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To evaluate the outcomes of unfavorable intermediate-risk (UIR) and high-risk (HR) prostate cancer patients treated with combined external beam radiation therapy (EBRT) and low-dose-rate prostate brachytherapy (LDR-PB). A population-based cohort of 568 prostate cancer patients treated with combined EBRT and LDR-PB from 2010 to 2016 was analyzed. All patients received EBRT followed by LDR-PB boost. Outcomes were compared with the results for the brachytherapy arm of the ASCENDE-RT trial. The median followup was 4.5 years. Sixty-nine percent (N = 391) had HR disease. Ninety-four percent of the HR and 57% of UIR were treated with androgen deprivation therapy (ADT) with a median duration of 12 months. The 5-year K-M biochemical progression-free survival (b-PFS), metastasis-free survival (MFS), and overall survival (OS) were 84 ± 2%, 90 ± 2%, and 88 ± 2%, similar to 89 ± 5%, 94 ± 4%, and 92 ± 4% for the ASCENDE-RT LDR-PB arm. The likelihood of achieving a PSA ≤0.2 ng/mL at 4 years was 88%, similar to 86% in the ASCENDE-RT LDR-PB arm. Thirty-three men (5.8%) would have been ineligible for ASCENDE-RT due to high-risk features. The 5-year K-M b-PFS, MFS and OS estimates were 86 ± 2%, 92 ± 1% and 89 ± 2% for the ASCENDE-RT eligible versus 56 ± 10% (p < 0.001), 73 ± 8% (p < 0.001), and 77 ± 9% (p = 0.098) for the ineligible patients. In this population-based cohort, combining LDR-PB with pelvic EBRT (+/- ADT) achieves very favorable b-PFS that compares to the LDR-PB arm of the ASCENDE-RT, supporting the generalizability of those results. Men ineligible for ASCENDE-RT, based on prognostic features, have a much higher risk of biochemical recurrence and metastatic relapse. [ABSTRACT FROM AUTHOR]

Abstract Purpose To compare biochemical failure using a prostate-specific antigen (PSA) threshold of >0.2 ng/mL to that using Phoenix threshold (nadir+2 ng/mL). Methods and Materials Androgen suppression combined with elective nodal and dose-escalated radiation therapy (the ASCENDE-RT trial) is a randomized control trial in which 276 high-risk and 122 intermediate-risk patients were randomized to (1) a standard arm with 12 months of androgen deprivation therapy, pelvic external beam radiation therapy (EBRT) to 46 Gy, and an EBRT boost (dose-escalated EBRT [DE-EBRT]) to 78 Gy, or (2) an experimental arm which substituted a low-dose-rate prostate brachytherapy boost (LDR-PB). The primary endpoint was biochemical progression-free survival (b-PFS) using the Phoenix threshold. In this reanalysis of ASCENDE-RT, the b-PFS using phoenix is compared to the surgical PSA threshold of >0.2 ng/mL. Results Compared to nadir+2 ng/mL, the >0.2 ng/mL PSA threshold doubled the number of relapse events from 69 to 139. However, the increase was confined to the DE-EBRT subjects. The 7-year Kaplan-Meier b-PFS after DE-EBRT declined from 76% using nadir+2 ng/mL to 38% using the >0.2 ng/mL threshold (p < 0.001). Among the LDR-PB subset, there was no significant difference in b-PFS; the 7-year Kaplan-Meier b-PFS was 85% (>0.2 ng/mL) versus 88% (nadir+2 ng/mL) (p = 0.319). Conclusions Replacing Phoenix with a surgical threshold greatly increased biochemical failure after DE-EBRT boost but had no effect after LDR-PB. As a result of this finding, PSA outcomes after surgery or brachytherapy can be directly compared by using the surgical definition of PSA failure. In this context, a brachytherapy boost appears to produce superior b-PFS compared to contemporary surgical series. [ABSTRACT FROM AUTHOR]

Purpose To describe outcomes of men with unfavorable (high-tier) intermediate risk prostate cancer (H-IR) treated with low-dose-rate (LDR) brachytherapy, with or without 6 months of androgen deprivation therapy (ADT). Methods and Materials Patients with H-IR prostate cancer, treated before 2012 with LDR brachytherapy without external radiation are included. Baseline tumor characteristics are described. Outcomes between groups receiving ADT are measured by Phoenix (nadir +2 ng/mL), and threshold 0.4 ng/mL biochemical relapse definitions (bNEDs), as well as clinical end points. Standard descriptive and actuarial statistics are used. Results Two hundred sixty men were eligible, 139 (53%) did not receive ADT and 121 (47%) did. Median follow-up was 5 years. Men treated with ADT had higher T stage and percent positive cores but lower pathologic grade group. bNED rates with and without ADT at 5 years are 86% and 85% ( p = 0.52) with the Phoenix definition, and 83% and 78% ( p = 0.13) with the threshold definition. Local recurrence or metastasis were rare in both groups (<5%, p = not significant). Death from prostate cancer only occurred in 4 patients, 2 in each group. Overall survival was 85% in those treated with ADT and 93% without at 8 years, p = 0.15. Conclusions The addition of 6 months of ADT to LDR brachytherapy for H-IR prostate cancer does not improve 5 year prostate specific antigen control, and we no longer routinely recommended it. [ABSTRACT FROM AUTHOR]

