243Am neutron-induced fission cross section in the fast neutron energy range

The existing evaluations of the 243Am neutron-induced fission cross section have been questioned by recent measurements performed at the GNEISS facility. In the neutron energy range from 1 to 6 MeV, the GNEISS data present deviations of more than 15% with respect to the evaluations. In order to solve this problem, we have measured this cross section in reference to three different standard cross sections. The first standard reaction used corresponds to the neutron on proton elastic scattering cross section, which is known with a precision better than 0.5% over a wide neutron-energy range of 1 meV to 20 MeV. The other two experiments were conducted in reference to the 235U(n, f) and 238U(n, f) reactions. The comparison between these three standard reactions ensures that systematic parameters have been correctly evaluated. Moreover, a sensitivity analysis of parameters and correlations of parameters is described and a complete variance-covariance matrix of the measurements is presented and discussed.JRC.D.4-Standards for Nuclear Safety, Security and Safeguard

Definitive Tumor Directed Therapy for Metachronous Oligometastatic HPV-Associated Oropharyngeal Cancer Following Trans-Oral Robotic Surgery

Recent landmark trials have suggested a survival benefit to definitive tumor directed therapies (DTDT) for selected patients with metastatic disease for various malignancies. We sought 1) to confirm the prognostic significance of metachronous oligometastatic burden for human papillomavirus (HPV)-associated oropharyngeal squamous cell carcinoma (OPSCC) and 2) to evaluate disease outcomes for oligometastatic HPV-associated OPSCC after upfront DTDT versus upfront systemic therapy. This was a single institution retrospective observational cohort study of patients with HPV-associated OPSCC who developed metachronous metastases ≥3 months after primary treatment with trans-oral robotic surgery (TORS) from 2008-2017. At metastatic presentation, patients were classified as oligometastatic (≤5 metastases) or polymetastatic (> 5 metastases). Treatment was classified as DTDT (all metastases initially treated with surgery/radiotherapy) or as upfront systemic therapy. Overall survival (OS) was compared using log-rank tests at a significance of P < 0.05. Univariable and multivariable (MV) Cox proportional hazard models were used to assess the association of patient, disease, and treatment characteristics with survival. Variables with P < 0.15 on univariable analysis (initial metastatic treatment, metastatic site, and number of metastases) were included in the multivariable model. Of 676 patients undergoing primary surgical management for HPV-associated OPSCC, 36 patients subsequently developed metachronous metastases. For those 36 patients, the median follow-up time after surgery was 27.5 months (range 4.5-127.0), and the median OS was 42.8 months. The median age at distant metastasis was 62 (range 32-86), and most patients were male (86.1%) and Caucasian (97.2%). Overall, 27 patients presented with oligometastasis and 9 with polymetastasis. Oligometastatic patients had improved median OS compared to polymetastatic patients (47.9 vs. 22.7 months, P = 0.020). For the 27 oligometastatic patients, 12 were initially treated with DTDT while 15 received systemic therapy. DTDT was associated with an improved median OS when compared to systemic therapy (median OS not reached for DTDT vs 40.7 months, P = 0.021), with 3 year OS of 90.0% and 55.0% respectively. DTDT was also associated with improved OS on MV Cox regression (hazard ratio = 0.06, 95% CI 0.004-0.73, P = 0.027) compared to systemic therapy when controlling for number of metastases and metastatic site. Our study findings suggest that the extent of metastatic disease at metastatic presentation is related to prognosis, with oligometastasis associated with improved overall survival compared to polymetastasis. Among patients with oligometastatic disease, initial DTDT is associated with superior overall survival when compared to upfront systemic therapy