title: Comorbidity and KPS are independent prognostic factors in stage I non-small-cell lung cancer.
abstract: OBJECTIVE
  To determine the prognostic role of comorbidity in Stage I non-small-cell lung cancer (NSCLC) treated with surgery or radiotherapy (RT).
  
  
  METHODS
  One hundred sixty-three patients with clinical Stage I NSCLC were analyzed for overall survival (OS) and comorbidity. One hundred thirteen patients underwent surgery (surgical group) and 50 patients received definitive radiotherapy (RT group). Ninety-six percent of the surgical group had lobectomy or pneumonectomy, and negative margins were achieved in 96% of the patients. The median dose to the tumor for the RT group was 61.2 Gy (range 30.8-77.4). The Cumulative Illness Rating Scale for Geriatrics (CIRS-G) and the Charlson scale were used to rate comorbidity. Karnofsky performance scores (KPS) were available in 42 patients; the rest of the scores were determined retrospectively by two physicians independently, with 97% agreement.
  
  
  RESULTS
  The OS was 44% for the surgical group and 5% for the RT group at 5 years. Noncancer-related mortality was observed in 31% and 62% of the surgical and RT patients, respectively. On univariate analysis, performed on all patients (n = 163), squamous cell histologic type (p <0.001), clinical Stage T2 (p = 0.062), tumor size >4 cm (p = 0.065), >40 pack-year tobacco use (p <0.001), presence of a CIRS-G score of 4 (extremely severe, CIRS-G4: [+]) (p <0.001), severity index of >2 (p <0.001), Charlson score >2 (p = 0.004), KPS <70 (p <0.001), and treatment with RT (p <0.001) were associated with a statistically significant inferior OS. Multivariate analysis with histologic features, clinical T stage, age, tobacco use, KPS, comorbidity [CIRS-G(4)] and treatment group on all patients showed that squamous cell histology, >40 pack-year tobacco use, KPS <70, and presence of CIRS-G(4) were independently associated with an inferior OS. Treatment modality, T stage, and age did not have any statistically significant effect on OS. Statistically significant differences were found between the surgical and RT groups in Charlson score (p = 0.001), CIRS-G total score (p = 0.004), severity index (p = 0.006), CIRS-G4(+) (p <0.001), KPS (p <0.001), amount of tobacco use (p = 0.002), clinical tumor size (p <0.001), clinical T stage (p = 0.01), forced expiratory volume in 1 s (p = 0.001), and age (p = 0.008), in favor of the surgical group.
  
  
  CONCLUSIONS
  The presence of significant comorbidity and KPS of <70 are both important prognostic factors, but were found to be independent of each other in Stage I NSCLC. Therefore, comorbidity and KPS assessment are recommended when analyzing the prognostic effects of tumor or treatment-related factors on OS.
authors.affiliation: Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, WI 53226, USA. sfirat@mcw.edu
authors.forename: Selim
authors.initials: S
authors.lastname: Firat
authors.forename: Michael
authors.initials: M
authors.lastname: Bousamra
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Gore
authors.forename: Roger W
authors.initials: RW
authors.lastname: Byhardt
mesh_terms: D000230:Adenocarcinoma / Q000401:mortality / Q000532:radiotherapy / Q000601:surgery; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D018287:Carcinoma, Large Cell / Q000401:mortality / Q000532:radiotherapy / Q000601:surgery; D002289:Carcinoma, Non-Small-Cell Lung / Q000401:mortality / Q000532:radiotherapy* / Q000601:surgery*; D002294:Carcinoma, Squamous Cell / Q000401:mortality / Q000532:radiotherapy / Q000601:surgery; D015897:Comorbidity; D005260:Female; D006801:Humans; D017567:Karnofsky Performance Status; D008175:Lung Neoplasms / Q000401:mortality / Q000532:radiotherapy* / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012720:Severity of Illness Index; D016019:Survival Analysis