Purpose: To report the patient-reported health-related quality of life (HR-QoL) outcomes for a multicenter randomized trial evaluating the safety and efficacy of 2 different techniques for dose escalation.Methods and Materials: A total of 357 men with intermediate- and high-risk prostate cancer were stratified by risk group and randomized (1:1) to either a dose-escalated external beam (DE-EBRT) boost (n=177) or a low-dose-rate prostate brachytherapy (LDR-PB) boost (n=180) as part of combined modality therapy. The HR-QoL was assessed using the SF36v2 questionnaire, with additional scales for urinary, bowel, and sexual function. Date of starting androgen deprivation therapy was considered time zero, the median follow-up of 6 years. Scales were scored from 0 to 100; a decline in a mean score ≥10 compared with baseline was considered a clinically significant decline. This was an intent-to-treat analysis.Results: Mean domain scores at baseline were well balanced between the 2 treatment arms. A clinically significant decline in mean scores in both the arms compared with baseline was noted for role physical (DE-EBRT [-11.4] and LDR-PB [-15.3]) and sexual function scale (DE-EBRT [-15.1] and LDR-PB [-19.2]). There was a significantly larger drop in mean scores in the LDR-PB group compared with the DE-EBRT group for physical function (-15.3 vs -6.9; P=.03), urinary function (-3.6 vs -0.5; P=.04).Conclusion: At 6 years' follow up, there were no significant differences in mean scores in 9 of 11 scales compared with baseline in both arms. A clinically significant decline in mean scores was noted in both arms for role physical and sexual function scales. There was a statistically significant decline in physical function and urinary function scales in the LDR-PB arm compared with the DE-EBRT arm. [ABSTRACT FROM AUTHOR]

Purpose: To report the primary endpoint of biochemical progression-free survival (b-PFS) and secondary survival endpoints from ASCENDE-RT, a randomized trial comparing 2 methods of dose escalation for intermediate- and high-risk prostate cancer.Methods and Materials: ASCENDE-RT enrolled 398 men, with a median age of 68 years; 69% (n=276) had high-risk disease. After stratification by risk group, the subjects were randomized to a standard arm with 12 months of androgen deprivation therapy, pelvic irradiation to 46 Gy, followed by a dose-escalated external beam radiation therapy (DE-EBRT) boost to 78 Gy, or an experimental arm that substituted a low-dose-rate prostate brachytherapy (LDR-PB) boost. Of the 398 trial subjects, 200 were assigned to DE-EBRT boost and 198 to LDR-PB boost. The median follow-up was 6.5 years.Results: In an intent-to-treat analysis, men randomized to DE-EBRT were twice as likely to experience biochemical failure (multivariable analysis [MVA] hazard ratio [HR] 2.04; P=.004). The 5-, 7-, and 9-year Kaplan-Meier b-PFS estimates were 89%, 86%, and 83% for the LDR-PB boost versus 84%, 75%, and 62% for the DE-EBRT boost (log-rank P<.001). The LDR-PB boost benefited both intermediate- and high-risk patients. Because the b-PFS curves for the treatment arms diverge sharply after 4 years, the relative advantage of the LDR-PB should increase with longer follow-up. On MVA, the only variables correlated with reduced overall survival were age (MVA HR 1.06/y; P=.004) and biochemical failure (MVA HR 6.30; P<.001). Although biochemical failure was associated with increased mortality and randomization to DE-EBRT doubled the rate of biochemical failure, no significant overall survival difference was observed between the treatment arms (MVA HR 1.13; P=.62).Conclusions: Compared with 78 Gy EBRT, men randomized to the LDR-PB boost were twice as likely to be free of biochemical failure at a median follow-up of 6.5 years. [ABSTRACT FROM AUTHOR]

Objectives This study examined patterns of recurrence after low–dose-rate prostate brachytherapy (LDR-PB), estimated local recurrence rate and compared that rate to the estimated local recurrence rate after radical prostatectomy (RP). Methods and Materials A prospective database was maintained with clinical, dosimetric, and outcome data for all LDR-PB implantation procedures performed at our institution. From 1998 to 2008, 2223 patients with prostate cancer received LDR-PB without supplemental external beam radiation therapy. Patients who developed Phoenix-defined biochemical failure were reviewed for sites of relapse and investigations completed. Results At a median follow-up of 5 years, 108 of 2223 patients (4.8%) developed biochemical relapse. In 1 additional patient, local relapse was found on transurethral prostate resection, but his prostate-specific antigen concentration was well short of triggering Phoenix-defined failure. Of the 109 patients with disease relapse, 18 of 2223 (0.8%) had a proven local recurrence, and 30 of 2223 (1.3%) had a proven distant recurrence. The remaining 61 of 2223 patients (2.7%) had unidentified sites of recurrence; of these, 57 patients (93%) had digital rectal examinations (DREs), 18 (30%) had post-treatment biopsies, 45 (74%) had bone scans, and 34 (56%) had computed tomography imaging of the abdomen and pelvis. If every biochemical failure were local, the local recurrence rate would be as high as 4.9%; however, by excluding those with proven distant failure and those with both a negative DRE and biopsy, we estimate that the local recurrence rate is 2.7% or less. Conclusions In the context of limitations of the study design, our population-based analysis indicates that the local recurrence rate after LDR-PB is as low or lower than that after RP in our jurisdiction. [ABSTRACT FROM AUTHOR]

