Permanent 125I-seed prostate brachytherapy: early prostate specific antigen value as a predictor of PSA bounce occurrence

<p>Abstract</p> <p>Purpose</p> <p>To evaluate predictive factors for PSA bounce after ¹²⁵I permanent seed prostate brachytherapy and identify criteria that distinguish between benign bounces and biochemical relapses.</p> <p>Materials and methods</p> <p>Men treated with exclusive permanent ¹²⁵I seed brachytherapy from November 1999, with at least a 36 months follow-up were included. Bounce was defined as an increase ≥ 0.2 ng/ml above the nadir, followed by a spontaneous return to the nadir. Biochemical failure (BF) was defined using the criteria of the Phoenix conference: nadir +2 ng/ml.</p> <p>Results</p> <p>198 men were included. After a median follow-up of 63.9 months, 21 patients experienced a BF, and 35.9% had at least one bounce which occurred after a median period of 17 months after implantation (4-50). Bounce amplitude was 0.6 ng/ml (0.2-5.1), and duration was 13.6 months (4.0-44.9). In 12.5%, bounce magnitude exceeded the threshold defining BF. Age at the time of treatment and high PSA level assessed at 6 weeks were significantly correlated with bounce but not with BF. Bounce patients had a higher BF free survival than the others (100% versus 92%, p = 0,007). In case of PSA increase, PSA doubling time and velocity were not significantly different between bounce and BF patients. Bounces occurred significantly earlier than relapses and than nadir + 0.2 ng/ml in BF patients (17 vs 27.8 months, p < 0.0001).</p> <p>Conclusion</p> <p>High PSA value assessed 6 weeks after brachytherapy and young age were significantly associated to a higher risk of bounces but not to BF. Long delays between brachytherapy and PSA increase are more indicative of BF.</p

Radical Prostatectomy, External Beam Radiotherapy, or External Beam Radiotherapy With Brachytherapy Boost and Disease Progression and Mortality in Patients With Gleason Score 9-10 Prostate Cancer

Importance The optimal treatment for Gleason score 9-10 prostate cancer is unknown. Objective To compare clinical outcomes of patients with Gleason score 9-10 prostate cancer after definitive treatment. Design, Setting, and Participants Retrospective cohort study in 12 tertiary centers (11 in the United States, 1 in Norway), with 1809 patients treated between 2000 and 2013. Exposures Radical prostatectomy (RP), external beam radiotherapy (EBRT) with androgen deprivation therapy, or EBRT plus brachytherapy boost (EBRT+BT) with androgen deprivation therapy. Main Outcomes and Measures The primary outcome was prostate cancer–specific mortality; distant metastasis-free survival and overall survival were secondary outcomes. Results Of 1809 men, 639 underwent RP, 734 EBRT, and 436 EBRT+BT. Median ages were 61, 67.7, and 67.5 years; median follow-up was 4.2, 5.1, and 6.3 years, respectively. By 10 years, 91 RP, 186 EBRT, and 90 EBRT+BT patients had died. Adjusted 5-year prostate cancer–specific mortality rates were RP, 12% (95% CI, 8%-17%); EBRT, 13% (95% CI, 8%-19%); and EBRT+BT, 3% (95% CI, 1%-5%). EBRT+BT was associated with significantly lower prostate cancer–specific mortality than either RP or EBRT (cause-specific HRs of 0.38 [95% CI, 0.21-0.68] and 0.41 [95% CI, 0.24-0.71]). Adjusted 5-year incidence rates of distant metastasis were RP, 24% (95% CI, 19%-30%); EBRT, 24% (95% CI, 20%-28%); and EBRT+BT, 8% (95% CI, 5%-11%). EBRT+BT was associated with a significantly lower rate of distant metastasis (propensity-score-adjusted cause-specific HRs of 0.27 [95% CI, 0.17-0.43] for RP and 0.30 [95% CI, 0.19-0.47] for EBRT). Adjusted 7.5-year all-cause mortality rates were RP, 17% (95% CI, 11%-23%); EBRT, 18% (95% CI, 14%-24%); and EBRT+BT, 10% (95% CI, 7%-13%). Within the first 7.5 years of follow-up, EBRT+BT was associated with significantly lower all-cause mortality (cause-specific HRs of 0.66 [95% CI, 0.46-0.96] for RP and 0.61 [95% CI, 0.45-0.84] for EBRT). After the first 7.5 years, the corresponding HRs were 1.16 (95% CI, 0.70-1.92) and 0.87 (95% CI, 0.57-1.32). No significant differences in prostate cancer–specific mortality, distant metastasis, or all-cause mortality (≤7.5 and \u3e7.5 years) were found between men treated with EBRT or RP (cause-specific HRs of 0.92 [95% CI, 0.67-1.26], 0.90 [95% CI, 0.70-1.14], 1.07 [95% CI, 0.80-1.44], and 1.34 [95% CI, 0.85-2.11]). Conclusions and Relevance Among patients with Gleason score 9-10 prostate cancer, treatment with EBRT+BT with androgen deprivation therapy was associated with significantly better prostate cancer–specific mortality and longer time to distant metastasis compared with EBRT with androgen deprivation therapy or with RP

AN OVERVIEW OF THE GERMAN GEL PROPULSION TECHNOLOGY PROGRAM

Gelled fluids are homogeneous mixtures of a liquid and a gelling agent. They behave like a solid at rest in the tank but can be liquefied if a sufficiently high shear stress is applied upon injection into the combustion chamber. Gelled propellants are of interest for rocket and ramjet propulsion systems because of their inherent safety and performance benefits compared to pure storable liquids. Due to their non-Newtonian flow behavior, gelled propellants combine the advantages of liquid and solid propellants. Engines with gelled propellants can be throttled and restarted, similar to engines with liquid propellants. On the other hand, engines with gelled propellants have simple handling and storage characteristics and reduced sloshing. Gelled propellants spill not through leaks and have a reduced vapor pressure in comparison to their basic (Newtonian) fluid. In this respect gel propellant engines behave like solid-propellant motors. In the last two decades a growing interest in gelled propellants for rocket and ramjet propulsion applications has been observed worldwide. In Germany, within the German Gel Propulsion Technology Program (GGPT), which was started in 2001, necessary technologies to build a green gel propellant rocket engine are developed and its capabilities demonstrated by static tests and in 2009 two successful demonstration flights. Ongoing activities comprise development of next generation gelled propellants which combine relatively high ballistic performance with insensitivity and low environmental hazards, maturing technologies like thermal management and control as well as deepening the knowledge on the combustion chamber processes i.e. injection, atomization, evaporation and combustion. The paper gives an extensive overview on challenges, activities and findings obtained within the GGPT

Estimation of Flow Properties of Gelled Fuels with Regard to Propulsion Systems

Gelled fuels and propellants are shear-thinning non-Newtonian fluids. Their dependency of the shear viscosity from the shear rate can be described with sufficient accuracy by an extended version of the Herschel-Bulkley equation in the whole rocket and ramjet propulsion-relevant shear-rate range. Additionally to the analytically determined generalized Reynolds number for fluids, which follow the extended Herschel-Bulkley equation, a method for the estimation of critical Reynolds numbers (as a phenomenological approach) is presented. Both dimensionless numbers are useful for the characterization of the flow and partially also of the spray processes of gel fluids. The results show furthermore that both the shear-thinning property and the yield stress tend to stabilize the laminar flow and thus shift the critical Reynolds number to higher values when compared to Newtonian liquids