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.