Atypical Histology in Pulmonary Biopsies Obtained Using Robotic-Assisted Bronchoscopy: Natural History and Clinical Practice.

BACKGROUND: A recent consensus statement recommends that atypical cells are considered nondiagnostic specimens in the calculation of diagnostic yield. This study investigated the natural history and malignancy rate of atypical cells and practice patterns of clinicians encountering these biopsy results. METHODS: This was a subset analysis of a prospective, multicenter study evaluating the safety and diagnostic outcomes of robotic-assisted bronchoscopy for pulmonary nodules. Nondiagnostic samples, including those with and without atypical cells, were included for this analysis, with an ultimate diagnosis of benign if lesion size remained stable or decreased through 12 months or malignant if enlarging on computed tomography or on the basis of repeat biopsy. Lesion characteristics and clinical outcomes were compared with the Fisher exact test. RESULTS: Of 679 patients in the study, 196 had a nondiagnostic biopsy without atypical cells (NDwo), and 47 nondiagnostic biopsies had evidence of atypical cells (NDwA). Pretest probability for malignancy was similar (79% NDwo and 83% NDwA, medium risk with Brock University prediction; P = .870). Malignancy was the final diagnosis in 33% of NDwo and 68% of NDwA (P < .001). A total of 48% of NDwo and 26% of NDwA were diagnosed as benign, and 19% and 6% of NDwo and NDwA, respectively, were inconclusive. A total of 21% of NDwA, compared with 4.6% of NDwo, were in patients referred directly to cancer therapy without repeat imaging or biopsy (P < .001). CONCLUSIONS: More than two-thirds of biopsies resulting in NDwA status manifest in malignancy on follow-up. One in 5 patients with these results is referred to treatment without further interventions.