Context: Small tissue biopsies obtained through minimally invasive methods have become the primary diagnostic tools for the pathologic characterization and testing of lung masses. In view of recent advances in targeted therapy for non-small cell lung carcinoma, and lung adenocarcinoma in particular, pathologists are now expected to thoroughly characterize lung lesions microscopically while making certain that enough tissue remains for potential molecular analysis if indicated.
Objective: To report our experience with computed tomography (CT)-guided lung needle biopsies with particular concentration on diagnostic yield, diagnostic accuracy, and adequacy of tissue for molecular testing if indicated.
Methods: A retrospective observational study analyzed 224 biopsies in 222 patients undergoing CT-guided lung needle biopsies. Accuracy of diagnosis and adequacy of tissue for molecular testing, if applicable, was evaluated. A standardized protocol for specimen evaluation, triage, and processing was used. This protocol included intraprocedural real-time microscopic specimen evaluation and triage by a pathologist and use of a histologic protocol specifically designed to conserve tissue for ancillary testing. The initial biopsy was considered successful if the specimen was malignant, had specific benign features, or had nonspecific benign features with follow-up supporting benign lesion. Initial biopsy failure cases were those with inadequate tissue or a nonspecific result with highly suspicious imaging or clinical findings.
Results: Of the 224 biopsies, 8 cases with benign but nonspecific findings lacked follow-up and were excluded from the study. The biopsy was diagnostically successful in 189 of 216 (88%) cases. Of these 189 cases, 154 (81%) were malignant, and 35 (19%) were benign. There were 28 diagnostic failures. Subsequent tissue sampling of 13 of 28 diagnostic failures found 9 (69%) to be malignant. Molecular studies were requested on 25 cases: 24 had sufficient material for some of the requested tests, and 20 had enough tissue for all requested testing.
Conclusion: A standardized protocol and team approach for CT-guided lung needle biopsy optimizes the ability to achieve a high accurate diagnostic yield with adequate tissue for molecular testing.