Diagnostic utility and limitations of CT-guided transthoracic fine-needle aspiration biopsy in Lung-RADS 4 pulmonary nodules ≤2 cm.

BACKGROUND

Managing small Lung-RADS 4 pulmonary nodules is clinically challenging. While CT-guided TTFNAB is standard, its efficacy and safety for lesions ≤2 cm require further evaluation to optimize outcomes and reduce unnecessary surgeries.

OBJECTIVES

This study aimed to evaluate the diagnostic accuracy, safety, and factors influencing the outcomes of CT-guided TTFNAB in Lung-RADS category 4 pulmonary nodules measuring ≤2 cm.

DESIGN

Retrospective study.

SETTING

Single-center, a tertiary referral center.

MATERIALS AND

METHODS

A retrospective analysis was performed on 95 patients who underwent CT-guided TTFNAB between January 2021 and April 2024. Data included demographics, lesion characteristics (size, location, density, and pleural proximity), histopathological findings, and procedural outcomes.

MAIN OUTCOME MEASURES: The primary endpoints were diagnostic accuracy, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and factors influencing TTFNAB results, alongside procedural complications-specifically pneumothorax and chest tube requirement.

SAMPLE SIZE: 95 patients.

RESULTS

Of the 95 nodules, 26 (27%) were benign and 69 (73%) were malignant according to TTFNAB. Final pathology confirmed 18 (19%) benign and 77 (81%) malignant lesions. All biopsies yielded sufficient material. Sensitivity, specificity, and overall diagnostic accuracy were 83%, 94%, and 89%, respectively. The PPV was 98%, while the NPV was 65%. Pleural thickening was significantly more frequent in both the TTFNAB benign group (38% vs. 13%, P=.006) and final benign diagnosis group (44% vs. 14%, P=.008). Pneumothorax occurred in 30% of cases, with 24% of these requiring chest tube drainage. No significant associations were found between diagnostic accuracy or complications and variables such as age, emphysema, Lung-RADS category, or nodule size.

CONCLUSION

CT-guided TTFNAB is an effective diagnostic method for confirming malignancy in pulmonary nodules ≤2 cm classified as Lung-RADS 4, providing an overall accuracy of 89% and a PPV of 98%. However, a benign TTFNAB result cannot be considered diagnostically safe: the NPV of 65% and false-negative rate of 35% indicate that a negative biopsy does not reliably exclude malignancy. Clinicians must not rely on a negative result alone; close radiological follow-up or surgical biopsy is essential for these high-risk lesions.

LIMITATIONS: The retrospective single-center design, small sample size, and limited generalizability.

IRB APPROVAL NUMBER: 2024/010.99/6/23 (Date: 26.07.2024).