Purpose: To compare disease-free survival (DFS) rates using a >0.4 ng/mL biochemical failure definition with the Phoenix (nadir+2 ng/mL) failure definition by analyzing a consecutive cohort of 1006 patients treated with low-dose-rate prostate brachytherapy (LDR-PB) monotherapy. Methods and Materials: Data for first 1006 consecutive LDR-PB implants (1998–2003) were extracted from a prospective database. Patients had low- (58%) or intermediate (42%)-risk disease. Three months neoadjuvant and 3 months concomitant androgen deprivation therapy were used in 65% of cases. The Phoenix definition was modified to “unfail” patients who had a benign prostate-specific antigen (PSA) bounce. Results: The median followup is 7.5 years. The median PSA at latest followup for disease-free patients was 0.04 ng/mL. The Phoenix definition yielded 5- and 10-year Kaplan–Meier DFS estimates of 96.5 ± 1.2% and 93.7 ± 2.0%, respectively. Applying the >0.4 ng/mL threshold reduced these estimates to 94.4 ± 1.6% and 88.8 ± 3.0% (log rank, p = 0.015). Conclusions: Compared with Phoenix, applying a >0.4 ng/mL failure definition increased biochemical failure by ∼2% at 5 years and ∼5% at 10 years. These data show that Phoenix did not greatly exaggerate DFS estimates compared with a surgical-type threshold. However, this observation is a consequence of the exceptionally low residual PSA values characteristic of LDR-PB and cannot be generalized to other forms of radiation therapy. [ABSTRACT FROM AUTHOR]

Purpose: To determine (1) the prognostic utility of prostate-specific antigen (PSA) concentration at 45 to 60 months (48mPSA) after low-dose-rate prostate brachytherapy (LDR-PB); (2) the predictors of 48mPSA; and (3) the prognostic utility of directional trends between PSA levels at 24, 36, and 48 months after LDR-PB. Methods and Materials: Between 1998 and 2008, 2223 patients with low- and intermediate-risk prostate cancer received LDR-PB monotherapy. A cohort of 1434 of these patients was identified with a documented 48mPSA and no evidence of disease relapse prior to the 48mPSA. In addition, a subset of this cohort (n=585) was identified with ≥72 months of follow-up and documented PSA values at both 24 and 36 months after implantation. Results: Median follow-up time was 76 months. Eight-year Kaplan-Meier disease-free survival (DFS) rates were 100% vs 73.4% for patients with 48mPSA ≤0.2 vs those with >0.2 ng/mL; 99.1% versus 53.8% for a 48mPSA threshold of ≤0.4 versus >0.4 ng/mL, respectively; and 97.3% versus 0% for a threshold of ≤1.0 versus >1.0 ng/mL, respectively. On multivariate analysis, the only factor predictive of DFS was 48mPSA (P<.0001). On subset analysis (n=585), 29 patients had a PSA rise (defined as >0.2 ng/mL) between 24 and 36 months, 24 patients had a rise between 36 and 48 months, and 11 patients had rises over both intervals. Failure rates in these patients were 52%, 79%, and 100%, respectively. On multivariate analysis, initial PSA, androgen deprivation therapy, and dose to 90% of the prostate significantly correlated with 48mPSA but together accounted for only ∼5% of its total variance. Conclusions: The 48mPSA after LDR-PB is highly predictive of long-term DFS. Patients with 48mPSA ≤0.4 ng/mL had a <1% risk of disease relapse at 8 years, whereas all patients with 48mPSA >1.0 ng/mL relapsed. Consecutive PSA rises of >0.2 ng/mL from 24 to 36 months and from 36 to 48 months were also highly predictive of subsequent failure. [Copyright &y& Elsevier]

