0.005% vs. 0.010%, p = 0.003; V₇₅ < 0.005% vs. 0.14%, p < 0.0005; V₇₀ 0.09% vs. 0.88%, p < 0.0005; V₆₀ = 1.16% vs. 3.08%, p < 0.0005); similar results were seen for rectal volume in cubic centimeters. One patient who received SpaceOAR developed a perineal abscess 1 month after treatment.ConclusionsTransperineal insertion of SpaceOAR hydrogel at the time of HDR brachytherapy is feasible and decreases rectal radiation dose. Further investigation is needed to assess the clinical impact of this dosimetric improvement and potential toxicity reduction.     

Use of a rectal spacer with low-dose-rate brachytherapy for treatment of prostate cancer in previously irradiated patients: Initial experience and short-term results

BackgroundSalvage brachytherapy in patients with prior pelvic radiation carries a risk of rectal injury. Herein, we report our initial experience using a hydrogel spacer between the prostate and the rectum during salvage brachytherapy.Methods and MaterialsA total of 11 patients with prostate cancer and prior radiotherapy (5 prostate brachytherapy, 2 prostate external beam radiation therapy [EBRT], and 4 rectal cancer EBRT) received ¹²⁵I brachytherapy after attempted placement of 10 cc of a diluted hydrogel spacer between the prostate and rectum.ResultsSpacing was achieved in 8 of the 11 (73%) patients but was not possible in 3 (1 prior brachytherapy and 2 prior EBRT) owing to fibrosis and adhesions. For the 8 patients in whom spacing was accomplished, the median space between the prostate and rectum was 10.9 mm (prior EBRT) vs. 7.7 mm (prior brachytherapy), p = 0.048. Median followup was 15.7 months. One patient developed a prostato-rectal fistula requiring a diverting colostomy. The 16-month estimate of late Grade 3 or 4 gastrointestinal or genitourinary toxicity was 26%. One patient developed lymph node–positive recurrence. The 16-month prostate-specific antigen failure-free survival rate was 89%. Compared with baseline, Expanded Prostate Cancer Index Composite for Clinical Practice urinary quality of life (QoL) was significantly worse at 3 and 6 months but not significantly worse by 1 year. There were no significant changes throughout the study period in bowel or sexual QoL.ConclusionHydrogel spacer placements may be feasible in most patients with prior pelvic radiation. Further followup is needed to determine whether spacer placement will produce long-term improvements in toxicity or QoL.     

Clinical and dosimetric factors associated with acute rectal toxicity in patients treated with 131Cs brachytherapy for prostate cancer

Purpose¹³¹Cs has been recently introduced for use in prostate brachytherapy. We wished to identify clinical and dosimetric factors associated with acute bowel/rectal toxicity in patients treated with ¹³¹Cs.Methods and MaterialsPatients treated with ¹³¹Cs prostate brachytherapy at the University of Pittsburgh were asked to complete expanded prostate cancer index composite surveys preoperatively and at 2–4 weeks and 3 months postimplant. We identified patients who experienced acute and persistent acute bowel toxicity to determine if any factors could correlate with either situation.ResultsOne hundred six patients were treated with ¹³¹Cs from September 2006 to May 2008. Thirty-eight percent of patients met our criteria for patient-appreciated acute bowel symptoms. On multivariate analysis, the volume of rectum receiving 50% of the prescribed dose (R-V₅₀; 4.1 vs. 2.6 cc, p = 0.01), R-V₇₅ (1.3 vs. 0.62 cc, p = 0.01), the percentage of the prescribed dose received by 1 cc of the rectum (R-D-1cc; 75% vs. 64%, p = 0.02), and R-D-2cc (63% vs. 54%, p = 0.003) were found to be factors associated with a greater risk of severe acute bowel toxicity. At 3-month followup, 28% of patients had persistent acute bowel toxicity. On multivariate analysis, no factors were identified that correlated with persistent acute bowel toxicity.ConclusionsThis study identifies R-V₅₀, R-V₇₅, R-D-1cc, and R-D-2cc as factors associated with patient-appreciated acute rectal toxicity. We are performing dosimetric analysis to determine the optimal distance for the posterior needles from the prostate–rectal interface to decrease rectal dose while still maintaining adequate coverage of prostate.     

