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PURPOSE: To determine which head and neck adaptive radiotherapy (ART) correction objectives are feasible and to derive efficient ART patient selection guidelines. METHODS: We considered various head and neck ART objectives including independent consideration of dose-sparing of the brainstem/spinal cord, parotid glands, and pharyngeal constrictor, as well as prediction of patient weight loss. Two-hundred head and neck cancer patients were used for model development and an additional 50 for model validation. Patient chart data, pre-treatment images, treatment plans, on-unit patient measurements, and combinations thereof were assessed as potential predictors of each objective. A stepwise approach identified combinations of predictors maximizing the Youden index of random forest (RF) models. A heuristic translated RF results into simple patient selection guidelines which were further refined to balance predictive capability and practical resource costs. Generalizability of the RF models and simplified guidelines to new data was tested using the validation set. RESULTS: Top performing RF models used various categories of predictors, however, final simplified patient selection guidelines only required pre-treatment information for ART predictions, indicating the potential for significant ART process streamlining. The simplified guidelines for each objective predicted which patients would experience increases in dose to: brainstem/spinal cord with sensitivity = 1.0, specificity = 0.66; parotid glands with sensitivity = 0.82, specificity = 0.70; and pharyngeal constrictor with sensitivity = 0.84, specificity = 0.68. Weight loss could be predicted with sensitivity = 0.60 and specificity = 0.55. Furthermore, depending on the ART objective, 28%-58% of patients required replan assessment, less than for previous studies, indicating a step towards more effective patient selection. CONCLUSIONS: The above ART objectives appear to be practically achievable, with patients selected for ART according to simple clinical patient selection guidelines. Explicit ART guidelines are rare in the literature, and our guidelines may aid in balancing the potential clinical gains of ART with high associated resource costs, formalizing ART trials, and ensuring the reproducibility of clinical successes.
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OBJECTIVES: Congenital syphilis is a significant cause of adverse pregnancy outcomes. In South Africa, rural clinics perform antenatal screening offsite, but unreliable transport and poor client follow up impede effective treatment. We compared 3 syphilis screening strategies at rural clinics: on-site rapid plasma reagin (RPR), on-site treponemal immunochromatographic strip (ICS) test, and the standard practice offsite RPR with Treponema pallidum hemagglutination assay (RPR/TPHA). METHODS: Eight rural clinics performed the on-site RPR and ICS tests and provided immediate treatment. Results were compared with RPR/TPHA at a reference laboratory. Chart reviews at 8 standard practice clinics established diagnosis and treatment rates for offsite RPR/TPHA. FINDINGS: Seventy-nine (6.3%) of 1,250 women screened on-site had active syphilis according to the reference laboratory. The on-site ICS resulted in the highest percentage of pregnant women correctly diagnosed and treated for syphilis (89.4% ICS, 63.9% on-site RPR, 60.8% offsite RPR/TPHA). The on-site RPR had low sensitivity (71.4% for high-titer syphilis). The offsite approach suffered from poor client return rates. One percent of women screened with the ICS may have received penicillin unnecessarily. There were no adverse treatment outcomes. CONCLUSIONS: The on-site ICS test can reduce syphilis-related adverse outcomes of pregnancy through accurate diagnosis and immediate treatment of pregnant women with syphilis.