Abstract: Purpose: To examine the relationship between whole prostate dose metrics and disease-free survival (DFS) after 125I low-dose-rate prostate brachytherapy (LDR-PB). Methods and Materials: Data for the first 2000 LDR-PB monotherapy implants were extracted from a database containing patient, tumor, dosimetric, and outcomes information. By National Comprehensive Cancer Network criteria, half (n = 1006) had low-risk disease and half (n = 990) had intermediate-risk disease (four had high-risk disease). Most patients (58.4%) and 75.3% of intermediate-risk patients received 3 months neoadjuvant and 3 months concomitant androgen deprivation therapy (ADT). Univariate and multivariate analyses were conducted using recognized prognostic factors and the whole prostate dose metrics D 90 (the minimum dose received by 90% of the postimplant CT-based prostate volume) and V 100 (the percent of the postimplant CT-based prostate volume that received at least 100% of the prescription dose). Results: The median followup is 5 years (maximum, 12.5 years); the 5-, 7-, and 10-year actuarial DFS estimates are 96.0%, 94.4%, and 93.0%, respectively. Of the recognized prognostic factors, only pretreatment prostate-specific antigen (p = 0.012) and Gleason sum (p = 0.010) were predictive of DFS. When analyzed as continuous variables, dose metrics were not predictive of DFS. However, most nonsignificant trends favored higher doses, and D 90 values <130 Gy were predictive of an increased risk of recurrence in the non-ADT subset (N = 833; log rank, p = 0.018). Conclusions: Although D 90 values of <130 Gy were predictive of an increased risk of recurrence in the non-ADT subset, neither D 90 nor V 100, when used as continuous variables, was predictive of DFS when applied to the entire cohort or in the subset analysis. This observation informs us that dose metrics are not equivalent to oncologic end points and must be calibrated against DFS for each physician and each institution offering LDR-PB. [Copyright &y& Elsevier]

Abstract: Background and purpose: To evaluate outcome in patients with Gleason 7 prostate cancer treated with iodine-125 brachytherapy at the British Columbia Cancer Agency. Materials and methods: Between 20th July 1998 and 7th February 2006, 1500 patients underwent I-125 prostate brachytherapy without supplemental external beam radiation therapy. Of these, 439 had Gleason 7 disease; 362 had Gleason 3+4 and 77 had 4+3 disease. Generally, patients received 6months of androgen suppression. We compared biochemical no evidence of disease (bNED) between patients with Gleason ⩽6 and Gleason 7 and between Gleason 3+4 and 4+3 using the Phoenix definition of biochemical recurrence. Results: Median follow-up was 60months. Estimated 5year bNED was 97% for patients with Gleason score ⩽6 and 94% for patients with Gleason 7 disease (p =0.037). Estimated bNED was 95% and 94% for 3+4 and 4+3, respectively (p =0.791). There was no difference in bNED between implants achieving D90⩾versus

Abstract: Purpose: The British Columbia Cancer Agency has been performing iodine-125 prostate brachytherapy since 1998, initially using loose seeds and phasing into the exclusive use of RAPIDStrand (RS) (Oncura Inc., Plymouth Meeting, PA) by November 2000. The aim of this study was to investigate rates of biochemical no evidence of disease (bNED) in patients treated with loose seeds compared with RS from this population-based cohort. Methods and materials: Between July 1998 and February 2006, 1500 implants were performed (327 loose and 1173 RS). Biochemical failure is reported using the Phoenix definition and prostate-specific antigen (PSA) >0.4ng/mL at ≥48 months postimplant. Actuarial estimates were calculated by the Kaplan–Meier method. Analysis was repeated with the first 100 loose and stranded implants excluded to assess the learning curve effect. Log-rank test was used to evaluate differences in bNED. Variables showing association with bNED were included in a multivariate model. Results: There was no difference between loose and stranded seeds. Estimated rate of bNED was 93.5% (95% confidence interval [CI], 90.6–96.4) at 7 years for patients treated with loose seeds and 94.0% (95% CI, 91.8–96.2) for patients treated with RS according to Phoenix definition (p =0.846). Using the PSA >0.4ng/mL definition, estimated rates were 91.3% (95% CI, 88.0–94.6) and 91.9% (95% CI, 89.7–94.1) for loose and stranded seeds, respectively (p =0.871). Exclusion of the first 100 loose and stranded implants also revealed no difference in bNED. Conclusion: This study of 1500 patients treated with iodine-125 brachytherapy demonstrates no difference in bNED between loose and stranded seeds, using either Phoenix or PSA >0.4ng/mL definitions of biochemical failure. [Copyright &y& Elsevier]

Abstract: Purpose: To evaluate region-specific dose metrics as predictors of biochemical relapse in prostate brachytherapy patients. Methods and Materials: In a cohort of 1006 low-risk and “low-tier” intermediate-risk prostate brachytherapy patients treated to a planned dose of 144Gy mPD (minimal peripheral dose), 30 of 32 with biochemical relapse (nadir+2ng/mL definition) had postimplant CT scans available for retrospective analysis. These were matched to nonrelapsing controls from the same era. Three copies of each CT were created and, after randomization and deletion of identifiers and original contours, were re-contoured by three radiation oncologists. Prostate contours were then divided into quadrants: Anterior-Superior (ASQ), Posterior-Superior (PSQ), Anterior-Inferior (AIQ), and Posterior-Inferior (PIQ), and dosimetric parameters calculated. Results were analyzed using mixed-effects linear regression and multivariate logistic regression. Results: Whole prostate volume of the prostate receiving at least 100% of the prescribed dose (V 100) and minimum dose, as a percentage of the prescribed dose, received by 90% of the prostate volume (D 90) were similar for relapses and controls (p =0.40 and 0.48, respectively). Among the quadrants, the largest differences between relapses and controls were seen for the AIQ. Mean AIQ V 100s were 91.2% (relapses) and 95.5% (controls) (p =0.096), and D 90s were 112.8% (relapses) and 119.3% (controls) (p =0.145). Overall, the lowest doses were in the ASQ, but were not very different for relapses and controls (V 100 =76.5% and 78.5%, respectively) (p =0.54). On multivariate analysis along with various clinical parameters, AIQ metrics approached significance at the p ≤ 0.05 level in models that also included initial prostate-specific antigen, androgen suppression, and risk group. Conclusions: Although whole prostate dose metrics did not predict for biochemical relapse in our data set, dose to the AIQ was predictive in multivariate analysis. [Copyright &y& Elsevier]

