This 2-center retrospective study was approved by our institutional review board. The requirement of informed consent was waived because of the retrospective nature.
Patients
From January 2011 to December 2015, a total of 141 patients with CNB-based benign results from LNs were collected. Among them, 96 patients with CNB-based non-specific benign results were included in this study as the training group that detected the predictors of true-negative results (Fig. 1). From January 2016 to December 2018, additional 57 patients were included as a validation group that tested the reliability of the predictors.
The decision for lung biopsy was made based on the recommendation of the management of LNs [11]. The inclusion criteria were: (a) patients with LN and (b) patients with CNB-based benign results. The exclusion criteria were: (a) CNB-based specific benign results; (b) patients with distant metastasis; and (c) lesions without a definite final diagnosis.
CT-guided CNB procedure
All procedures were performed by a chest radiologist with more than 5 years of biopsy experience. CNB was guided by a 16-detector CT (Philips, Cleveland, Ohio, USA). The tube voltage and current were 120 kV and 150 mA/s, respectively.
All patients were placed in an appropriate position according to the location of LN. An 18G semi-automatic cutting needle (Wego, Weihai, China) was punctured into the lung parenchyma, after which an additional CT scan was performed to establish the needle tip location to move it accordingly. When the needle tip touched the target lesion, a specimen was obtained from the lesion. One
This 2-center retrospective study was approved by our institutional review board. The requirement of informed consent was waived because of the retrospective nature.
Patients
From January 2011 to December 2015, a total of 141 patients with CNB-based benign results from LNs were collected. Among them, 96 patients with CNB-based non-specific benign results were included in this study as the training group that detected the predictors of true-negative results (Fig. 1). From January 2016 to December 2018, additional 57 patients were included as a validation group that tested the reliability of the predictors.
The decision for lung biopsy was made based on the recommendation of the management of LNs [11]. The inclusion criteria were: (a) patients with LN and (b) patients with CNB-based benign results. The exclusion criteria were: (a) CNB-based specific benign results; (b) patients with distant metastasis; and (c) lesions without a definite final diagnosis.
CT-guided CNB procedure
All procedures were performed by a chest radiologist with more than 5 years of biopsy experience. CNB was guided by a 16-detector CT (Philips, Cleveland, Ohio, USA). The tube voltage and current were 120 kV and 150 mA/s, respectively.
All patients were placed in an appropriate position according to the location of LN. An 18G semi-automatic cutting needle (Wego, Weihai, China) was punctured into the lung parenchyma, after which an additional CT scan was performed to establish the needle tip location to move it accordingly. When the needle tip touched the target lesion, a specimen was obtained from the lesion. One specimen was considered enough when the specimen length reached 5–10 mm. The obtained specimens were placed in 10% formaldehyde until pathological examination. In the end, a repeat CT scan was performed to evaluate potential CNB-related complications.
Definitions
LN is defined as a round or oval lesion ≤ 3 cm that is completely surrounded by pulmonary parenchyma without other abnormalities [1-4]. CNB-based benign results can be divided into specific and non-specific benign results [10]. Specific benign results were defined as benign tumors or infectious diseases with identified pathogens. Non-specific benign results were defined as the presence of benign pathological features such as inflammatory cells or fibrosis that was insufficient to render a specific diagnosis.
CNB-based benign results were considered to be true-negatives if the lesions were benign upon final diagnosis. A final benign diagnosis could be made in 1 of the 3 ways: (a) surgery; (b) determination of a specific benign lesion upon pathological analysis of the lung biopsy sample; or (c) a decrease > 20% in lesion diameter, stability in size (without anticancer treatment) over a minimum of 2 years [10]. If lesions did not meet the criteria mentioned above, final diagnoses were listed as non-diagnostic lesions.
Statistical Analysis
The statistical analysis was performed using SPSS 16.0 (SPSS Inc., Chicago, IL, USA). Continuous variables were summarized as the mean ± standard deviation. Numeric data were analyzed using χ2 tests or Fisher exact probability tests. Predictors of true-negative findings were identified using univariate and multivariate logistic regression analyses. The covariates incorporated into the multivariate analysis were variables with P < 0.1 in the univariate analysis. Receiver operator characteristic (ROC) curves were created and areas under the curves were calculated. A p value < 0.05 was considered statistically significant.
specimen was considered enough when the specimen length reached 5–10 mm. The obtained specimens were placed in 10% formaldehyde until pathological examination. In the end, a repeat CT scan was performed to evaluate potential CNB-related complications.
Definitions
LN is defined as a round or oval lesion ≤ 3 cm that is completely surrounded by pulmonary parenchyma without other abnormalities [1-4]. CNB-based benign results can be divided into specific and non-specific benign results [10]. Specific benign results were defined as benign tumors or infectious diseases with identified pathogens. Non-specific benign results were defined as the presence of benign pathological features such as inflammatory cells or fibrosis that was insufficient to render a specific diagnosis.
CNB-based benign results were considered to be true-negatives if the lesions were benign upon final diagnosis. A final benign diagnosis could be made in 1 of the 3 ways: (a) surgery; (b) determination of a specific benign lesion upon pathological analysis of the lung biopsy sample; or (c) a decrease > 20% in lesion diameter, stability in size (without anticancer treatment) over a minimum of 2 years [10]. If lesions did not meet the criteria mentioned above, final diagnoses were listed as non-diagnostic lesions.
Statistical Analysis
The statistical analysis was performed using SPSS 16.0 (SPSS Inc., Chicago, IL, USA). Continuous variables were summarized as the mean ± standard deviation. Numeric data were analyzed using χ2 tests or Fisher exact probability tests. Predictors of true-negative findings were identified using univariate and multivariate logistic regression analyses. The covariates incorporated into the multivariate analysis were variables with P < 0.1 in the univariate analysis. Receiver operator characteristic (ROC) curves were created and areas under the curves were calculated. A p value < 0.05 was considered statistically significant.