Tissue requirements in lung cancer diagnosis for tumor heterogeneity, mutational analysis and targeted therapies: initial experience with intra-operative Frozen Section Evaluation (FROSE) in bronchoscopic biopsies.

Background: Recent advances in lung cancer treatment have changed the requirement for the amount and quality of biopsy specimens needed to characterize the tumor and select the best treatment. One adjunct to guide the bronchoscopist on the quality and quantity of specimens during bronchoscopic biopsies for the diagnosis of lung cancer is rapid on-site evaluation (ROSE) of cytological specimens. This technique has been shown to add to the diagnostic yield of bronchoscopy when obtaining adequate specimens for molecular profiling in lung cancer. ROSE is not available at all medical centers. We describe our initial experience using intra-procedural Frozen Section Evaluation (FROSE) of bronchoscopic biopsy specimens as an alternative to ROSE.

Methods: A retrospective analysis of all interventional pulmonology cases using FROSE between February and July 2015 was performed. Results analyzed to evaluate the success in obtaining adequate specimens for molecular profiling.

Results: A total of 88 interventional pulmonology cases employing a frozen section in at least one site were identified. In 94.3% of cases, a definitive diagnosis of benign or malignant was made. The concordance of frozen section diagnoses of benign or malignant was 100% with final diagnoses. Thirteen of the eighty-eight cases were ultimately sent for molecular analysis. Of these, twelve of thirteen (92.3%) cases were adequate to perform all ordered molecular testing. In all cases there was sufficient tissue to perform EGFR and ALK testing.

Conclusions: In medical centers where ROSE may not be available, the use of FROSE by the local pathologist can be an effective technique to obtain adequate tissue and cytological samples for the diagnosis and molecular profiling of lung cancers. Further prospective study in bronchoscopic tissue sampling techniques to obtain the optimum quantity and quality of samples for molecular profiling of lung cancers for targeted treatments is needed.