[422] Classification of NSCLCs by Fine Needle Aspiration Biopsy Combined with Core Needle Biopsy: How Specific Can We Be?

WU Todd, DS Zander, CS Abendroth. Penn State Milton S. Hershey Medical Center, Hershey, PA

Background: The recent introduction of new, targeted agents for lung cancer treatment has changed oncologists' expectations about pathologic diagnosis of non-small cell lung carcinomas (NSCLCs). Since decisions about treatment options are based on the histologic type of NSCLC, specific morphologic categorization of NSCLCs is necessary, rather than the more general interpretation of non-small cell carcinoma. Our goal was to assess the frequency with which specific morphologic classification could be accomplished by fine needle aspiration biopsy (FNAB) and concurrent core needle biopsy (CNB).
Design: 34 NSCLCs were evaluated by three cytopathologists. For all cases, FNAB and CNB samples were reviewed and classified using the World Health Organization scheme. A consensus diagnosis was determined, with all pathologists blinded to the diagnosis of the subsequent surgical specimen. The consensus diagnoses were compared with the subsequent surgical excisional material, which was considered the gold standard diagnosis for each case. The Fisher exact test was used to determine significance.
Results: In 29 cases, diagnostic material was obtained by FNAB; five other cases were classified as atypical or non-diagnostic. 27/29 (93%) cases were classifiable as a specific histologic type of NSCLC, and matched the classification of the corresponding resection specimen. The addition of a CNB allowed only 1 more case (97%) to be correctly and specifically classified, a rate that was not significantly different than FNAB alone (p=0.99). The two cases in which the consensus FNAB and subsequent surgical pathology diagnoses differed were an adenocarcinoma with hepatoid features and a pleomorphic carcinoma.
Conclusions: FNAB can achieve specific morphologic categorization for most NSCLCs. CNB offers a small, but non-significant, increase in the number of cases for which specific classification is possible. Uncommon histologic types of NSCLCs may be less likely to be accurately classified by FNAB.
Category: Cytopathology

Wednesday, March 11, 2009 1:00 PM

Poster Session VI # 43, Wednesday Afternoon