title: The effect of non-small cell lung cancer histology on survival as measured by the graded prognostic assessment in patients with brain metastases treated by hypofractionated stereotactic radiotherapy.
abstract: BACKGROUND
  The purpose of this study was to investigate the impact of histology on survival stratified by the Graded Prognostic Assessment (GPA) for non-small cell lung cancer (NSCLC) in a group of selected patients treated recently.
  
  
  METHODS
  A total of 171 NSCLC patients with brain metastases treated by hypofractionated stereotactic radiotherapy with or without whole-brain radiotherapy between 2001 and 2011 were included. The GPA score was calculated for each patient. Tumor histologies were categorized into adenocarcinoma (ADCA) and non-ADCA. Median survival time (MST, in months) was calculated using the Kaplan-Meier method. The log-rank test was used to determine statistical differences.
  
  
  RESULTS
  MSTs by histology were: ADCA 15 (n = 92) and non-ADCA 10 (n = 79) (p < 0.001). For all patients, the MSTs by GPA score were: GPA 3.5-4, 24; GPA 2.5-3, 15; GPA 1.5-2, 9 and GPA 0-1, 6 (p < 0.001). The histology of ADCA showed a statistically significant higher MST than non-ADCA for patients with GPA 2.5-4. For GPA 2.5-3, MSTs were: ADCA 18, non-ADCA 10 (p = 0.007); for GPA 3.5-4, MSTs were: ADCA 30, non-ADCA 17 (p = 0.046). For GPA 0-2, MSTs did not differ significantly by histology. For GPA 0-1, MSTs were: ADCA 8, non-ADCA 4 (p = 0.146); GPA 1.5-2, MSTs were: ADCA 10, non-ADCA 8 (p = 0.291). We further found that non-ADCA in upper GPA class (3.5-4) had similar survival with ADCA in lower GPA class (2.5-3) (MSTs were 17 and 18, respectively, p = 0.775). This phenomenon also happened between patients of non-ADCA in upper GPA class (2.5-3) and those of ADCA in lower GPA class (1.5-2) (MSTs were both 10, p = 0.724).
  
  
  CONCLUSIONS
  We confirmed that the histology of NSCLC had effect on the GPA in these selected patients treated recently. ADCA showed a statistically significant higher MST than non-ADCA with GPA 2.5-4. The non-ADCA in upper GPA classes (3.5-4 and 2.5-3) had similar survival to ADCA in lower GPA classes (2.5-3 and 1.5-2, respectively). The histology as a new factor should be added to the original GPA for NSCLC.
authors.affiliation: Department of Radiation Oncology, The First Affiliated Hospital of China Medical University, 155 North Nanjing Street, Heping District, Shenyang, 110001, Liaoning, China.
authors.forename: Liang-Hua
authors.initials: LH
authors.lastname: Ma
authors.affiliation: Department of Radiation Oncology, The First Affiliated Hospital of China Medical University, 155 North Nanjing Street, Heping District, Shenyang, 110001, Liaoning, China. 13804058616@163.com.
authors.forename: Guang
authors.initials: G
authors.lastname: Li
authors.affiliation: Department of Radiation Oncology, The First Affiliated Hospital of China Medical University, 155 North Nanjing Street, Heping District, Shenyang, 110001, Liaoning, China.
authors.forename: Hong-Wei
authors.initials: HW
authors.lastname: Zhang
authors.affiliation: Department of Radiation Oncology, The First Affiliated Hospital of China Medical University, 155 North Nanjing Street, Heping District, Shenyang, 110001, Liaoning, China.
authors.forename: Zhi-Yu
authors.initials: ZY
authors.lastname: Wang
authors.affiliation: Department of Radiation Oncology, The First Affiliated Hospital of China Medical University, 155 North Nanjing Street, Heping District, Shenyang, 110001, Liaoning, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Dang
authors.affiliation: Department of Radiation Oncology, The First Affiliated Hospital of China Medical University, 155 North Nanjing Street, Heping District, Shenyang, 110001, Liaoning, China.
authors.forename: Shuo
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Department of Radiation Oncology, The First Affiliated Hospital of China Medical University, 155 North Nanjing Street, Heping District, Shenyang, 110001, Liaoning, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Yao
mesh_terms: D000230:Adenocarcinoma / Q000401:mortality / Q000532:radiotherapy / Q000556:secondary / Q000601:surgery; D001932:Brain Neoplasms / Q000401:mortality* / Q000532:radiotherapy / Q000556:secondary / Q000601:surgery; D018287:Carcinoma, Large Cell / Q000401:mortality / Q000532:radiotherapy / Q000556:secondary / Q000601:surgery; D002289:Carcinoma, Non-Small-Cell Lung / Q000401:mortality* / Q000473:pathology / Q000532:radiotherapy / Q000601:surgery; D002294:Carcinoma, Squamous Cell / Q000401:mortality / Q000532:radiotherapy / Q000556:secondary / Q000601:surgery; D016371:Cranial Irradiation / Q000401:mortality*; D019583:Dose Fractionation, Radiation; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008175:Lung Neoplasms / Q000401:mortality* / Q000473:pathology / Q000532:radiotherapy / Q000601:surgery; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D011379:Prognosis; D016634:Radiosurgery / Q000401:mortality*; D015996:Survival Rate
keywords: Brain metastases; Graded prognostic assessment; Histology; Hypofractionated stereotactic radiotherapy; Non-small cell lung cancer