Dose to the dominant intraprostatic lesion using HDR vs. LDR monotherapy: A Phase II randomized trial

PurposeTo present the dosimetric results of a Phase II randomized trial comparing dose escalation to the MRI-defined dominant intraprostatic lesion (DIL) using either low-dose-rate (LDR) or high-dose-rate (HDR) prostate brachytherapy.Material and MethodsPatients receiving prostate brachytherapy as monotherapy were randomized to LDR or HDR brachytherapy. Prostate and DILs were contoured on preoperative multiparametric MRI. These images were registered with transrectal ultrasound for treatment planning. LDR brachytherapy was preplanned using I-125 seeds. HDR brachytherapy used intraoperative transrectal ultrasound–based planning to deliver 27 Gy/2 fractions in separate implants. DIL location was classified as peripheral, central, or anterior. A student t-test compared DIL D₉₀ between modalities and DIL locations.ResultsOf 60 patients, 31 underwent LDR and 29 HDR brachytherapy. Up to three DILs were identified per patient (100 total) with 74 peripheral, six central, and 20 anterior DILs. Mean DIL volume was 1.9 cc (SD: 1.7 cc) for LDR and 1.6 cc (SD 1.3 cc) for HDR (p = 0.279). Mean DIL D₉₀ was 151% (SD 30%) for LDR and 132% (SD 13%) for HDR. For LDR, mean peripheral DIL D₉₀ was 159% (SD 27%) and central or anterior 127% (SD 13%). HDR peripheral DILs received 137% (SD 12%) and central or anterior 119% (SD 7%). DIL D₉₀ for peripheral lesions was higher than anterior and central (p < 0.001).ConclusionsDIL location affects dose escalation, particularly because of urethral proximity, such as for anterior and central DILs. HDR brachytherapy may dose escalate better when target DIL is close to critical organs.     

Brachytherapy provides comparable outcomes and improved cost-effectiveness in the treatment of low/intermediate prostate cancer

PurposeTo evaluate the cost-effectiveness and outcomes of low-dose-rate (LDR) and high-dose-rate (HDR) brachytherapy compared with intensity-modulated radiation therapy (IMRT) in patients with low/intermediate risk of prostate cancer.Methods and MaterialsOne thousand three hundred twenty-eight patients with low or intermediate risk of prostate cancer were treated with LDR (n = 207), HDR with four fractions (n = 252), or IMRT (n = 869) between January 1992 and December 2008. LDR patients were treated with palladium seeds to a median dose of 120 Gy, whereas HDR patients were treated to a median dose 38.0 Gy (four fractions). IMRT patients received 42–44 fractions with a median dose of 75.6 Gy. Clinical outcomes were compared, including biochemical failure, cause-specific survival, and overall survival.ResultsOverall, no differences in 5-year biochemical control (BC) or cause-specific survival were noted among treatment modalities. The calculated reimbursement for LDR brachytherapy, HDR brachytherapy with four fractions, and IMRT was $9,938; $17,514; and $29,356, respectively. HDR and LDR brachytherapy were statistically less costly to Medicare and the institution than IMRT (p < 0.001), and LDR brachytherapy was less costly than HDR brachytherapy (p = 0.01 and p < 0.001). Incremental cost-effectiveness ratios for cost to Medicare for BC with IMRT were $4045 and $2754 per percent of BC for LDR and HDR brachytherapy, respectively. Incremental cost-effectiveness ratio using institutional cost comparing IMRT with LDR and HDR brachytherapy was $4962 and $4824 per 1% improvement in BC.ConclusionsIn this study of patients with low and intermediate risk of prostate cancer, comparable outcomes at 5 years were noted between modalities with increased costs associated with IMRT.     

