Pathologic diagnosis of advanced lung cancer based on small biopsies and cytology: a paradigm shift.

With some exceptions, the field of lung cancer disease has been relatively static during the past several decades with few major practice-changing advances. In this issue of the journal 2, articles address the diagnosis of non-small cell lung cancer (NSCLC) based on small biopsies and/or cytology, an area of lung cancer diagnosis in which a paradigm shift has occurred for both pathologists and clinicians. 1,2 This topic is important because the majority patients with lung cancer present with unresectable disease, and the diagnosis is established based on such small specimens. Moreover, with increasing use of minimally invasive biopsy methods, pathologists are being asked to do more with less tissue. HISTORY OF LUNG CANCER DIAGNOSIS IN SMALL BIOPSIES AND CYTOLOGY The World Health Organization classifications of lung tumors through the 1999 edition 3‐5 did not address lung cancer diagnosis based on small biopsies and cytology, because these were recommendations for the histologic classifications of resection specimens. In the 2004 World Health Organization classification, cytology was addressed for the first time, but classification in small biopsies was not addressed. 6 Currently, no internationally recognized standard of criteria or terminology for the diagnosis of lung cancer in small biopsies is available.