Endobronchial Ultrasonography With Guide-Sheath Combined With Virtual Bronchoscopy Navigation For Peripheral Lung Cancer

BackgroundPeripheral lung cancer(PLC)lie in the lungs below the bronchi until the small bronchi.The common types of PLC are adenocarcinoma and squamous cell carcinoma.The early imaging of peripheral lung cancer is manifested as isolated solitary nodules in the lungs.In recent years,the incidence of peripheral lung cancer has a clear upward trend.Because the early symptoms of peripheral lung cancer is not obvious and it is not easy to identify with other nodular disease so that most patients have been diagnosed in the late stage and lost the chance of surgery.So the early diagnosis and treatment of peripheral lung cancer to improve its prognosis is of great significance.At present,there are many clinical methods to diagnose peripheral lung cancer,such as chest X-ray,chest computed tomography(CT),PET-CT,lung tumor markers and sputum exfoliative cytology,which act as the conventional screening means to improve the detection rate and to provide indirect evidence for the diagnosis of PLC.Fiberopticbronchoscopy,imaging-guided percutaneous lung puncture,thoracoscopy and thoracotomy surgery can get histopathologyto provide direct evidence for the diagnosis of the disease.As a micro-invasive examination method,fiberoptic bronchoscopy has become one of the main clinical means of diagnosis of lung cancer.Pathological examination is the clinical diagnostic gold standard forpulmonary nodules.Peripheral pulmonary lesions beyond the scope of bronchoscopy,which is the blind area of bronchoscopy.Positive rate of conventional bronchoscopylung biopsy is only about 30%,and the positive rate of bronchoscopy sputum and lavage is also not high.Consequently,how to take the biopsy of isolated solitary pulmonary nodules has become a major problem that has plagued medical workers.Endobronchial ultrasonography with guide-sheath(EBUS-GS)is a bronchoscopy-mediated minimally invasive diagnostic technique that provides a visualized image of the bronchial tree,the surrounding lung parenchyma,and the mediastinal structure,compensating for the lack of conventional bronchoscopy.Virtual bronchoscopy navigation(VBN)system can process the chest CT images of the patients by the computer software into a virtual three-dimensional visualization model of the lungs,which can be synchronized with the electronic bronchoscopy video and direct the the bronchoscopy to the lung lesions.The current trend is to use the two together to see if they can improve the diagnostic rate and diagnostic efficiency of peripheral lung cancer.ObjectiveTo explore the diagnostic value and safety of endobronchial ultrasonography with guide-sheath combined with virtual bronchoscopy navigation in peripheral lung cancer.MethodsOne hundred and fifty eight patients(74 males and 60 females,aged between 24 and75 years,median age 60 years)with peripheral pulmonary lesions confirmed by computed tomography(CT)were involved in between January 2015 to December 2016.Patients were randomly divided into non-VBN assisted group(NVBNA group)and VBN assisted group(VBNA group)based on the use of VBN system.83 cases were involved in NVBNA group and 75 cases were involved in VBNA group.They finished therebronchoscopy examination in our department of respiratory by rigorously trained doctors that could be able to regulate the use of endoscopic.The ethical review committee approved the study and the patients enrolled in the group were required to sign informed consent.All patients needed to do the conventional bronchoscopy first and the case would be removed from the group if the conventional bronchoscope could see the lesion directly.NVBNA group actually involved in 77 patients and VBNA group involved in 71 cases after removing 10 cases.The EBUS-GS were guidedto the lesionby the operation physicianaccording to the position of the nodule on the CT image of the patient in the NVBNA group and the EBUS-GS were guided to the target lesion by VBN inthe VBNA group.EBUS-GS took biopsy after seeing a typical abnormal echo and took blind inspection or lavage when the operator was uncertain of the lesion location or did not see the lesion after it arrived near the target lesion.The diagnostic yield,visibility rate,complications and operation time of bronchoscope were compared according to the results of the two groups.ResultsThere was no significant difference in the visibility rate between the VBNA group and the NVBNA group(87.5% vs.81.4%,P = 0.334).The visual rate of 8~ 20 mm pulmonary nodules was 72.7% in the VBNA group and 65.5% in the NVBNA group.There was no statistically difference between the two groups(P=0.583).The visual rate of21~30mm pulmonary nodules was 95.2% in the VBNA group and 92.7% in the NVBNA group,and there was no statistically significant difference(P=0.625).But there was a big significant difference in the visual rate between the 21~30mm pulmonary nodules and the8~20mm pulmonary nodules in the VBNA group and NVBNA group(P<0.05).The total visibility rate of 21~30mm lesions was much higher than that of 8~20mm lesions(P<0.001).There was no significant difference in the diagnostic yield between the VBNA group and the NVBNA group(78.1% vs.75.7%,P= 0.838).The diagnostic rate of pulmonary nodules in the 8 ~ 20 mm size was 72.7% in the VBNA group and 62.1% in the NVBNA group(P = 0.424).The diagnostic yield of the pulmonary nodules in the21~30mm size was 83.3% in the VBNA group and 82.9% in the NVBNA group(P =0.961).The totaldiagnostic yield of EBUS-GS transbronchial lung biopsy was 76.9%(103/134).The diagnostic rate of the probe located within the lesion and adjacent to the lesion were significantly higher than that of the probe outside the lesion(93.2% vs.79.5%vs.14.3%,P<0.001),the diagnostic yield of 21~30mm nodules was higher than that of8~20mm nodules(83.1% vs.66.7%,P = 0.028),and the difference was statistically significant.The total operation time of bronchoscope was 25.23 ± 4.78 min in the VBNA group and 26.68 ± 6.01 min in the NVBNA group,the difference was not statistically significant(P = 0.524).The time of confirming the target lesions was 5.79 ±1.33 min in the VBNA group and 9.79 ±1.50 min in the NVBNA group and the difference between them was statistically significant(P < 0.001).Among the 134 patients with pathological results,there were no adverse reactions such as pneumothorax,chest pain,cough,severe asthma and so on.No serious adverse events occurred in both of groups.There were 3patients in the VBNA group and 7 patients in the NVBNA group with a small amount of biopsy site bleeding.The incidence of complications did not differ between the two groups.ConclusionsVBN did not improve the diagnostic yield and visibility rate of EBUS-GS.However,VBN could shorten the time needed to confirm the target lesions,and VBN did not increase the incidence of EBUS-GS complication,which was a safe diagnostic method.This experiment confirmed thatthe relationship between the position of the ultrasonic probe and the lesion and the size of the lesion were closely related to the diagnostic rate of the EBUS-GS transbronchial lung biopsy.EBUS-GS was an important method for peripheral lung cancer clinically,combining with VBN can improve its operation efficiency.The combination of the two was a safe detection method,less complications,less damage to patients and more tolerable.The cost of VBN was more expensive and could be selectively applied to EBUS-GS when the lesion was not found.