Abstract

Background: Computed tomography (CT) and fine needle guided biopsy (FNB) are often used in the assessment of patients with lung nodules. The influence of these techniques on clinical decision making has not been quantified, especially for small solitary pulmonary nodules (SPN) where the probability of malignancy is lower. A study was undertaken to determine the effect of CT and FNB derived information on clinical decision making in patients with a solitary pulmonary nodule < 3 cm in diameter on initial chest radiography.

Methods: Clinical, physiological, and outcome data on 114 patients with an SPN < 3 cm who had subsequent thoracic CT and FNB were extracted from the records of a specialist cardiorespiratory hospital in Auckland, New Zealand. Chest radiographs and CT scans were reported according to specified criteria by a thoracic radiologist. Computer generated summary sheets were used to present cases to each of six clinicians. Each case was presented three times: (1) with clinical data and chest radiograph only; (2) with the addition of the CT report; and (3) with all data including the result of the FNB. Clinicians were asked to specify their management on each occasion and to estimate the probability of the lesion being malignant. Reproducibility was assessed by re-evaluating 24 cases 1 month later.

Results: 33 (29%) nodules were benign, 35 (31%) nodules (malignant) were resected with negative node sampling, and 46 (40%) had a non-curative outcome (radiotherapy, incomplete resection, refused therapy). Intra-clinician decision making was consistent for all three levels of clinical data (median κ values 0.79–0.89). Agreement between clinicians on the need for surgery was lowest with chest radiography alone (κ=0.33), rose with CT information (κ=0.44), and increased further with the addition of the FNB data (κ=0.57). The proportion of successful decisions on surgical intervention (against the known outcome) increased with the addition of CT reports and further with FNB reports (p=0.006, Friedman's test). The major benefit of the information added by CT and FNB reports was a reduction in unnecessary surgery, especially when the clinical perception of pre-test probability of malignancy was intermediate (31–70%). FNB data contributed most to the benefit (p<0.001). The addition of CT and FNB was cost efficient and can be applied specifically to patients with a low or intermediate probability of malignancy.

Conclusion: Both CT and FNB make cost effective contributions to the clinical management of SPN < 3 cm in diameter by reducing unnecessary operations and increasing agreement between physicians on the need for surgery.