Purpose: The purpose of this study was to assess the incidence of nondiagnostic computed tomography-guided lung biopsy results, stratified by biopsy indication, and determine the final diagnosis in such cases.
Materials and methods: Following institutional review board approval, pathology results from CT-guided lung biopsies over a 5-year period at 2 institutions were categorized as diagnostic or nondiagnostic. Each biopsy's indication was categorized as being for a lesion considered likely to be cancer, infection, or uncertain. For all nondiagnostic biopsies, the medical chart was reviewed to determine the final clinical diagnosis.
Results: A total of 660 biopsies were evaluated, 139 (21%) of which were nondiagnostic. Of these 139 patients, the final clinical diagnosis was infection in 37%, cancer in 30%, and a benign noninfectious diagnosis in 10%; 23% remained undiagnosed at last available follow-up. Among the patients in whom there was a high pretest suspicion for cancer, 13% were nondiagnostic, 45% of which were cancer and 27% were infection. Among biopsies of lesions with pretest probability for both cancer and infection, 51% were nondiagnostic; on clinical follow-up these were determined to be infection in 34% and cancer in 14%. When there was high pretest suspicion for infection, 73% were nondiagnostic, of which 13% were cancer on clinical follow-up, and 88% were infection. The rate of nondiagnostic biopsies was statistically significantly different (P<0.001) among the 3 groups.
Conclusions: Nondiagnostic biopsies are common and occur most frequently when there is a moderate or high pretest suspicion for infection. Among all nondiagnostic biopsies, regardless of indication, cancer and infection were diagnosed on follow-up in similar proportions.