ABSTRACT
OBJECTIVES: The goal of this study was to investigate whether an operation can offer survival benefits for patients with a second primary non-small-cell lung cancer (NSCLC) after a lobectomy for a first primary NSCLC and to analyse the characteristics affecting the survival of those patients. METHODS: We performed survival analyses of patients with a second primary NSCLC based on the Surveillance, Epidemiology and End Results program and used propensity score matching to reduce the potential bias and analyse the data. In addition, the primary observational end point was overall survival (OS), and the secondary observational end point was histologic migration. RESULTS: The data from 944 patients were used to perform the main analysis. A total of 36.2% of patients experienced a shift in tumour histologic type between 2 diagnoses of primary NSCLC, and this shift significantly affected OS (P = 0.0065). The median survival time in patients with surgical resection and those without an operation was 52.0 months versus 33.0 months, respectively. Patients with surgical resection at the secondary diagnosis had better survival than those without surgery (5-year OS rate: 48.0% vs 34.0%, P < 0.001). In addition, compared with a pneumonectomy and a sublobar resection, a lobectomy was the optimal surgical procedure for patients diagnosed with a second primary NSCLC after adjusting for other confounders (adjusted hazard ratio: 0.68, P < 0.01). However, in the subgroup analysis, lobar and sublobar resections could provide similar survival benefits for patients with tumour size ≤20 mm (P = 0.5). CONCLUSIONS: The operation, especially a lobectomy, can prolong OS in patients with a second primary NSCLC. Besides, sublobar resection can be performed in selected patients with tumour size ≤20 mm. Moreover, histologic migration may impact the survival of those patients with a secondary primary NSCLC.
ABSTRACT
OBJECTIVE: To establish the optimal image post-processing parameters for digital chest radiography as preliminary research for introducing digital radiography (DR) to pneumoconiosis diagnosis in China. METHODS: A total of 204 pneumoconiosis patients and 31 dust-exposed workers were enrolled as the subjects in this research. Film-screen radiography (FSR) and DR images were taken for all subjects. DR films were printed after raw images were processed and parameters were altered using DR workstation (GE Healthcare, U.S.A.). Image gradations, lung textures, and the imaging of thoracic vertebra were evaluated by pneumoconiosis experts, and the optimal post-processing parameters were selected. Optical density was measured for both DR films and FSR films. RESULTS: For the DR machine used in this research, the contrast adjustment (CA) and brightness adjustment (BA) were the main parameters that determine the brightness and gray levels of images. The optimal ranges for CA and BA were 115%â¼120% and 160%â¼165%, respectively. The quality of DR chest films would be optimized when tissue contrast was adjusted to a maximum of 0.15, edge to a minimum of 1, and both noise reduction and tissue equalization to0.The failure rate of chest DR (0.4%) was significantly lower than that of chest FSR (17%) (P < 0.05). CONCLUSION: After appropriate image post-processing on DR machine purchased from GE Healthcare, the DR chest films can meet all requirements for the quality of chest X-ray films in the Chinese diagnostic criteria for pneumoconiosis.
