Background Severe swallowing dysfunction necessitating enteral support is a well-known late sequela of nonsurgical therapy for oropharyngeal cancer, but its incidence after intensity-modulated radiotherapy has not been quantified comprehensively outside of small single-institution series. Methods This was a multi-institution, institutional review board-approved retrospective study. Consecutive patients with oropharyngeal squamous cell carcinoma treated with definitive intensity-modulated radiotherapy from 1998 to 2011 were identified from three academic centers. Results A total of 2315 patients were included. The American Joint Committee on Cancer staging distribution was as follows: stage I, 2.1%; stage II, 4.4%; stage III, 14.7%; and stage IV, 77.3%. Among 1459 (63%) patients who received a g-tube, placement was prophylactic in 52%, reactive in 48%. Among patients with stage III-IV disease, 58% received concurrent chemotherapy. The median follow-up was 43.7 months (range 0.1 to 164). The g-tube dependence rates at 1- and 2-years were 7.0% and 3.7%, respectively. Among 1238 patients with stage III-IV disease who received concurrent chemotherapy, the 1- and 2-year rates of g-tube dependence were 8.6% and 4.4%, respectively. The 1-year g-tube dependence rates for stage I-II disease was 5.0%; stage III-IV, T1-2/N0-2, 5.2%; and stage III-IV, T3-4 or N3, 10.1%. On multivariate analysis, advanced age (OR:1.066; p<0.001), greater number of smoking pack-years (OR:1.008; p=0.04), advanced N-category (OR:1.13; p=0.049), and cytotoxic chemotherapy (OR:2.26; p=0.02) were predictive of g-tube dependence at 1-year. Conclusion This multi-institution series of 2315 patients treated at 3 institutions demonstrates that modern nonsurgical therapy for oropharyngeal cancer is associated with a low rate of long-term g-tube dependence.

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Tremendous amounts of nitrogen (N) fertilizer have been added to arable lands, often resulting in substantial effects on terrestrial ecosystems, including soil acidification, altered enzyme activities and changes in microbial community composition. Soil microbes are the major drivers of soil carbon (C) and N cycling; therefore, understanding the response of microbial communities to elevated N inputs is of significant importance. This study was carried out to investigate the influences of different N fertilization rates (0, 182, and 225 kg ha-1 representing control, low, and high N supply for each crop season for summer maize and winter wheat) on soil biochemical attributes, extracellular enzyme activities, and the microbial community composition in a winter wheat-summer maize rotation cropping system in north-central China. The results showed that N addition significantly decreased the soil pH in both the wheat and maize seasons. Microbial biomass N (MBN) decreased following N fertilization in the wheat season, while the opposite trend in MBN was observed in the maize season. Response ratio analysis showed that the activities of enzymes involved in C, N, and phosphorus cycling were significantly enhanced under N enrichment in both the wheat and maize seasons, and higher enzyme activities were noted in the high N addition treatment than in the low N addition treatment. A linear increase in fungal abundance with the N addition gradient was observed in the wheat season, whereas the fungal abundance increased and then decreased in the maize season. The bacterial abundance showed an increased and then decreased trend in response to the N addition gradient in both the wheat and maize crop seasons. Moreover, the partial least squares path model (PLS-PM) analysis showed that soil pH and soil organic carbon (SOC) were the most important soil variables, causing shifts in the soil bacteria. Furthermore, compared with the N-cycling enzymes, the C-cycling enzymes were significantly affected by the soil pH and SOC. Taken together, these results suggest that the effect of N addition on enzyme activities was consistent in both crop seasons, while the effects on MBN and microbial community composition to N addition were highly variable in the two crop seasons. Moreover, N fertilization-induced changes in the soil chemical properties such as soil acidity and SOC played a substantial role in shaping the microbial community.