Abstract: Purpose: To compare the predicted outcome by radical retropubic prostatectomy (RRP) of patients actually treated with prostate brachytherapy (PB) for low- and intermediate-risk prostate cancer, using a surgical nomogram. Methods and Materials: Data of consecutive patients treated with PB from the start of our program in 1998 to February 1, 2005 were extracted from a prospectively maintained database that records patient, tumor, and outcomes information. Prognostic features of each patient and brachytherapist experience were entered into a nomogram of surgical outcomes that incorporates surgeon experience. The definition of failure was a rising prostate specific antigen (PSA) >0.4ng/mL or secondary intervention. Comparisons of actual PB outcome vs. predicted surgical outcome were compared using the log-rank test. Results: One thousand two hundred fifty-four patients were treated in this era, and all are included for analysis. The median followup is 56 months. Forty-six percent have stage T1, and 54% have stage T2 cancer. Twenty-five percent have Gleason 7 disease, and the median PSA is 6.3ng/mL (range, 0.3–19.6ng/mL). Fifty-eight percent have low-risk disease, and 41% have intermediate-risk disease. Androgen deprivation therapy was used for 6 months in 92% of intermediate-risk and 46% of low-risk cases. The median PSA at last followup is 0.06ng/mL. Five-year biochemical no evidence of disease rate with PB is 90.6%, and that predicted with RRP is 86.8%, p =0.003. Conclusions: Excellent PB outcomes are observed that exceed that predicted from the use of RRP. [ABSTRACT FROM AUTHOR]

Purpose: To analyze dosimetric outcomes after permanent brachytherapy for men with low-risk and “low-tier” intermediate-risk prostate cancer and explore the relationship between the traditional dosimetric values, V100 (volume of prostate receiving 100% of the prescribed dose) and D90 (minimum dose to 90% of the prostate), and risk of biochemical failure. Methods and Materials: A total of 1,006 consecutive patients underwent implantation between July 20, 1998, and Oct 23, 2003. Most (58%) had low-risk disease; the remaining 42% comprised a selected low-tier subgroup of intermediate-risk patients. The prescribed minimum peripheral dose (MPD) was 144 Gy. All implants used 0.33 mCi 125I sources using a preplan technique featuring right-left symmetry and a strong posterior-peripheral dose bias. Sixty-five percent of patients had 6 months of androgen deprivation therapy. Postimplantation dosimetry was calculated using day-28 CT scans. Results: With a median follow-up of 54 months, the actuarial 5-year rate of freedom from biochemical recurrence (bNED) was 95.6% ± 1.6%. Median D90 was 105% of MPD, median V100 was 92%, median V150 was 58%, and median V200 was 9%. Dosimetric values were not predictive of biochemical recurrence on univariate or multivariate analysis. Analysis of dosimetric values by implantation number showed statistically significant increases in all values with time (D90, V100, V150, and V200; p < 0.001), but this did not translate into improved bNED. Conclusions: In contrast to some previous studies, dosimetric outcomes did not correlate with biochemical recurrence in the first 1,006 patients treated with 125I prostate brachytherapy at the British Columbia Cancer Agency. Despite a median D90 of only 105% of MPD, our bNED rates are indistinguishable from series that reported higher D90 values. [Copyright &y& Elsevier]

