title: Prognostic significance of the non-size-based AJCC T2 descriptors: visceral pleura invasion, hilar atelectasis, or obstructive pneumonitis in stage IB non-small cell lung cancer is dependent on tumor size.
abstract: BACKGROUND
  The T2 descriptor for staging non-small cell lung cancer (NSCLC) contains several non-size-based criteria. It remains unknown whether the prognostic significance of these non-size-based criteria is dependent on tumor size.
  
  
  METHODS
  A total of 10,545 patients with stage IB NSCLC from the California Cancer Registry between 1989 to 2003 were categorized into the following three nonoverlapping criteria: (1) tumor size (T2S); (2) visceral pleura invasion, hilar atelectasis, or obstructive pneumonitis (T2P); and (3) main bronchus involvement > or = 2 cm from the carina (T2C). Univariate survival analyses were performed using the Kaplan-Meier method. Multivariate survival analyses were performed using Cox proportional hazards ratios.
  
  
  RESULTS
  A total of 51.1% of patients with stage IB NSCLC were staged by T2S, 43.2% by T2P, and 5.7% by T2C; 2,224 stage IB patients (total, 21.1%; 18.9% T2P + 2.2% T2C) had tumors < or = 3 cm in size. The 5-year survival rate and the median survival time of these stage IB patients with tumors < or = 3 cm in size were as follows: T2P, 51.2% and 64 months, respectively; T2C, 49.0% and 58 months, respectively. These values were similar to the 53.2% 5-year survival rate and 67-month median survival time for patients with stage IA NSCLC (p = 0.40). Cox proportional hazards model revealed T2P of > 3 cm was a poor prognostic factor for survival (vs T2S; hazard ratio [HR], 1.16; 95% confidence interval [CI], 1.08 to 1.24). Conversely, T2P < or = 3 cm was a favorable prognostic factor for survival (vs T2S; HR, 0.89; 95% CI, 0.82 to 0.96). T2C was not an independent prognostic factor for survival.
  
  
  CONCLUSIONS
  Prognostic significance of the non-size-based T2 descriptor T2P is dependent on tumor size.
authors.affiliation: Chao Family Comprehensive Cancer Center, Division of Hematology/Oncology, Department of Medicine, University of California Irvine Medical Center, Orange, CA 92868-3298, USA. ignatius.ou@uci.edu
authors.forename: Sai-Hong Ignatius
authors.initials: SH
authors.lastname: Ou
authors.forename: Jason A
authors.initials: JA
authors.lastname: Zell
authors.forename: Argyrios
authors.initials: A
authors.lastname: Ziogas
authors.forename: Hoda
authors.initials: H
authors.lastname: Anton-Culver
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002140:California / Q000453:epidemiology; D002289:Carcinoma, Non-Small-Cell Lung / Q000150:complications / Q000473:pathology*; D002648:Child; D002675:Child, Preschool; D003251:Constriction, Pathologic; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D008175:Lung Neoplasms / Q000150:complications / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D010997:Pleural Neoplasms / Q000453:epidemiology / Q000473:pathology*; D011014:Pneumonia / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology*; D011379:Prognosis; D001261:Pulmonary Atelectasis / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology*; D012189:Retrospective Studies; D012720:Severity of Illness Index; D015996:Survival Rate / Q000639:trends; D013997:Time Factors