BackgroundA study was conducted to investigate the clinicopathological features and survival outcomes of gastrointestinal stromal tumors (GISTs) that are synchronous with other gastrointestinal cancers.MethodsClinical and pathological data of 286 patients with primary GIST from a single institution from January 2009 to December 2014 were reviewed.ResultsThe entire study population comprised 286 patients with GISTs. Of these patients, 167 (58.4 %) were males and 119 (41.6 %) were females. The median age was 58 years old (in the range 29–86 years). A total of 47 patients were diagnosed with GISTs synchronous with other digestive tract malignancies (synchronous group), whereas 239 patients were diagnosed with non-synchronous disease (non-synchronous group). The concomitant digestive tumors in 27, 12, 7, and 1 patients were diagnosed as gastric carcinoma, esophageal carcinoma, colorectal carcinoma, and pancreatic adenocarcinoma, respectively. Compared with the synchronous group, the non-synchronous group exhibited a higher percentage of increased mitotic count (P = 0.011). The difference in tumor diameter between the two groups was statistically significant (P < 0.001). Patients in the non-synchronous group exhibited larger tumor size than the patients in the synchronous group (5.9 ± 3.5 cm vs. 1.6 ± 0.4 cm, P < 0.001). The majority of GIST lesions in the synchronous group were located in the stomach (P = 0.020). Lower risk stratifications and worse ECOG performance statuses were observed in the synchronous group (P < 0.001) than in the non-synchronous group. The 5-year overall survival rate was significantly higher in patients with no synchronous digestive tract malignancies than in patients with synchronous disease (70.8 vs. 34.1 %, P < 0.001).ConclusionsPatients with GIST synchronous with other gastrointestinal cancers show worse prognosis than those with non-synchronous tumors. Clinicians should pay more attention to this subgroup.

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Voltage sag causes serious economic losses to sensitive customers. However, the existing optimal placement methods of sag monitors ignore the economic needs of customers. The optimal placement model of voltage sag monitor is proposed in this paper, which considers the sag economic loss weight, realizes the redundant coverage of important customers, and reduces the risk of sag loss of them. The model is also suitable for the system with a large number of DG access. Firstly, the calculation model of exposed area based on Chebyshev iterative method is established to obtain the system exposed area quickly, and the influence of DG replacing traditional generator on exposed area and economic loss is analyzed qualitatively. Then, the economic loss is quantitatively evaluated based on the exposed area. What’s more, the priority of important customers is determined accordingly, and the optimal placement model of sag monitor is proposed. Finally, simulation results show that in large-scale DG access, the customer’s economic loss caused by sag will increase. Compared with traditional methods, this method can reduce the risk of loss and ensure the economic benefits of important customers.