Statement of problem: The design of a removable dental prosthesis (RDP) must balance functional strength, comfort to the patient, and the health of the tissue. While research has been conducted to enhance the strength of major connectors, little has been done to determine if the dimensions of major connectors can be reduced in order to enhance patient comfort and tissue health. Purpose: The purpose of this study was to determine the minimum major connector dimensions of 1 mandibular and 2 maxillary major connectors that would provide adequate functional strength. Material and methods: Sixty chromium-cobalt alloy (Vitallium) RDP frameworks were fabricated. The major connector designs were: a mandibular lingual bar, a maxillary palatal strap, and a maxillary anterior-posterior (A-P) palatal strap. Four groups of 5 frameworks with diminishing dimensions were fabricated for each major connector design. The lingual bar was tested at 4, 3, 2.5, and 2 mm in height, occlusogingivally, and 1.6 mm in thickness; the palatal strap at 8, 6, 4, and 2 mm, anteroposteriorly; and the A-P palatal strap at 10 × 6, 8 × 4, 6 × 2.5, and 4 × 2 mm, anteroposteriorly. All maxillary frameworks were 0.65 mm in thickness. The frameworks were of a Kennedy Class II Mod I design with 3 widely separated vertical reference points to measure deformation. Two tests were conducted to evaluate the functional strength for each framework. The first test was masticatory simulation, or torsional force. The second test was a drop test from a height of 3 feet. Permanent deformation was then determined after each test. The Cochran-Armitage test (α=.05) was used for both the torsion test and the drop test. Results: A statistically significant difference in permanent deformation was found for the palatal strap design among the 4 different dimensions for the compressive test (P=.015) and the drop test (P=.044). Conclusion: It is safe to reduce the dimensions of some major connectors under normal loads. The reduced size of the connectors places the removable partial denture at increased risk for deformation when dropped from a height. [Copyright &y& Elsevier]

Statement of problem: Clinicians have used resistance form as a basis for determining guidelines for preparation design to ensure clinical success of cemented cast restorations. Disagreement on whether clinical success follows the on-off or linear nature of resistance form continues. Purpose: The purpose of this study was to evaluate the number of cycles required to dislodge a cemented complete crown casting under a cyclic lateral load as a function of taper and to compare this relationship for the resistive and nonresistive ranges of taper. Material and methods: Three dies were milled from stainless steel at each of the following tapers: 4, 8, 12, 16, 20, 24, 28, and 32 degrees. A gold-palladium metal-ceramic alloy crown was fabricated for each die, cemented, and subjected to lateral cyclic loading until failure or 1,000,000 cycles. The limiting taper for the dies with their given height and base was 26.6 degrees. Dies with taper less than 26.6 degrees had resistance form, whereas dies with taper larger than 26.6 degrees did not. A linear regression (α=.05) was used to evaluate the relation of cycles at dislodgement to taper. Results: The average number of cycles to crown dislodgement or completion for each taper (SD), in units of 10,000, was as follows: 4 degrees, 100 (0); 8 degrees, 100 (0); 12 degrees, 93.54 (16.56); 16 degrees, 61.33 (38.47); 20 degrees, 25.73 (34.67); 24 degrees, 4.33 (7.36); 28 degrees, 0.06 (0.08); and 32 degrees, 0.05 (0.09). The crowns in the resistive area less than 26.6 degrees that demonstrated failure showed a linear regression with a correlation coefficient of −0.995 between the average number of cycles to dislodge the crown and the taper. The slope was significantly different from zero (P=.0048), with a value of −7.58 and a standard error of 0.53. Conclusion: The number of cycles required to cause crown dislodgement was linear after 12 degrees in the resistive area and nearly zero for preparations in the nonresistive area. The limiting taper concept closely predicted the transition point where the slope of the graph of cycles to dislodgement as a function of taper abruptly changed. [Copyright &y& Elsevier]

Statement of problem: Removable partial denture frameworks are complex castings fabricated from high-shrinkage alloys. This may result in difficulty in achieving accurate fit. Purpose: The purpose of this study was to evaluate which component(s) of the clasp assembly contact the abutment tooth clinically. Material and methods: New and existing frameworks with at least 1 conventional prepared occlusal rest were evaluated for fit. The spacing between the bottom of each of the rests of the 50 clasp assemblies and the corresponding rest seat were recorded with vinyl polysiloxane. The fit of each rest was determined with the use of a dial caliper by measuring, in micrometers, the thickness of the record between the rest and the bottom of the rest seat. The Kennedy classification was also recorded. A 2-sample t test was used to evaluate the difference in fit between tooth-tissue supported and tooth-supported designs (α=.05). Results: The average space between the rest and prepared rest seat was 193 ± 203 μm, with a range of 0 to 828 μm. Twenty tooth-tissue frameworks had an average space of 136 ± 160 μm and 30 tooth-supported frameworks had an average space of 230 ± 222 μm. The 2-sample t test showed no significant difference for fit between tooth-tissue supported and tooth-supported frameworks (P=.1081). Twenty-four percent of rests had contact in the prepared rest seat. Conclusion: The majority of rests evaluated did not contact the intended surfaces. [Copyright &y& Elsevier]

The corrosion susceptibility of as-received reinforcing steel bars (rebars) in solutions simulating the pore liquid of alkaline and carbonated concrete has been studied by means of potentiodynamic polarisation tests and polarisation resistance measurements. The effect of different degrees of carbonation and the presence of several chloride contents in the simulated pore solutions was investigated. Results show the beneficial effect of high alkalinity on the localised corrosion of steel caused by chloride ions. From the results of the potentiodynamic tests a critical chloride concentration above which pitting could take place was evaluated for each solution. The chloride threshold values here found are of the same order than those previously reported in the literature for film-free steel. The results obtained in solutions simulating carbonated concrete showed that under weak carbonation conditions carbon steel does not passivate while in the presence of high levels of carbonate and bicarbonate the resistance to localised corrosion is improved. [Copyright &y& Elsevier]

