Clinical Application Of CT-guided Percutaneous Transthoracic Needle Biopsy In Patients With Indeterminate Thoracic Nodules

BACKGROUND Lung cancer is the most common cancer,and the leading cause of cancer related deaths in China.Therefore,caring for patients with lung cancer has an enormous socioeconomic impact on our country.Suspected lung cancer is investigated and treated within a multidisciplinary setting, including radiologists, physicians, and pathologists, all working together to streamline agreed care pathways and ultimately deliver patient care in the most timely and effective manner.Histological validation of pulmonary lesions is a fundamental requirement for ensuring personalized multimodality treatment. Multiple diagnostic options are available:CT-guided biopsy,bronchoscopy with transbronchial biopsy,or diagnostic surgical removal of the lesion. With the technical developments in CT-guided percutaneous transthoracic needle biopsy(CT-PTNB)during the last two decades, this procedure has become a reliable technique for pulmonary lesions diagnosis.It has several advantages including lower cost, lower morbidity, and can be performed in an outpatient setting under local anesthesia.In addition, the diagnostic accuracy of CT-PTNB was reported to be 64-97%.However,there are several known complications,including pneumothorax, hemorrhage, air embolism, and tumor seeding.Recent advances in the personalize chemotherapy and novel targeted therapy strategies gave rise to the increasing demands for diagnosis of tumor histopathologic subtypes and molecular markers, which have led to increasing need for more amount of tissues.The identification of activating mutations in the tyrosine kinase domain of EGFR in tumor tissues is supportive of treatment selection based on molecular classification.METHODSWe retrospectively analyzed the results of CT-PTNB for 114 patients to evaluate the diagnostic accuracy and complication rates. Variables such as gender, age at diagnosis, smoking status, CT findings,histologic diagnosis and the result of EGFR mutation were analyzed. Data analysis was performed with the chi-square test for comparison of two proportions.RESULTS1.Patient characteristics.Of the 114 patients studied,51 (44.7%) were smokers and 62 (54.4%)were male. The diameter of malignant lesions ranged from 1.1cm to 11.1cm.2. Diagnostic resultsOf the 114 patients,21 had negative results, and 93 had positive results for malignancy. A final diagnosis of benign disease was made in 15 patients based on confirmations of the surgical specimen, lesion regression without anticancer therapy, or stable lesion size for at least 12 months. A final diagnosis of malignant disease was made in 99 patients. These malignant diagnoses were confirmed by the surgical specimen, similarities between the histology of the biopsy specimen and a patient’s known malignancy of the other organs, or post-procedural malignant processes.3. Diagnostic accuracyThe diagnostic accuracy was 93.8%(108/114 patients). For the diagnosis of malignant disease the overall sensitivity was 93.9%(93/99), specificity was 100% (15/15), PPV was 100%(93/93), and NPV was 71.4%(15/21).4.The rate of complications.Pneumothorax is the most common complication in our study, occurring in 35 patients (30.7%).Pneumothorax requiring temporal drainage or chest tube insertion occurred in 5 patients (5%), the rest 30 patients were asymptomatic and did not require any treatment. Hemorrhage is the second most common complication after pneumothorax.There were 34 patients (29.8%) with pulmonary hemorrhage;5 patients (4.4%) with hemoptysis(Fig 3); two patients (1.8%) with hemothorax.5.The feasibility of CT-PTNB as a tool to get tissues for therapeutic instruction and EGFR mutation analysis.In the 93 patients who were diagnosed of malignant tumors,61 patients received chemotherapy according to pathological type,4 patients experienced surgery,4 patients received 125Ⅰ seed implantation,2 patients recived microwave ablation,7 patients received targeted therapy,4 patients received chemotherapy and microwave ablation and 8 patients didn’t undertake any anti-cancer therapy.There were 56(59.6%) adenocarcinomas, the specimens of 22 patients were sent for EGFR mutation analysis in our study.Eleven (50.0%)of them revealed mutants (mutations to EGFR gene), and 11 (50.0%) were nonmutants. Our data suggest that CT-guided percutaneous transthoracic needle biopsy is feasible for EGFR mutation analysis.6. The risk factors related to the incidence of complications.The data were also analysed to assess which factors influence the incidence of pneumothorax and hemorrhage post biopsy.Initially, eight factors were considered, namely the size of the lesion, the depth of the lesion from the pleural surface, the age and sex of patients,emphysema seen on CT scan,the location of lesion and the insertion angle of needle.Results are displayed in Table 5 and Table 6.In the evaluation of length from pleura to lesion as a risk factor, there was a trend toward an increase in the pneumothorax and hemorrhage risk with increasing length (p<0.05 and p< 0.001). In the case of lesions with a distance of 1.8cm or more, the pneumothorax rate was 41.8%(23/55),and the hemorrhage rate was 53.8%(28/52).We also find that in cases the lesion is in the chest wall, mediastinum, pleura, or subpleural lung, the likelihood of pneumothorax is minimal(p<0.05).CONCLUSIONS1.CT-guided percutaneous transthoracic needle biopsy is a reliable diagnostic method for the diagnoses of transthoracic malignant tumors.2.CT-guided percutaneous transthoracic needle biopsy is a safe and the rate of complications is acceptable.3.CT-guided percutaneous transthoracic needle biopsy is feasible for EGFR mutation analysis.