Development and Validation of a Prognostic Nomogram for HR+ HER- Breast Cancer.

Purpose: We aimed to develop a nomogram to predict prognosis of HR+ HER2- breast cancer patients and guide the application of postoperative adjuvant chemotherapy. Methods: We identified 310 eligible HR+ HER- breast cancer patients and randomly divided the database into a training group and a validation group. The endpoint was disease free survival (DFS). Concordance index (C-index), area under the curve (AUC) and calibration curves were used to evaluate predictive accuracy and discriminative ability of the nomogram. We also compared the predictive accuracy and discriminative ability of our nomogram with the eighth AJCC staging system using overall data. Results: According to the training group, platelet-to-lymphocyte ratio (PLR), tumor size, positive lymph nodes and Ki-67 index were used to construct the nomogram of DFS. The C-index of DFS was 0.708 (95% CI: 0.623-0.793) in the training group and 0.67 (95% CI: 0.544-0.796) in the validation group. The calibration curves revealed great consistencies in both groups. Conclusion: We have developed and validated a novel and practical nomogram that can provide individual prediction of DFS for patients with HR+ HER- breast cancer. This nomogram may help clinicians in risk consulting and guiding the application of postoperative adjuvant chemotherapy.

Note: Possibilities of detecting the trace-level erosion products from an electric propulsion hollow cathode plasma source by the method of time-of-flight mass spectrometry.

A hollow cathode produces electrons which neutralize ions from electric propulsion thrusters. After hundreds to thousands of hours of operation in space, the cathode materials can be significantly eroded due to ion bombardment. As a result, the electric propulsion system performance will be obviously changed or even fail. In this work, the erosion products from a LaB6 hollow cathode (widely used presently in electric propulsion systems) are studied by using a specific detection system, which consists of a molecular beam sampler and a time-of-flight mass spectrometer. This system measures trace-level-concentration (10-6-10-3) products. Boron (B), tantalum (Ta), and tungsten (W)-originating from the emitter, keeper, and orifice of the hollow cathode-are measured. It is found that the erosion rate is significantly influenced by the gas flow rate to the cathode.