The chloride threshold (ClTH) concentration for rebar corrosion initiation has received extensive attention over the last years. The chloride threshold concentration depends on several factors involving concrete composition and quality, exposure conditions and rebar surface characteristics. As a consequence, many researchers have proposed ClTH ranges that take into account the relative influence of each of these many factors. On the other hand, the electrical resistivity of concrete has proven to be an effective parameter that can be used to estimate the risk of reinforcing steel corrosion, particularly when corrosion is induced by chloride attack. The present study is based on a correlation of electrochemical parameters such as corrosion potential (Ecorr) and current density (icorr) together with concrete resistivity (ρ) and chloride concentration data. A relationship between chloride threshold values for rebar corrosion initiation and resistivity values (indicative of concrete quality) is proposed. According to this correlation, when the electrical resistivity of concrete increases from 2 to 100 kΩ cm, the value of ClTH increases from 0.44 to 2.32% relative to the weight of cement. [Copyright &y& Elsevier]

Several experimental techniques were used to study the corrosion products formed on steel rebars embedded in concrete during 65 years. The research has the objective of understanding the stages of rusting of steel in concrete. Such understanding would provide information concerning the environmental conditions that produce rusting. It was found that rust was composed of two layers: an inner one composed mainly of non-stoichiometric magnetite and probably Ca and Al substituted magnetite firmly adhered to the substrate, and an outer one composed of α- and γ-iron oxyhydroxides, final steel corrosion products. The chemical and mechanical properties of steel rebars and the surrounding concrete were investigated in order to establish the causes of corrosion initiation which were the drop of the concrete pH due to a carbonation process and the loss of steel passivity. [Copyright &y& Elsevier]

The measurement of 54Mn and 65Zn by liquid scintillation coincidence counting results in low detection efficiencies. The activity obtained from the extrapolation of efficiency data can therefore become problematic if curvature is present. The simple decay scheme exhibited by these radionuclides, with the emission of an energetic gamma ray, allows the absolute activity to be determined from 4πe–γ data by direct calculation without the need for efficiency extrapolation. The method, which relies on determining the probability of the γ-ray interacting with the scintillator solution, is described and validated by measurements made on 60Co. [Copyright &y& Elsevier]

Purpose: To evaluate the incidence and duration of urinary retention requiring catheterization and the factors predictive for these end points.Methods and Materials: Two hundred eighty-two patients treated with prostate brachytherapy alone were evaluated. Clinical and treatment-related factors examined included: age, baseline International Prostate Symptom Score (IPSS), presence of comorbidity, planning ultrasound target volume (PUTV), postimplant prostate CT scan volume, the CT:PUTV ratio, number of seeds inserted, number of needles used, use of neoadjuvant hormones, procedural physician, clinical stage, Gleason score, and pretreatment PSA. Dosimetric quality indicators were also examined.Results: Urinary obstruction after prostate brachytherapy developed in 43 (15%) patients. The median duration of catheter insertion was 21 days (mean 49, range 1–365). Univariate analysis demonstrated that presence of diabetes, preimplant volume, postimplant volume, CT:PUTV ratio, number of needles, and dosimetric parameters were predictive for catheterization. However, in multivariate analysis, only the baseline IPSS, CT:PUTV ratio, and presence of diabetes were significant independent predictive factors for catheterization.Conclusion: Baseline IPSS was the most important predictive factor for postimplantation catheterization. The extent of postimplant edema, as reflected by the CT:PUTV ratio, predicted for need and duration of catheterization. The presence of diabetes was predictive for catheterization, but may relate to the absence of prophylactic steroids, and therefore requires further evaluation. [Copyright &y& Elsevier]

Purpose: To investigate postimplant dosimetry for different regions of the prostate gland in patients treated with transperineal 125Iodine brachytherapy implants for low- and intermediate-risk prostate cancer.Methods and Materials: Two hundred eighty-four patients treated with permanent interstitial prostate brachytherapy comprised the study population. A nonuniform, urethral-sparing algorithm was used to plan all patients. Prostate contours were outlined on postimplant CT images. Prostate volumes were then divided into four quadrants: anterior-superior quadrant (ASQ), posterior-superior quadrant (PSQ), anterior-inferior quadrant (AIQ), and posterior-inferior quadrant (PIQ). Dose-volume histograms (DVHs) were calculated for the whole prostate and each quadrant.Results: The mean postimplant V100 ± 95% confidence (the percent prostate volume encompassed within the isodose surface comprising the prescription dose = 144 Gy) for the ASQ was 78.5 ± 1.9, which was significantly lower than that of the PSQ, AIQ, and PIQ in which the V100 ± 95% confidence values were 94.9 ± 0.8, 92.6 ± 1.2, and 98.7 ± 0.3, respectively. The mean V100 ± 95% confidence for the whole prostate was 90.4 ± 0.8. Mean values for V150 and D90 (the minimum dose in Gy received by 90% of the target volume) for the four quadrants and the whole prostate showed similar results.Conclusions: Underdosed areas of the planning target volume (PTV), if present, were largely confined to the ASQ, which received a significantly lower dose, on average, compared to the other three quadrants of the prostate. [Copyright &y& Elsevier]