The impact of body mass index on rectal dose in locally advanced cervical cancer treated with high-dose-rate brachytherapy

PurposeThe impact of body mass index (BMI) on rectal dose in brachytherapy for cervical cancer is unknown. We assessed the association of BMI on rectal dose and lower gastrointestinal (GI) toxicity.Methods and MaterialsBetween 2007 and 2010, 51 patients with 97 brachytherapy planning images were reviewed. Volumetric measurements of the maximum percentage, mean percentage, dose to 2cc (D2cc), and dose to 1cc (D1cc) of the rectum, and the Internal Commission on Radiation Units and Measurement (ICRU) rectal point were recorded. Linear mixed effect models, analysis of variance, and regression analyses were used to determine the correlation between multiple observations or to detect a difference in the mean. The GI acute and late toxicity were prospectively recorded and retrospectively analyzed.ResultsThe average BMI (kg/m²) was 27.7 with a range of 17.4–46.6. Among the patients, 8% were morbidly obese, 25% obese, 25% overweight, 40% normal weight, and 2% underweight. The mean D1cc, D2cc, mean rectal dose (%), maximum rectal dose (%), and ICRU rectum was 3.03 Gy, 2.78 Gy, 20%, 60%, and 2.99 Gy, respectively. On multivariate analysis, there was a significant decrease in the D1cc and D2cc rectal dose (p = 0.016), ICRU rectal point dose (p = 0.022), and mean rectal dose percentage (p = 0.021) with an increase in BMI. There was, however, no statistically significant relationship between BMI and GI toxicity.ConclusionsObesity decreases the rectal dose given in high-dose-rate brachytherapy for locally advanced cervical cancer because of an increase in fatty tissue in the recto-uterine space. There is no significant correlation between BMI and acute or late GI toxicity.     

Incidence and dosimetric predictive factors of late rectal toxicity after low-dose-rate brachytherapy combined with volumetric modulated arc therapy in high-risk prostate cancer at a single institution: Retrospective study

PurposeThe purpose of this study is to investigate the incidence of rectal toxicity and to identify the associated dosimetric predictive parameters after I-125 seed low-dose-rate brachytherapy (LDR-BT) combined with volumetric modulated arc therapy (VMAT) and dose constraints.Methods and MaterialsIn total, 110 patients with high-risk prostate cancer received 110 Gy LDR-BT, followed by 45 Gy VMAT. Rectal toxicity was recorded according to Common Terminology Criteria for Adverse Events v.4.03. The dosimetric factors associated with LDR-BT and VMAT were analyzed to determine their relationship with rectal toxicity. Receiver operating characteristic (ROC) curve analysis was performed for ≥ grade 2 (G2) rectal toxicity prediction.ResultsThe follow-up duration was 10.1–115.2 months (median 60.5 months). Seven patients had G2 rectal hemorrhage, and none of the patients had grade 3 rectal hemorrhage. In the univariate analysis, the rectal volume receiving 100% of the prescribed dose (rV₁₀₀) (p < 0.001), the dose covering 2 cc of the rectum (rD_2cc) during LDR-BT (p = 0.002), and the combined rD_2cc during LDR-BT and VMAT (p = 0.001) were identified as predictors of G2 rectal hemorrhage. In the ROC curve analysis, the cutoff value was 0.46 cc for rV₁₀₀, 74.0 Gy for rD_2cc, and 86.8 GyEQD₂ for combined rD_2cc.ConclusionPredictors of late ≥ G2 rectal hemorrhage are rV₁₀₀, rD_2cc, and combined rD_2cc. The incidence of rectal toxicity is low and acceptable in this setting and is highly dependent on the rectal dose of LDR-BT. The use of higher-quality LDR-BT and VMAT dose constraints may further reduce the rate of rectal hemorrhage.     

