title: Histological comparison between preoperative and surgical specimens of non-small cell lung cancer for distinguishing between "squamous" and "non-squamous" cell carcinoma.
abstract: BACKGROUND
  Non-small cell lung cancers (NSCLCs) are frequently heterogeneous and in approximately 70% of cases, NSCLCs are diagnosed and staged by small biopsies or cytology rather than by examination of surgically resected specimens. Thus, in most patients, the diagnosis is established based on examination of preoperative specimens alone. Recently, classification of NSCLC into pathologic subtypes has been shown to be important for selecting the appropriate systemic therapy, from both the point of view of treatment efficacy and prevention of toxicity.
  
  
  METHODS
  We retrospectively reviewed the data of 225 patients to compare the preoperative classification of the NSCLC subtype on biopsy specimens with the postoperative classification based on examination of the resected specimens, in order to compare the accuracy of the two for the diagnosis of various histological subtypes of NSCLC.
  
  
  RESULTS
  In 169 of the 225 (75.1%) patients, the preoperative diagnosis was definite malignancy. Histologically, the final pathologic diagnosis made from the surgical specimens was adenocarcinoma (ADC) in 169 patients, and in 75.5% of these cases, the diagnosis was concordant with the preoperative diagnosis. Among the patients who had squamous cell carcinoma (SQC) in the preoperative specimens, the diagnosis was concordant with the preoperative diagnosis in 65.7% of cases. Misclassified preoperative biopsies included an even number of SQCs and ADCs, with all the misclassified biopsies being ADCs morphologically mimicking SQC due to solid growth. Significantly higher specificity, negative predictive value and accuracy were observed for the diagnosis of SQC.
  
  
  CONCLUSIONS
  Our study suggested that the concordance rates for diagnosis of the NSCLC subtypes, especially the "squamous" or "non-squamous" histologies, between preoperative and surgical specimens were satisfactory, as compared with previous reports. Therefore, pretreatment diagnosis of lung cancer using small samples is reasonable for selecting the optimal treatment. However, in order not to lose the opportunity for selecting an effective treatment, we should be aware that the diagnosis in preoperative small samples might be different from that based on examination of the surgical specimens.
  The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/2032698427120488.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Yamagishi
authors.affiliation: Department of General Thoracic Surgery, Kawasaki Medical School, 577 Matsushima, Kurashiki, Okayama 701-0192, Japan. kshimizu@med.kawasaki-m.ac.jp.
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Shimizu
authors.forename: Nobuaki
authors.initials: N
authors.lastname: Ochi
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Yamane
authors.forename: Isao
authors.initials: I
authors.lastname: Irei
authors.forename: Yoshito
authors.initials: Y
authors.lastname: Sadahira
authors.forename: Nagio
authors.initials: N
authors.lastname: Takigawa
authors.forename: Mikio
authors.initials: M
authors.lastname: Oka
authors.forename: Masao
authors.initials: M
authors.lastname: Nakata
mesh_terms: D000230:Adenocarcinoma / Q000145:classification / Q000175:diagnosis*; D000368:Aged; D001706:Biopsy; D002289:Carcinoma, Non-Small-Cell Lung / Q000145:classification / Q000175:diagnosis*; D002294:Carcinoma, Squamous Cell / Q000145:classification / Q000175:diagnosis*; D003581:Cytodiagnosis / Q000379:methods; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000145:classification / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity