Survival outcomes of radiotherapy with or without androgen-deprivation therapy for patients with intermediate-risk prostate cancer using the National Cancer Data Base.

PURPOSE: Presently no reported prospective, randomized trials have clearly defined the role of androgen-deprivation therapy (ADT) for patients with intermediate-risk prostate cancer in the setting of radiation therapy (RT) dose escalation. This study׳s objective was to evaluate the survival benefit of adding ADT to high-dose RT for patients with intermediate-risk prostate cancer using the National Cancer Data Base. MATERIALS AND METHODS: The National Cancer Data Base was queried for patients with intermediate-risk prostate cancer treated from 2004 to 2006, with available data for Gleason Score, prostate-specific antigen, TNM staging, and receipt of radiation and ADT. Start of RT was within 1 to 180 days of ADT; radiation included external beam alone (≥70Gy) or external beam RT plus brachytherapy boost. Overall survival was evaluated using multivariate (MVA) Cox regression and propensity score-matched (PSM) analyses. RESULTS: A total of 14,126 patients were included of which 7,568 (53.6%) received no ADT and 6,558 (46.4%) received ADT. Median follow-up was 85.8 months (6.0-119.9mo). Median RT dose was 75.6Gy in 42 fractions. Under MVA, the addition of ADT for patients with intermediate-risk prostate cancer had no overall survival benefit compared with RT alone (hazard ratio [HR] = 0.97, P = 0.316). PSM also confirmed no survival benefit with the addition of ADT for the entire intermediate-risk cohort (HR = 0.98, P = 0.560). On subset analysis, those with 3 intermediate-risk factors had a survival benefit with the addition of ADT on both MVA (HR = 0.69, P = 0.037) and PSM (HR = 0.61, P = 0.026). Limitations include retrospective design and incomplete data on the type of ADT and duration. CONCLUSIONS: With the exception of men who present with all 3 intermediate-risk factors, a significant association with decreased all-cause mortality risk and ADT was not observed for patients with intermediate-risk prostate cancer.

Survival Outcomes of Whole-Pelvic Versus Prostate-Only Radiation Therapy for High-Risk Prostate Cancer Patients With Use of the National Cancer Data Base.

PURPOSE/OBJECTIVES: The addition of whole pelvic (WP) compared with prostate-only (PO) radiation therapy (RT) for clinically node-negative prostate cancer remains controversial. The purpose of our study was to evaluate the survival benefit of adding WPRT versus PO-RT for high-risk, node-negative prostate cancer, using the National Cancer Data Base (NCDB). METHODS AND MATERIALS: Patients with high-risk prostate cancer treated from 2004 to 2006, with available data for RT volume, coded as prostate and pelvis (WPRT) or prostate alone (PO-RT) were included. Multivariate analysis (MVA) and propensity-score matched analysis (PSM) were performed. Recursive partitioning analysis (RPA) based on overall survival (OS) using Gleason score (GS), T stage, and pretreatment prostate-specific antigen (PSA) was also conducted. RESULTS: A total of 14,817 patients were included: 7606 (51.3%) received WPRT, and 7211 (48.7%) received PO-RT. The median follow-up time was 81 months (range, 2-122 months). Under MVA, the addition of WPRT for high-risk patients had no OS benefit compared with PO-RT (HR 1.05; P=.100). On subset analysis, patients receiving dose-escalated RT also did not benefit from WPRT (HR 1.01; P=.908). PSM confirmed no survival benefit with the addition of WPRT for high-risk patients (HR 1.05; P=.141). In addition, RPA was unable to demonstrate a survival benefit of WPRT for any subset. Other prognostic factors for inferior OS under MVA included older age (HR 1.25; P<.001), increasing comorbidity scores (HR 1.46; P<.001), higher T stage (HR 1.17; P<.001), PSA (HR 1.81; P<.001), and GS (HR 1.29; P<.001), and decreasing median county household income (HR 1.15; P=.011). Factors improving OS included the addition of androgen deprivation therapy (HR 0.92; P=.033), combination external beam RT plus brachytherapy boost (HR 0.71; P<.001), and treatment at an academic/research institution (HR 0.84; P=.002). CONCLUSION: In the largest reported analysis of WPRT for patients with high-risk prostate cancer treated in the dose-escalated era, the addition of WPRT demonstrated no survival advantage compared with PO-RT.

Examination of radioargon production by cosmic neutron interactions.

Radioargon isotopes, particularly (37)Ar, are currently being considered for use as an On-Site Inspection (OSI) relevant radionuclide within the context of the Comprehensive Nuclear-Test-Ban Treaty (CTBT). In order to understand any soil air measurements taken during an OSI, the radioargon background due to cosmic ray induced activation along with other sources must be understood. An MCNP6 model was developed using the cosmic ray source feature within the code to examine the neutron flux at ground level as a function of various conditions: date during the solar magnetic activity cycle, latitude of sampling location, geology of the sampling location, and sampling depth. Once the cosmic neutron flux was obtained, calculations were performed to determine the rate of radioargon production for the main interactions. Radioargon production was shown to be highly dependent on the soil composition, and a range of (37)Ar production values at 1 m depth was found with a maximum production rate of 4.012 atoms/sec/m(3) in carbonate geologies and a minimum production rate of 0.070 atoms/sec/m(3) in low calcium granite. The sampling location latitude was also shown to have a measurable effect on the radioargon production rate, where the production of (37)Ar in an average continental crust is shown to vary by a factor of two between the equator and the poles. The sampling date's position within the solar magnetic activity cycle was also shown to cause a smaller change, less than a factor of 1.2, in activation between solar maxima and solar minima.