New approach of ultra-focal brachytherapy for low- and intermediate-risk prostate cancer with custom-linked I-125 seeds: A feasibility study of optimal dose coverage

PurposeTo present the feasibility study of optimal dose coverage in ultra-focal brachytherapy (UFB) with multiparametric MRI for low- and intermediate-risk prostate cancer.Methods and MaterialsUFB provisional dose plans for small target volumes (<7 cc) were calculated on a prostate training phantom to optimize the seeds number and strength. Clinical UFB consisted in a contour-based nonrigid registration (MRI/Ultrasound) to implant a fiducial marker at the location of the tumor focus. Dosimetry was performed with iodine-125 seeds and a prescribed dose of 160 Gy. On CT scans acquired at 1 month, dose coverage of 152 Gy to the ultra-focal gross tumor volume was evaluated. Registrations between magnetic resonance and CT scans were assessed on the first 8 patients with three software solutions: VariSeed, 3D Slicer, and Mirada, and quantitative evaluations of the registrations were performed. Impact of these registrations on the initial dose matrix was performed.ResultsMean differences between simulated dose plans and extrapolated Bard nomogram for UFB volumes were 36.3% (26–56) for the total activity, 18.3% (10–30) for seed strength, and 22.5% (16–38) for number of seeds. Registration method implemented in Mirada performed significantly better than VariSeed and 3D Slicer (p = 0.0117 and p = 0.0357, respectively). For dose plan evaluation between Mirada and VariSeed, D₁₀₀% (Gy) for ultra-focal gross tumor volume had a mean difference of 28.06 Gy, mean values being still above the objective of 152 Gy. D₉₀% for the prostate had a mean difference of 1.17 Gy. For urethra and rectum, dose limits were far below the recommendations.ConclusionsThis UFB study confirmed the possibility to treat with optimal dose coverage target volumes smaller than 7 cc.     

First report on the use of a thinner 125I radioactive seed within 20-gauge needles for permanent radioactive seed prostate brachytherapy: Evaluation of postimplant dosimetry and acute toxicity

PurposeTo compare postoperative dosimetry and acute toxicity of new 0.5-mm ¹²⁵I seeds in 20-gauge (20G) diameter prostate brachytherapy (PB) needles with standard 0.8-mm seeds in 18G needles.Methods and MaterialsPostoperative dosimetry was performed on 100 consecutive PB patients treated with ThinSeeds in 20G needles and compared with 100 consecutively treated PB patients using standard-sized seeds and needles (18G). Dosimetry was performed on postoperative Day 1 CT scans. Acute urinary retention was also compared between these two groups. Acute toxicity was evaluated in 22 consecutively treated patients with thinner seeds/needles and compared with 22 consecutive concurrent patients treated with standard seeds and needles. All patients were evaluated by pre- and post-PB self-administered surveys, physical examinations on post-PB Day 1, and telephone surveys on Day 7. Endpoints included dysuria, acute urinary retention, hematuria, perineal pain/bruising, and International Prostate Symptom Score.ResultsPost-PB dosimetric comparison demonstrated that the V₁₀₀ (95% vs. 91%), D₉₀ (161 Gy vs.149 Gy), V₁₅₀ (55% vs. 45%), and RV₁₀₀ (0.43 cc vs. 0.30 cc) were significantly (p < 0.0004) higher in the 20G group. Urinary retention rates were 8% and 7% and median catheter-dependent durations were 7 and 14 days for the 20G and 18G groups, respectively. No significant differences were found for dysuria, hematuria, or International Prostate Symptom Score. Post-PB Day 1 perineal bruising and pain scores on Days 1 and 7 were significantly less (p < 0.04) in 20G cohort.ConclusionsSmaller diameter needles and seeds resulted in improved post-PB Day 1 V₁₀₀ and D₉₀ dosimetry, and significantly less acute perineal pain and bruising.     