The performance of a surface-applied migrating corrosion inhibitor (MCI) based on an alkylaminoalcohol was evaluated on concrete specimens containing reinforcing steel bar (rebar) segments. Two water/cement ratios (w/c''s), various chloride contents and two exposure conditions were investigated. The inhibiting efficiency was followed over a period of 1000 days by means of parameters such as corrosion potential, corrosion current and electrical resistance. Results show that when concrete is exposed to the marine environment, the inhibitor is able to reduce the corrosion rate (CR) only when the initial chloride content is below 0.16 wt.% relative to cement content. Efficiency increases as the w/c increases. There is no beneficial effect when the initial chloride content is greater than 0.43%. When concrete is immersed in a saline solution, no beneficial effect associated to the use of the inhibitor could be appreciated, regardless of w/c or initial chloride content in concrete. [Copyright &y& Elsevier]

Purpose: To determine whether the use of 6 months' adjuvant androgen deprivation therapy (ADT) combined with brachytherapy for intermediate-risk (IR) and low-risk (LR) prostate cancer is associated with an increased risk of cardiovascular death.Methods and Materials: This is a retrospective analysis of prospectively collected data from men treated in the British Columbia Cancer Agency brachytherapy program from 1998 to 2012. Men were categorized by risk group and ADT use. Cardiac and other comorbidities were recorded and compared between groups. Biochemical control (Phoenix definition, nadir + 2 ng/mL) was ascertained. Overall, prostate, cardiac, and other-cause mortality were analyzed by the Kaplan-Meier method and Fine and Gray competing-risk analysis.Results: The study included 3155 men (1142 with LR cancer and 2013 with IR cancer) who have been followed up for a median of 7.9 years. ADT was received by 47% of IR patients and 37% of LR patients for a median of 6 months. Men with IR cancer were older and had more cardiac and other comorbidities than LR cases (P<.01). Biochemical control improved from 86% to 89% at 10 years with the use of ADT (P=.006). Overall survival was inferior in patients receiving ADT (84% vs 86% at 10 years, P=.0274), and on competing-risk analysis, cardiovascular mortality in patients receiving ADT was higher in IR cases, 5.2% versus 3.6% at 10 years (P=.0493), but not in LR cases. Multivariate analysis confirmed increased cardiac mortality in IR patients receiving ADT (hazard ratio, 1.95 [95% confidence interval, 1.15-3.34]; P=.014).Conclusions: ADT adds little meaningful benefit in terms of biochemical control for IR men treated with low-dose-rate brachytherapy but likely decreases overall survival because of increased cardiac mortality. IR patients were older and had more cardiac risk factors than LR prostate cases; this may be because of a screening effect, case selection, or common etiologic cause. [ABSTRACT FROM AUTHOR]

Purpose: To report the genitourinary (GU) and gastrointestinal (GI) morbidity and erectile dysfunction in a randomized trial comparing 2 methods of dose escalation for high- and intermediate-risk prostate cancer.Methods and Materials: ASCENDE-RT (Androgen Suppression Combined with Elective Nodal and Dose Escalated Radiation Therapy) enrolled 398 men, median age 68 years, who were then randomized to either a standard arm that included 12 months of androgen deprivation therapy and pelvic irradiation to 46 Gy followed by a dose-escalated external beam radiation therapy (DE-EBRT) boost to 78 Gy, or an experimental arm that substituted a low-dose-rate prostate brachytherapy (LDR-PB) boost. At clinic visits, investigators recorded GU and GI morbidity and information on urinary continence, catheter use, and erectile function. Exclusion of 15 who received nonprotocol treatment and correction of 14 crossover events left 195 men who actually received a DE-EBRT boost and 188, an LDR-PB boost. Median follow-up was 6.5 years.Results: The LDR-PB boost increased the risk of needing temporary catheterization and/or requiring incontinence pads. At 5 years the cumulative incidence of grade 3 GU events was 18.4% for LDR-PB, versus 5.2% for DE-EBRT (P<.001). Compared with the cumulative incidence, the 5-year prevalence of grade 3 GU morbidity was substantially lower for both arms (8.6% vs 2.2%, P=.058). The 5-year cumulative incidence of grade 3 GI events was 8.1% for LDR-PB, versus 3.2% for DE-EBRT (P=.124). The 5-year prevalence of grade 3 GI toxicity was lower than the cumulative incidence for both arms (1.0% vs 2.2%, respectively). Among men reporting adequate baseline erections, 45% of LDR-PB patients reported similar erectile function at 5 years, versus 37% after DE-EBRT (P=.30).Conclusions: The incidence of acute and late GU morbidity was higher after LDR-PB boost, and there was a nonsignificant trend for worse GI morbidity. No differences in the frequency of erectile dysfunction were observed. [ABSTRACT FROM AUTHOR]