[Clinical role of CT-guided transthoracic needle biopsy in the diagnosis of solitary pulmonary nodules].

PURPOSE

The aim of this prospective study was to assess the overall diagnostic accuracy of CT-guided transthoracic biopsy of solitary pulmonary nodules, to compare the reliability of the diagnosis of malignancy made at prebiopsy CT and to investigate the final clinical impact of cyto-histologic results.

MATERIALS AND METHODS

A prospective study was carried out on 128 CT-guided transthoracic biopsies performed in 119 subjects with a solitary pulmonary nodule to assess the diagnostic accuracy of the method. The cyto-histologic diagnosis was then compared to the previous radiologic and CT diagnosis and to clinical outcome, to define the reliability of the previous CT diagnosis and the clinical impact of lung biopsy in relation to its risk. For each needle biopsy, the lesion site, diameter and depth, the number of punctures and needle size were related to the complications, their latency and treatment. The cyto-histologic diagnosis was compared with the results of the macro- and microscopic examination of the surgical specimens in the surgical patients (no. 44).

RESULTS

As for the drawbacks of our approach, 40 patients (31%) developed pneumothorax which required thoracic drainage in 10% of cases. A self-resolving, clinically asymptomatic blood effusion was observed around the lesion site or adjacent to the needle path in 21 patients. All the complications were only related to the number of needle punctures and to perilesional emphysema. 113 of 128 (88%) needle biopsies of isolated pulmonary nodules were diagnostic, with 88 malignant and 25 benign lesions. All malignant diagnoses had surgical (42 cases) of follow-up confirmation. No false positives were observed in our series but we had 4 false negatives; specificity was 100%, sensitivity 95%, PPV 100% and NPV 84% and overall diagnostic accuracy 96%. The CT diagnosis of malignancy was correct in 68% of cases and we had 16 false positives and 20 false negatives. Thus, CT had 77% sensitivity and 36% specificity in malignant characterization and particularly in identifying benign lesions (9 of 25 cases). The results of biopsy had an unquestionable impact on diagnosis and treatment in 44% of patients: the previous CT diagnosis was modified in 32% and treatment planning changed accordingly. In the other 14 patients whose CT diagnosis was correct (4 lymphomas, 3 small cell carcinomas, 3 mesotheliomas, 4 benign lesions), biopsy was the cornerstone of subsequent treatment planning.

CONCLUSIONS

CT-guided thoracic biopsy, allowing an accurate histologic diagnosis, is confirmed as a safe procedure with a strong impact on the diagnostic protocol of the solitary pulmonary nodule.