Rectal sparing in prostate radiotherapy with combination-brachytherapy and hydrogel spacer

BackgroundThough some techniques that facilitate rectal sparing such as brachytherapy and intensity modulated radiotherapy (IMRT) have been examined in detail, technical aspects of hydrogel spacer (HS) have been studied less exhaustively. We examined HS quality metrics and approaches to placement for superior dosimetric outcomes.Materials and methodsA single site retrospective review of radiation plans was conducted for patients who received combination-brachytherapy (CBT) with 90 Gy low-dose-rate implant followed by external beam radiotherapy (45 Gy/25 fractions) with operating room (OR) placed HS (2017–2021). A randomly selected set of patients that received CBT without HS over the same time period was used for comparison. Dosimetric outcomes included D1cc and D5% rectum. Dose gradients were quantified. Student's t-test was used for statistical comparisons.ResultsSixty patients (30 with and 30 without HS) who received CBT for prostate cancer were examined. Those with HS had lower mean D1cc [65.31 Gy (SD = 13.53)] and D5% [53.20 Gy (SD = 10.18)] compared to those treated without HS [91.67 Gy (SD = 8.31) and 75.00 Gy (SD = 8.45), respectively, p < 0.001]. Patients with superior HS (average thickness ≥1 cm; n = 12) had lower mean D1cc [58.49 Gy (SD = 13.25, p = 0.026)] and D5% [48.69 Gy (SD = 9.85, p = 0.049)] than those with thinner HS. When dose gradients were considered, HS spanning the interface between the prostate and perirectal tissues to a thickness ≥1 cm can reduce rectal maximum dose to 50–60 Gy.ConclusionsThrough effective use of CBT and HS, extreme rectal dose restriction is possible. The goal for HS placement should be thickness ≥1 cm from base to apex.     

Transperineal mapping biopsy improves selection of brachytherapy boost for men with localized prostate cancer

PURPOSETo determine if transperineal mapping biopsy (TPMB) can improve the selection of brachytherapy alone (BT) or brachytherapy boost (BTB) in men with localized prostate cancer.Methods and MaterialsTwo hundred and eighteen men underwent TPMB with a mean of 48.6 cores retrieved. Comparisons were made between prebiopsy risk features and biopsy results to treatment choice with associations tested with ANOVA (bootstrap), χ² test (Pearson), and linear regression. Survival estimates were tested by the Kaplan–Meier method with comparisons by log rank.ResultsMean age, prostate specific antigen (PSA), prostate specific antigen density (PSAD), and prostate volume were 67.2 years, 8.1 ng/mL, 0.19, and 50.3 cc, respectively. 105 (48.2%) biopsies were positive for Gleason Group (GG) 1: 34 (32.4%), 2: 21 (20%), 3: 31 (29.5%), 4: 7 (6.7%), and 5: 12 (11.4%). The mean number of positive cores (PCs) was 7.3 (median 6, range 1–37). Men with six or more PCs had higher PSA (11.3 vs. 6.0 ng/mL, p = 0.025) and PSAD (0.34 vs. 0.13, p = 0.013). Overall brachytherapy was used in 74 (70.5%) as either monotherapy or boost therapy. Men with BTB had higher PSA (9.7 vs. 6.7 ng/mL, p = 0.029), PSAD (0.27 vs. 0.16, p = 0.007), GG (3.3 vs. 1.8, p < 0.001), more bilateral disease (75.9% vs. 55.6%, odds ratio 3.9, p = 0.008), and PCs (10.9 vs. 4.4, p < 0.001). On linear regression, only GG (p = 0.008) and PCs (p = 0.044) were associated with BTB. Biochemical-free failure at 5 years was 92.7%.ConclusionsTPMB improves the selection of patients for BTB. Men with more PCs are more likely to have BTB. Restricting the need for BTB to those with greater volume prostate cancer may reduce radiation side effects.     

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.