As treatments for non–small-cell lung cancer (NSCLC) become personalized, cellular and molecular differentiation of the tumor is becoming the standard of care. Our objective is to compare the yield of different diagnostic procedures for cellular differentiation of NSCLC and analysis of epidermal growth factor receptor (EGFR) mutation.
We evaluated all patients diagnosed with NSCLC from January 2004 to September 2010 at the Jewish General Hospital, Montreal. Diagnostic procedures included surgical biopsies, nonsurgical histologic biopsies (endobronchial and core needle), transbronchial needle aspirate (TBNA) and transthoracic needle aspirate (TTNA), bronchoalveolar lavage (BAL), and pleural fluid samples.
We included 702 subjects investigated for histopathologic differentiation of NSCLC. Of these, 269 were also investigated for EGFR mutation. Failure to ascertain the cellular subtype and EGFR mutation status was least likely with surgical specimens (0% and 1.8%, respectively); followed by TTNA (14% and 10%, respectively) and histologic biopsy (18% for both); and was frequent with TBNA (39% and 30%, respectively). Although BAL and pleural fluid specimens provided reasonable yield for cellular differentiation (20 % and 11%, respectively), their results were not accurate in 6% of their samples when compared with concurrent or subsequent surgical specimens (reference standard) performed in a subgroup of patients.
Radiologically guided TTNA and histologic biopsies provided high yield for both molecular and histologic analyses. The yield of unguided TBNA was relatively low. Further studies are needed to assess the adequacy of BAL and pleural fluid samples for EGFR mutation analysis and accurate characterization of cellular subtypes of NSCLC.